xref: /titanic_41/usr/src/uts/common/io/scsi/targets/st.c (revision 5aefb6555731130ca4fd295960123d71f2d21fe8)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * SCSI	 SCSA-compliant and not-so-DDI-compliant Tape Driver
31  */
32 
33 #if defined(lint) && !defined(DEBUG)
34 #define	DEBUG	1
35 #endif
36 
37 #include <sys/modctl.h>
38 #include <sys/scsi/scsi.h>
39 #include <sys/mtio.h>
40 #include <sys/scsi/targets/stdef.h>
41 #include <sys/file.h>
42 #include <sys/stat.h>
43 #include <sys/kstat.h>
44 #include <sys/ddidmareq.h>
45 #include <sys/ddi.h>
46 #include <sys/sunddi.h>
47 
48 #define	IOSP	KSTAT_IO_PTR(un->un_stats)
49 /*
50  * stats maintained only for reads/writes as commands
51  * like rewind etc skew the wait/busy times
52  */
53 #define	IS_RW(bp) 	((bp)->b_bcount > 0)
54 #define	ST_DO_KSTATS(bp, kstat_function) \
55 	if ((bp != un->un_sbufp) && un->un_stats && IS_RW(bp)) { \
56 		kstat_function(IOSP); \
57 	}
58 
59 #define	ST_DO_ERRSTATS(un, x)  \
60 	if (un->un_errstats) { \
61 		struct st_errstats *stp; \
62 		stp = (struct st_errstats *)un->un_errstats->ks_data; \
63 		stp->x.value.ul++; \
64 	}
65 
66 #define	FILL_SCSI1_LUN(devp, pkt) 					\
67 	if ((devp)->sd_inq->inq_ansi == 0x1) {				\
68 		int _lun;						\
69 		_lun = ddi_prop_get_int(DDI_DEV_T_ANY, (devp)->sd_dev,	\
70 		    DDI_PROP_DONTPASS, SCSI_ADDR_PROP_LUN, 0);		\
71 		if (_lun > 0) {						\
72 			((union scsi_cdb *)(pkt)->pkt_cdbp)->scc_lun =	\
73 			    _lun;					\
74 		}							\
75 	}
76 
77 /*
78  * get an available contig mem header, cp.
79  * when big_enough is true, we will return NULL, if no big enough
80  * contig mem is found.
81  * when big_enough is false, we will try to find cp containing big
82  * enough contig mem. if not found, we will ruturn the last cp available.
83  *
84  * used by st_get_contig_mem()
85  */
86 #define	ST_GET_CONTIG_MEM_HEAD(un, cp, len, big_enough) {		\
87 	struct contig_mem *tmp_cp = NULL;				\
88 	for ((cp) = (un)->un_contig_mem;				\
89 	    (cp) != NULL;						\
90 	    tmp_cp = (cp), (cp) = (cp)->cm_next) { 			\
91 		if (((cp)->cm_len >= (len)) || 				\
92 		    (!(big_enough) && ((cp)->cm_next == NULL))) { 	\
93 			if (tmp_cp == NULL) { 				\
94 				(un)->un_contig_mem = (cp)->cm_next; 	\
95 			} else { 					\
96 				tmp_cp->cm_next = (cp)->cm_next; 	\
97 			} 						\
98 			(cp)->cm_next = NULL; 				\
99 			(un)->un_contig_mem_available_num--; 		\
100 			break; 						\
101 		} 							\
102 	} 								\
103 }
104 
105 #define	ST_NUM_MEMBERS(array)	(sizeof (array) / sizeof (array[0]))
106 
107 /*
108  * Global External Data Definitions
109  */
110 extern struct scsi_key_strings scsi_cmds[];
111 
112 /*
113  * Local Static Data
114  */
115 static void *st_state;
116 static char *st_label = "st";
117 
118 #if defined(__i386) || defined(__amd64)
119 /*
120  * We need to use below DMA attr to alloc physically contiguous
121  * memory to do I/O in big block size
122  */
123 static ddi_dma_attr_t st_contig_mem_dma_attr = {
124 	DMA_ATTR_V0,    /* version number */
125 	0x0,		/* lowest usable address */
126 	0xFFFFFFFFull,  /* high DMA address range */
127 	0xFFFFFFFFull,  /* DMA counter register */
128 	1,		/* DMA address alignment */
129 	1,		/* DMA burstsizes */
130 	1,		/* min effective DMA size */
131 	0xFFFFFFFFull,  /* max DMA xfer size */
132 	0xFFFFFFFFull,  /* segment boundary */
133 	1,		/* s/g list length */
134 	1,		/* granularity of device */
135 	0		/* DMA transfer flags */
136 };
137 
138 static ddi_device_acc_attr_t st_acc_attr = {
139 	DDI_DEVICE_ATTR_V0,
140 	DDI_NEVERSWAP_ACC,
141 	DDI_STRICTORDER_ACC
142 };
143 
144 /* set limitation for the number of contig_mem */
145 static int st_max_contig_mem_num = ST_MAX_CONTIG_MEM_NUM;
146 #endif
147 
148 /*
149  * Tunable parameters
150  *
151  * DISCLAIMER
152  * ----------
153  * These parameters are intended for use only in system testing; if you use
154  * them in production systems, you do so at your own risk. Altering any
155  * variable not listed below may cause unpredictable system behavior.
156  *
157  * st_check_media_time
158  *
159  *   Three second state check
160  *
161  * st_allow_large_xfer
162  *
163  *   Gated with ST_NO_RECSIZE_LIMIT
164  *
165  *   0 - Transfers larger than 64KB will not be allowed
166  *       regardless of the setting of ST_NO_RECSIZE_LIMIT
167  *   1 - Transfers larger than 64KB will be allowed
168  *       if ST_NO_RECSIZE_LIMIT is TRUE for the drive
169  *
170  * st_report_soft_errors_on_close
171  *
172  *  Gated with ST_SOFT_ERROR_REPORTING
173  *
174  *  0 - Errors will not be reported on close regardless
175  *      of the setting of ST_SOFT_ERROR_REPORTING
176  *
177  *  1 - Errors will be reported on close if
178  *      ST_SOFT_ERROR_REPORTING is TRUE for the drive
179  */
180 static int st_selection_retry_count = ST_SEL_RETRY_COUNT;
181 static int st_retry_count	= ST_RETRY_COUNT;
182 
183 static int st_io_time		= ST_IO_TIME;
184 static int st_long_timeout_x	= ST_LONG_TIMEOUT_X;
185 
186 static int st_space_time	= ST_SPACE_TIME;
187 static int st_long_space_time_x	= ST_LONG_SPACE_TIME_X;
188 
189 static int st_error_level	= SCSI_ERR_RETRYABLE;
190 static int st_check_media_time	= 3000000;	/* 3 Second State Check */
191 
192 static int st_max_throttle	= ST_MAX_THROTTLE;
193 
194 static clock_t st_wait_cmds_complete = ST_WAIT_CMDS_COMPLETE;
195 
196 static int st_allow_large_xfer = 1;
197 static int st_report_soft_errors_on_close = 1;
198 
199 /*
200  * End of tunable parameters list
201  */
202 
203 
204 
205 /*
206  * Asynchronous I/O and persistent errors, refer to PSARC/1995/228
207  *
208  * Asynchronous I/O's main offering is that it is a non-blocking way to do
209  * reads and writes.  The driver will queue up all the requests it gets and
210  * have them ready to transport to the HBA.  Unfortunately, we cannot always
211  * just ship the I/O requests to the HBA, as there errors and exceptions
212  * that may happen when we don't want the HBA to continue.  Therein comes
213  * the flush-on-errors capability.  If the HBA supports it, then st will
214  * send in st_max_throttle I/O requests at the same time.
215  *
216  * Persistent errors : This was also reasonably simple.  In the interrupt
217  * routines, if there was an error or exception (FM, LEOT, media error,
218  * transport error), the persistent error bits are set and shuts everything
219  * down, but setting the throttle to zero.  If we hit and exception in the
220  * HBA, and flush-on-errors were set, we wait for all outstanding I/O's to
221  * come back (with CMD_ABORTED), then flush all bp's in the wait queue with
222  * the appropriate error, and this will preserve order. Of course, depending
223  * on the exception we have to show a zero read or write before we show
224  * errors back to the application.
225  */
226 
227 extern const int st_ndrivetypes;	/* defined in st_conf.c */
228 extern const struct st_drivetype st_drivetypes[];
229 
230 #ifdef STDEBUG
231 static int st_soft_error_report_debug = 0;
232 static int st_debug = 0;
233 #endif
234 
235 #define	ST_MT02_NAME	"Emulex  MT02 QIC-11/24  "
236 
237 static const struct driver_minor_data {
238 	char	*name;
239 	int	minor;
240 } st_minor_data[] = {
241 	/*
242 	 * The top 4 entries are for the default densities,
243 	 * don't alter their position.
244 	 */
245 	{"",	0},
246 	{"n",	MT_NOREWIND},
247 	{"b",	MT_BSD},
248 	{"bn",	MT_NOREWIND | MT_BSD},
249 	{"l",	MT_DENSITY1},
250 	{"m",	MT_DENSITY2},
251 	{"h",	MT_DENSITY3},
252 	{"c",	MT_DENSITY4},
253 	{"u",	MT_DENSITY4},
254 	{"ln",	MT_DENSITY1 | MT_NOREWIND},
255 	{"mn",	MT_DENSITY2 | MT_NOREWIND},
256 	{"hn",	MT_DENSITY3 | MT_NOREWIND},
257 	{"cn",	MT_DENSITY4 | MT_NOREWIND},
258 	{"un",	MT_DENSITY4 | MT_NOREWIND},
259 	{"lb",	MT_DENSITY1 | MT_BSD},
260 	{"mb",	MT_DENSITY2 | MT_BSD},
261 	{"hb",	MT_DENSITY3 | MT_BSD},
262 	{"cb",	MT_DENSITY4 | MT_BSD},
263 	{"ub",	MT_DENSITY4 | MT_BSD},
264 	{"lbn",	MT_DENSITY1 | MT_NOREWIND | MT_BSD},
265 	{"mbn",	MT_DENSITY2 | MT_NOREWIND | MT_BSD},
266 	{"hbn",	MT_DENSITY3 | MT_NOREWIND | MT_BSD},
267 	{"cbn",	MT_DENSITY4 | MT_NOREWIND | MT_BSD},
268 	{"ubn",	MT_DENSITY4 | MT_NOREWIND | MT_BSD}
269 };
270 
271 /* strings used in many debug and warning messages */
272 static const char wr_str[]  = "write";
273 static const char rd_str[]  = "read";
274 static const char wrg_str[] = "writing";
275 static const char rdg_str[] = "reading";
276 
277 /* default density offsets in the table above */
278 #define	DEF_BLANK	0
279 #define	DEF_NOREWIND	1
280 #define	DEF_BSD		2
281 #define	DEF_BSD_NR	3
282 
283 /* Sense Key, ASC/ASCQ for which tape ejection is needed */
284 
285 static struct tape_failure_code {
286 	uchar_t key;
287 	uchar_t add_code;
288 	uchar_t qual_code;
289 } st_tape_failure_code[] = {
290 	{ KEY_HARDWARE_ERROR, 0x15, 0x01},
291 	{ KEY_HARDWARE_ERROR, 0x44, 0x00},
292 	{ KEY_HARDWARE_ERROR, 0x53, 0x00},
293 	{ KEY_HARDWARE_ERROR, 0x53, 0x01},
294 	{ KEY_NOT_READY, 0x53, 0x00},
295 	{ 0xff}
296 };
297 
298 /*  clean bit position and mask */
299 
300 static struct cln_bit_position {
301 	ushort_t cln_bit_byte;
302 	uchar_t cln_bit_mask;
303 } st_cln_bit_position[] = {
304 	{ 21, 0x08},
305 	{ 70, 0xc0},
306 	{ 18, 0x81}  /* 80 bit indicates in bit mode, 1 bit clean light is on */
307 };
308 
309 /*
310  * architecture dependent allocation restrictions. For x86, we'll set
311  * dma_attr_addr_hi to st_max_phys_addr and dma_attr_sgllen to
312  * st_sgl_size during _init().
313  */
314 #if defined(__sparc)
315 static ddi_dma_attr_t st_alloc_attr = {
316 	DMA_ATTR_V0,	/* version number */
317 	0x0,		/* lowest usable address */
318 	0xFFFFFFFFull,	/* high DMA address range */
319 	0xFFFFFFFFull,	/* DMA counter register */
320 	1,		/* DMA address alignment */
321 	1,		/* DMA burstsizes */
322 	1,		/* min effective DMA size */
323 	0xFFFFFFFFull,	/* max DMA xfer size */
324 	0xFFFFFFFFull,	/* segment boundary */
325 	1,		/* s/g list length */
326 	512,		/* granularity of device */
327 	0		/* DMA transfer flags */
328 };
329 #elif defined(__x86)
330 static ddi_dma_attr_t st_alloc_attr = {
331 	DMA_ATTR_V0,	/* version number */
332 	0x0,		/* lowest usable address */
333 	0x0,		/* high DMA address range [set in _init()] */
334 	0xFFFFull,	/* DMA counter register */
335 	512,		/* DMA address alignment */
336 	1,		/* DMA burstsizes */
337 	1,		/* min effective DMA size */
338 	0xFFFFFFFFull,	/* max DMA xfer size */
339 	0xFFFFFFFFull,  /* segment boundary */
340 	0,		/* s/g list length */
341 	512,		/* granularity of device [set in _init()] */
342 	0		/* DMA transfer flags */
343 };
344 uint64_t st_max_phys_addr = 0xFFFFFFFFull;
345 int st_sgl_size = 0xF;
346 
347 #endif
348 
349 /*
350  * Configuration Data:
351  *
352  * Device driver ops vector
353  */
354 static int st_aread(dev_t dev, struct aio_req *aio, cred_t *cred_p);
355 static int st_awrite(dev_t dev, struct aio_req *aio, cred_t *cred_p);
356 static int st_read(dev_t  dev,  struct   uio   *uio_p,   cred_t *cred_p);
357 static int st_write(dev_t  dev,  struct  uio   *uio_p,   cred_t *cred_p);
358 static int st_open(dev_t  *devp,  int  flag,  int  otyp,  cred_t *cred_p);
359 static int st_close(dev_t  dev,  int  flag,  int  otyp,  cred_t *cred_p);
360 static int st_strategy(struct buf *bp);
361 static int st_ioctl(dev_t dev, int cmd, intptr_t arg, int  flag,
362 	cred_t *cred_p, int *rval_p);
363 extern int nulldev(), nodev();
364 
365 static struct cb_ops st_cb_ops = {
366 	st_open,			/* open */
367 	st_close,		/* close */
368 	st_strategy,		/* strategy */
369 	nodev,			/* print */
370 	nodev,			/* dump */
371 	st_read,		/* read */
372 	st_write,		/* write */
373 	st_ioctl,		/* ioctl */
374 	nodev,			/* devmap */
375 	nodev,			/* mmap */
376 	nodev,			/* segmap */
377 	nochpoll,		/* poll */
378 	ddi_prop_op,		/* cb_prop_op */
379 	0,			/* streamtab  */
380 	D_64BIT | D_MP | D_NEW | D_HOTPLUG,	/* Driver compatibility flag */
381 	CB_REV,			/* cb_rev */
382 	st_aread, 		/* async I/O read entry point */
383 	st_awrite		/* async I/O write entry point */
384 
385 };
386 
387 static int stinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg,
388 		void **result);
389 static int st_probe(dev_info_t *dev);
390 static int st_attach(dev_info_t *dev, ddi_attach_cmd_t cmd);
391 static int st_detach(dev_info_t *dev, ddi_detach_cmd_t cmd);
392 
393 static struct dev_ops st_ops = {
394 	DEVO_REV,		/* devo_rev, */
395 	0,			/* refcnt  */
396 	stinfo,			/* info */
397 	nulldev,		/* identify */
398 	st_probe,		/* probe */
399 	st_attach,		/* attach */
400 	st_detach,		/* detach */
401 	nodev,			/* reset */
402 	&st_cb_ops,		/* driver operations */
403 	(struct bus_ops *)0,	/* bus operations */
404 	nulldev			/* power */
405 };
406 
407 /*
408  * Local Function Declarations
409  */
410 static void st_clean_print(dev_info_t *dev, char *label, uint_t level,
411 	char *title, char *data, int len);
412 static int st_doattach(struct scsi_device *devp, int (*canwait)());
413 static void st_known_tape_type(struct scsi_tape *un);
414 static int st_get_conf_from_st_dot_conf(struct scsi_tape *, char *,
415     struct st_drivetype *);
416 static int st_get_conf_from_st_conf_dot_c(struct scsi_tape *, char *,
417     struct st_drivetype *);
418 static int st_get_default_conf(struct scsi_tape *, char *,
419     struct st_drivetype *);
420 static int st_rw(dev_t dev, struct uio *uio, int flag);
421 static int st_arw(dev_t dev, struct aio_req *aio, int flag);
422 static int st_find_eom(dev_t dev);
423 static int st_check_density_or_wfm(dev_t dev, int wfm, int mode, int stepflag);
424 static int st_ioctl_cmd(dev_t dev, struct uscsi_cmd *,
425 	enum uio_seg, enum uio_seg, enum uio_seg);
426 static int st_mtioctop(struct scsi_tape *un, intptr_t arg, int flag);
427 static void st_start(struct scsi_tape *un);
428 static int st_handle_start_busy(struct scsi_tape *un, struct buf *bp,
429     clock_t timeout_interval);
430 static int st_handle_intr_busy(struct scsi_tape *un, struct buf *bp,
431     clock_t timeout_interval);
432 static int st_handle_intr_retry_lcmd(struct scsi_tape *un, struct buf *bp);
433 static void st_done_and_mutex_exit(struct scsi_tape *un, struct buf *bp);
434 static void st_init(struct scsi_tape *un);
435 static void st_make_cmd(struct scsi_tape *un, struct buf *bp,
436     int (*func)(caddr_t));
437 static void st_make_uscsi_cmd(struct scsi_tape *, struct uscsi_cmd *,
438     struct buf *bp, int (*func)(caddr_t));
439 static void st_intr(struct scsi_pkt *pkt);
440 static void st_set_state(struct scsi_tape *un);
441 static void st_test_append(struct buf *bp);
442 static int st_runout(caddr_t);
443 static int st_cmd(dev_t dev, int com, int count, int wait);
444 static int st_set_compression(struct scsi_tape *un);
445 static int st_write_fm(dev_t dev, int wfm);
446 static int st_determine_generic(dev_t dev);
447 static int st_determine_density(dev_t dev, int rw);
448 static int st_get_density(dev_t dev);
449 static int st_set_density(dev_t dev);
450 static int st_loadtape(dev_t dev);
451 static int st_modesense(struct scsi_tape *un);
452 static int st_modeselect(struct scsi_tape *un);
453 static int st_handle_incomplete(struct scsi_tape *un, struct buf *bp);
454 static int st_wrongtapetype(struct scsi_tape *un);
455 static int st_check_error(struct scsi_tape *un, struct scsi_pkt *pkt);
456 static int st_handle_sense(struct scsi_tape *un, struct buf *bp);
457 static int st_handle_autosense(struct scsi_tape *un, struct buf *bp);
458 static int st_decode_sense(struct scsi_tape *un, struct buf *bp, int amt,
459 	struct scsi_status *);
460 static int st_report_soft_errors(dev_t dev, int flag);
461 static void st_delayed_cv_broadcast(void *arg);
462 static int st_check_media(dev_t dev, enum mtio_state state);
463 static int st_media_watch_cb(caddr_t arg, struct scsi_watch_result *resultp);
464 static void st_intr_restart(void *arg);
465 static void st_start_restart(void *arg);
466 static int st_gen_mode_sense(struct scsi_tape *un, int page,
467     struct seq_mode *page_data, int page_size);
468 static int st_change_block_size(dev_t dev, uint32_t nblksz);
469 static int st_gen_mode_select(struct scsi_tape *un, struct seq_mode *page_data,
470     int page_size);
471 static int st_tape_init(dev_t dev);
472 static void st_flush(struct scsi_tape *un);
473 static void st_set_pe_errno(struct scsi_tape *un);
474 static void st_hba_unflush(struct scsi_tape *un);
475 static void st_turn_pe_on(struct scsi_tape *un);
476 static void st_turn_pe_off(struct scsi_tape *un);
477 static void st_set_pe_flag(struct scsi_tape *un);
478 static void st_clear_pe(struct scsi_tape *un);
479 static void st_wait_for_io(struct scsi_tape *un);
480 static int st_set_devconfig_page(struct scsi_tape *un, int compression_on);
481 static int st_set_datacomp_page(struct scsi_tape *un, int compression_on);
482 static int st_tape_reservation_init(dev_t dev);
483 static int st_reserve_release(dev_t dev, int command);
484 static int st_take_ownership(dev_t dev);
485 static int st_check_asc_ascq(struct scsi_tape *un);
486 static int st_check_clean_bit(dev_t dev);
487 static int st_check_alert_clean_bit(dev_t dev);
488 static int st_check_sequential_clean_bit(dev_t dev);
489 static int st_check_sense_clean_bit(dev_t dev);
490 static int st_clear_unit_attentions(dev_t dev_instance, int max_trys);
491 static void st_calculate_timeouts(struct scsi_tape *un);
492 
493 #if defined(__i386) || defined(__amd64)
494 /*
495  * routines for I/O in big block size
496  */
497 static void st_release_contig_mem(struct scsi_tape *un, struct contig_mem *cp);
498 static struct contig_mem *st_get_contig_mem(struct scsi_tape *un, size_t len,
499     int alloc_flags);
500 static int st_bigblk_xfer_done(struct buf *bp);
501 static struct buf *st_get_bigblk_bp(struct buf *bp);
502 #endif
503 
504 /*
505  * error statistics create/update functions
506  */
507 static int st_create_errstats(struct scsi_tape *, int);
508 static void st_uscsi_minphys(struct buf *bp);
509 static int st_validate_tapemarks(struct scsi_tape *un, int fileno, daddr_t bn);
510 
511 #ifdef STDEBUG
512 static void st_debug_cmds(struct scsi_tape *un, int com, int count, int wait);
513 static char *st_dev_name(dev_t dev);
514 #endif /* STDEBUG */
515 
516 #if !defined(lint)
517 _NOTE(SCHEME_PROTECTS_DATA("unique per pkt", scsi_pkt buf uio scsi_cdb))
518 _NOTE(SCHEME_PROTECTS_DATA("unique per pkt", scsi_extended_sense scsi_status))
519 _NOTE(SCHEME_PROTECTS_DATA("stable data", scsi_device))
520 _NOTE(DATA_READABLE_WITHOUT_LOCK(st_drivetype scsi_address))
521 #endif
522 
523 /*
524  * autoconfiguration routines.
525  */
526 char _depends_on[] = "misc/scsi";
527 
528 static struct modldrv modldrv = {
529 	&mod_driverops,		/* Type of module. This one is a driver */
530 	"SCSI tape Driver %I%", /* Name of the module. */
531 	&st_ops			/* driver ops */
532 };
533 
534 static struct modlinkage modlinkage = {
535 	MODREV_1, &modldrv, NULL
536 };
537 
538 /*
539  * Notes on Post Reset Behavior in the tape driver:
540  *
541  * When the tape drive is opened, the driver  attempts  to make sure that
542  * the tape head is positioned exactly where it was left when it was last
543  * closed  provided  the  medium  is not  changed.  If the tape  drive is
544  * opened in O_NDELAY mode, the repositioning  (if necessary for any loss
545  * of position due to reset) will happen when the first tape operation or
546  * I/O occurs.  The repositioning (if required) may not be possible under
547  * certain situations such as when the device firmware not able to report
548  * the medium  change in the REQUEST  SENSE data  because of a reset or a
549  * misbehaving  bus  not  allowing  the  reposition  to  happen.  In such
550  * extraordinary  situations, where the driver fails to position the head
551  * at its  original  position,  it will fail the open the first  time, to
552  * save the applications from overwriting the data.  All further attempts
553  * to open the tape device will result in the driver  attempting  to load
554  * the  tape at BOT  (beginning  of  tape).  Also a  warning  message  to
555  * indicate  that further  attempts to open the tape device may result in
556  * the tape being  loaded at BOT will be printed on the  console.  If the
557  * tape  device is opened  in  O_NDELAY  mode,  failure  to  restore  the
558  * original tape head  position,  will result in the failure of the first
559  * tape  operation  or I/O,  Further,  the  driver  will  invalidate  its
560  * internal tape position  which will  necessitate  the  applications  to
561  * validate the position by using either a tape  positioning  ioctl (such
562  * as MTREW) or closing and reopening the tape device.
563  *
564  */
565 
566 int
567 _init(void)
568 {
569 	int e;
570 
571 	if (((e = ddi_soft_state_init(&st_state,
572 	    sizeof (struct scsi_tape), ST_MAXUNIT)) != 0)) {
573 		return (e);
574 	}
575 
576 	if ((e = mod_install(&modlinkage)) != 0) {
577 		ddi_soft_state_fini(&st_state);
578 	}
579 
580 #if defined(__x86)
581 	/* set the max physical address for iob allocs on x86 */
582 	st_alloc_attr.dma_attr_addr_hi = st_max_phys_addr;
583 
584 	/*
585 	 * set the sgllen for iob allocs on x86. If this is set less than
586 	 * the number of pages the buffer will take (taking into account
587 	 * alignment), it would force the allocator to try and allocate
588 	 * contiguous pages.
589 	 */
590 	st_alloc_attr.dma_attr_sgllen = st_sgl_size;
591 #endif
592 
593 	return (e);
594 }
595 
596 int
597 _fini(void)
598 {
599 	int e;
600 
601 	if ((e = mod_remove(&modlinkage)) != 0) {
602 		return (e);
603 	}
604 
605 	ddi_soft_state_fini(&st_state);
606 
607 	return (e);
608 }
609 
610 int
611 _info(struct modinfo *modinfop)
612 {
613 	return (mod_info(&modlinkage, modinfop));
614 }
615 
616 
617 static int
618 st_probe(dev_info_t *devi)
619 {
620 	int instance;
621 	struct scsi_device *devp;
622 	int rval;
623 
624 #if !defined(__sparc)
625 	char    *tape_prop;
626 	int	tape_prop_len;
627 #endif
628 
629 	/* If self identifying device */
630 	if (ddi_dev_is_sid(devi) == DDI_SUCCESS) {
631 		return (DDI_PROBE_DONTCARE);
632 	}
633 
634 #if !defined(__sparc)
635 	/*
636 	 * Since some x86 HBAs have devnodes that look like SCSI as
637 	 * far as we can tell but aren't really SCSI (DADK, like mlx)
638 	 * we check for the presence of the "tape" property.
639 	 */
640 	if (ddi_prop_op(DDI_DEV_T_NONE, devi, PROP_LEN_AND_VAL_ALLOC,
641 	    DDI_PROP_CANSLEEP, "tape",
642 	    (caddr_t)&tape_prop, &tape_prop_len) != DDI_PROP_SUCCESS) {
643 		return (DDI_PROBE_FAILURE);
644 	}
645 	if (strncmp(tape_prop, "sctp", tape_prop_len) != 0) {
646 		kmem_free(tape_prop, tape_prop_len);
647 		return (DDI_PROBE_FAILURE);
648 	}
649 	kmem_free(tape_prop, tape_prop_len);
650 #endif
651 
652 	devp = ddi_get_driver_private(devi);
653 	instance = ddi_get_instance(devi);
654 
655 	if (ddi_get_soft_state(st_state, instance) != NULL) {
656 		return (DDI_PROBE_PARTIAL);
657 	}
658 
659 
660 	/*
661 	 * Turn around and call probe routine to see whether
662 	 * we actually have a tape at this SCSI nexus.
663 	 */
664 	if (scsi_probe(devp, NULL_FUNC) == SCSIPROBE_EXISTS) {
665 
666 		/*
667 		 * In checking the whole inq_dtype byte we are looking at both
668 		 * the Peripheral Qualifier and the Peripheral Device Type.
669 		 * For this driver we are only interested in sequential devices
670 		 * that are connected or capable if connecting to this logical
671 		 * unit.
672 		 */
673 		if (devp->sd_inq->inq_dtype ==
674 		    (DTYPE_SEQUENTIAL | DPQ_POSSIBLE)) {
675 			ST_DEBUG6(devi, st_label, SCSI_DEBUG,
676 			    "probe exists\n");
677 			rval = DDI_PROBE_SUCCESS;
678 		} else {
679 			rval = DDI_PROBE_FAILURE;
680 		}
681 	} else {
682 		ST_DEBUG6(devi, st_label, SCSI_DEBUG,
683 		    "probe failure: nothing there\n");
684 		rval = DDI_PROBE_FAILURE;
685 	}
686 	scsi_unprobe(devp);
687 	return (rval);
688 }
689 
690 static int
691 st_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
692 {
693 	int 	instance;
694 	int	wide;
695 	int 	dev_instance;
696 	int	ret_status;
697 	struct	scsi_device *devp;
698 	int	node_ix;
699 	struct	scsi_tape *un;
700 
701 	devp = ddi_get_driver_private(devi);
702 	instance = ddi_get_instance(devi);
703 
704 	switch (cmd) {
705 		case DDI_ATTACH:
706 			if (st_doattach(devp, SLEEP_FUNC) == DDI_FAILURE) {
707 				return (DDI_FAILURE);
708 			}
709 			break;
710 		case DDI_RESUME:
711 			/*
712 			 * Suspend/Resume
713 			 *
714 			 * When the driver suspended, there might be
715 			 * outstanding cmds and therefore we need to
716 			 * reset the suspended flag and resume the scsi
717 			 * watch thread and restart commands and timeouts
718 			 */
719 
720 			if (!(un = ddi_get_soft_state(st_state, instance))) {
721 				return (DDI_FAILURE);
722 			}
723 			dev_instance = ((un->un_dev == 0) ? MTMINOR(instance) :
724 			    un->un_dev);
725 
726 			mutex_enter(ST_MUTEX);
727 
728 			un->un_throttle = un->un_max_throttle;
729 			un->un_tids_at_suspend = 0;
730 			un->un_pwr_mgmt = ST_PWR_NORMAL;
731 
732 			if (un->un_swr_token) {
733 				scsi_watch_resume(un->un_swr_token);
734 			}
735 
736 			/*
737 			 * Restart timeouts
738 			 */
739 			if ((un->un_tids_at_suspend & ST_DELAY_TID) != 0) {
740 				mutex_exit(ST_MUTEX);
741 				un->un_delay_tid =
742 				    timeout(st_delayed_cv_broadcast, un,
743 					drv_usectohz((clock_t)
744 					MEDIA_ACCESS_DELAY));
745 				mutex_enter(ST_MUTEX);
746 			}
747 
748 			if (un->un_tids_at_suspend & ST_HIB_TID) {
749 				mutex_exit(ST_MUTEX);
750 				un->un_hib_tid = timeout(st_intr_restart, un,
751 				    ST_STATUS_BUSY_TIMEOUT);
752 				mutex_enter(ST_MUTEX);
753 			}
754 
755 			ret_status = st_clear_unit_attentions(dev_instance, 5);
756 
757 			/*
758 			 * now check if we need to restore the tape position
759 			 */
760 			if ((un->un_suspend_fileno > 0) ||
761 			    (un->un_suspend_blkno > 0)) {
762 				if (ret_status != 0) {
763 					/*
764 					 * tape didn't get good TUR
765 					 * just print out error messages
766 					 */
767 					scsi_log(ST_DEVINFO, st_label, CE_WARN,
768 					    "st_attach-RESUME: tape failure "
769 					    " tape position will be lost");
770 				} else {
771 					/* this prints errors */
772 					(void) st_validate_tapemarks(un,
773 					    un->un_suspend_fileno,
774 					    un->un_suspend_blkno);
775 				}
776 				/*
777 				 * there are no retries, if there is an error
778 				 * we don't know if the tape has changed
779 				 */
780 				un->un_suspend_fileno = 0;
781 				un->un_suspend_blkno = 0;
782 			}
783 
784 			/* now we are ready to start up any queued I/Os */
785 			if (un->un_ncmds || un->un_quef) {
786 				st_start(un);
787 			}
788 
789 			cv_broadcast(&un->un_suspend_cv);
790 			mutex_exit(ST_MUTEX);
791 			return (DDI_SUCCESS);
792 
793 		default:
794 			return (DDI_FAILURE);
795 	}
796 
797 	un = ddi_get_soft_state(st_state, instance);
798 
799 	ST_DEBUG(devi, st_label, SCSI_DEBUG,
800 	    "st_attach: instance=%x\n", instance);
801 
802 	/*
803 	 * find the drive type for this target
804 	 */
805 	st_known_tape_type(un);
806 
807 	for (node_ix = 0; node_ix < ST_NUM_MEMBERS(st_minor_data); node_ix++) {
808 		int minor;
809 		char *name;
810 
811 		name  = st_minor_data[node_ix].name;
812 		minor = st_minor_data[node_ix].minor;
813 
814 		/*
815 		 * For default devices set the density to the
816 		 * preferred default density for this device.
817 		 */
818 		if (node_ix <= DEF_BSD_NR) {
819 			minor |= un->un_dp->default_density;
820 		}
821 		minor |= MTMINOR(instance);
822 
823 		if (ddi_create_minor_node(devi, name, S_IFCHR, minor,
824 		    DDI_NT_TAPE, NULL) == DDI_SUCCESS) {
825 			continue;
826 		}
827 
828 		ddi_remove_minor_node(devi, NULL);
829 		if (un) {
830 			cv_destroy(&un->un_clscv);
831 			cv_destroy(&un->un_sbuf_cv);
832 			cv_destroy(&un->un_queue_cv);
833 			cv_destroy(&un->un_state_cv);
834 			cv_destroy(&un->un_suspend_cv);
835 			cv_destroy(&un->un_tape_busy_cv);
836 
837 			if (un->un_sbufp) {
838 				freerbuf(un->un_sbufp);
839 			}
840 			if (un->un_uscsi_rqs_buf) {
841 				kmem_free(un->un_uscsi_rqs_buf, SENSE_LENGTH);
842 			}
843 			if (un->un_mspl) {
844 				i_ddi_mem_free((caddr_t)un->un_mspl, 0);
845 			}
846 			scsi_destroy_pkt(un->un_rqs);
847 			scsi_free_consistent_buf(un->un_rqs_bp);
848 			ddi_soft_state_free(st_state, instance);
849 			devp->sd_private = NULL;
850 			devp->sd_sense = NULL;
851 
852 		}
853 		ddi_prop_remove_all(devi);
854 		return (DDI_FAILURE);
855 	}
856 
857 	/*
858 	 * Add a zero-length attribute to tell the world we support
859 	 * kernel ioctls (for layered drivers)
860 	 */
861 	(void) ddi_prop_create(DDI_DEV_T_NONE, devi, DDI_PROP_CANSLEEP,
862 	    DDI_KERNEL_IOCTL, NULL, 0);
863 
864 	ddi_report_dev((dev_info_t *)devi);
865 
866 	/*
867 	 * If it's a SCSI-2 tape drive which supports wide,
868 	 * tell the host adapter to use wide.
869 	 */
870 	wide = ((devp->sd_inq->inq_rdf == RDF_SCSI2) &&
871 	    (devp->sd_inq->inq_wbus16 || devp->sd_inq->inq_wbus32)) ?
872 		1 : 0;
873 
874 	if (scsi_ifsetcap(ROUTE, "wide-xfer", wide, 1) == 1) {
875 		ST_DEBUG(devi, st_label, SCSI_DEBUG,
876 		    "Wide Transfer %s\n", wide ? "enabled" : "disabled");
877 	}
878 
879 	/*
880 	 * enable autorequest sense; keep the rq packet around in case
881 	 * the autorequest sense fails because of a busy condition
882 	 * do a getcap first in case the capability is not variable
883 	 */
884 	if (scsi_ifgetcap(ROUTE, "auto-rqsense", 1) == 1) {
885 		un->un_arq_enabled = 1;
886 	} else {
887 		un->un_arq_enabled =
888 		    ((scsi_ifsetcap(ROUTE, "auto-rqsense", 1, 1) == 1) ? 1 : 0);
889 	}
890 
891 
892 	ST_DEBUG(devi, st_label, SCSI_DEBUG, "auto request sense %s\n",
893 		(un->un_arq_enabled ? "enabled" : "disabled"));
894 
895 	un->un_untagged_qing =
896 	    (scsi_ifgetcap(ROUTE, "untagged-qing", 0) == 1);
897 
898 	/*
899 	 * XXX - This is just for 2.6.  to tell users that write buffering
900 	 *	has gone away.
901 	 */
902 	if (un->un_arq_enabled && un->un_untagged_qing) {
903 		if (ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
904 		    "tape-driver-buffering", 0) != 0) {
905 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
906 			    "Write Data Buffering has been depricated. Your "
907 			    "applications should continue to work normally.\n"
908 			    " But, they should  ported to use Asynchronous "
909 			    " I/O\n"
910 			    " For more information, read about "
911 			    " tape-driver-buffering "
912 			    "property in the st(7d) man page\n");
913 		}
914 	}
915 
916 	un->un_max_throttle = un->un_throttle = un->un_last_throttle = 1;
917 	un->un_flush_on_errors = 0;
918 	un->un_mkr_pkt = (struct scsi_pkt *)NULL;
919 
920 	ST_DEBUG(devi, st_label, SCSI_DEBUG,
921 	    "throttle=%x, max_throttle = %x\n",
922 	    un->un_throttle, un->un_max_throttle);
923 
924 	/* initialize persistent errors to nil */
925 	un->un_persistence = 0;
926 	un->un_persist_errors = 0;
927 
928 	/*
929 	 * Get dma-max from HBA driver. If it is not defined, use 64k
930 	 */
931 	un->un_maxdma	= scsi_ifgetcap(&devp->sd_address, "dma-max", 1);
932 	if (un->un_maxdma == -1) {
933 		un->un_maxdma = (64 * 1024);
934 	}
935 
936 	un->un_maxbsize = MAXBSIZE_UNKNOWN;
937 
938 	un->un_mediastate = MTIO_NONE;
939 	un->un_HeadClean  = TAPE_ALERT_SUPPORT_UNKNOWN;
940 
941 	/*
942 	 * initialize kstats
943 	 */
944 	un->un_stats = kstat_create("st", instance, NULL, "tape",
945 			KSTAT_TYPE_IO, 1, KSTAT_FLAG_PERSISTENT);
946 	if (un->un_stats) {
947 		un->un_stats->ks_lock = ST_MUTEX;
948 		kstat_install(un->un_stats);
949 	}
950 	(void) st_create_errstats(un, instance);
951 
952 	return (DDI_SUCCESS);
953 }
954 
955 /*
956  * st_detach:
957  *
958  * we allow a detach if and only if:
959  *	- no tape is currently inserted
960  *	- tape position is at BOT or unknown
961  *		(if it is not at BOT then a no rewind
962  *		device was opened and we have to preserve state)
963  *	- it must be in a closed state : no timeouts or scsi_watch requests
964  *		will exist if it is closed, so we don't need to check for
965  *		them here.
966  */
967 /*ARGSUSED*/
968 static int
969 st_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
970 {
971 	int 	instance;
972 	int 	dev_instance;
973 	struct scsi_device *devp;
974 	struct scsi_tape *un;
975 	clock_t wait_cmds_complete;
976 
977 	instance = ddi_get_instance(devi);
978 
979 	if (!(un = ddi_get_soft_state(st_state, instance))) {
980 		return (DDI_FAILURE);
981 	}
982 
983 	switch (cmd) {
984 
985 	case DDI_DETACH:
986 		/*
987 		 * Undo what we did in st_attach & st_doattach,
988 		 * freeing resources and removing things we installed.
989 		 * The system framework guarantees we are not active
990 		 * with this devinfo node in any other entry points at
991 		 * this time.
992 		 */
993 
994 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
995 		    "st_detach: instance=%x, un=%p\n", instance,
996 		    (void *)un);
997 
998 		if (((un->un_dp->options & ST_UNLOADABLE) == 0) ||
999 		    (un->un_ncmds != 0) || (un->un_quef != NULL) ||
1000 		    (un->un_state != ST_STATE_CLOSED)) {
1001 			/*
1002 			 * we cannot unload some targets because the
1003 			 * inquiry returns junk unless immediately
1004 			 * after a reset
1005 			 */
1006 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
1007 			    "cannot unload instance %x\n", instance);
1008 			return (DDI_FAILURE);
1009 		}
1010 
1011 		/*
1012 		 * if the tape has been removed then we may unload;
1013 		 * do a test unit ready and if it returns NOT READY
1014 		 * then we assume that it is safe to unload.
1015 		 * as a side effect, fileno may be set to -1 if the
1016 		 * the test unit ready fails;
1017 		 * also un_state may be set to non-closed, so reset it
1018 		 */
1019 		if ((un->un_dev) &&		/* Been opened since attach */
1020 		    ((un->un_fileno > 0) ||	/* Known position not rewound */
1021 		    (un->un_blkno != 0))) {	/* Or within first file */
1022 			mutex_enter(ST_MUTEX);
1023 			/*
1024 			 * Send Test Unit Ready in the hopes that if
1025 			 * the drive is not in the state we think it is.
1026 			 * And the state will be changed so it can be detached.
1027 			 * If the command fails to reach the device and
1028 			 * the drive was not rewound or unloaded we want
1029 			 * to fail the detach till a user command fails
1030 			 * where after the detach will succead.
1031 			 */
1032 			(void) st_cmd(un->un_dev, SCMD_TEST_UNIT_READY,
1033 			    0, SYNC_CMD);
1034 			/*
1035 			 * After TUR un_state may be set to non-closed,
1036 			 * so reset it back.
1037 			 */
1038 			un->un_state = ST_STATE_CLOSED;
1039 			mutex_exit(ST_MUTEX);
1040 		}
1041 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
1042 		    "un_status=%x, fileno=%x, blkno=%lx\n",
1043 		    un->un_status, un->un_fileno, un->un_blkno);
1044 
1045 		/*
1046 		 * check again:
1047 		 * if we are not at BOT then it is not safe to unload
1048 		 */
1049 		if ((un->un_dev) &&		/* Been opened since attach */
1050 		    ((un->un_fileno > 0) ||	/* Known position not rewound */
1051 		    (un->un_blkno != 0))) {	/* Or within first file */
1052 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
1053 			    "cannot detach: fileno=%x, blkno=%lx\n",
1054 			    un->un_fileno, un->un_blkno);
1055 			return (DDI_FAILURE);
1056 		}
1057 
1058 		/*
1059 		 * Just To make sure that we have released the
1060 		 * tape unit .
1061 		 */
1062 		if (un->un_dev && (un->un_rsvd_status & ST_RESERVE) &&
1063 		    !DEVI_IS_DEVICE_REMOVED(devi)) {
1064 			mutex_enter(ST_MUTEX);
1065 			(void) st_cmd(un->un_dev, SCMD_RELEASE, 0, SYNC_CMD);
1066 			mutex_exit(ST_MUTEX);
1067 		}
1068 
1069 		/*
1070 		 * now remove other data structures allocated in st_doattach()
1071 		 */
1072 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
1073 		    "destroying/freeing\n");
1074 		cv_destroy(&un->un_clscv);
1075 		cv_destroy(&un->un_sbuf_cv);
1076 		cv_destroy(&un->un_queue_cv);
1077 		cv_destroy(&un->un_suspend_cv);
1078 		cv_destroy(&un->un_tape_busy_cv);
1079 
1080 		if (un->un_hib_tid) {
1081 			(void) untimeout(un->un_hib_tid);
1082 			un->un_hib_tid = 0;
1083 		}
1084 
1085 		if (un->un_delay_tid) {
1086 			(void) untimeout(un->un_delay_tid);
1087 			un->un_delay_tid = 0;
1088 		}
1089 		cv_destroy(&un->un_state_cv);
1090 
1091 #if defined(__i386) || defined(__amd64)
1092 		if (un->un_contig_mem_hdl != NULL) {
1093 			ddi_dma_free_handle(&un->un_contig_mem_hdl);
1094 		}
1095 #endif
1096 		if (un->un_sbufp) {
1097 			freerbuf(un->un_sbufp);
1098 		}
1099 		if (un->un_uscsi_rqs_buf) {
1100 			kmem_free(un->un_uscsi_rqs_buf, SENSE_LENGTH);
1101 		}
1102 		if (un->un_mspl) {
1103 			i_ddi_mem_free((caddr_t)un->un_mspl, 0);
1104 		}
1105 		if (un->un_rqs) {
1106 			scsi_destroy_pkt(un->un_rqs);
1107 			scsi_free_consistent_buf(un->un_rqs_bp);
1108 		}
1109 		if (un->un_mkr_pkt) {
1110 			scsi_destroy_pkt(un->un_mkr_pkt);
1111 		}
1112 		if (un->un_arq_enabled) {
1113 			(void) scsi_ifsetcap(ROUTE, "auto-rqsense", 0, 1);
1114 		}
1115 		if (un->un_dp_size) {
1116 			kmem_free(un->un_dp, un->un_dp_size);
1117 		}
1118 		if (un->un_stats) {
1119 			kstat_delete(un->un_stats);
1120 			un->un_stats = (kstat_t *)0;
1121 		}
1122 		if (un->un_errstats) {
1123 			kstat_delete(un->un_errstats);
1124 			un->un_errstats = (kstat_t *)0;
1125 		}
1126 		devp = ST_SCSI_DEVP;
1127 		ddi_soft_state_free(st_state, instance);
1128 		devp->sd_private = NULL;
1129 		devp->sd_sense = NULL;
1130 		scsi_unprobe(devp);
1131 		ddi_prop_remove_all(devi);
1132 		ddi_remove_minor_node(devi, NULL);
1133 		ST_DEBUG(0, st_label, SCSI_DEBUG, "st_detach done\n");
1134 		return (DDI_SUCCESS);
1135 
1136 	case DDI_SUSPEND:
1137 
1138 		/*
1139 		 * Suspend/Resume
1140 		 *
1141 		 * To process DDI_SUSPEND, we must do the following:
1142 		 *
1143 		 *  - check ddi_removing_power to see if power will be turned
1144 		 *    off. if so, return DDI_FAILURE
1145 		 *  - check if we are already suspended,
1146 		 *    if so, return DDI_FAILURE
1147 		 *  - check if device state is CLOSED,
1148 		 *    if not, return DDI_FAILURE.
1149 		 *  - wait until outstanding operations complete
1150 		 *  - save tape state
1151 		 *  - block new operations
1152 		 *  - cancel pending timeouts
1153 		 *
1154 		 */
1155 
1156 		if (ddi_removing_power(devi))
1157 			return (DDI_FAILURE);
1158 
1159 		mutex_enter(ST_MUTEX);
1160 
1161 		/*
1162 		 * Shouldn't already be suspended, if so return failure
1163 		 */
1164 		if (un->un_pwr_mgmt == ST_PWR_SUSPENDED) {
1165 			mutex_exit(ST_MUTEX);
1166 			return (DDI_FAILURE);
1167 		}
1168 		if (un->un_state != ST_STATE_CLOSED) {
1169 			mutex_exit(ST_MUTEX);
1170 			return (DDI_FAILURE);
1171 		}
1172 
1173 		/*
1174 		 * Wait for all outstanding I/O's to complete
1175 		 *
1176 		 * we wait on both ncmds and the wait queue for times
1177 		 * when we are flushing after persistent errors are
1178 		 * flagged, which is when ncmds can be 0, and the
1179 		 * queue can still have I/O's.  This way we preserve
1180 		 * order of biodone's.
1181 		 */
1182 		wait_cmds_complete = ddi_get_lbolt();
1183 		wait_cmds_complete +=
1184 		    st_wait_cmds_complete * drv_usectohz(1000000);
1185 		while (un->un_ncmds || un->un_quef ||
1186 		    (un->un_state == ST_STATE_RESOURCE_WAIT)) {
1187 
1188 			if (cv_timedwait(&un->un_tape_busy_cv, ST_MUTEX,
1189 			    wait_cmds_complete) == -1) {
1190 				/*
1191 				 * Time expired then cancel the command
1192 				 */
1193 				mutex_exit(ST_MUTEX);
1194 				if (scsi_reset(ROUTE, RESET_TARGET) == 0) {
1195 					mutex_enter(ST_MUTEX);
1196 					if (un->un_last_throttle) {
1197 						un->un_throttle =
1198 						    un->un_last_throttle;
1199 					}
1200 					mutex_exit(ST_MUTEX);
1201 					return (DDI_FAILURE);
1202 				} else {
1203 					mutex_enter(ST_MUTEX);
1204 					break;
1205 				}
1206 			}
1207 		}
1208 
1209 		/*
1210 		 * DDI_SUSPEND says that the system "may" power down, we
1211 		 * remember the file and block number before rewinding.
1212 		 * we also need to save state before issuing
1213 		 * any WRITE_FILE_MARK command.
1214 		 */
1215 		if (un->un_fileno < 0) {
1216 			un->un_suspend_fileno = 0;
1217 			un->un_suspend_blkno  = 0;
1218 		} else {
1219 			un->un_suspend_fileno = un->un_fileno;
1220 			un->un_suspend_blkno = un->un_blkno;
1221 		}
1222 		dev_instance = ((un->un_dev == 0) ? MTMINOR(instance) :
1223 		    un->un_dev);
1224 
1225 		/*
1226 		 * Issue a zero write file fmk command to tell the drive to
1227 		 * flush any buffered tape marks
1228 		 */
1229 		(void) st_cmd(dev_instance, SCMD_WRITE_FILE_MARK, 0, SYNC_CMD);
1230 
1231 		/*
1232 		 * Because not all tape drives correctly implement buffer
1233 		 * flushing with the zero write file fmk command, issue a
1234 		 * synchronous rewind command to force data flushing.
1235 		 * st_validate_tapemarks() will do a rewind during DDI_RESUME
1236 		 * anyway.
1237 		 */
1238 		(void) st_cmd(dev_instance, SCMD_REWIND, 0, SYNC_CMD);
1239 
1240 		/* stop any new operations */
1241 		un->un_pwr_mgmt = ST_PWR_SUSPENDED;
1242 		un->un_throttle = 0;
1243 
1244 		/*
1245 		 * cancel any outstanding timeouts
1246 		 */
1247 		if (un->un_delay_tid) {
1248 			timeout_id_t temp_id = un->un_delay_tid;
1249 			un->un_delay_tid = 0;
1250 			un->un_tids_at_suspend |= ST_DELAY_TID;
1251 			mutex_exit(ST_MUTEX);
1252 			(void) untimeout(temp_id);
1253 			mutex_enter(ST_MUTEX);
1254 		}
1255 
1256 		if (un->un_hib_tid) {
1257 			timeout_id_t temp_id = un->un_hib_tid;
1258 			un->un_hib_tid = 0;
1259 			un->un_tids_at_suspend |= ST_HIB_TID;
1260 			mutex_exit(ST_MUTEX);
1261 			(void) untimeout(temp_id);
1262 			mutex_enter(ST_MUTEX);
1263 		}
1264 
1265 		/*
1266 		 * Suspend the scsi_watch_thread
1267 		 */
1268 		if (un->un_swr_token) {
1269 			opaque_t temp_token = un->un_swr_token;
1270 			mutex_exit(ST_MUTEX);
1271 			scsi_watch_suspend(temp_token);
1272 		} else {
1273 			mutex_exit(ST_MUTEX);
1274 		}
1275 
1276 		return (DDI_SUCCESS);
1277 
1278 	default:
1279 		ST_DEBUG(0, st_label, SCSI_DEBUG, "st_detach failed\n");
1280 		return (DDI_FAILURE);
1281 	}
1282 }
1283 
1284 
1285 /* ARGSUSED */
1286 static int
1287 stinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
1288 {
1289 	dev_t dev;
1290 	struct scsi_tape *un;
1291 	int instance, error;
1292 	switch (infocmd) {
1293 	case DDI_INFO_DEVT2DEVINFO:
1294 		dev = (dev_t)arg;
1295 		instance = MTUNIT(dev);
1296 		if ((un = ddi_get_soft_state(st_state, instance)) == NULL)
1297 			return (DDI_FAILURE);
1298 		*result = (void *) ST_DEVINFO;
1299 		error = DDI_SUCCESS;
1300 		break;
1301 	case DDI_INFO_DEVT2INSTANCE:
1302 		dev = (dev_t)arg;
1303 		instance = MTUNIT(dev);
1304 		*result = (void *)(uintptr_t)instance;
1305 		error = DDI_SUCCESS;
1306 		break;
1307 	default:
1308 		error = DDI_FAILURE;
1309 	}
1310 	return (error);
1311 }
1312 
1313 static int
1314 st_doattach(struct scsi_device *devp, int (*canwait)())
1315 {
1316 	struct scsi_pkt *rqpkt = NULL;
1317 	struct scsi_tape *un = NULL;
1318 	int km_flags = (canwait != NULL_FUNC) ? KM_SLEEP : KM_NOSLEEP;
1319 	int instance;
1320 	struct buf *bp;
1321 	size_t rlen;
1322 
1323 	/*
1324 	 * Call the routine scsi_probe to do some of the dirty work.
1325 	 * If the INQUIRY command succeeds, the field sd_inq in the
1326 	 * device structure will be filled in.
1327 	 */
1328 	ST_DEBUG(devp->sd_dev, st_label, SCSI_DEBUG,
1329 		"st_doattach(): probing\n");
1330 
1331 	if (scsi_probe(devp, canwait) == SCSIPROBE_EXISTS) {
1332 
1333 		/*
1334 		 * In checking the whole inq_dtype byte we are looking at both
1335 		 * the Peripheral Qualifier and the Peripheral Device Type.
1336 		 * For this driver we are only interested in sequential devices
1337 		 * that are connected or capable if connecting to this logical
1338 		 * unit.
1339 		 */
1340 		if (devp->sd_inq->inq_dtype ==
1341 		    (DTYPE_SEQUENTIAL | DPQ_POSSIBLE)) {
1342 			ST_DEBUG(devp->sd_dev, st_label, SCSI_DEBUG,
1343 			    "probe exists\n");
1344 		} else {
1345 			/* Something there but not a tape device */
1346 			scsi_unprobe(devp);
1347 			return (DDI_FAILURE);
1348 		}
1349 	} else {
1350 		/* Nothing there */
1351 		ST_DEBUG(devp->sd_dev, st_label, SCSI_DEBUG,
1352 		    "probe failure: nothing there\n");
1353 		scsi_unprobe(devp);
1354 		return (DDI_FAILURE);
1355 	}
1356 
1357 	bp = scsi_alloc_consistent_buf(&devp->sd_address, (struct buf *)NULL,
1358 	    SENSE_LENGTH, B_READ, canwait, NULL);
1359 	if (!bp) {
1360 		goto error;
1361 	}
1362 	rqpkt = scsi_init_pkt(&devp->sd_address,
1363 	    (struct scsi_pkt *)NULL, bp, CDB_GROUP0, 1, 0,
1364 	    PKT_CONSISTENT, canwait, NULL);
1365 	if (!rqpkt) {
1366 		goto error;
1367 	}
1368 	devp->sd_sense = (struct scsi_extended_sense *)bp->b_un.b_addr;
1369 	ASSERT(geterror(bp) == NULL);
1370 
1371 	(void) scsi_setup_cdb((union scsi_cdb *)rqpkt->pkt_cdbp,
1372 	    SCMD_REQUEST_SENSE, 0, SENSE_LENGTH, 0);
1373 	FILL_SCSI1_LUN(devp, rqpkt);
1374 
1375 	/*
1376 	 * The actual unit is present.
1377 	 * Now is the time to fill in the rest of our info..
1378 	 */
1379 	instance = ddi_get_instance(devp->sd_dev);
1380 
1381 	if (ddi_soft_state_zalloc(st_state, instance) != DDI_SUCCESS) {
1382 		goto error;
1383 	}
1384 	un = ddi_get_soft_state(st_state, instance);
1385 
1386 	un->un_sbufp = getrbuf(km_flags);
1387 
1388 	un->un_uscsi_rqs_buf = kmem_alloc(SENSE_LENGTH, KM_SLEEP);
1389 
1390 	/*
1391 	 * use i_ddi_mem_alloc() for now until we have an interface to allocate
1392 	 * memory for DMA which doesn't require a DMA handle. ddi_iopb_alloc()
1393 	 * is obsolete and we want more flexibility in controlling the DMA
1394 	 * address constraints.
1395 	 */
1396 	(void) i_ddi_mem_alloc(devp->sd_dev, &st_alloc_attr,
1397 	    sizeof (struct seq_mode), ((km_flags == KM_SLEEP) ? 1 : 0), 0,
1398 	    NULL, (caddr_t *)&un->un_mspl, &rlen, NULL);
1399 
1400 	if (!un->un_sbufp || !un->un_mspl) {
1401 		if (un->un_mspl) {
1402 			i_ddi_mem_free((caddr_t)un->un_mspl, 0);
1403 		}
1404 		ST_DEBUG6(devp->sd_dev, st_label, SCSI_DEBUG,
1405 		    "probe partial failure: no space\n");
1406 		goto error;
1407 	}
1408 
1409 	bzero(un->un_mspl, sizeof (struct seq_mode));
1410 
1411 	cv_init(&un->un_sbuf_cv, NULL, CV_DRIVER, NULL);
1412 	cv_init(&un->un_queue_cv, NULL, CV_DRIVER, NULL);
1413 	cv_init(&un->un_clscv, NULL, CV_DRIVER, NULL);
1414 	cv_init(&un->un_state_cv, NULL, CV_DRIVER, NULL);
1415 #if defined(__i386) || defined(__amd64)
1416 	cv_init(&un->un_contig_mem_cv, NULL, CV_DRIVER, NULL);
1417 #endif
1418 
1419 	/* Initialize power managemnet condition variable */
1420 	cv_init(&un->un_suspend_cv, NULL, CV_DRIVER, NULL);
1421 	cv_init(&un->un_tape_busy_cv, NULL, CV_DRIVER, NULL);
1422 
1423 	rqpkt->pkt_flags |= (FLAG_SENSING | FLAG_HEAD | FLAG_NODISCON);
1424 
1425 	un->un_fileno	= -1;
1426 	rqpkt->pkt_time = st_io_time;
1427 	rqpkt->pkt_comp = st_intr;
1428 	un->un_rqs	= rqpkt;
1429 	un->un_sd	= devp;
1430 	un->un_rqs_bp	= bp;
1431 	un->un_swr_token = (opaque_t)NULL;
1432 	un->un_comp_page = ST_DEV_DATACOMP_PAGE | ST_DEV_CONFIG_PAGE;
1433 
1434 	un->un_suspend_fileno 	= 0;
1435 	un->un_suspend_blkno 	= 0;
1436 
1437 #if defined(__i386) || defined(__amd64)
1438 	if (ddi_dma_alloc_handle(ST_DEVINFO, &st_contig_mem_dma_attr,
1439 		DDI_DMA_SLEEP, NULL, &un->un_contig_mem_hdl) != DDI_SUCCESS) {
1440 		ST_DEBUG6(devp->sd_dev, st_label, SCSI_DEBUG,
1441 		    "allocation of contiguous memory dma handle failed!");
1442 		un->un_contig_mem_hdl = NULL;
1443 		goto error;
1444 	}
1445 #endif
1446 
1447 	/*
1448 	 * Since this driver manages devices with "remote" hardware,
1449 	 * i.e. the devices themselves have no "reg" properties,
1450 	 * the SUSPEND/RESUME commands in detach/attach will not be
1451 	 * called by the power management framework unless we request
1452 	 * it by creating a "pm-hardware-state" property and setting it
1453 	 * to value "needs-suspend-resume".
1454 	 */
1455 	if (ddi_prop_update_string(DDI_DEV_T_NONE, devp->sd_dev,
1456 	    "pm-hardware-state", "needs-suspend-resume") !=
1457 	    DDI_PROP_SUCCESS) {
1458 
1459 		ST_DEBUG(devp->sd_dev, st_label, SCSI_DEBUG,
1460 		    "ddi_prop_update(\"pm-hardware-state\") failed\n");
1461 		goto error;
1462 	}
1463 
1464 	if (ddi_prop_create(DDI_DEV_T_NONE, devp->sd_dev, DDI_PROP_CANSLEEP,
1465 	    "no-involuntary-power-cycles", NULL, 0) != DDI_PROP_SUCCESS) {
1466 
1467 		ST_DEBUG(devp->sd_dev, st_label, SCSI_DEBUG,
1468 		    "ddi_prop_create(\"no-involuntary-power-cycles\") "
1469 		    "failed\n");
1470 		goto error;
1471 	}
1472 
1473 	ST_DEBUG6(devp->sd_dev, st_label, SCSI_DEBUG, "probe success\n");
1474 	return (DDI_SUCCESS);
1475 
1476 error:
1477 	devp->sd_sense = NULL;
1478 
1479 	ddi_remove_minor_node(devp->sd_dev, NULL);
1480 	if (un) {
1481 		if (un->un_mspl) {
1482 			i_ddi_mem_free((caddr_t)un->un_mspl, 0);
1483 		}
1484 		if (un->un_sbufp) {
1485 			freerbuf(un->un_sbufp);
1486 		}
1487 		if (un->un_uscsi_rqs_buf) {
1488 			kmem_free(un->un_uscsi_rqs_buf, SENSE_LENGTH);
1489 		}
1490 #if defined(__i386) || defined(__amd64)
1491 		if (un->un_contig_mem_hdl != NULL) {
1492 			ddi_dma_free_handle(&un->un_contig_mem_hdl);
1493 		}
1494 #endif
1495 		ddi_soft_state_free(st_state, instance);
1496 		devp->sd_private = NULL;
1497 	}
1498 
1499 	if (rqpkt) {
1500 		scsi_destroy_pkt(rqpkt);
1501 	}
1502 
1503 	if (bp) {
1504 		scsi_free_consistent_buf(bp);
1505 	}
1506 
1507 	if (devp->sd_inq) {
1508 		scsi_unprobe(devp);
1509 	}
1510 	return (DDI_FAILURE);
1511 }
1512 
1513 typedef int
1514 (*cfg_functp)(struct scsi_tape *, char *vidpid, struct st_drivetype *);
1515 
1516 static cfg_functp config_functs[] = {
1517 	st_get_conf_from_st_dot_conf,
1518 	st_get_conf_from_st_conf_dot_c,
1519 	st_get_default_conf
1520 };
1521 
1522 
1523 /*
1524  * determine tape type, using tape-config-list or built-in table or
1525  * use a generic tape config entry
1526  */
1527 static void
1528 st_known_tape_type(struct scsi_tape *un)
1529 {
1530 	struct st_drivetype *dp;
1531 	cfg_functp *config_funct;
1532 
1533 	/*
1534 	 * XXX:  Emulex MT-02 (and emulators) predates SCSI-1 and has
1535 	 *	 no vid & pid inquiry data.  So, we provide one.
1536 	 */
1537 	if (ST_INQUIRY->inq_len == 0 ||
1538 		(bcmp("\0\0\0\0\0\0\0\0", ST_INQUIRY->inq_vid, 8) == 0)) {
1539 		(void) strcpy((char *)ST_INQUIRY->inq_vid, ST_MT02_NAME);
1540 	}
1541 
1542 	un->un_dp_size = sizeof (struct st_drivetype);
1543 	dp = kmem_zalloc((size_t)un->un_dp_size, KM_SLEEP);
1544 	un->un_dp = dp;
1545 
1546 	/*
1547 	 * Loop through the configuration methods till one works.
1548 	 */
1549 	for (config_funct = &config_functs[0]; ; config_funct++) {
1550 		if ((*config_funct)(un, ST_INQUIRY->inq_vid, dp)) {
1551 			break;
1552 		}
1553 	}
1554 
1555 	/*
1556 	 * If we didn't just make up this configuration and
1557 	 * all the density codes are the same..
1558 	 * Set Auto Density over ride.
1559 	 */
1560 	if (*config_funct != st_get_default_conf) {
1561 		/*
1562 		 * If this device is one that is configured and all
1563 		 * densities are the same, This saves doing gets and set
1564 		 * that yield nothing.
1565 		 */
1566 		if ((dp->densities[0]) == (dp->densities[1]) &&
1567 		    (dp->densities[0]) == (dp->densities[2]) &&
1568 		    (dp->densities[0]) == (dp->densities[3])) {
1569 
1570 			dp->options |= ST_AUTODEN_OVERRIDE;
1571 		}
1572 	}
1573 
1574 
1575 	/*
1576 	 * Store tape drive characteristics.
1577 	 */
1578 	un->un_status = 0;
1579 	un->un_attached = 1;
1580 	un->un_init_options = dp->options;
1581 
1582 	/* setup operation time-outs based on options */
1583 	st_calculate_timeouts(un);
1584 
1585 	/* make sure if we are supposed to be variable, make it variable */
1586 	if (dp->options & ST_VARIABLE) {
1587 		dp->bsize = 0;
1588 	}
1589 
1590 	scsi_log(ST_DEVINFO, st_label, CE_NOTE, "?<%s>\n", dp->name);
1591 }
1592 
1593 
1594 typedef struct {
1595 	int mask;
1596 	int bottom;
1597 	int top;
1598 	char *name;
1599 } conf_limit;
1600 
1601 static const conf_limit conf_limits[] = {
1602 
1603 	-1,		1,		2,		"conf version",
1604 	-1,		MT_ISTS,	ST_LAST_TYPE,	"drive type",
1605 	-1,		0,		0xffffff,	"block size",
1606 	ST_VALID_OPTS,	0,		ST_VALID_OPTS,	"options",
1607 	-1,		0,		4,		"number of densities",
1608 	-1,		0,		UINT8_MAX,	"density code",
1609 	-1,		0,		3,		"default density",
1610 	-1,		0,		UINT16_MAX,	"non motion timeout",
1611 	-1,		0,		UINT16_MAX,	"I/O timeout",
1612 	-1,		0,		UINT16_MAX,	"space timeout",
1613 	-1,		0,		UINT16_MAX,	"load timeout",
1614 	-1,		0,		UINT16_MAX,	"unload timeout",
1615 	-1,		0,		UINT16_MAX,	"erase timeout",
1616 	0,		0,		0,		NULL
1617 };
1618 
1619 static int
1620 st_validate_conf_data(struct scsi_tape *un, int *list, int list_len,
1621     const char *conf_name)
1622 {
1623 	int dens;
1624 	int ndens;
1625 	int value;
1626 	int type;
1627 	int count;
1628 	const conf_limit *limit = &conf_limits[0];
1629 
1630 	ST_DEBUG3(ST_DEVINFO, st_label, CE_NOTE,
1631 	    "Checking %d entrys total with %d densities\n", list_len, list[4]);
1632 
1633 	count = list_len;
1634 	type = *list;
1635 	for (;  count && limit->name; count--, list++, limit++) {
1636 
1637 		value = *list;
1638 		if (value & ~limit->mask) {
1639 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1640 			    "%s %s value invalid bits set: 0x%X\n",
1641 			    conf_name, limit->name, value & ~limit->mask);
1642 			*list &= limit->mask;
1643 		} else if (value < limit->bottom) {
1644 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1645 			    "%s %s value too low: value = %d limit %d\n",
1646 			    conf_name, limit->name, value, limit->bottom);
1647 		} else if (value > limit->top) {
1648 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1649 			    "%s %s value too high: value = %d limit %d\n",
1650 			    conf_name, limit->name, value, limit->top);
1651 		} else {
1652 			ST_DEBUG3(ST_DEVINFO, st_label, CE_CONT,
1653 			    "%s %s value = 0x%X\n",
1654 			    conf_name, limit->name, value);
1655 		}
1656 
1657 		/* If not the number of densities continue */
1658 		if (limit != &conf_limits[4]) {
1659 			continue;
1660 		}
1661 
1662 		/* If number of densities is not in range can't use config */
1663 		if (value < limit->bottom || value > limit->top) {
1664 			return (-1);
1665 		}
1666 
1667 		ndens = min(value, NDENSITIES);
1668 		if ((type == 1) && (list_len - ndens) != 6) {
1669 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1670 			    "%s conf version 1 with %d densities has %d items"
1671 			    " should have %d",
1672 			    conf_name, ndens, list_len, 6 + ndens);
1673 		} else if ((type == 2) && (list_len - ndens) != 13) {
1674 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1675 			    "%s conf version 2 with %d densities has %d items"
1676 			    " should have %d",
1677 			    conf_name, ndens, list_len, 13 + ndens);
1678 		}
1679 
1680 		limit++;
1681 		for (dens = 0; dens < ndens && count; dens++) {
1682 			count--;
1683 			list++;
1684 			value = *list;
1685 			if (value < limit->bottom) {
1686 				scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1687 				    "%s density[%d] value too low: value ="
1688 				    " 0x%X limit 0x%X\n",
1689 				    conf_name, dens, value, limit->bottom);
1690 			} else if (value > limit->top) {
1691 				scsi_log(ST_DEVINFO, st_label, CE_NOTE,
1692 				    "%s density[%d] value too high: value ="
1693 				    " 0x%X limit 0x%X\n",
1694 				    conf_name, dens, value, limit->top);
1695 			} else {
1696 				ST_DEBUG3(ST_DEVINFO, st_label, CE_CONT,
1697 				    "%s density[%d] value = 0x%X\n",
1698 				    conf_name, dens, value);
1699 			}
1700 		}
1701 	}
1702 
1703 	return (0);
1704 }
1705 
1706 static int
1707 st_get_conf_from_st_dot_conf(struct scsi_tape *un, char *vidpid,
1708     struct st_drivetype *dp)
1709 {
1710 	caddr_t config_list = NULL;
1711 	caddr_t data_list = NULL;
1712 	int	*data_ptr;
1713 	caddr_t vidptr, prettyptr, datanameptr;
1714 	size_t	vidlen, prettylen, datanamelen, tripletlen = 0;
1715 	int config_list_len, data_list_len, len, i;
1716 	int version;
1717 	int found = 0;
1718 
1719 
1720 	/*
1721 	 * Determine type of tape controller. Type is determined by
1722 	 * checking the vendor ids of the earlier inquiry command and
1723 	 * comparing those with vids in tape-config-list defined in st.conf
1724 	 */
1725 	if (ddi_getlongprop(DDI_DEV_T_ANY, ST_DEVINFO, DDI_PROP_DONTPASS,
1726 	    "tape-config-list", (caddr_t)&config_list, &config_list_len)
1727 	    != DDI_PROP_SUCCESS) {
1728 		return (found);
1729 	}
1730 
1731 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
1732 	    "st_get_conf_from_st_dot_conf(): st.conf has tape-config-list\n");
1733 
1734 	/*
1735 	 * Compare vids in each triplet - if it matches, get value for
1736 	 * data_name and contruct a st_drivetype struct
1737 	 * tripletlen is not set yet!
1738 	 */
1739 	for (len = config_list_len, vidptr = config_list;
1740 	    len > 0;
1741 	    vidptr += tripletlen, len -= tripletlen) {
1742 
1743 		vidlen = strlen(vidptr);
1744 		prettyptr = vidptr + vidlen + 1;
1745 		prettylen = strlen(prettyptr);
1746 		datanameptr = prettyptr + prettylen + 1;
1747 		datanamelen = strlen(datanameptr);
1748 		tripletlen = vidlen + prettylen + datanamelen + 3;
1749 
1750 		if (vidlen == 0) {
1751 			continue;
1752 		}
1753 
1754 		/*
1755 		 * If inquiry vid dosen't match this triplets vid,
1756 		 * try the next.
1757 		 */
1758 		if (strncasecmp(vidpid, vidptr, vidlen)) {
1759 			continue;
1760 		}
1761 
1762 		/*
1763 		 * if prettylen is zero then use the vid string
1764 		 */
1765 		if (prettylen == 0) {
1766 			prettyptr = vidptr;
1767 			prettylen = vidlen;
1768 		}
1769 
1770 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
1771 		    "vid = %s, pretty=%s, dataname = %s\n",
1772 		    vidptr, prettyptr, datanameptr);
1773 
1774 		/*
1775 		 * get the data list
1776 		 */
1777 		if (ddi_getlongprop(DDI_DEV_T_ANY, ST_DEVINFO, 0,
1778 		    datanameptr, (caddr_t)&data_list,
1779 		    &data_list_len) != DDI_PROP_SUCCESS) {
1780 			/*
1781 			 * Error in getting property value
1782 			 * print warning!
1783 			 */
1784 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
1785 			    "data property (%s) has no value\n",
1786 			    datanameptr);
1787 			continue;
1788 		}
1789 
1790 		/*
1791 		 * now initialize the st_drivetype struct
1792 		 */
1793 		(void) strncpy(dp->name, prettyptr, ST_NAMESIZE - 1);
1794 		dp->length = (int)min(vidlen, (VIDPIDLEN - 1));
1795 		(void) strncpy(dp->vid, vidptr, dp->length);
1796 		data_ptr = (int *)data_list;
1797 		/*
1798 		 * check if data is enough for version, type,
1799 		 * bsize, options, # of densities, density1,
1800 		 * density2, ..., default_density
1801 		 */
1802 		if ((data_list_len < 5 * sizeof (int)) ||
1803 		    (data_list_len < 6 * sizeof (int) +
1804 		    *(data_ptr + 4) * sizeof (int))) {
1805 			/*
1806 			 * print warning and skip to next triplet.
1807 			 */
1808 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
1809 			    "data property (%s) incomplete\n",
1810 			    datanameptr);
1811 			kmem_free(data_list, data_list_len);
1812 			continue;
1813 		}
1814 
1815 		if (st_validate_conf_data(un, data_ptr,
1816 		    data_list_len / sizeof (int), datanameptr)) {
1817 			kmem_free(data_list, data_list_len);
1818 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
1819 			    "data property (%s) rejected\n",
1820 			    datanameptr);
1821 			continue;
1822 		}
1823 
1824 		/*
1825 		 * check version
1826 		 */
1827 		version = *data_ptr++;
1828 		if (version != 1 && version != 2) {
1829 			/* print warning but accept it */
1830 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
1831 			    "Version # for data property (%s) "
1832 			    "not set to 1 or 2\n", datanameptr);
1833 		}
1834 
1835 		dp->type    = *data_ptr++;
1836 		dp->bsize   = *data_ptr++;
1837 		dp->options = *data_ptr++;
1838 		dp->options |= ST_DYNAMIC;
1839 		len = *data_ptr++;
1840 		for (i = 0; i < NDENSITIES; i++) {
1841 			if (i < len) {
1842 				dp->densities[i] = *data_ptr++;
1843 			}
1844 		}
1845 		dp->default_density = *data_ptr << 3;
1846 		if (version == 2 &&
1847 		    data_list_len >= (13 + len) * sizeof (int)) {
1848 			data_ptr++;
1849 			dp->non_motion_timeout	= *data_ptr++;
1850 			dp->io_timeout		= *data_ptr++;
1851 			dp->rewind_timeout	= *data_ptr++;
1852 			dp->space_timeout	= *data_ptr++;
1853 			dp->load_timeout	= *data_ptr++;
1854 			dp->unload_timeout	= *data_ptr++;
1855 			dp->erase_timeout	= *data_ptr++;
1856 		}
1857 		kmem_free(data_list, data_list_len);
1858 		found = 1;
1859 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
1860 		    "found in st.conf: vid = %s, pretty=%s\n",
1861 		    dp->vid, dp->name);
1862 		break;
1863 	}
1864 
1865 	/*
1866 	 * free up the memory allocated by ddi_getlongprop
1867 	 */
1868 	if (config_list) {
1869 		kmem_free(config_list, config_list_len);
1870 	}
1871 	return (found);
1872 }
1873 
1874 static int
1875 st_get_conf_from_st_conf_dot_c(struct scsi_tape *un, char *vidpid,
1876     struct st_drivetype *dp)
1877 {
1878 	int i;
1879 
1880 	/*
1881 	 * Determine type of tape controller.  Type is determined by
1882 	 * checking the result of the earlier inquiry command and
1883 	 * comparing vendor ids with strings in a table declared in st_conf.c.
1884 	 */
1885 	ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
1886 	    "st_get_conf_from_st_conf_dot_c(): looking at st_drivetypes\n");
1887 
1888 	for (i = 0; i < st_ndrivetypes; i++) {
1889 		if (st_drivetypes[i].length == 0) {
1890 			continue;
1891 		}
1892 		if (strncasecmp(vidpid, st_drivetypes[i].vid,
1893 		    st_drivetypes[i].length)) {
1894 			continue;
1895 		}
1896 		bcopy(&st_drivetypes[i], dp, sizeof (st_drivetypes[i]));
1897 		return (1);
1898 	}
1899 	return (0);
1900 }
1901 
1902 static int
1903 st_get_default_conf(struct scsi_tape *un, char *vidpid, struct st_drivetype *dp)
1904 {
1905 	int i;
1906 
1907 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
1908 	    "st_get_default_conf(): making drivetype from INQ cmd\n");
1909 
1910 
1911 	/*
1912 	 * Make up a name
1913 	 */
1914 	bcopy("Vendor '", dp->name, 8);
1915 	bcopy(vidpid, &dp->name[8], VIDLEN);
1916 	bcopy("' Product '", &dp->name[16], 11);
1917 	bcopy(&vidpid[8], &dp->name[27], PIDLEN);
1918 	dp->name[ST_NAMESIZE - 2] = '\'';
1919 	dp->name[ST_NAMESIZE - 1] = '\0';
1920 	dp->length = min(strlen(ST_INQUIRY->inq_vid), (VIDPIDLEN - 1));
1921 	(void) strncpy(dp->vid, ST_INQUIRY->inq_vid, dp->length);
1922 	/*
1923 	 * 'clean' vendor and product strings of non-printing chars
1924 	 */
1925 	for (i = 0; i < ST_NAMESIZE - 2; i++) {
1926 		if (dp->name[i] < ' ' || dp->name[i] > '~') {
1927 			dp->name[i] = '.';
1928 		}
1929 	}
1930 	dp->type = ST_TYPE_INVALID;
1931 	dp->options |= (ST_DYNAMIC | ST_UNLOADABLE | ST_MODE_SEL_COMP);
1932 
1933 	return (1); /* Can Not Fail */
1934 }
1935 
1936 /*
1937  * Regular Unix Entry points
1938  */
1939 
1940 
1941 
1942 /* ARGSUSED */
1943 static int
1944 st_open(dev_t *dev_p, int flag, int otyp, cred_t *cred_p)
1945 {
1946 	dev_t dev = *dev_p;
1947 	int rval = 0;
1948 
1949 	GET_SOFT_STATE(dev);
1950 
1951 	/*
1952 	 * validate that we are addressing a sensible unit
1953 	 */
1954 	mutex_enter(ST_MUTEX);
1955 
1956 #ifdef	STDEBUG
1957 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
1958 	    "st_open(node = %s dev = 0x%lx, flag = %d, otyp = %d)\n",
1959 	    st_dev_name(dev), *dev_p, flag, otyp);
1960 #endif
1961 
1962 	/*
1963 	 * All device accesss go thru st_strategy() where we check
1964 	 * suspend status
1965 	 */
1966 
1967 	if (!un->un_attached) {
1968 		st_known_tape_type(un);
1969 		if (!un->un_attached) {
1970 			rval = ENXIO;
1971 			goto exit;
1972 		}
1973 
1974 	}
1975 
1976 	/*
1977 	 * Check for the case of the tape in the middle of closing.
1978 	 * This isn't simply a check of the current state, because
1979 	 * we could be in state of sensing with the previous state
1980 	 * that of closing.
1981 	 *
1982 	 * And don't allow multiple opens.
1983 	 */
1984 	if (!(flag & (FNDELAY | FNONBLOCK)) && IS_CLOSING(un)) {
1985 		un->un_laststate = un->un_state;
1986 		un->un_state = ST_STATE_CLOSE_PENDING_OPEN;
1987 		while (IS_CLOSING(un) ||
1988 		    un->un_state == ST_STATE_CLOSE_PENDING_OPEN) {
1989 			if (cv_wait_sig(&un->un_clscv, ST_MUTEX) == 0) {
1990 				rval = EINTR;
1991 				un->un_state = un->un_laststate;
1992 				goto exit;
1993 			}
1994 		}
1995 	} else if (un->un_state != ST_STATE_CLOSED) {
1996 		rval = EBUSY;
1997 		goto busy;
1998 	}
1999 
2000 	/*
2001 	 * record current dev
2002 	 */
2003 	un->un_dev = dev;
2004 	un->un_oflags = flag;	/* save for use in st_tape_init() */
2005 	un->un_errno = 0;	/* no errors yet */
2006 	un->un_restore_pos = 0;
2007 	un->un_rqs_state = 0;
2008 
2009 	/*
2010 	 * If we are opening O_NDELAY, or O_NONBLOCK, we don't check for
2011 	 * anything, leave internal states alone, if fileno >= 0
2012 	 */
2013 	if (flag & (FNDELAY | FNONBLOCK)) {
2014 		if (un->un_fileno < 0 || (un->un_fileno == 0 &&
2015 			un->un_blkno == 0)) {
2016 			un->un_state = ST_STATE_OFFLINE;
2017 		} else {
2018 			/*
2019 			 * set un_read_only/write-protect status.
2020 			 *
2021 			 * If the tape is not bot we can assume
2022 			 * that mspl->wp_status is set properly.
2023 			 * else
2024 			 * we need to do a mode sense/Tur once
2025 			 * again to get the actual tape status.(since
2026 			 * user might have replaced the tape)
2027 			 * Hence make the st state OFFLINE so that
2028 			 * we re-intialize the tape once again.
2029 			 */
2030 			if (un->un_fileno > 0 ||
2031 			    (un->un_fileno == 0 && un->un_blkno != 0)) {
2032 				un->un_read_only =
2033 				    (un->un_oflags & FWRITE) ? 0 : 1;
2034 				un->un_state = ST_STATE_OPEN_PENDING_IO;
2035 			} else {
2036 				un->un_state = ST_STATE_OFFLINE;
2037 			}
2038 		}
2039 		rval = 0;
2040 	} else {
2041 		/*
2042 		 * If reserve/release is supported on this drive.
2043 		 * then call st_tape_reservation_init().
2044 		 */
2045 		un->un_state = ST_STATE_OPENING;
2046 
2047 		if (ST_RESERVE_SUPPORTED(un)) {
2048 			rval = st_tape_reservation_init(dev);
2049 			if (rval) {
2050 				goto exit;
2051 			}
2052 		}
2053 		rval = st_tape_init(dev);
2054 		if (rval) {
2055 			/*
2056 			 * Release the tape unit, if no preserve reserve
2057 			 */
2058 			if ((ST_RESERVE_SUPPORTED(un)) &&
2059 			    !(un->un_rsvd_status & ST_PRESERVE_RESERVE)) {
2060 				(void) st_reserve_release(dev, ST_RELEASE);
2061 			}
2062 		} else {
2063 			un->un_state = ST_STATE_OPEN_PENDING_IO;
2064 		}
2065 	}
2066 
2067 exit:
2068 	/*
2069 	 * we don't want any uninvited guests scrogging our data when we're
2070 	 * busy with something, so for successful opens or failed opens
2071 	 * (except for EBUSY), reset these counters and state appropriately.
2072 	 */
2073 	if (rval != EBUSY) {
2074 		if (rval) {
2075 			un->un_state = ST_STATE_CLOSED;
2076 		}
2077 		un->un_err_resid = 0;
2078 		un->un_retry_ct = 0;
2079 		un->un_tran_retry_ct = 0;
2080 	}
2081 busy:
2082 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
2083 	    "st_open: return val = %x, state = %d\n", rval, un->un_state);
2084 	mutex_exit(ST_MUTEX);
2085 	return (rval);
2086 
2087 }
2088 
2089 #define	ST_LOST_RESERVE_BETWEEN_OPENS  \
2090 		(ST_RESERVE | ST_LOST_RESERVE | ST_PRESERVE_RESERVE)
2091 
2092 int
2093 st_tape_reservation_init(dev_t dev)
2094 {
2095 	int rval = 0;
2096 
2097 	GET_SOFT_STATE(dev);
2098 
2099 	ASSERT(mutex_owned(ST_MUTEX));
2100 
2101 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
2102 	    "st_tape_reservation_init(dev = 0x%lx)\n", dev);
2103 
2104 	/*
2105 	 * Issue a Throw-Away reserve command to clear the
2106 	 * check condition.
2107 	 * If the current behaviour of reserve/release is to
2108 	 * hold reservation across opens , and if a Bus reset
2109 	 * has been issued between opens then this command
2110 	 * would set the ST_LOST_RESERVE flags in rsvd_status.
2111 	 * In this case return an EACCES so that user knows that
2112 	 * reservation has been lost in between opens.
2113 	 * If this error is not returned and we continue with
2114 	 * successful open , then user may think position of the
2115 	 * tape is still the same but inreality we would rewind the
2116 	 * tape and continue from BOT.
2117 	 */
2118 	rval = st_reserve_release(dev, ST_RESERVE);
2119 
2120 	if (rval) {
2121 		if ((un->un_rsvd_status & ST_LOST_RESERVE_BETWEEN_OPENS) ==
2122 			ST_LOST_RESERVE_BETWEEN_OPENS) {
2123 				un->un_rsvd_status &=
2124 					~(ST_LOST_RESERVE | ST_RESERVE);
2125 				un->un_errno = EACCES;
2126 				return (EACCES);
2127 		}
2128 		rval = st_reserve_release(dev, ST_RESERVE);
2129 	}
2130 	if (rval == 0)
2131 		un->un_rsvd_status |= ST_INIT_RESERVE;
2132 
2133 	return (rval);
2134 }
2135 
2136 static int
2137 st_tape_init(dev_t dev)
2138 {
2139 	int err;
2140 	int rval = 0;
2141 
2142 	GET_SOFT_STATE(dev);
2143 
2144 	ASSERT(mutex_owned(ST_MUTEX));
2145 
2146 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
2147 	    "st_tape_init(dev = 0x%lx, oflags = %d)\n", dev, un->un_oflags);
2148 
2149 	/*
2150 	 * Clean up after any errors left by 'last' close.
2151 	 * This also handles the case of the initial open.
2152 	 */
2153 	if (un->un_state != ST_STATE_INITIALIZING) {
2154 		un->un_laststate = un->un_state;
2155 		un->un_state = ST_STATE_OPENING;
2156 	}
2157 
2158 	un->un_kbytes_xferred = 0;
2159 
2160 	/*
2161 	 * do a throw away TUR to clear check condition
2162 	 */
2163 	err = st_cmd(dev, SCMD_TEST_UNIT_READY, 0, SYNC_CMD);
2164 
2165 	/*
2166 	 * If test unit ready fails because the drive is reserved
2167 	 * by another host fail the open for no access.
2168 	 */
2169 	if (err) {
2170 		if (un->un_rsvd_status & ST_RESERVATION_CONFLICT) {
2171 			un->un_state = ST_STATE_CLOSED;
2172 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
2173 				"st_tape_init: RESERVATION CONFLICT\n");
2174 			rval = EACCES;
2175 			goto exit;
2176 		}
2177 	}
2178 
2179 	/*
2180 	 * See whether this is a generic device that we haven't figured
2181 	 * anything out about yet.
2182 	 */
2183 	if (un->un_dp->type == ST_TYPE_INVALID) {
2184 		if (st_determine_generic(dev)) {
2185 			un->un_state = ST_STATE_CLOSED;
2186 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2187 			    "st_open: EIO invalid type\n");
2188 			rval = EIO;
2189 			goto exit;
2190 		}
2191 		/*
2192 		 * If this is a Unknown Type drive,
2193 		 * Use the READ BLOCK LIMITS to determine if
2194 		 * allow large xfer is approprate if not globally
2195 		 * disabled with st_allow_large_xfer.
2196 		 */
2197 		un->un_allow_large_xfer = (uchar_t)st_allow_large_xfer;
2198 	} else {
2199 
2200 		/*
2201 		 * If we allow_large_xfer (ie >64k) and have not yet found out
2202 		 * the max block size supported by the drive,
2203 		 * find it by issueing a READ_BLKLIM command.
2204 		 * if READ_BLKLIM cmd fails, assume drive doesn't
2205 		 * allow_large_xfer and min/max block sizes as 1 byte and 63k.
2206 		 */
2207 		un->un_allow_large_xfer = st_allow_large_xfer &&
2208 		    (un->un_dp->options & ST_NO_RECSIZE_LIMIT);
2209 	}
2210 	/*
2211 	 * if maxbsize is unknown, set the maximum block size.
2212 	 */
2213 	if (un->un_maxbsize == MAXBSIZE_UNKNOWN) {
2214 
2215 		/*
2216 		 * Get the Block limits of the tape drive.
2217 		 * if un->un_allow_large_xfer = 0 , then make sure
2218 		 * that maxbsize is <= ST_MAXRECSIZE_FIXED.
2219 		 */
2220 		un->un_rbl = kmem_zalloc(RBLSIZE, KM_SLEEP);
2221 
2222 		err = st_cmd(dev, SCMD_READ_BLKLIM, RBLSIZE, SYNC_CMD);
2223 		if (err) {
2224 			/* Retry */
2225 			err = st_cmd(dev, SCMD_READ_BLKLIM, RBLSIZE, SYNC_CMD);
2226 		}
2227 		if (!err) {
2228 
2229 			/*
2230 			 * if cmd successful, use limit returned
2231 			 */
2232 			un->un_maxbsize = (un->un_rbl->max_hi << 16) +
2233 					(un->un_rbl->max_mid << 8) +
2234 					un->un_rbl->max_lo;
2235 			un->un_minbsize = (un->un_rbl->min_hi << 8) +
2236 					un->un_rbl->min_lo;
2237 			un->un_data_mod = 1 << un->un_rbl->granularity;
2238 			if ((un->un_maxbsize == 0) ||
2239 			    (un->un_allow_large_xfer == 0 &&
2240 			    un->un_maxbsize > ST_MAXRECSIZE_FIXED)) {
2241 				un->un_maxbsize = ST_MAXRECSIZE_FIXED;
2242 
2243 			} else if (un->un_dp->type == ST_TYPE_DEFAULT) {
2244 				/*
2245 				 * Drive is not one that is configured, But the
2246 				 * READ BLOCK LIMITS tells us it can do large
2247 				 * xfers.
2248 				 */
2249 				if (un->un_maxbsize > ST_MAXRECSIZE_FIXED) {
2250 					un->un_dp->options |=
2251 					    ST_NO_RECSIZE_LIMIT;
2252 				}
2253 				/*
2254 				 * If max and mimimum block limits are the
2255 				 * same this is a fixed block size device.
2256 				 */
2257 				if (un->un_maxbsize == un->un_minbsize) {
2258 					un->un_dp->options &= ~ST_VARIABLE;
2259 				}
2260 			}
2261 
2262 			if (un->un_minbsize == 0) {
2263 				un->un_minbsize = 1;
2264 			}
2265 
2266 		} else { /* error on read block limits */
2267 
2268 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
2269 				"!st_tape_init: Error on READ BLOCK LIMITS,"
2270 				" errno = %d un_rsvd_status = 0x%X\n",
2271 				err, un->un_rsvd_status);
2272 
2273 			/*
2274 			 * since read block limits cmd failed,
2275 			 * do not allow large xfers.
2276 			 * use old values in st_minphys
2277 			 */
2278 			if (un->un_rsvd_status & ST_RESERVATION_CONFLICT) {
2279 				rval = EACCES;
2280 			} else {
2281 				un->un_allow_large_xfer = 0;
2282 				scsi_log(ST_DEVINFO, st_label, CE_NOTE,
2283 					"!Disabling large transfers\n");
2284 
2285 				/*
2286 				 * we guess maxbsize and minbsize
2287 				 */
2288 				if (un->un_bsize) {
2289 					un->un_maxbsize = un->un_minbsize =
2290 						un->un_bsize;
2291 				} else {
2292 					un->un_maxbsize = ST_MAXRECSIZE_FIXED;
2293 					un->un_minbsize = 1;
2294 				}
2295 				/*
2296 				 * Data Mod must be set,
2297 				 * Even if read block limits fails.
2298 				 * Prevents Divide By Zero in st_rw().
2299 				 */
2300 				un->un_data_mod = 1;
2301 			}
2302 		}
2303 		if (un->un_rbl) {
2304 			kmem_free(un->un_rbl, RBLSIZE);
2305 			un->un_rbl = NULL;
2306 		}
2307 
2308 		if (rval) {
2309 			goto exit;
2310 		}
2311 	}
2312 
2313 	ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
2314 	    "maxdma = %d, maxbsize = %d, minbsize = %d, %s large xfer\n",
2315 	    un->un_maxdma, un->un_maxbsize, un->un_minbsize,
2316 	    (un->un_allow_large_xfer ? "ALLOW": "DON'T ALLOW"));
2317 
2318 	err = st_cmd(dev, SCMD_TEST_UNIT_READY, 0, SYNC_CMD);
2319 
2320 	if (err != 0) {
2321 		if (err == EINTR) {
2322 			un->un_laststate = un->un_state;
2323 			un->un_state = ST_STATE_CLOSED;
2324 			rval = EINTR;
2325 			goto exit;
2326 		}
2327 		/*
2328 		 * Make sure the tape is ready
2329 		 */
2330 		un->un_fileno = -1;
2331 		if (un->un_status != KEY_UNIT_ATTENTION) {
2332 			/*
2333 			 * allow open no media.  Subsequent MTIOCSTATE
2334 			 * with media present will complete the open
2335 			 * logic.
2336 			 */
2337 			un->un_laststate = un->un_state;
2338 			if (un->un_oflags & (FNONBLOCK|FNDELAY)) {
2339 				un->un_mediastate = MTIO_EJECTED;
2340 				un->un_state = ST_STATE_OFFLINE;
2341 				rval = 0;
2342 				goto exit;
2343 			} else {
2344 				un->un_state = ST_STATE_CLOSED;
2345 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2346 		    "st_open EIO no media, not opened O_NONBLOCK|O_EXCL\n");
2347 				rval = EIO;
2348 				goto exit;
2349 			}
2350 		}
2351 	}
2352 
2353 	/*
2354 	 * On each open, initialize block size from drivetype struct,
2355 	 * as it could have been changed by MTSRSZ ioctl.
2356 	 * Now, ST_VARIABLE simply means drive is capable of variable
2357 	 * mode. All drives are assumed to support fixed records.
2358 	 * Hence, un_bsize tells what mode the drive is in.
2359 	 *	un_bsize	= 0	- variable record length
2360 	 *			= x	- fixed record length is x
2361 	 */
2362 	un->un_bsize = un->un_dp->bsize;
2363 
2364 	if (un->un_restore_pos) {
2365 		if (st_validate_tapemarks(un, un->un_save_fileno,
2366 		    un->un_save_blkno) != 0) {
2367 			un->un_restore_pos = 0;
2368 			un->un_laststate = un->un_state;
2369 			un->un_state = ST_STATE_CLOSED;
2370 			rval = EIO;
2371 			goto exit;
2372 		}
2373 		un->un_restore_pos = 0;
2374 	}
2375 
2376 	if ((un->un_fileno < 0) && st_loadtape(dev)) {
2377 		un->un_laststate = un->un_state;
2378 		un->un_state = ST_STATE_CLOSED;
2379 		ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2380 		    "st_open : EIO can't open tape\n");
2381 		rval = EIO;
2382 		goto exit;
2383 	}
2384 
2385 	/*
2386 	 * do a mode sense to pick up state of current write-protect,
2387 	 */
2388 	(void) st_modesense(un);
2389 
2390 	/*
2391 	 * If we are opening the tape for writing, check
2392 	 * to make sure that the tape can be written.
2393 	 */
2394 	if (un->un_oflags & FWRITE) {
2395 		err = 0;
2396 		if (un->un_mspl->wp)  {
2397 			un->un_status = KEY_WRITE_PROTECT;
2398 			un->un_laststate = un->un_state;
2399 			un->un_state = ST_STATE_CLOSED;
2400 			rval = EACCES;
2401 			goto exit;
2402 		} else {
2403 			un->un_read_only = 0;
2404 		}
2405 	} else {
2406 		un->un_read_only = 1;
2407 	}
2408 
2409 	/*
2410 	 * If we're opening the tape write-only, we need to
2411 	 * write 2 filemarks on the HP 1/2 inch drive, to
2412 	 * create a null file.
2413 	 */
2414 	if ((un->un_oflags == FWRITE) && (un->un_dp->options & ST_REEL)) {
2415 		un->un_fmneeded = 2;
2416 	} else if (un->un_oflags == FWRITE) {
2417 		un->un_fmneeded = 1;
2418 	} else {
2419 		un->un_fmneeded = 0;
2420 	}
2421 
2422 	ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
2423 	    "fmneeded = %x\n", un->un_fmneeded);
2424 
2425 	/*
2426 	 * Make sure the density can be selected correctly.
2427 	 */
2428 	if (st_determine_density(dev, B_WRITE)) {
2429 		un->un_status = KEY_ILLEGAL_REQUEST;
2430 		un->un_laststate = un->un_state;
2431 		un->un_state = ST_STATE_CLOSED;
2432 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
2433 		    "st_open: EIO can't determine density\n");
2434 		rval = EIO;
2435 		goto exit;
2436 	}
2437 
2438 	/*
2439 	 * Destroy the knowledge that we have 'determined'
2440 	 * density so that a later read at BOT comes along
2441 	 * does the right density determination.
2442 	 */
2443 
2444 	un->un_density_known = 0;
2445 
2446 
2447 	/*
2448 	 * Okay, the tape is loaded and either at BOT or somewhere past.
2449 	 * Mark the state such that any I/O or tape space operations
2450 	 * will get/set the right density, etc..
2451 	 */
2452 	un->un_laststate = un->un_state;
2453 	un->un_lastop = ST_OP_NIL;
2454 	un->un_mediastate = MTIO_INSERTED;
2455 	cv_broadcast(&un->un_state_cv);
2456 
2457 	/*
2458 	 *  Set test append flag if writing.
2459 	 *  First write must check that tape is positioned correctly.
2460 	 */
2461 	un->un_test_append = (un->un_oflags & FWRITE);
2462 
2463 exit:
2464 	un->un_err_resid = 0;
2465 	un->un_last_resid = 0;
2466 	un->un_last_count = 0;
2467 
2468 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
2469 	    "st_tape_init: return val = %x\n", rval);
2470 	return (rval);
2471 
2472 }
2473 
2474 
2475 
2476 /* ARGSUSED */
2477 static int
2478 st_close(dev_t dev, int flag, int otyp, cred_t *cred_p)
2479 {
2480 	int err = 0;
2481 	int norew, count, last_state;
2482 #if defined(__i386) || defined(__amd64)
2483 	struct contig_mem *cp, *cp_temp;
2484 #endif
2485 
2486 	GET_SOFT_STATE(dev);
2487 
2488 	/*
2489 	 * wait till all cmds in the pipeline have been completed
2490 	 */
2491 	mutex_enter(ST_MUTEX);
2492 
2493 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
2494 	    "st_close(dev = 0x%lx, flag = %d, otyp = %d)\n", dev, flag, otyp);
2495 
2496 	st_wait_for_io(un);
2497 
2498 	/* turn off persistent errors on close, as we want close to succeed */
2499 	TURN_PE_OFF(un);
2500 
2501 	/*
2502 	 * set state to indicate that we are in process of closing
2503 	 */
2504 	last_state = un->un_laststate = un->un_state;
2505 	un->un_state = ST_STATE_CLOSING;
2506 
2507 	/*
2508 	 * BSD behavior:
2509 	 * a close always causes a silent span to the next file if we've hit
2510 	 * an EOF (but not yet read across it).
2511 	 */
2512 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
2513 	    "st_close1: fileno=%x, blkno=%lx, un_eof=%x\n", un->un_fileno,
2514 	    un->un_blkno, un->un_eof);
2515 
2516 
2517 	if (BSD_BEHAVIOR && (un->un_eof == ST_EOF)) {
2518 		if (un->un_fileno >= 0) {
2519 			un->un_fileno++;
2520 			un->un_blkno = 0;
2521 		}
2522 		un->un_eof = ST_NO_EOF;
2523 	}
2524 
2525 	/*
2526 	 * rewinding?
2527 	 */
2528 	norew = (getminor(dev) & MT_NOREWIND);
2529 
2530 	/*
2531 	 * SVR4 behavior for skipping to next file:
2532 	 *
2533 	 * If we have not seen a filemark, space to the next file
2534 	 *
2535 	 * If we have already seen the filemark we are physically in the next
2536 	 * file and we only increment the filenumber
2537 	 */
2538 
2539 	if (norew && SVR4_BEHAVIOR && (flag & FREAD) && (un->un_blkno != 0) &&
2540 	    (un->un_lastop != ST_OP_WRITE)) {
2541 		switch (un->un_eof) {
2542 		case ST_NO_EOF:
2543 			/*
2544 			 * if we were reading and did not read the complete file
2545 			 * skip to the next file, leaving the tape correctly
2546 			 * positioned to read the first record of the next file
2547 			 * Check first for REEL if we are at EOT by trying to
2548 			 * read a block
2549 			 */
2550 			if ((un->un_dp->options & ST_REEL) &&
2551 				(!(un->un_dp->options & ST_READ_IGNORE_EOFS)) &&
2552 			    (un->un_blkno == 0)) {
2553 				if (st_cmd(dev, SCMD_SPACE, Blk(1), SYNC_CMD)) {
2554 					ST_DEBUG2(ST_DEVINFO, st_label,
2555 					    SCSI_DEBUG,
2556 					    "st_close : EIO can't space\n");
2557 					err = EIO;
2558 					break;
2559 				}
2560 				if (un->un_eof >= ST_EOF_PENDING) {
2561 					un->un_eof = ST_EOT_PENDING;
2562 					un->un_fileno += 1;
2563 					un->un_blkno   = 0;
2564 					break;
2565 				}
2566 			}
2567 			if (st_cmd(dev, SCMD_SPACE, Fmk(1), SYNC_CMD)) {
2568 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2569 				    "st_close: EIO can't space #2\n");
2570 				err = EIO;
2571 			} else {
2572 				ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
2573 				    "st_close2: fileno=%x,blkno=%lx,"
2574 				    "un_eof=%x\n",
2575 				    un->un_fileno, un->un_blkno, un->un_eof);
2576 				un->un_eof = ST_NO_EOF;
2577 			}
2578 			break;
2579 
2580 		case ST_EOF_PENDING:
2581 		case ST_EOF:
2582 			un->un_fileno += 1;
2583 			un->un_blkno   = 0;
2584 			un->un_eof = ST_NO_EOF;
2585 			break;
2586 
2587 		case ST_EOT:
2588 		case ST_EOT_PENDING:
2589 			/* nothing to do */
2590 			break;
2591 		}
2592 	}
2593 
2594 
2595 	/*
2596 	 * For performance reasons (HP 88780), the driver should
2597 	 * postpone writing the second tape mark until just before a file
2598 	 * positioning ioctl is issued (e.g., rewind).	This means that
2599 	 * the user must not manually rewind the tape because the tape will
2600 	 * be missing the second tape mark which marks EOM.
2601 	 * However, this small performance improvement is not worth the risk.
2602 	 */
2603 
2604 	/*
2605 	 * We need to back up over the filemark we inadvertently popped
2606 	 * over doing a read in between the two filemarks that constitute
2607 	 * logical eot for 1/2" tapes. Note that ST_EOT_PENDING is only
2608 	 * set while reading.
2609 	 *
2610 	 * If we happen to be at physical eot (ST_EOM) (writing case),
2611 	 * the writing of filemark(s) will clear the ST_EOM state, which
2612 	 * we don't want, so we save this state and restore it later.
2613 	 */
2614 
2615 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
2616 	    "flag=%x, fmneeded=%x, lastop=%x, eof=%x\n",
2617 		flag, un->un_fmneeded, un->un_lastop, un->un_eof);
2618 
2619 	if (un->un_eof == ST_EOT_PENDING) {
2620 		if (norew) {
2621 			if (st_cmd(dev, SCMD_SPACE, Fmk((-1)), SYNC_CMD)) {
2622 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2623 				    "st_close: EIO can't space #3\n");
2624 				err = EIO;
2625 			} else {
2626 				un->un_blkno = 0;
2627 				un->un_eof = ST_EOT;
2628 			}
2629 		} else {
2630 			un->un_eof = ST_NO_EOF;
2631 		}
2632 
2633 	/*
2634 	 * Do we need to write a file mark?
2635 	 *
2636 	 * only write filemarks if there are fmks to be written and
2637 	 *   - open for write (possibly read/write)
2638 	 *   - the last operation was a write
2639 	 * or:
2640 	 *   -	opened for wronly
2641 	 *   -	no data was written
2642 	 */
2643 	} else if ((un->un_fileno >= 0) && (un->un_fmneeded > 0) &&
2644 	    (((flag & FWRITE) && (un->un_lastop == ST_OP_WRITE)) ||
2645 	    ((flag & FWRITE) && (un->un_lastop == ST_OP_WEOF)) ||
2646 	    ((flag == FWRITE) && (un->un_lastop == ST_OP_NIL)))) {
2647 
2648 		/* save ST_EOM state */
2649 		int was_at_eom = (un->un_eof == ST_EOM) ? 1 : 0;
2650 
2651 		/*
2652 		 * Note that we will write a filemark if we had opened
2653 		 * the tape write only and no data was written, thus
2654 		 * creating a null file.
2655 		 *
2656 		 * If the user already wrote one, we only have to write 1 more.
2657 		 * If they wrote two, we don't have to write any.
2658 		 */
2659 
2660 		count = un->un_fmneeded;
2661 		if (count > 0) {
2662 			if (st_cmd(dev, SCMD_WRITE_FILE_MARK,
2663 			    count, SYNC_CMD)) {
2664 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2665 				    "st_close : EIO can't wfm\n");
2666 				err = EIO;
2667 			}
2668 			if ((un->un_dp->options & ST_REEL) && norew) {
2669 				if (st_cmd(dev, SCMD_SPACE, Fmk((-1)),
2670 				    SYNC_CMD)) {
2671 					ST_DEBUG2(ST_DEVINFO, st_label,
2672 					    SCSI_DEBUG,
2673 					    "st_close : EIO space fmk(-1)\n");
2674 					err = EIO;
2675 				}
2676 				un->un_eof = ST_NO_EOF;
2677 				/* fix up block number */
2678 				un->un_blkno = 0;
2679 			}
2680 		}
2681 
2682 		/*
2683 		 * If we aren't going to be rewinding, and we were at
2684 		 * physical eot, restore the state that indicates we
2685 		 * are at physical eot. Once you have reached physical
2686 		 * eot, and you close the tape, the only thing you can
2687 		 * do on the next open is to rewind. Access to trailer
2688 		 * records is only allowed without closing the device.
2689 		 */
2690 		if (norew == 0 && was_at_eom)
2691 			un->un_eof = ST_EOM;
2692 	}
2693 
2694 	/*
2695 	 * report soft errors if enabled and available, if we never accessed
2696 	 * the drive, don't get errors. This will prevent some DAT error
2697 	 * messages upon LOG SENSE.
2698 	 */
2699 	if (st_report_soft_errors_on_close &&
2700 	    (un->un_dp->options & ST_SOFT_ERROR_REPORTING) &&
2701 	    (last_state != ST_STATE_OFFLINE)) {
2702 		/*
2703 		 * Make sure we have reserve the tape unit.
2704 		 * This is the case when we do a O_NDELAY open and
2705 		 * then do a close without any I/O.
2706 		 */
2707 		if (!(un->un_rsvd_status & ST_INIT_RESERVE) &&
2708 			ST_RESERVE_SUPPORTED(un)) {
2709 			if ((err = st_tape_reservation_init(dev))) {
2710 				goto error;
2711 			}
2712 		}
2713 		(void) st_report_soft_errors(dev, flag);
2714 	}
2715 
2716 
2717 	/*
2718 	 * Do we need to rewind? Can we rewind?
2719 	 */
2720 	if (norew == 0 && un->un_fileno >= 0 && err == 0) {
2721 		/*
2722 		 * We'd like to rewind with the
2723 		 * 'immediate' bit set, but this
2724 		 * causes problems on some drives
2725 		 * where subsequent opens get a
2726 		 * 'NOT READY' error condition
2727 		 * back while the tape is rewinding,
2728 		 * which is impossible to distinguish
2729 		 * from the condition of 'no tape loaded'.
2730 		 *
2731 		 * Also, for some targets, if you disconnect
2732 		 * with the 'immediate' bit set, you don't
2733 		 * actually return right away, i.e., the
2734 		 * target ignores your request for immediate
2735 		 * return.
2736 		 *
2737 		 * Instead, we'll fire off an async rewind
2738 		 * command. We'll mark the device as closed,
2739 		 * and any subsequent open will stall on
2740 		 * the first TEST_UNIT_READY until the rewind
2741 		 * completes.
2742 		 *
2743 		 */
2744 		if (!(un->un_rsvd_status & ST_INIT_RESERVE) &&
2745 			ST_RESERVE_SUPPORTED(un)) {
2746 			if ((err = st_tape_reservation_init(dev))) {
2747 				goto error;
2748 			}
2749 		}
2750 		if (ST_RESERVE_SUPPORTED(un)) {
2751 			(void) st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD);
2752 		} else {
2753 			(void) st_cmd(dev, SCMD_REWIND, 0, ASYNC_CMD);
2754 		}
2755 	}
2756 
2757 	/*
2758 	 * eject tape if necessary
2759 	 */
2760 	if (un->un_eject_tape_on_failure) {
2761 		un->un_eject_tape_on_failure = 0;
2762 		if (st_cmd(dev, SCMD_LOAD, 0, SYNC_CMD)) {
2763 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2764 			    "st_close : can't unload tape\n");
2765 		} else {
2766 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
2767 			    "st_close : tape unloaded \n");
2768 			un->un_eof = ST_NO_EOF;
2769 			un->un_mediastate = MTIO_EJECTED;
2770 		}
2771 	}
2772 	/*
2773 	 * Release the tape unit, if default reserve/release
2774 	 * behaviour.
2775 	 */
2776 	if (ST_RESERVE_SUPPORTED(un) &&
2777 		!(un->un_rsvd_status & ST_PRESERVE_RESERVE) &&
2778 		    (un->un_rsvd_status & ST_INIT_RESERVE)) {
2779 		(void) st_reserve_release(dev, ST_RELEASE);
2780 	}
2781 
2782 error:
2783 	/*
2784 	 * clear up state
2785 	 */
2786 	un->un_laststate = un->un_state;
2787 	un->un_state = ST_STATE_CLOSED;
2788 	un->un_lastop = ST_OP_NIL;
2789 	un->un_throttle = 1;	/* assume one request at time, for now */
2790 	un->un_retry_ct = 0;
2791 	un->un_tran_retry_ct = 0;
2792 	un->un_errno = 0;
2793 	un->un_swr_token = (opaque_t)NULL;
2794 	un->un_rsvd_status &= ~(ST_INIT_RESERVE);
2795 
2796 	/* Restore the options to the init time settings */
2797 	if (un->un_init_options & ST_READ_IGNORE_ILI) {
2798 		un->un_dp->options |= ST_READ_IGNORE_ILI;
2799 	} else {
2800 		un->un_dp->options &= ~ST_READ_IGNORE_ILI;
2801 	}
2802 
2803 	if (un->un_init_options & ST_READ_IGNORE_EOFS) {
2804 		un->un_dp->options |= ST_READ_IGNORE_EOFS;
2805 	} else {
2806 		un->un_dp->options &= ~ST_READ_IGNORE_EOFS;
2807 	}
2808 
2809 	if (un->un_init_options & ST_SHORT_FILEMARKS) {
2810 		un->un_dp->options |= ST_SHORT_FILEMARKS;
2811 	} else {
2812 		un->un_dp->options &= ~ST_SHORT_FILEMARKS;
2813 	}
2814 
2815 	ASSERT(mutex_owned(ST_MUTEX));
2816 
2817 	/*
2818 	 * Signal anyone awaiting a close operation to complete.
2819 	 */
2820 	cv_signal(&un->un_clscv);
2821 
2822 	/*
2823 	 * any kind of error on closing causes all state to be tossed
2824 	 */
2825 	if (err && un->un_status != KEY_ILLEGAL_REQUEST) {
2826 		un->un_density_known = 0;
2827 		/*
2828 		 * note that st_intr has already set un_fileno to -1
2829 		 */
2830 	}
2831 
2832 #if defined(__i386) || defined(__amd64)
2833 	/*
2834 	 * free any contiguous mem alloc'ed for big block I/O
2835 	 */
2836 	cp = un->un_contig_mem;
2837 	while (cp) {
2838 		if (cp->cm_addr) {
2839 			ddi_dma_mem_free(&cp->cm_acc_hdl);
2840 		}
2841 		cp_temp = cp;
2842 		cp = cp->cm_next;
2843 		kmem_free(cp_temp,
2844 		    sizeof (struct contig_mem) + biosize());
2845 	}
2846 	un->un_contig_mem_total_num = 0;
2847 	un->un_contig_mem_available_num = 0;
2848 	un->un_contig_mem = NULL;
2849 	un->un_max_contig_mem_len = 0;
2850 #endif
2851 
2852 	ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
2853 	    "st_close3: return val = %x, fileno=%x, blkno=%lx, un_eof=%x\n",
2854 			    err, un->un_fileno, un->un_blkno, un->un_eof);
2855 
2856 	mutex_exit(ST_MUTEX);
2857 	return (err);
2858 }
2859 
2860 /*
2861  * These routines perform raw i/o operations.
2862  */
2863 
2864 /* ARGSUSED2 */
2865 static int
2866 st_aread(dev_t dev, struct aio_req *aio, cred_t *cred_p)
2867 {
2868 	return (st_arw(dev, aio, B_READ));
2869 }
2870 
2871 
2872 /* ARGSUSED2 */
2873 static int
2874 st_awrite(dev_t dev, struct aio_req *aio, cred_t *cred_p)
2875 {
2876 	return (st_arw(dev, aio, B_WRITE));
2877 }
2878 
2879 
2880 
2881 /* ARGSUSED */
2882 static int
2883 st_read(dev_t dev, struct uio *uiop, cred_t *cred_p)
2884 {
2885 	return (st_rw(dev, uiop, B_READ));
2886 }
2887 
2888 /* ARGSUSED */
2889 static int
2890 st_write(dev_t dev, struct uio *uiop, cred_t *cred_p)
2891 {
2892 	return (st_rw(dev, uiop, B_WRITE));
2893 }
2894 
2895 /*
2896  * Due to historical reasons, old limits are: For variable-length devices:
2897  * if greater than 64KB - 1 (ST_MAXRECSIZE_VARIABLE), block into 64 KB - 2
2898  * ST_MAXRECSIZE_VARIABLE_LIMIT) requests; otherwise,
2899  * (let it through unmodified. For fixed-length record devices:
2900  * 63K (ST_MAXRECSIZE_FIXED) is max (default minphys).
2901  *
2902  * The new limits used are un_maxdma (retrieved using scsi_ifgetcap()
2903  * from the HBA) and un_maxbsize (retrieved by sending SCMD_READ_BLKLIM
2904  * command to the drive).
2905  *
2906  */
2907 static void
2908 st_minphys(struct buf *bp)
2909 {
2910 	struct scsi_tape *un;
2911 
2912 #if !defined(lint)
2913 	_NOTE(SCHEME_PROTECTS_DATA("stable data", scsi_tape::un_sd));
2914 #endif
2915 
2916 	un = ddi_get_soft_state(st_state, MTUNIT(bp->b_edev));
2917 
2918 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
2919 	    "st_minphys(bp = 0x%p): b_bcount = 0x%lx\n", (void *)bp,
2920 	    bp->b_bcount);
2921 
2922 	if (un->un_allow_large_xfer) {
2923 
2924 		/*
2925 		 * check un_maxbsize for variable length devices only
2926 		 */
2927 		if (un->un_bsize == 0 && bp->b_bcount > un->un_maxbsize) {
2928 			bp->b_bcount = un->un_maxbsize;
2929 		}
2930 		/*
2931 		 * can't go more that HBA maxdma limit in either fixed-length
2932 		 * or variable-length tape drives.
2933 		 */
2934 		if (bp->b_bcount > un->un_maxdma) {
2935 			bp->b_bcount = un->un_maxdma;
2936 		}
2937 	} else {
2938 
2939 		/*
2940 		 *  use old fixed limits
2941 		 */
2942 		if (un->un_bsize == 0) {
2943 			if (bp->b_bcount > ST_MAXRECSIZE_VARIABLE) {
2944 				bp->b_bcount = ST_MAXRECSIZE_VARIABLE_LIMIT;
2945 			}
2946 		} else {
2947 			if (bp->b_bcount > ST_MAXRECSIZE_FIXED) {
2948 				bp->b_bcount = ST_MAXRECSIZE_FIXED;
2949 			}
2950 		}
2951 	}
2952 
2953 #if !defined(lint)
2954 _NOTE(DATA_READABLE_WITHOUT_LOCK(scsi_tape::un_sbufp));
2955 #endif /* lint */
2956 	/*
2957 	 * For regular raw I/O and Fixed Block length devices, make sure
2958 	 * the adjusted block count is a whole multiple of the device
2959 	 * block size.
2960 	 */
2961 	if (bp != un->un_sbufp && un->un_bsize) {
2962 		bp->b_bcount -= (bp->b_bcount % un->un_bsize);
2963 	}
2964 }
2965 
2966 /*ARGSUSED*/
2967 static void
2968 st_uscsi_minphys(struct buf *bp)
2969 {
2970 	/*
2971 	 * do not break up because the CDB count would then be
2972 	 * incorrect and create spurious data underrun errors.
2973 	 */
2974 }
2975 
2976 static int
2977 st_rw(dev_t dev, struct uio *uio, int flag)
2978 {
2979 	int rval = 0;
2980 	long len;
2981 
2982 	GET_SOFT_STATE(dev);
2983 
2984 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
2985 	    "st_rw(dev = 0x%lx, flag = %s)\n", dev,
2986 	    (flag == B_READ ? rd_str: wr_str));
2987 
2988 	/* get local copy of transfer length */
2989 	len = uio->uio_iov->iov_len;
2990 
2991 	mutex_enter(ST_MUTEX);
2992 
2993 	/*
2994 	 * If in fixed block size mode and requested read or write
2995 	 * is not an even multiple of that block size.
2996 	 */
2997 	if ((un->un_bsize != 0) && (len % un->un_bsize != 0)) {
2998 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
2999 		    "%s: not modulo %d block size\n",
3000 		    (flag == B_WRITE) ? wr_str : rd_str, un->un_bsize);
3001 		rval = EINVAL;
3002 	}
3003 
3004 	/* If device has set granularity in the READ_BLKLIM we honor it. */
3005 	if ((un->un_data_mod != 0) && (len % un->un_data_mod != 0)) {
3006 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
3007 		    "%s: not modulo %d device granularity\n",
3008 		    (flag == B_WRITE) ? wr_str : rd_str, un->un_data_mod);
3009 		rval = EINVAL;
3010 	}
3011 
3012 	if (rval != 0) {
3013 		un->un_errno = rval;
3014 		mutex_exit(ST_MUTEX);
3015 		return (rval);
3016 	}
3017 
3018 	un->un_silent_skip = 0;
3019 	mutex_exit(ST_MUTEX);
3020 
3021 	len = uio->uio_resid;
3022 
3023 	rval = physio(st_strategy, (struct buf *)NULL,
3024 		dev, flag, st_minphys, uio);
3025 	/*
3026 	 * if we have hit logical EOT during this xfer and there is not a
3027 	 * full residue, then set un_eof back  to ST_EOM to make sure that
3028 	 * the user will see at least one zero write
3029 	 * after this short write
3030 	 */
3031 	mutex_enter(ST_MUTEX);
3032 	if (un->un_eof > ST_NO_EOF) {
3033 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3034 		"un_eof=%d resid=%lx\n", un->un_eof, uio->uio_resid);
3035 	}
3036 	if (un->un_eof >= ST_EOM && (flag == B_WRITE)) {
3037 		if ((uio->uio_resid != len) && (uio->uio_resid != 0)) {
3038 			un->un_eof = ST_EOM;
3039 		} else if (uio->uio_resid == len) {
3040 			un->un_eof = ST_NO_EOF;
3041 		}
3042 	}
3043 
3044 	if (un->un_silent_skip && uio->uio_resid != len) {
3045 		un->un_eof = ST_EOF;
3046 		un->un_blkno = un->un_save_blkno;
3047 		un->un_fileno--;
3048 	}
3049 
3050 	un->un_errno = rval;
3051 
3052 	mutex_exit(ST_MUTEX);
3053 
3054 	return (rval);
3055 }
3056 
3057 static int
3058 st_arw(dev_t dev, struct aio_req *aio, int flag)
3059 {
3060 	struct uio *uio = aio->aio_uio;
3061 	int rval = 0;
3062 	long len;
3063 
3064 	GET_SOFT_STATE(dev);
3065 
3066 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
3067 	    "st_rw(dev = 0x%lx, flag = %s)\n", dev,
3068 	    (flag == B_READ ? rd_str: wr_str));
3069 
3070 	/* get local copy of transfer length */
3071 	len = uio->uio_iov->iov_len;
3072 
3073 	mutex_enter(ST_MUTEX);
3074 
3075 	/*
3076 	 * If in fixed block size mode and requested read or write
3077 	 * is not an even multiple of that block size.
3078 	 */
3079 	if ((un->un_bsize != 0) && (len % un->un_bsize != 0)) {
3080 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
3081 		    "%s: not modulo %d block size\n",
3082 		    (flag == B_WRITE) ? wr_str : rd_str, un->un_bsize);
3083 		rval = EINVAL;
3084 	}
3085 
3086 	/* If device has set granularity in the READ_BLKLIM we honor it. */
3087 	if ((un->un_data_mod != 0) && (len % un->un_data_mod != 0)) {
3088 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
3089 		    "%s: not modulo %d device granularity\n",
3090 		    (flag == B_WRITE) ? wr_str : rd_str, un->un_data_mod);
3091 		rval = EINVAL;
3092 	}
3093 
3094 	if (rval != 0) {
3095 		un->un_errno = rval;
3096 		mutex_exit(ST_MUTEX);
3097 		return (rval);
3098 	}
3099 
3100 	mutex_exit(ST_MUTEX);
3101 
3102 	len = uio->uio_resid;
3103 
3104 	rval = aphysio(st_strategy, anocancel, dev, flag, st_minphys, aio);
3105 
3106 	/*
3107 	 * if we have hit logical EOT during this xfer and there is not a
3108 	 * full residue, then set un_eof back  to ST_EOM to make sure that
3109 	 * the user will see at least one zero write
3110 	 * after this short write
3111 	 *
3112 	 * we keep this here just in case the application is not using
3113 	 * persistent errors
3114 	 */
3115 	mutex_enter(ST_MUTEX);
3116 	if (un->un_eof > ST_NO_EOF) {
3117 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3118 		    "un_eof=%d resid=%lx\n", un->un_eof, uio->uio_resid);
3119 	}
3120 	if (un->un_eof >= ST_EOM && (flag == B_WRITE)) {
3121 		if ((uio->uio_resid != len) && (uio->uio_resid != 0)) {
3122 			un->un_eof = ST_EOM;
3123 		} else if (uio->uio_resid == len && !IS_PE_FLAG_SET(un)) {
3124 			un->un_eof = ST_NO_EOF;
3125 		}
3126 	}
3127 	un->un_errno = rval;
3128 	mutex_exit(ST_MUTEX);
3129 
3130 	return (rval);
3131 }
3132 
3133 
3134 
3135 static int
3136 st_strategy(struct buf *bp)
3137 {
3138 	struct scsi_tape *un;
3139 	dev_t dev = bp->b_edev;
3140 
3141 	/*
3142 	 * validate arguments
3143 	 */
3144 	if ((un = ddi_get_soft_state(st_state, MTUNIT(bp->b_edev))) == NULL) {
3145 		bp->b_resid = bp->b_bcount;
3146 		mutex_enter(ST_MUTEX);
3147 		st_bioerror(bp, ENXIO);
3148 		mutex_exit(ST_MUTEX);
3149 		goto error;
3150 	}
3151 
3152 	mutex_enter(ST_MUTEX);
3153 
3154 	while (un->un_pwr_mgmt == ST_PWR_SUSPENDED) {
3155 		cv_wait(&un->un_suspend_cv, ST_MUTEX);
3156 	}
3157 
3158 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
3159 	    "st_strategy(): bcount=0x%lx, fileno=%d, blkno=%lx, eof=%d\n",
3160 	    bp->b_bcount, un->un_fileno, un->un_blkno, un->un_eof);
3161 
3162 	/*
3163 	 * If persistent errors have been flagged, just nix this one. We wait
3164 	 * for any outstanding I/O's below, so we will be in order.
3165 	 */
3166 	if (IS_PE_FLAG_SET(un))
3167 		goto exit;
3168 
3169 	if (bp != un->un_sbufp) {
3170 		char reading = bp->b_flags & B_READ;
3171 		int wasopening = 0;
3172 
3173 		/*
3174 		 * If we haven't done/checked reservation on the tape unit
3175 		 * do it now.
3176 		 */
3177 		if (!(un->un_rsvd_status & ST_INIT_RESERVE)) {
3178 		    if (ST_RESERVE_SUPPORTED(un)) {
3179 				if (st_tape_reservation_init(dev)) {
3180 					st_bioerror(bp, un->un_errno);
3181 					goto exit;
3182 				}
3183 		    } else if (un->un_state == ST_STATE_OPEN_PENDING_IO) {
3184 				/*
3185 				 * Enter here to restore position for possible
3186 				 * resets when the device was closed and opened
3187 				 * in O_NDELAY mode subsequently
3188 				 */
3189 				un->un_state = ST_STATE_INITIALIZING;
3190 				(void) st_cmd(dev, SCMD_TEST_UNIT_READY,
3191 				    0, SYNC_CMD);
3192 				un->un_state = ST_STATE_OPEN_PENDING_IO;
3193 			}
3194 		    un->un_rsvd_status |= ST_INIT_RESERVE;
3195 		}
3196 
3197 		/*
3198 		 * If we are offline, we have to initialize everything first.
3199 		 * This is to handle either when opened with O_NDELAY, or
3200 		 * we just got a new tape in the drive, after an offline.
3201 		 * We don't observe O_NDELAY past the open,
3202 		 * as it will not make sense for tapes.
3203 		 */
3204 		if (un->un_state == ST_STATE_OFFLINE || un->un_restore_pos) {
3205 			/* reset state to avoid recursion */
3206 			un->un_state = ST_STATE_INITIALIZING;
3207 			if (st_tape_init(dev)) {
3208 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3209 					"stioctl : OFFLINE init failure ");
3210 				un->un_state = ST_STATE_OFFLINE;
3211 				un->un_fileno = -1;
3212 				goto b_done_err;
3213 			}
3214 			un->un_state = ST_STATE_OPEN_PENDING_IO;
3215 		}
3216 		/*
3217 		 * Check for legal operations
3218 		 */
3219 		if (un->un_fileno < 0) {
3220 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3221 			    "strategy with un->un_fileno < 0\n");
3222 			goto b_done_err;
3223 		}
3224 
3225 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3226 		    "st_strategy(): regular io\n");
3227 
3228 		/*
3229 		 * Process this first. If we were reading, and we're pending
3230 		 * logical eot, that means we've bumped one file mark too far.
3231 		 */
3232 
3233 		/*
3234 		 * Recursion warning: st_cmd will route back through here.
3235 		 */
3236 		if (un->un_eof == ST_EOT_PENDING) {
3237 			if (st_cmd(dev, SCMD_SPACE, Fmk((-1)), SYNC_CMD)) {
3238 				un->un_fileno = -1;
3239 				un->un_density_known = 0;
3240 				goto b_done_err;
3241 			}
3242 			un->un_blkno = 0; /* fix up block number.. */
3243 			un->un_eof = ST_EOT;
3244 		}
3245 
3246 		/*
3247 		 * If we are in the process of opening, we may have to
3248 		 * determine/set the correct density. We also may have
3249 		 * to do a test_append (if QIC) to see whether we are
3250 		 * in a position to append to the end of the tape.
3251 		 *
3252 		 * If we're already at logical eot, we transition
3253 		 * to ST_NO_EOF. If we're at physical eot, we punt
3254 		 * to the switch statement below to handle.
3255 		 */
3256 		if ((un->un_state == ST_STATE_OPEN_PENDING_IO) ||
3257 		    (un->un_test_append && (un->un_dp->options & ST_QIC))) {
3258 
3259 			if (un->un_state == ST_STATE_OPEN_PENDING_IO) {
3260 				if (st_determine_density(dev, (int)reading)) {
3261 					goto b_done_err;
3262 				}
3263 			}
3264 
3265 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3266 			    "pending_io@fileno %d rw %d qic %d eof %d\n",
3267 			    un->un_fileno, (int)reading,
3268 			    (un->un_dp->options & ST_QIC) ? 1 : 0,
3269 			    un->un_eof);
3270 
3271 			if (!reading && un->un_eof != ST_EOM) {
3272 				if (un->un_eof == ST_EOT) {
3273 					un->un_eof = ST_NO_EOF;
3274 				} else if (un->un_fileno > 0 &&
3275 				    (un->un_dp->options & ST_QIC)) {
3276 					/*
3277 					 * st_test_append() will do it all
3278 					 */
3279 					st_test_append(bp);
3280 					goto done;
3281 				}
3282 			}
3283 			if (un->un_state == ST_STATE_OPEN_PENDING_IO) {
3284 				wasopening = 1;
3285 			}
3286 			un->un_laststate = un->un_state;
3287 			un->un_state = ST_STATE_OPEN;
3288 		}
3289 
3290 
3291 		/*
3292 		 * Process rest of END OF FILE and END OF TAPE conditions
3293 		 */
3294 
3295 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3296 		    "un_eof=%x, wasopening=%x\n",
3297 		    un->un_eof, wasopening);
3298 
3299 		switch (un->un_eof) {
3300 		case ST_EOM:
3301 			/*
3302 			 * This allows writes to proceed past physical
3303 			 * eot. We'll *really* be in trouble if the
3304 			 * user continues blindly writing data too
3305 			 * much past this point (unwind the tape).
3306 			 * Physical eot really means 'early warning
3307 			 * eot' in this context.
3308 			 *
3309 			 * Every other write from now on will succeed
3310 			 * (if sufficient  tape left).
3311 			 * This write will return with resid == count
3312 			 * but the next one should be successful
3313 			 *
3314 			 * Note that we only transition to logical EOT
3315 			 * if the last state wasn't the OPENING state.
3316 			 * We explicitly prohibit running up to physical
3317 			 * eot, closing the device, and then re-opening
3318 			 * to proceed. Trailer records may only be gotten
3319 			 * at by keeping the tape open after hitting eot.
3320 			 *
3321 			 * Also note that ST_EOM cannot be set by reading-
3322 			 * this can only be set during writing. Reading
3323 			 * up to the end of the tape gets a blank check
3324 			 * or a double-filemark indication (ST_EOT_PENDING),
3325 			 * and we prohibit reading after that point.
3326 			 *
3327 			 */
3328 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "EOM\n");
3329 			if (wasopening == 0) {
3330 				/*
3331 				 * this allows st_rw() to reset it back to
3332 				 * ST_EOM to make sure that the application
3333 				 * will see a zero write
3334 				 */
3335 				un->un_eof = ST_WRITE_AFTER_EOM;
3336 			}
3337 			un->un_status = SUN_KEY_EOT;
3338 			goto b_done;
3339 
3340 		case ST_WRITE_AFTER_EOM:
3341 		case ST_EOT:
3342 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "EOT\n");
3343 			un->un_status = SUN_KEY_EOT;
3344 			if (SVR4_BEHAVIOR && reading) {
3345 				goto b_done_err;
3346 			}
3347 
3348 			if (reading) {
3349 				goto b_done;
3350 			}
3351 			un->un_eof = ST_NO_EOF;
3352 			break;
3353 
3354 		case ST_EOF_PENDING:
3355 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3356 			    "EOF PENDING\n");
3357 			un->un_status = SUN_KEY_EOF;
3358 			if (SVR4_BEHAVIOR) {
3359 				un->un_eof = ST_EOF;
3360 				goto b_done;
3361 			}
3362 			/* FALLTHROUGH */
3363 		case ST_EOF:
3364 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "EOF\n");
3365 			un->un_status = SUN_KEY_EOF;
3366 			if (SVR4_BEHAVIOR) {
3367 				goto b_done_err;
3368 			}
3369 
3370 			if (BSD_BEHAVIOR) {
3371 				un->un_eof = ST_NO_EOF;
3372 				un->un_fileno += 1;
3373 				un->un_blkno   = 0;
3374 			}
3375 
3376 			if (reading) {
3377 				ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3378 				    "now file %d (read)\n",
3379 				    un->un_fileno);
3380 				goto b_done;
3381 			}
3382 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3383 			    "now file %d (write)\n", un->un_fileno);
3384 			break;
3385 		default:
3386 			un->un_status = 0;
3387 			break;
3388 		}
3389 	}
3390 
3391 	bp->b_flags &= ~(B_DONE);
3392 	st_bioerror(bp, 0);
3393 	bp->av_forw = NULL;
3394 	bp->b_resid = 0;
3395 	SET_BP_PKT(bp, 0);
3396 
3397 
3398 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3399 	    "st_strategy: cmd=0x%p  count=%ld  resid=%ld flags=0x%x"
3400 	    " pkt=0x%p\n",
3401 	    (void *)bp->b_forw, bp->b_bcount,
3402 	    bp->b_resid, bp->b_flags, (void *)BP_PKT(bp));
3403 
3404 #if defined(__i386) || defined(__amd64)
3405 	/*
3406 	 * We will replace bp with a new bp that can do big blk xfer
3407 	 * if the requested xfer size is bigger than ST_BIGBLK_XFER
3408 	 *
3409 	 * Also, we need to make sure that we're handling real I/O
3410 	 * by checking group 0/1 SCSI I/O commands, if needed
3411 	 */
3412 	if (bp->b_bcount > ST_BIGBLK_XFER &&
3413 	    (bp != un->un_sbufp					||
3414 	    (uchar_t)(uintptr_t)bp->b_forw == SCMD_READ		||
3415 	    (uchar_t)(uintptr_t)bp->b_forw == SCMD_READ_G1	||
3416 	    (uchar_t)(uintptr_t)bp->b_forw == SCMD_WRITE	||
3417 	    (uchar_t)(uintptr_t)bp->b_forw == SCMD_WRITE_G1)) {
3418 		mutex_exit(ST_MUTEX);
3419 		bp = st_get_bigblk_bp(bp);
3420 		mutex_enter(ST_MUTEX);
3421 	}
3422 #endif
3423 
3424 	/* put on wait queue */
3425 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3426 	    "st_strategy: un->un_quef = 0x%p, bp = 0x%p\n",
3427 	    (void *)un->un_quef, (void *)bp);
3428 
3429 	if (un->un_quef) {
3430 		un->un_quel->b_actf = bp;
3431 	} else {
3432 		un->un_quef = bp;
3433 	}
3434 	un->un_quel = bp;
3435 
3436 	ST_DO_KSTATS(bp, kstat_waitq_enter);
3437 
3438 	st_start(un);
3439 
3440 done:
3441 	mutex_exit(ST_MUTEX);
3442 	return (0);
3443 
3444 
3445 error:
3446 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3447 	    "st_strategy: error exit\n");
3448 
3449 	biodone(bp);
3450 	return (0);
3451 
3452 b_done_err:
3453 	st_bioerror(bp, EIO);
3454 	ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3455 	    "st_strategy : EIO b_done_err\n");
3456 
3457 b_done:
3458 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3459 	    "st_strategy: b_done\n");
3460 
3461 exit:
3462 	/*
3463 	 * make sure no commands are outstanding or waiting before closing,
3464 	 * so we can guarantee order
3465 	 */
3466 	st_wait_for_io(un);
3467 	un->un_err_resid = bp->b_resid = bp->b_bcount;
3468 
3469 	/* override errno here, if persistent errors were flagged */
3470 	if (IS_PE_FLAG_SET(un))
3471 		bioerror(bp, un->un_errno);
3472 
3473 	mutex_exit(ST_MUTEX);
3474 
3475 	biodone(bp);
3476 	ASSERT(mutex_owned(ST_MUTEX) == 0);
3477 	return (0);
3478 }
3479 
3480 
3481 
3482 /*
3483  * this routine spaces forward over filemarks
3484  */
3485 static int
3486 st_space_fmks(dev_t dev, int count)
3487 {
3488 	int rval = 0;
3489 
3490 	GET_SOFT_STATE(dev);
3491 
3492 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
3493 	    "st_space_fmks(dev = 0x%lx, count = %d)\n", dev, count);
3494 
3495 	ASSERT(mutex_owned(ST_MUTEX));
3496 
3497 	/*
3498 	 * the risk with doing only one space operation is that we
3499 	 * may accidentily jump in old data
3500 	 * the exabyte 8500 reading 8200 tapes cannot use KNOWS_EOD
3501 	 * because the 8200 does not append a marker; in order not to
3502 	 * sacrifice the fast file skip, we do a slow skip if the low
3503 	 * density device has been opened
3504 	 */
3505 
3506 	if ((un->un_dp->options & ST_KNOWS_EOD) &&
3507 	    !((un->un_dp->type == ST_TYPE_EXB8500 && MT_DENSITY(dev) == 0))) {
3508 		if (st_cmd(dev, SCMD_SPACE, Fmk(count), SYNC_CMD)) {
3509 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3510 			    "space_fmks : EIO can't do space cmd #1\n");
3511 			rval = EIO;
3512 		}
3513 	} else {
3514 		while (count > 0) {
3515 			if (st_cmd(dev, SCMD_SPACE, Fmk(1), SYNC_CMD)) {
3516 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3517 				    "space_fmks : EIO can't do space cmd #2\n");
3518 				rval = EIO;
3519 				break;
3520 			}
3521 			count -= 1;
3522 			/*
3523 			 * read a block to see if we have reached
3524 			 * end of medium (double filemark for reel or
3525 			 * medium error for others)
3526 			 */
3527 			if (count > 0) {
3528 				if (st_cmd(dev, SCMD_SPACE, Blk(1),
3529 				    SYNC_CMD)) {
3530 					ST_DEBUG2(ST_DEVINFO, st_label,
3531 					    SCSI_DEBUG,
3532 					    "space_fmks : EIO can't do "
3533 					    "space cmd #3\n");
3534 					rval = EIO;
3535 					break;
3536 				}
3537 				if ((un->un_eof >= ST_EOF_PENDING) &&
3538 				    (un->un_dp->options & ST_REEL)) {
3539 					un->un_status = SUN_KEY_EOT;
3540 					ST_DEBUG2(ST_DEVINFO, st_label,
3541 					    SCSI_DEBUG,
3542 					    "space_fmks : EIO ST_REEL\n");
3543 					rval = EIO;
3544 					break;
3545 				} else if (IN_EOF(un)) {
3546 					un->un_eof = ST_NO_EOF;
3547 					un->un_fileno++;
3548 					un->un_blkno = 0;
3549 					count--;
3550 				} else if (un->un_eof > ST_EOF) {
3551 					ST_DEBUG2(ST_DEVINFO, st_label,
3552 					    SCSI_DEBUG,
3553 					    "space_fmks, EIO > ST_EOF\n");
3554 					rval = EIO;
3555 					break;
3556 				}
3557 
3558 			}
3559 		}
3560 		un->un_err_resid = count;
3561 		un->un_err_fileno = un->un_fileno;
3562 		un->un_err_blkno = un->un_blkno;
3563 	}
3564 	ASSERT(mutex_owned(ST_MUTEX));
3565 	return (rval);
3566 }
3567 
3568 /*
3569  * this routine spaces to EOM
3570  *
3571  * it keeps track of the current filenumber and returns the filenumber after
3572  * the last successful space operation, we keep the number high because as
3573  * tapes are getting larger, the possibility of more and more files exist,
3574  * 0x100000 (1 Meg of files) probably will never have to be changed any time
3575  * soon
3576  */
3577 #define	MAX_SKIP	0x100000 /* somewhat arbitrary */
3578 
3579 static int
3580 st_find_eom(dev_t dev)
3581 {
3582 	int count, savefile;
3583 	struct scsi_tape *un;
3584 	int instance;
3585 
3586 	instance = MTUNIT(dev);
3587 	if ((un = ddi_get_soft_state(st_state, instance)) == NULL)
3588 		return (-1);
3589 
3590 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
3591 	    "st_find_eom(dev = 0x%lx): fileno = %d\n", dev, un->un_fileno);
3592 
3593 	ASSERT(mutex_owned(ST_MUTEX));
3594 
3595 	savefile = un->un_fileno;
3596 
3597 	/*
3598 	 * see if the drive is smart enough to do the skips in
3599 	 * one operation; 1/2" use two filemarks
3600 	 * the exabyte 8500 reading 8200 tapes cannot use KNOWS_EOD
3601 	 * because the 8200 does not append a marker; in order not to
3602 	 * sacrifice the fast file skip, we do a slow skip if the low
3603 	 * density device has been opened
3604 	 */
3605 	if ((un->un_dp->options & ST_KNOWS_EOD) &&
3606 	    !((un->un_dp->type == ST_TYPE_EXB8500 && MT_DENSITY(dev) == 0))) {
3607 		count = MAX_SKIP;
3608 	} else {
3609 		count = 1;
3610 	}
3611 
3612 	while (st_cmd(dev, SCMD_SPACE, Fmk(count), SYNC_CMD) == 0) {
3613 
3614 		savefile = un->un_fileno;
3615 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3616 			"count=%x, eof=%x, status=%x\n", count,  un->un_eof,
3617 			un->un_status);
3618 
3619 		/*
3620 		 * If we're not EOM smart,  space a record
3621 		 * to see whether we're now in the slot between
3622 		 * the two sequential filemarks that logical
3623 		 * EOM consists of (REEL) or hit nowhere land
3624 		 * (8mm).
3625 		 */
3626 		if (count == 1) {
3627 			/*
3628 			 * no fast skipping, check a record
3629 			 */
3630 			if (st_cmd(dev, SCMD_SPACE, Blk((1)), SYNC_CMD))
3631 				break;
3632 			else if ((un->un_eof >= ST_EOF_PENDING) &&
3633 			    (un->un_dp->options & ST_REEL)) {
3634 				un->un_status = KEY_BLANK_CHECK;
3635 				un->un_fileno++;
3636 				un->un_blkno = 0;
3637 				break;
3638 			} else if (IN_EOF(un)) {
3639 				un->un_eof = ST_NO_EOF;
3640 				un->un_fileno++;
3641 				un->un_blkno = 0;
3642 			} else if (un->un_eof > ST_EOF) {
3643 				break;
3644 			}
3645 		} else {
3646 			if (un->un_eof >  ST_EOF) {
3647 				break;
3648 			}
3649 		}
3650 	}
3651 
3652 	if (un->un_dp->options & ST_KNOWS_EOD) {
3653 		savefile = un->un_fileno;
3654 	}
3655 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
3656 	    "st_find_eom: %x\n", savefile);
3657 	ASSERT(mutex_owned(ST_MUTEX));
3658 	return (savefile);
3659 }
3660 
3661 
3662 /*
3663  * this routine is frequently used in ioctls below;
3664  * it determines whether we know the density and if not will
3665  * determine it
3666  * if we have written the tape before, one or more filemarks are written
3667  *
3668  * depending on the stepflag, the head is repositioned to where it was before
3669  * the filemarks were written in order not to confuse step counts
3670  */
3671 #define	STEPBACK    0
3672 #define	NO_STEPBACK 1
3673 
3674 static int
3675 st_check_density_or_wfm(dev_t dev, int wfm, int mode, int stepflag)
3676 {
3677 
3678 	GET_SOFT_STATE(dev);
3679 
3680 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
3681 	"st_check_density_or_wfm(dev= 0x%lx, wfm= %d, mode= %d, stpflg= %d)\n",
3682 	dev, wfm, mode, stepflag);
3683 
3684 	ASSERT(mutex_owned(ST_MUTEX));
3685 
3686 	/*
3687 	 * If we don't yet know the density of the tape we have inserted,
3688 	 * we have to either unconditionally set it (if we're 'writing'),
3689 	 * or we have to determine it. As side effects, check for any
3690 	 * write-protect errors, and for the need to put out any file-marks
3691 	 * before positioning a tape.
3692 	 *
3693 	 * If we are going to be spacing forward, and we haven't determined
3694 	 * the tape density yet, we have to do so now...
3695 	 */
3696 	if (un->un_state == ST_STATE_OPEN_PENDING_IO) {
3697 		if (st_determine_density(dev, mode)) {
3698 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3699 			    "check_density_or_wfm : EIO can't determine "
3700 			    "density\n");
3701 			un->un_errno = EIO;
3702 			return (EIO);
3703 		}
3704 		/*
3705 		 * Presumably we are at BOT. If we attempt to write, it will
3706 		 * either work okay, or bomb. We don't do a st_test_append
3707 		 * unless we're past BOT.
3708 		 */
3709 		un->un_laststate = un->un_state;
3710 		un->un_state = ST_STATE_OPEN;
3711 
3712 	} else if (un->un_fileno >= 0 && un->un_fmneeded > 0 &&
3713 	    ((un->un_lastop == ST_OP_WEOF && wfm) ||
3714 	    (un->un_lastop == ST_OP_WRITE && wfm))) {
3715 
3716 		daddr_t blkno = un->un_blkno;
3717 		int fileno = un->un_fileno;
3718 
3719 		/*
3720 		 * We need to write one or two filemarks.
3721 		 * In the case of the HP, we need to
3722 		 * position the head between the two
3723 		 * marks.
3724 		 */
3725 		if ((un->un_fmneeded > 0) || (un->un_lastop == ST_OP_WEOF)) {
3726 			wfm = un->un_fmneeded;
3727 			un->un_fmneeded = 0;
3728 		}
3729 
3730 		if (st_write_fm(dev, wfm)) {
3731 			un->un_fileno = -1;
3732 			un->un_density_known = 0;
3733 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3734 			    "check_density_or_wfm : EIO can't write fm\n");
3735 			un->un_errno = EIO;
3736 			return (EIO);
3737 		}
3738 
3739 		if (stepflag == STEPBACK) {
3740 			if (st_cmd(dev, SCMD_SPACE, Fmk((-wfm)), SYNC_CMD)) {
3741 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3742 				    "check_density_or_wfm : EIO can't space "
3743 				    "(-wfm)\n");
3744 				un->un_errno = EIO;
3745 				return (EIO);
3746 			}
3747 			un->un_blkno = blkno;
3748 			un->un_fileno = fileno;
3749 		}
3750 	}
3751 
3752 	/*
3753 	 * Whatever we do at this point clears the state of the eof flag.
3754 	 */
3755 
3756 	un->un_eof = ST_NO_EOF;
3757 
3758 	/*
3759 	 * If writing, let's check that we're positioned correctly
3760 	 * at the end of tape before issuing the next write.
3761 	 */
3762 	if (!un->un_read_only) {
3763 		un->un_test_append = 1;
3764 	}
3765 
3766 	ASSERT(mutex_owned(ST_MUTEX));
3767 	return (0);
3768 }
3769 
3770 
3771 /*
3772  * Wait for all outstaning I/O's to complete
3773  *
3774  * we wait on both ncmds and the wait queue for times when we are flushing
3775  * after persistent errors are flagged, which is when ncmds can be 0, and the
3776  * queue can still have I/O's.  This way we preserve order of biodone's.
3777  */
3778 static void
3779 st_wait_for_io(struct scsi_tape *un)
3780 {
3781 	ASSERT(mutex_owned(ST_MUTEX));
3782 	while (un->un_ncmds || un->un_quef) {
3783 		cv_wait(&un->un_queue_cv, ST_MUTEX);
3784 	}
3785 }
3786 
3787 /*
3788  * This routine implements the ioctl calls.  It is called
3789  * from the device switch at normal priority.
3790  */
3791 /*ARGSUSED*/
3792 static int
3793 st_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cred_p,
3794     int *rval_p)
3795 {
3796 	int tmp, rval = 0;
3797 
3798 	GET_SOFT_STATE(dev);
3799 
3800 	mutex_enter(ST_MUTEX);
3801 
3802 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
3803 	    "st_ioctl(): fileno=%x, blkno=%lx, un_eof=%x, state = %d, "
3804 	    "pe_flag = %d\n",
3805 	    un->un_fileno, un->un_blkno, un->un_eof, un->un_state,
3806 	    IS_PE_FLAG_SET(un));
3807 
3808 	/*
3809 	 * We don't want to block on these, so let them through
3810 	 * and we don't care about setting driver states here.
3811 	 */
3812 	if ((cmd == MTIOCGETDRIVETYPE) ||
3813 	    (cmd == MTIOCGUARANTEEDORDER) ||
3814 	    (cmd == MTIOCPERSISTENTSTATUS)) {
3815 		goto check_commands;
3816 	}
3817 
3818 	/*
3819 	 * wait for all outstanding commands to complete, or be dequeued.
3820 	 * And because ioctl's are synchronous commands, any return value
3821 	 * after this,  will be in order
3822 	 */
3823 	st_wait_for_io(un);
3824 
3825 	/*
3826 	 * allow only a through clear errors and persistent status, and
3827 	 * status
3828 	 */
3829 	if (IS_PE_FLAG_SET(un)) {
3830 		if ((cmd == MTIOCLRERR) ||
3831 		    (cmd == MTIOCPERSISTENT) ||
3832 		    (cmd == MTIOCGET) ||
3833 		    (cmd == USCSIGETRQS)) {
3834 			goto check_commands;
3835 		} else {
3836 			rval = un->un_errno;
3837 			goto exit;
3838 		}
3839 	}
3840 
3841 	un->un_throttle = 1;	/* > 1 will never happen here */
3842 	un->un_errno = 0;	/* start clean from here */
3843 
3844 	/*
3845 	 * first and foremost, handle any ST_EOT_PENDING cases.
3846 	 * That is, if a logical eot is pending notice, notice it.
3847 	 */
3848 	if (un->un_eof == ST_EOT_PENDING) {
3849 		int resid = un->un_err_resid;
3850 		uchar_t status = un->un_status;
3851 		uchar_t lastop = un->un_lastop;
3852 
3853 		if (st_cmd(dev, SCMD_SPACE, Fmk((-1)), SYNC_CMD)) {
3854 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
3855 			    "stioctl : EIO can't space fmk(-1)\n");
3856 			rval = EIO;
3857 			goto exit;
3858 		}
3859 		un->un_lastop = lastop; /* restore last operation */
3860 		if (status == SUN_KEY_EOF) {
3861 			un->un_status = SUN_KEY_EOT;
3862 		} else {
3863 			un->un_status = status;
3864 		}
3865 		un->un_err_resid  = resid;
3866 		un->un_err_blkno = un->un_blkno = 0; /* fix up block number */
3867 		un->un_eof = ST_EOT;	/* now we're at logical eot */
3868 	}
3869 
3870 	/*
3871 	 * now, handle the rest of the situations
3872 	 */
3873 check_commands:
3874 	switch (cmd) {
3875 	case MTIOCGET:
3876 		{
3877 #ifdef _MULTI_DATAMODEL
3878 			/*
3879 			 * For use when a 32 bit app makes a call into a
3880 			 * 64 bit ioctl
3881 			 */
3882 			struct mtget32		mtg_local32;
3883 			struct mtget32 		*mtget_32 = &mtg_local32;
3884 #endif /* _MULTI_DATAMODEL */
3885 
3886 			/* Get tape status */
3887 			struct mtget mtg_local;
3888 			struct mtget *mtget = &mtg_local;
3889 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
3890 				"st_ioctl: MTIOCGET\n");
3891 
3892 			bzero(mtget, sizeof (struct mtget));
3893 			mtget->mt_erreg = un->un_status;
3894 			mtget->mt_resid = un->un_err_resid;
3895 			mtget->mt_dsreg = un->un_retry_ct;
3896 			mtget->mt_fileno = un->un_err_fileno;
3897 			mtget->mt_blkno = un->un_err_blkno;
3898 			mtget->mt_type = un->un_dp->type;
3899 			mtget->mt_flags = MTF_SCSI | MTF_ASF;
3900 			if (un->un_dp->options & ST_REEL) {
3901 				mtget->mt_flags |= MTF_REEL;
3902 				mtget->mt_bf = 20;
3903 			} else {		/* 1/4" cartridges */
3904 				switch (mtget->mt_type) {
3905 				/* Emulex cartridge tape */
3906 				case MT_ISMT02:
3907 					mtget->mt_bf = 40;
3908 					break;
3909 				default:
3910 					mtget->mt_bf = 126;
3911 					break;
3912 				}
3913 			}
3914 
3915 			/*
3916 			 * If large transfers are allowed and drive options
3917 			 * has no record size limit set. Calculate blocking
3918 			 * factor from the lesser of maxbsize and maxdma.
3919 			 */
3920 			if ((un->un_allow_large_xfer) &&
3921 			    (un->un_dp->options & ST_NO_RECSIZE_LIMIT)) {
3922 				mtget->mt_bf = min(un->un_maxbsize,
3923 				    un->un_maxdma) / SECSIZE;
3924 			}
3925 
3926 			rval = st_check_clean_bit(dev);
3927 			if (rval == -1) {
3928 				rval = EIO;
3929 				goto exit;
3930 			} else {
3931 				mtget->mt_flags |= (ushort_t)rval;
3932 				rval = 0;
3933 			}
3934 
3935 			un->un_status = 0;		/* Reset status */
3936 			un->un_err_resid = 0;
3937 			tmp = sizeof (struct mtget);
3938 
3939 #ifdef _MULTI_DATAMODEL
3940 
3941 		switch (ddi_model_convert_from(flag & FMODELS)) {
3942 		case DDI_MODEL_ILP32:
3943 			/*
3944 			 * Convert 64 bit back to 32 bit before doing
3945 			 * copyout. This is what the ILP32 app expects.
3946 			 */
3947 			mtget_32->mt_erreg = 	mtget->mt_erreg;
3948 			mtget_32->mt_resid = 	mtget->mt_resid;
3949 			mtget_32->mt_dsreg = 	mtget->mt_dsreg;
3950 			mtget_32->mt_fileno = 	(daddr32_t)mtget->mt_fileno;
3951 			mtget_32->mt_blkno = 	(daddr32_t)mtget->mt_blkno;
3952 			mtget_32->mt_type =  	mtget->mt_type;
3953 			mtget_32->mt_flags = 	mtget->mt_flags;
3954 			mtget_32->mt_bf = 	mtget->mt_bf;
3955 
3956 			if (ddi_copyout(mtget_32, (void *)arg,
3957 			    sizeof (struct mtget32), flag)) {
3958 				rval = EFAULT;
3959 			}
3960 			break;
3961 
3962 		case DDI_MODEL_NONE:
3963 			if (ddi_copyout(mtget, (void *)arg, tmp, flag)) {
3964 				rval = EFAULT;
3965 			}
3966 			break;
3967 		}
3968 #else /* ! _MULTI_DATAMODE */
3969 		if (ddi_copyout(mtget, (void *)arg, tmp, flag)) {
3970 			rval = EFAULT;
3971 		}
3972 #endif /* _MULTI_DATAMODE */
3973 
3974 			break;
3975 		}
3976 	case MTIOCSTATE:
3977 		{
3978 			/*
3979 			 * return when media presence matches state
3980 			 */
3981 			enum mtio_state state;
3982 
3983 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
3984 				"st_ioctl: MTIOCSTATE\n");
3985 
3986 			if (ddi_copyin((void *)arg, &state, sizeof (int), flag))
3987 				rval = EFAULT;
3988 
3989 			mutex_exit(ST_MUTEX);
3990 
3991 			rval = st_check_media(dev, state);
3992 
3993 			mutex_enter(ST_MUTEX);
3994 
3995 			if (rval != 0) {
3996 				break;
3997 			}
3998 
3999 			if (ddi_copyout(&un->un_mediastate, (void *)arg,
4000 			    sizeof (int), flag))
4001 				rval = EFAULT;
4002 			break;
4003 
4004 		}
4005 
4006 	case MTIOCGETDRIVETYPE:
4007 		{
4008 #ifdef _MULTI_DATAMODEL
4009 		/*
4010 		 * For use when a 32 bit app makes a call into a
4011 		 * 64 bit ioctl
4012 		 */
4013 		struct mtdrivetype_request32	mtdtrq32;
4014 #endif /* _MULTI_DATAMODEL */
4015 
4016 			/*
4017 			 * return mtdrivetype
4018 			 */
4019 			struct mtdrivetype_request mtdtrq;
4020 			struct mtdrivetype mtdrtyp;
4021 			struct mtdrivetype *mtdt = &mtdrtyp;
4022 			struct st_drivetype *stdt = un->un_dp;
4023 
4024 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4025 				"st_ioctl: MTIOCGETDRIVETYPE\n");
4026 
4027 #ifdef _MULTI_DATAMODEL
4028 		switch (ddi_model_convert_from(flag & FMODELS)) {
4029 		case DDI_MODEL_ILP32:
4030 		{
4031 			if (ddi_copyin((void *)arg, &mtdtrq32,
4032 			    sizeof (struct mtdrivetype_request32), flag)) {
4033 				rval = EFAULT;
4034 				break;
4035 			}
4036 			mtdtrq.size = mtdtrq32.size;
4037 			mtdtrq.mtdtp =
4038 			    (struct  mtdrivetype *)(uintptr_t)mtdtrq32.mtdtp;
4039 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4040 				"st_ioctl: size 0x%x\n", mtdtrq.size);
4041 			break;
4042 		}
4043 		case DDI_MODEL_NONE:
4044 			if (ddi_copyin((void *)arg, &mtdtrq,
4045 			    sizeof (struct mtdrivetype_request), flag)) {
4046 				rval = EFAULT;
4047 				break;
4048 			}
4049 			break;
4050 		}
4051 
4052 #else /* ! _MULTI_DATAMODEL */
4053 		if (ddi_copyin((void *)arg, &mtdtrq,
4054 		    sizeof (struct mtdrivetype_request), flag)) {
4055 			rval = EFAULT;
4056 			break;
4057 		}
4058 #endif /* _MULTI_DATAMODEL */
4059 
4060 			/*
4061 			 * if requested size is < 0 then return
4062 			 * error.
4063 			 */
4064 			if (mtdtrq.size < 0) {
4065 				rval = EINVAL;
4066 				break;
4067 			}
4068 			bzero(mtdt, sizeof (struct mtdrivetype));
4069 			(void) strncpy(mtdt->name, stdt->name, ST_NAMESIZE);
4070 			(void) strncpy(mtdt->vid, stdt->vid, VIDPIDLEN - 1);
4071 			mtdt->type = stdt->type;
4072 			mtdt->bsize = stdt->bsize;
4073 			mtdt->options = stdt->options;
4074 			mtdt->max_rretries = stdt->max_rretries;
4075 			mtdt->max_wretries = stdt->max_wretries;
4076 			for (tmp = 0; tmp < NDENSITIES; tmp++)
4077 				mtdt->densities[tmp] = stdt->densities[tmp];
4078 			mtdt->default_density = stdt->default_density;
4079 			/*
4080 			 * Speed hasn't been used since the hayday of reel tape.
4081 			 * For all drives not setting the option ST_KNOWS_MEDIA
4082 			 * the speed member renamed to mediatype are zeros.
4083 			 * Those drives that have ST_KNOWS_MEDIA set use the
4084 			 * new mediatype member which is used to figure the
4085 			 * type of media loaded.
4086 			 *
4087 			 * So as to not break applications speed in the
4088 			 * mtdrivetype structure is not renamed.
4089 			 */
4090 			for (tmp = 0; tmp < NDENSITIES; tmp++) {
4091 				mtdt->speeds[tmp] = stdt->mediatype[tmp];
4092 			}
4093 			mtdt->non_motion_timeout = stdt->non_motion_timeout;
4094 			mtdt->io_timeout = stdt->io_timeout;
4095 			mtdt->rewind_timeout = stdt->rewind_timeout;
4096 			mtdt->space_timeout = stdt->space_timeout;
4097 			mtdt->load_timeout = stdt->load_timeout;
4098 			mtdt->unload_timeout = stdt->unload_timeout;
4099 			mtdt->erase_timeout = stdt->erase_timeout;
4100 
4101 			/*
4102 			 * Limit the maximum length of the result to
4103 			 * sizeof (struct mtdrivetype).
4104 			 */
4105 			tmp = sizeof (struct mtdrivetype);
4106 			if (mtdtrq.size < tmp)
4107 				tmp = mtdtrq.size;
4108 			if (ddi_copyout(mtdt, mtdtrq.mtdtp, tmp, flag)) {
4109 				rval = EFAULT;
4110 			}
4111 			break;
4112 		}
4113 	case MTIOCPERSISTENT:
4114 		{
4115 			int persistence = 0;
4116 
4117 			if (ddi_copyin((void *)arg, &persistence,
4118 			    sizeof (int), flag)) {
4119 				rval = EFAULT;
4120 				break;
4121 			}
4122 
4123 			/* non zero sets it, only 0 turns it off */
4124 			un->un_persistence = (uchar_t)persistence ? 1 : 0;
4125 
4126 			if (un->un_persistence)
4127 				TURN_PE_ON(un);
4128 			else
4129 				TURN_PE_OFF(un);
4130 
4131 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4132 			    "st_ioctl: MTIOCPERSISTENT : persistence = %d\n",
4133 			    un->un_persistence);
4134 
4135 			break;
4136 		}
4137 	case MTIOCPERSISTENTSTATUS:
4138 		{
4139 			int persistence = (int)un->un_persistence;
4140 
4141 			if (ddi_copyout(&persistence, (void *)arg,
4142 			    sizeof (int), flag)) {
4143 				rval = EFAULT;
4144 			}
4145 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4146 			    "st_ioctl: MTIOCPERSISTENTSTATUS:persistece = %d\n",
4147 			    un->un_persistence);
4148 
4149 			break;
4150 		}
4151 
4152 
4153 	case MTIOCLRERR:
4154 		{
4155 			/* clear persistent errors */
4156 
4157 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4158 			    "st_ioctl: MTIOCLRERR\n");
4159 
4160 			CLEAR_PE(un);
4161 
4162 			break;
4163 		}
4164 
4165 	case MTIOCGUARANTEEDORDER:
4166 		{
4167 			/*
4168 			 * this is just a holder to make a valid ioctl and
4169 			 * it won't be in any earlier release
4170 			 */
4171 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4172 			    "st_ioctl: MTIOCGUARANTEEDORDER\n");
4173 
4174 			break;
4175 		}
4176 
4177 	case MTIOCRESERVE:
4178 		{
4179 			ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
4180 			    "st_ioctl: MTIOCRESERVE\n");
4181 
4182 			/*
4183 			 * Check if Reserve/Release is supported.
4184 			 */
4185 			if (!(ST_RESERVE_SUPPORTED(un))) {
4186 				rval = ENOTTY;
4187 				break;
4188 			}
4189 
4190 			rval = st_reserve_release(dev, ST_RESERVE);
4191 
4192 			if (rval == 0) {
4193 				un->un_rsvd_status |= ST_PRESERVE_RESERVE;
4194 			}
4195 			break;
4196 		}
4197 
4198 	case MTIOCRELEASE:
4199 		{
4200 			ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
4201 			    "st_ioctl: MTIOCRELEASE\n");
4202 
4203 			/*
4204 			 * Check if Reserve/Release is supported.
4205 			 */
4206 			if (!(ST_RESERVE_SUPPORTED(un))) {
4207 				rval = ENOTTY;
4208 				break;
4209 			}
4210 
4211 			un->un_rsvd_status &= ~ST_PRESERVE_RESERVE;
4212 
4213 			break;
4214 		}
4215 
4216 	case MTIOCFORCERESERVE:
4217 		{
4218 			ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
4219 			    "st_ioctl: MTIOCFORCERESERVE\n");
4220 
4221 			/*
4222 			 * Check if Reserve/Release is supported.
4223 			 */
4224 			if (!(ST_RESERVE_SUPPORTED(un))) {
4225 				rval = ENOTTY;
4226 				break;
4227 			}
4228 			/*
4229 			 * allow only super user to run this.
4230 			 */
4231 			if (drv_priv(cred_p) != 0) {
4232 				rval = EPERM;
4233 				break;
4234 			}
4235 			/*
4236 			 * Throw away reserve,
4237 			 * not using test-unit-ready
4238 			 * since reserve can succeed without tape being
4239 			 * present in the drive.
4240 			 */
4241 			(void) st_reserve_release(dev, ST_RESERVE);
4242 
4243 			rval = st_take_ownership(dev);
4244 
4245 			break;
4246 		}
4247 	case USCSIGETRQS:
4248 		{
4249 #ifdef _MULTI_DATAMODEL
4250 		/*
4251 		 * For use when a 32 bit app makes a call into a
4252 		 * 64 bit ioctl
4253 		 */
4254 		struct uscsi_rqs32	urqs_32;
4255 		struct uscsi_rqs32	*urqs_32_ptr = &urqs_32;
4256 #endif /* _MULTI_DATAMODEL */
4257 			struct uscsi_rqs	urqs;
4258 			struct uscsi_rqs	*urqs_ptr = &urqs;
4259 			ushort_t		len;
4260 #ifdef _MULTI_DATAMODEL
4261 		switch (ddi_model_convert_from(flag & FMODELS)) {
4262 		case DDI_MODEL_ILP32:
4263 		{
4264 			if (ddi_copyin((void *)arg, urqs_32_ptr,
4265 			    sizeof (struct uscsi_rqs32), flag)) {
4266 				rval = EFAULT;
4267 				break;
4268 			}
4269 			urqs_ptr->rqs_buflen = urqs_32_ptr->rqs_buflen;
4270 			urqs_ptr->rqs_bufaddr =
4271 			    (caddr_t)(uintptr_t)urqs_32_ptr->rqs_bufaddr;
4272 			break;
4273 		}
4274 		case DDI_MODEL_NONE:
4275 			if (ddi_copyin((void *)arg, urqs_ptr,
4276 			    sizeof (struct uscsi_rqs), flag)) {
4277 				rval = EFAULT;
4278 				break;
4279 			}
4280 		}
4281 #else /* ! _MULTI_DATAMODEL */
4282 		if (ddi_copyin((void *)arg, urqs_ptr, sizeof (urqs), flag)) {
4283 			rval = EFAULT;
4284 			break;
4285 		}
4286 #endif /* _MULTI_DATAMODEL */
4287 
4288 			urqs_ptr->rqs_flags = (int)un->un_rqs_state &
4289 			    (ST_RQS_OVR | ST_RQS_VALID);
4290 			if (urqs_ptr->rqs_buflen <= SENSE_LENGTH) {
4291 			    len = urqs_ptr->rqs_buflen;
4292 			    urqs_ptr->rqs_resid = 0;
4293 			} else {
4294 			    len = SENSE_LENGTH;
4295 			    urqs_ptr->rqs_resid = urqs_ptr->rqs_buflen
4296 				    - SENSE_LENGTH;
4297 			}
4298 			if (!(un->un_rqs_state & ST_RQS_VALID)) {
4299 			    urqs_ptr->rqs_resid = urqs_ptr->rqs_buflen;
4300 			}
4301 			un->un_rqs_state |= ST_RQS_READ;
4302 			un->un_rqs_state &= ~(ST_RQS_OVR);
4303 
4304 #ifdef _MULTI_DATAMODEL
4305 		switch (ddi_model_convert_from(flag & FMODELS)) {
4306 		case DDI_MODEL_ILP32:
4307 			urqs_32_ptr->rqs_flags = urqs_ptr->rqs_flags;
4308 			urqs_32_ptr->rqs_resid = urqs_ptr->rqs_resid;
4309 			if (ddi_copyout(&urqs_32, (void *)arg,
4310 			    sizeof (urqs_32), flag)) {
4311 				rval = EFAULT;
4312 			}
4313 			break;
4314 		case DDI_MODEL_NONE:
4315 			if (ddi_copyout(&urqs, (void *)arg, sizeof (urqs),
4316 			    flag)) {
4317 				rval = EFAULT;
4318 			}
4319 			break;
4320 		}
4321 
4322 		if (un->un_rqs_state & ST_RQS_VALID) {
4323 			if (ddi_copyout(un->un_uscsi_rqs_buf,
4324 			    urqs_ptr->rqs_bufaddr, len, flag)) {
4325 				rval = EFAULT;
4326 		    }
4327 		}
4328 #else /* ! _MULTI_DATAMODEL */
4329 		if (ddi_copyout(&urqs, (void *)arg, sizeof (urqs), flag)) {
4330 			rval = EFAULT;
4331 		}
4332 		if (un->un_rqs_state & ST_RQS_VALID) {
4333 			if (ddi_copyout(un->un_uscsi_rqs_buf,
4334 			    urqs_ptr->rqs_bufaddr, len, flag)) {
4335 				rval = EFAULT;
4336 		    }
4337 		}
4338 #endif /* _MULTI_DATAMODEL */
4339 			break;
4340 		}
4341 
4342 	case USCSICMD:
4343 		{
4344 		cred_t	*cr;
4345 #ifdef _MULTI_DATAMODEL
4346 		/*
4347 		 * For use when a 32 bit app makes a call into a
4348 		 * 64 bit ioctl
4349 		 */
4350 		struct uscsi_cmd32	ucmd_32;
4351 		struct uscsi_cmd32	*ucmd_32_ptr = &ucmd_32;
4352 #endif /* _MULTI_DATAMODEL */
4353 
4354 			/*
4355 			 * Run a generic USCSI command
4356 			 */
4357 			struct uscsi_cmd ucmd;
4358 			struct uscsi_cmd *ucmd_ptr = &ucmd;
4359 			enum uio_seg uioseg;
4360 
4361 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4362 				"st_ioctl: USCSICMD\n");
4363 
4364 			cr = ddi_get_cred();
4365 			if ((drv_priv(cred_p) != 0) && (drv_priv(cr) != 0)) {
4366 				rval = EPERM;
4367 				break;
4368 			}
4369 
4370 #ifdef _MULTI_DATAMODEL
4371 		switch (ddi_model_convert_from(flag & FMODELS)) {
4372 		case DDI_MODEL_ILP32:
4373 		{
4374 			if (ddi_copyin((void *)arg, ucmd_32_ptr,
4375 			    sizeof (struct uscsi_cmd32), flag)) {
4376 				rval = EFAULT;
4377 				break;
4378 			}
4379 			uscsi_cmd32touscsi_cmd(ucmd_32_ptr, ucmd_ptr);
4380 			break;
4381 		}
4382 		case DDI_MODEL_NONE:
4383 			if (ddi_copyin((void *)arg, ucmd_ptr, sizeof (ucmd),
4384 			    flag)) {
4385 				rval = EFAULT;
4386 				break;
4387 			}
4388 		}
4389 
4390 #else /* ! _MULTI_DATAMODEL */
4391 		if (ddi_copyin((void *)arg, ucmd_ptr, sizeof (ucmd), flag)) {
4392 			rval = EFAULT;
4393 			break;
4394 		}
4395 #endif /* _MULTI_DATAMODEL */
4396 
4397 
4398 			/*
4399 			 * If we haven't done/checked reservation on the
4400 			 * tape unit do it now.
4401 			 */
4402 			if (ST_RESERVE_SUPPORTED(un) &&
4403 				!(un->un_rsvd_status & ST_INIT_RESERVE)) {
4404 				if (rval = st_tape_reservation_init(dev))
4405 					goto exit;
4406 			}
4407 
4408 			/*
4409 			 * although st_ioctl_cmd() never makes use of these
4410 			 * now, we are just being safe and consistent
4411 			 */
4412 			ucmd.uscsi_flags &= ~(USCSI_NOINTR | USCSI_NOPARITY |
4413 			    USCSI_OTAG | USCSI_HTAG | USCSI_HEAD);
4414 
4415 
4416 			uioseg = (flag & FKIOCTL) ?
4417 			    UIO_SYSSPACE : UIO_USERSPACE;
4418 
4419 			rval = st_ioctl_cmd(dev, &ucmd, uioseg, uioseg, uioseg);
4420 
4421 
4422 #ifdef _MULTI_DATAMODEL
4423 		switch (ddi_model_convert_from(flag & FMODELS)) {
4424 		case DDI_MODEL_ILP32:
4425 			/*
4426 			 * Convert 64 bit back to 32 bit before doing
4427 			 * copyout. This is what the ILP32 app expects.
4428 			 */
4429 			uscsi_cmdtouscsi_cmd32(ucmd_ptr, ucmd_32_ptr);
4430 
4431 			if (ddi_copyout(&ucmd_32, (void *)arg,
4432 			    sizeof (ucmd_32), flag)) {
4433 				if (rval != 0)
4434 					rval = EFAULT;
4435 				}
4436 			break;
4437 
4438 		case DDI_MODEL_NONE:
4439 			if (ddi_copyout(&ucmd, (void *)arg,
4440 			    sizeof (ucmd), flag)) {
4441 				if (rval != 0)
4442 					rval = EFAULT;
4443 				}
4444 			break;
4445 		}
4446 #else /* ! _MULTI_DATAMODEL */
4447 		if (ddi_copyout(&ucmd, (void *)arg, sizeof (ucmd), flag)) {
4448 			if (rval != 0)
4449 				rval = EFAULT;
4450 		}
4451 #endif /* _MULTI_DATAMODEL */
4452 
4453 			break;
4454 		}
4455 
4456 	case MTIOCTOP:
4457 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4458 			"st_ioctl: MTIOCTOP\n");
4459 		rval = st_mtioctop(un, arg, flag);
4460 		break;
4461 
4462 	case MTIOCREADIGNOREILI:
4463 		{
4464 			int set_ili;
4465 
4466 			if (ddi_copyin((void *)arg, &set_ili,
4467 			    sizeof (set_ili), flag)) {
4468 				rval = EFAULT;
4469 				break;
4470 			}
4471 
4472 			if (un->un_bsize) {
4473 				rval = ENOTTY;
4474 				break;
4475 			}
4476 
4477 			switch (set_ili) {
4478 			case 0:
4479 				un->un_dp->options &= ~ST_READ_IGNORE_ILI;
4480 				break;
4481 
4482 			case 1:
4483 				un->un_dp->options |= ST_READ_IGNORE_ILI;
4484 				break;
4485 
4486 			default:
4487 				rval = EINVAL;
4488 				break;
4489 			}
4490 			break;
4491 		}
4492 
4493 	case MTIOCREADIGNOREEOFS:
4494 		{
4495 			int ignore_eof;
4496 
4497 			if (ddi_copyin((void *)arg, &ignore_eof,
4498 			    sizeof (ignore_eof), flag)) {
4499 				rval = EFAULT;
4500 				break;
4501 			}
4502 
4503 			if (!(un->un_dp->options & ST_REEL)) {
4504 				rval = ENOTTY;
4505 				break;
4506 			}
4507 
4508 			switch (ignore_eof) {
4509 			case 0:
4510 				un->un_dp->options &= ~ST_READ_IGNORE_EOFS;
4511 				break;
4512 
4513 			case 1:
4514 				un->un_dp->options |= ST_READ_IGNORE_EOFS;
4515 				break;
4516 
4517 			default:
4518 				rval = EINVAL;
4519 				break;
4520 			}
4521 			break;
4522 		}
4523 
4524 	case MTIOCSHORTFMK:
4525 		{
4526 			int short_fmk;
4527 
4528 			if (ddi_copyin((void *)arg, &short_fmk,
4529 			    sizeof (short_fmk), flag)) {
4530 				rval = EFAULT;
4531 				break;
4532 			}
4533 
4534 			switch (un->un_dp->type) {
4535 			case ST_TYPE_EXB8500:
4536 			case ST_TYPE_EXABYTE:
4537 				if (!short_fmk) {
4538 					un->un_dp->options &=
4539 						~ST_SHORT_FILEMARKS;
4540 				} else if (short_fmk == 1) {
4541 					un->un_dp->options |=
4542 						ST_SHORT_FILEMARKS;
4543 				} else {
4544 					rval = EINVAL;
4545 				}
4546 				break;
4547 
4548 			default:
4549 				rval = ENOTTY;
4550 				break;
4551 			}
4552 			break;
4553 		}
4554 
4555 	default:
4556 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4557 			"st_ioctl: unknown ioctl\n");
4558 		rval = ENOTTY;
4559 	}
4560 
4561 exit:
4562 	if (!IS_PE_FLAG_SET(un))
4563 		un->un_errno = rval;
4564 
4565 	mutex_exit(ST_MUTEX);
4566 
4567 	return (rval);
4568 }
4569 
4570 
4571 /*
4572  * do some MTIOCTOP tape operations
4573  */
4574 static int
4575 st_mtioctop(struct scsi_tape *un, intptr_t arg, int flag)
4576 {
4577 	struct mtop *mtop, local;
4578 	int savefile, tmp, rval = 0;
4579 	dev_t dev = un->un_dev;
4580 #ifdef _MULTI_DATAMODEL
4581 	/*
4582 	 * For use when a 32 bit app makes a call into a
4583 	 * 64 bit ioctl
4584 	 */
4585 	struct mtop32	mtop_32_for_64;
4586 #endif /* _MULTI_DATAMODEL */
4587 
4588 
4589 	ASSERT(mutex_owned(ST_MUTEX));
4590 
4591 	mtop = &local;
4592 #ifdef _MULTI_DATAMODEL
4593 		switch (ddi_model_convert_from(flag & FMODELS)) {
4594 		case DDI_MODEL_ILP32:
4595 		{
4596 			if (ddi_copyin((void *)arg, &mtop_32_for_64,
4597 			    sizeof (struct mtop32), flag)) {
4598 				return (EFAULT);
4599 			}
4600 			mtop->mt_op = mtop_32_for_64.mt_op;
4601 			mtop->mt_count =  (daddr_t)mtop_32_for_64.mt_count;
4602 			break;
4603 		}
4604 		case DDI_MODEL_NONE:
4605 			if (ddi_copyin((void *)arg, mtop,
4606 			    sizeof (struct mtop), flag)) {
4607 				return (EFAULT);
4608 			}
4609 			break;
4610 		}
4611 
4612 #else /* ! _MULTI_DATAMODEL */
4613 		if (ddi_copyin((void *)arg, mtop, sizeof (struct mtop), flag)) {
4614 			return (EFAULT);
4615 		}
4616 #endif /* _MULTI_DATAMODEL */
4617 
4618 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
4619 	    "st_mtioctop(): mt_op=%x\n", mtop->mt_op);
4620 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
4621 	    "fileno=%x, blkno=%lx, un_eof=%x\n", un->un_fileno, un->un_blkno,
4622 	    un->un_eof);
4623 
4624 	rval = 0;
4625 	un->un_status = 0;
4626 
4627 	/*
4628 	 * If we haven't done/checked reservation on the tape unit
4629 	 * do it now.
4630 	 */
4631 	if (ST_RESERVE_SUPPORTED(un) &&
4632 		!(un->un_rsvd_status & ST_INIT_RESERVE)) {
4633 		if (rval = st_tape_reservation_init(dev))
4634 			return (rval);
4635 	}
4636 	/*
4637 	 * if we are going to mess with a tape, we have to make sure we have
4638 	 * one and are not offline (i.e. no tape is initialized).  We let
4639 	 * commands pass here that don't actually touch the tape, except for
4640 	 * loading and initialization (rewinding).
4641 	 */
4642 	if (un->un_state == ST_STATE_OFFLINE) {
4643 		switch (mtop->mt_op) {
4644 		case MTLOAD:
4645 		case MTNOP:
4646 			/*
4647 			 * We don't want strategy calling st_tape_init here,
4648 			 * so, change state
4649 			 */
4650 			un->un_state = ST_STATE_INITIALIZING;
4651 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4652 			    "st_mtioctop : OFFLINE state = %d\n",
4653 			    un->un_state);
4654 			break;
4655 		default:
4656 			/*
4657 			 * reinitialize by normal means
4658 			 */
4659 			if (st_tape_init(dev)) {
4660 				un->un_state = ST_STATE_INITIALIZING;
4661 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4662 				    "st_mtioctop : OFFLINE init failure ");
4663 				un->un_state = ST_STATE_OFFLINE;
4664 				un->un_fileno = -1;
4665 				return (EIO);
4666 			}
4667 			un->un_state = ST_STATE_OPEN_PENDING_IO;
4668 			break;
4669 		}
4670 	}
4671 
4672 	/*
4673 	 * If the file position is invalid, allow only those
4674 	 * commands that properly position the tape and fail
4675 	 * the rest with EIO
4676 	 */
4677 	if (un->un_fileno < 0) {
4678 		switch (mtop->mt_op) {
4679 		case MTWEOF:
4680 		case MTRETEN:
4681 		case MTERASE:
4682 		case MTEOM:
4683 		case MTFSF:
4684 		case MTFSR:
4685 		case MTBSF:
4686 		case MTNBSF:
4687 		case MTBSR:
4688 		case MTSRSZ:
4689 		case MTGRSZ:
4690 			return (EIO);
4691 			/* NOTREACHED */
4692 		case MTREW:
4693 		case MTLOAD:
4694 		case MTOFFL:
4695 		case MTNOP:
4696 			break;
4697 
4698 		default:
4699 			return (ENOTTY);
4700 			/* NOTREACHED */
4701 		}
4702 	}
4703 
4704 	switch (mtop->mt_op) {
4705 	case MTERASE:
4706 		/*
4707 		 * MTERASE rewinds the tape, erase it completely, and returns
4708 		 * to the beginning of the tape
4709 		 */
4710 		if (un->un_dp->options & ST_REEL)
4711 			un->un_fmneeded = 2;
4712 
4713 		if (un->un_mspl->wp || un->un_read_only) {
4714 			un->un_status = KEY_WRITE_PROTECT;
4715 			un->un_err_resid = mtop->mt_count;
4716 			un->un_err_fileno = un->un_fileno;
4717 			un->un_err_blkno = un->un_blkno;
4718 			return (EACCES);
4719 		}
4720 		if (st_check_density_or_wfm(dev, 1, B_WRITE, NO_STEPBACK) ||
4721 		    st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD) ||
4722 		    st_cmd(dev, SCMD_ERASE, 0, SYNC_CMD)) {
4723 			un->un_fileno = -1;
4724 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4725 			    "st_mtioctop : EIO space or erase or check den)\n");
4726 			rval = EIO;
4727 		} else {
4728 			/* QIC and helical scan rewind after erase */
4729 			if (un->un_dp->options & ST_REEL) {
4730 				(void) st_cmd(dev, SCMD_REWIND, 0, ASYNC_CMD);
4731 			}
4732 		}
4733 		break;
4734 
4735 	case MTWEOF:
4736 		/*
4737 		 * write an end-of-file record
4738 		 */
4739 		if (un->un_mspl->wp || un->un_read_only) {
4740 			un->un_status = KEY_WRITE_PROTECT;
4741 			un->un_err_resid = mtop->mt_count;
4742 			un->un_err_fileno = un->un_fileno;
4743 			un->un_err_blkno = un->un_blkno;
4744 			return (EACCES);
4745 		}
4746 
4747 		/*
4748 		 * zero count means just flush buffers
4749 		 * negative count is not permitted
4750 		 */
4751 		if (mtop->mt_count < 0)
4752 			return (EINVAL);
4753 
4754 		if (!un->un_read_only) {
4755 			un->un_test_append = 1;
4756 		}
4757 
4758 		if (un->un_state == ST_STATE_OPEN_PENDING_IO) {
4759 			if (st_determine_density(dev, B_WRITE)) {
4760 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4761 				    "st_mtioctop : EIO : MTWEOF can't determine"
4762 				    "density");
4763 				return (EIO);
4764 			}
4765 		}
4766 
4767 		if (st_write_fm(dev, (int)mtop->mt_count)) {
4768 			/*
4769 			 * Failure due to something other than illegal
4770 			 * request results in loss of state (st_intr).
4771 			 */
4772 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4773 			    "st_mtioctop : EIO : MTWEOF can't write file mark");
4774 			rval = EIO;
4775 		}
4776 		break;
4777 
4778 	case MTRETEN:
4779 		/*
4780 		 * retension the tape
4781 		 */
4782 		if (st_check_density_or_wfm(dev, 1, 0, NO_STEPBACK) ||
4783 		    st_cmd(dev, SCMD_LOAD, 3, SYNC_CMD)) {
4784 			un->un_fileno = -1;
4785 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4786 			    "st_mtioctop : EIO : MTRETEN ");
4787 			rval = EIO;
4788 		}
4789 		break;
4790 
4791 	case MTREW:
4792 		/*
4793 		 * rewind  the tape
4794 		 */
4795 		if (st_check_density_or_wfm(dev, 1, 0, NO_STEPBACK)) {
4796 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4797 			    "st_mtioctop : EIO:MTREW check density/wfm failed");
4798 			return (EIO);
4799 		}
4800 		if (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD)) {
4801 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4802 			    "st_mtioctop : EIO : MTREW ");
4803 			rval = EIO;
4804 		}
4805 		break;
4806 
4807 	case MTOFFL:
4808 		/*
4809 		 * rewinds, and, if appropriate, takes the device offline by
4810 		 * unloading the tape
4811 		 */
4812 		if (st_check_density_or_wfm(dev, 1, 0, NO_STEPBACK)) {
4813 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4814 			    "st_mtioctop :EIO:MTOFFL check density/wfm failed");
4815 			return (EIO);
4816 		}
4817 		(void) st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD);
4818 		if (st_cmd(dev, SCMD_LOAD, 0, SYNC_CMD)) {
4819 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4820 			    "st_mtioctop : EIO : MTOFFL");
4821 			return (EIO);
4822 		}
4823 		un->un_eof = ST_NO_EOF;
4824 		un->un_laststate = un->un_state;
4825 		un->un_state = ST_STATE_OFFLINE;
4826 		un->un_mediastate = MTIO_EJECTED;
4827 		break;
4828 
4829 	case MTLOAD:
4830 		/*
4831 		 * This is to load a tape into the drive
4832 		 * Note that if the tape is not loaded, the device will have
4833 		 * to be opened via O_NDELAY or O_NONBLOCK.
4834 		 */
4835 		/*
4836 		 * Let's try and clean things up, if we are not
4837 		 * initializing, and then send in the load command, no
4838 		 * matter what.
4839 		 *
4840 		 * we try the load twice because some drives fail the first
4841 		 * load after a media change by the user.
4842 		 */
4843 
4844 		if (un->un_state > ST_STATE_INITIALIZING)
4845 			(void) st_check_density_or_wfm(dev, 1, 0, NO_STEPBACK);
4846 
4847 		if (st_cmd(dev, SCMD_LOAD, 1, SYNC_CMD) &&
4848 		    st_cmd(dev, SCMD_LOAD, 1, SYNC_CMD)) {
4849 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4850 			    "st_mtioctop : EIO : MTLOAD\n");
4851 			rval = EIO;
4852 
4853 			/*
4854 			 * If load tape fails, who knows what happened...
4855 			 */
4856 			un->un_fileno = -1;
4857 			rval = EIO;
4858 			break;
4859 		}
4860 
4861 		/*
4862 		 * reset all counters appropriately using rewind, as if LOAD
4863 		 * succeeds, we are at BOT
4864 		 */
4865 		un->un_state = ST_STATE_INITIALIZING;
4866 
4867 		if (st_tape_init(dev)) {
4868 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4869 			    "st_mtioctop : EIO : MTLOAD calls st_tape_init\n");
4870 			rval = EIO;
4871 			un->un_state = ST_STATE_OFFLINE;
4872 		}
4873 
4874 		break;
4875 
4876 	case MTNOP:
4877 		un->un_status = 0;		/* Reset status */
4878 		un->un_err_resid = 0;
4879 		break;
4880 
4881 	case MTEOM:
4882 		/*
4883 		 * positions the tape at a location just after the last file
4884 		 * written on the tape. For cartridge and 8 mm, this after
4885 		 * the last file mark; for reel, this is inbetween the two
4886 		 * last 2 file marks
4887 		 */
4888 		if ((un->un_eof >= ST_EOT) ||
4889 		    (un->un_lastop == ST_OP_WRITE) ||
4890 		    (un->un_lastop == ST_OP_WEOF)) {
4891 			/*
4892 			 * If the command wants to move to logical end
4893 			 * of media, and we're already there, we're done.
4894 			 * If we were at logical eot, we reset the state
4895 			 * to be *not* at logical eot.
4896 			 *
4897 			 * If we're at physical or logical eot, we prohibit
4898 			 * forward space operations (unconditionally).
4899 			 *
4900 			 * Also if the last operation was a write of any
4901 			 * kind the tape is at EOD.
4902 			 */
4903 			return (0);
4904 		}
4905 		/*
4906 		 * physical tape position may not be what we've been
4907 		 * telling the user; adjust the request accordingly
4908 		 */
4909 		if (IN_EOF(un)) {
4910 			un->un_fileno++;
4911 			un->un_blkno = 0;
4912 		}
4913 
4914 		if (st_check_density_or_wfm(dev, 1, B_READ, NO_STEPBACK)) {
4915 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4916 			    "st_mtioctop : EIO:MTEOM check density/wfm failed");
4917 			return (EIO);
4918 		}
4919 
4920 		/*
4921 		 * st_find_eom() returns the last fileno we knew about;
4922 		 */
4923 		savefile = st_find_eom(dev);
4924 
4925 		if ((un->un_status != KEY_BLANK_CHECK) &&
4926 		    (un->un_status != SUN_KEY_EOT)) {
4927 			un->un_fileno = -1;
4928 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4929 			    "st_mtioctop : EIO : MTEOM status check failed");
4930 			rval = EIO;
4931 		} else {
4932 			/*
4933 			 * For 1/2" reel tapes assume logical EOT marked
4934 			 * by two file marks or we don't care that we may
4935 			 * be extending the last file on the tape.
4936 			 */
4937 			if (un->un_dp->options & ST_REEL) {
4938 				if (st_cmd(dev, SCMD_SPACE, Fmk((-1)),
4939 				    SYNC_CMD)) {
4940 					un->un_fileno = -1;
4941 					ST_DEBUG2(ST_DEVINFO, st_label,
4942 					    SCSI_DEBUG,
4943 					    "st_mtioctop : EIO : MTEOM space "
4944 					    "cmd failed");
4945 					rval = EIO;
4946 					break;
4947 				}
4948 				/*
4949 				 * Fix up the block number.
4950 				 */
4951 				un->un_blkno = 0;
4952 				un->un_err_blkno = 0;
4953 			}
4954 			un->un_err_resid = 0;
4955 			un->un_fileno = savefile;
4956 			un->un_eof = ST_EOT;
4957 		}
4958 		un->un_status = 0;
4959 		break;
4960 
4961 	case MTFSF:
4962 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
4963 		    "fsf: count=%lx, eof=%x\n", mtop->mt_count,
4964 			un->un_eof);
4965 		/*
4966 		 * forward space over filemark
4967 		 *
4968 		 * For ASF we allow a count of 0 on fsf which means
4969 		 * we just want to go to beginning of current file.
4970 		 * Equivalent to "nbsf(0)" or "bsf(1) + fsf".
4971 		 * Allow stepping over double fmk with reel
4972 		 */
4973 		if ((un->un_eof >= ST_EOT) && (mtop->mt_count > 0) &&
4974 		    ((un->un_dp->options & ST_REEL) == 0)) {
4975 			/* we're at EOM */
4976 			un->un_err_resid = mtop->mt_count;
4977 			un->un_status = KEY_BLANK_CHECK;
4978 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
4979 			    "st_mtioctop : EIO : MTFSF at EOM");
4980 			return (EIO);
4981 		}
4982 
4983 		/*
4984 		 * physical tape position may not be what we've been
4985 		 * telling the user; adjust the request accordingly
4986 		 */
4987 		if (IN_EOF(un)) {
4988 			un->un_fileno++;
4989 			un->un_blkno = 0;
4990 			/*
4991 			 * For positive direction case, we're now covered.
4992 			 * For zero or negative direction, we're covered
4993 			 * (almost)
4994 			 */
4995 			mtop->mt_count--;
4996 		}
4997 
4998 		if (st_check_density_or_wfm(dev, 1, B_READ, STEPBACK)) {
4999 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5000 			    "st_mtioctop : EIO : MTFSF density/wfm failed");
5001 			return (EIO);
5002 		}
5003 
5004 
5005 		/*
5006 		 * Forward space file marks.
5007 		 * We leave ourselves at block zero
5008 		 * of the target file number.
5009 		 */
5010 		if (mtop->mt_count < 0) {
5011 			mtop->mt_count = -mtop->mt_count;
5012 			mtop->mt_op = MTNBSF;
5013 			goto bspace;
5014 		}
5015 fspace:
5016 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5017 		    "fspace: count=%lx, eof=%x\n", mtop->mt_count,
5018 			un->un_eof);
5019 		if ((tmp = mtop->mt_count) == 0) {
5020 			if (un->un_blkno == 0) {
5021 				un->un_err_resid = 0;
5022 				un->un_err_fileno = un->un_fileno;
5023 				un->un_err_blkno = un->un_blkno;
5024 				break;
5025 			} else if (un->un_fileno == 0) {
5026 				rval = st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD);
5027 			} else if (un->un_dp->options & ST_BSF) {
5028 				rval = (st_cmd(dev, SCMD_SPACE, Fmk((-1)),
5029 				    SYNC_CMD) ||
5030 				    st_cmd(dev, SCMD_SPACE, Fmk(1), SYNC_CMD));
5031 			} else {
5032 				tmp = un->un_fileno;
5033 				rval = (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD) ||
5034 				    st_cmd(dev, SCMD_SPACE, (int)Fmk(tmp),
5035 				    SYNC_CMD));
5036 			}
5037 			if (rval != 0) {
5038 				un->un_fileno = -1;
5039 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5040 				    "st_mtioctop : EIO : fspace fileno = -1");
5041 
5042 				rval = EIO;
5043 			}
5044 		} else {
5045 			rval = st_space_fmks(dev, tmp);
5046 		}
5047 
5048 		if (mtop->mt_op == MTBSF && rval != EIO) {
5049 			/*
5050 			 * we came here with a count < 0; we now need
5051 			 * to skip back to end up before the filemark
5052 			 */
5053 			mtop->mt_count = 1;
5054 			goto bspace;
5055 		}
5056 		break;
5057 
5058 
5059 	case MTFSR:
5060 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5061 		    "fsr: count=%lx, eof=%x\n", mtop->mt_count,
5062 			un->un_eof);
5063 		/*
5064 		 * forward space to inter-record gap
5065 		 *
5066 		 */
5067 		if ((un->un_eof >= ST_EOT) && (mtop->mt_count > 0)) {
5068 			/* we're at EOM */
5069 			un->un_err_resid = mtop->mt_count;
5070 			un->un_status = KEY_BLANK_CHECK;
5071 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5072 			    "st_mtioctop : EIO : MTFSR un_eof > ST_EOT");
5073 			return (EIO);
5074 		}
5075 
5076 		if (mtop->mt_count == 0) {
5077 			un->un_err_fileno = un->un_fileno;
5078 			un->un_err_blkno = un->un_blkno;
5079 			un->un_err_resid = 0;
5080 			if (IN_EOF(un) && SVR4_BEHAVIOR) {
5081 				un->un_status = SUN_KEY_EOF;
5082 			}
5083 			return (0);
5084 		}
5085 
5086 		/*
5087 		 * physical tape position may not be what we've been
5088 		 * telling the user; adjust the position accordingly
5089 		 */
5090 		if (IN_EOF(un)) {
5091 			daddr_t blkno = un->un_blkno;
5092 			int fileno = un->un_fileno;
5093 			uchar_t lastop = un->un_lastop;
5094 			if (st_cmd(dev, SCMD_SPACE, Fmk((-1)), SYNC_CMD)
5095 			    == -1) {
5096 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5097 				    "st_mtioctop : EIO :MTFSR count && IN_EOF");
5098 				return (EIO);
5099 			}
5100 
5101 			un->un_blkno = blkno;
5102 			un->un_fileno = fileno;
5103 			un->un_lastop = lastop;
5104 		}
5105 
5106 		if (st_check_density_or_wfm(dev, 1, B_READ, STEPBACK)) {
5107 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5108 			    "st_mtioctop : EIO : MTFSR st_check_den");
5109 			return (EIO);
5110 		}
5111 
5112 space_records:
5113 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5114 		    "space_records: count=%lx, eof=%x\n", mtop->mt_count,
5115 			un->un_eof);
5116 		tmp = un->un_blkno + mtop->mt_count;
5117 		if (tmp == un->un_blkno) {
5118 			un->un_err_resid = 0;
5119 			un->un_err_fileno = un->un_fileno;
5120 			un->un_err_blkno = un->un_blkno;
5121 			break;
5122 		} else if (un->un_blkno < tmp ||
5123 		    (un->un_dp->options & ST_BSR)) {
5124 			/*
5125 			 * If we're spacing forward, or the device can
5126 			 * backspace records, we can just use the SPACE
5127 			 * command.
5128 			 */
5129 			tmp = tmp - un->un_blkno;
5130 			if (st_cmd(dev, SCMD_SPACE, Blk(tmp), SYNC_CMD)) {
5131 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5132 				    "st_mtioctop :EIO:space_records can't spc");
5133 				rval = EIO;
5134 			} else if (un->un_eof >= ST_EOF_PENDING) {
5135 				/*
5136 				 * check if we hit BOT/EOT
5137 				 */
5138 				if (tmp < 0 && un->un_eof == ST_EOM) {
5139 					un->un_status = SUN_KEY_BOT;
5140 					un->un_eof = ST_NO_EOF;
5141 				} else if (tmp < 0 && un->un_eof ==
5142 				    ST_EOF_PENDING) {
5143 					int residue = un->un_err_resid;
5144 					/*
5145 					 * we skipped over a filemark
5146 					 * and need to go forward again
5147 					 */
5148 					if (st_cmd(dev, SCMD_SPACE, Fmk(1),
5149 					    SYNC_CMD)) {
5150 						ST_DEBUG2(ST_DEVINFO,
5151 						    st_label, SCSI_DEBUG,
5152 						    "st_mtioctop : EIO : "
5153 						    "space_records can't "
5154 						    "space #2");
5155 						rval = EIO;
5156 					}
5157 					un->un_err_resid = residue;
5158 				}
5159 				if (rval == 0) {
5160 					ST_DEBUG2(ST_DEVINFO, st_label,
5161 					    SCSI_DEBUG,
5162 					    "st_mtioctop : EIO : space_rec rval"
5163 					    " == 0");
5164 					rval = EIO;
5165 				}
5166 			}
5167 		} else {
5168 			/*
5169 			 * else we rewind, space forward across filemarks to
5170 			 * the desired file, and then space records to the
5171 			 * desired block.
5172 			 */
5173 
5174 			int t = un->un_fileno;	/* save current file */
5175 
5176 			if (tmp < 0) {
5177 				/*
5178 				 * Wups - we're backing up over a filemark
5179 				 */
5180 				if (un->un_blkno != 0 &&
5181 				    (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD) ||
5182 				    st_cmd(dev, SCMD_SPACE, Fmk(t), SYNC_CMD)))
5183 					un->un_fileno = -1;
5184 				un->un_err_resid = -tmp;
5185 				if (un->un_fileno == 0 && un->un_blkno == 0) {
5186 					un->un_status = SUN_KEY_BOT;
5187 					un->un_eof = ST_NO_EOF;
5188 				} else if (un->un_fileno > 0) {
5189 					un->un_status = SUN_KEY_EOF;
5190 					un->un_eof = ST_NO_EOF;
5191 				}
5192 				un->un_err_fileno = un->un_fileno;
5193 				un->un_err_blkno = un->un_blkno;
5194 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5195 				    "st_mtioctop :EIO:space_records : tmp < 0");
5196 				rval = EIO;
5197 			} else if (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD) ||
5198 				    st_cmd(dev, SCMD_SPACE, Fmk(t), SYNC_CMD) ||
5199 				    st_cmd(dev, SCMD_SPACE, Blk(tmp),
5200 					SYNC_CMD)) {
5201 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5202 				    "st_mtioctop : EIO :space_records : rewind "
5203 				    "and space failed");
5204 				un->un_fileno = -1;
5205 				rval = EIO;
5206 			}
5207 		}
5208 		break;
5209 
5210 
5211 	case MTBSF:
5212 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5213 		    "bsf: count=%lx, eof=%x\n", mtop->mt_count,
5214 			un->un_eof);
5215 		/*
5216 		 * backward space of file filemark (1/2" and 8mm)
5217 		 * tape position will end on the beginning of tape side
5218 		 * of the desired file mark
5219 		 */
5220 		if ((un->un_dp->options & ST_BSF) == 0) {
5221 			return (ENOTTY);
5222 		}
5223 
5224 		/*
5225 		 * If a negative count (which implies a forward space op)
5226 		 * is specified, and we're at logical or physical eot,
5227 		 * bounce the request.
5228 		 */
5229 
5230 		if (un->un_eof >= ST_EOT && mtop->mt_count < 0) {
5231 			un->un_err_resid = mtop->mt_count;
5232 			un->un_status = SUN_KEY_EOT;
5233 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5234 			    "st_ioctl : EIO : MTBSF : un_eof > ST_EOF");
5235 			return (EIO);
5236 		}
5237 		/*
5238 		 * physical tape position may not be what we've been
5239 		 * telling the user; adjust the request accordingly
5240 		 */
5241 		if (IN_EOF(un)) {
5242 			un->un_fileno++;
5243 			un->un_blkno = 0;
5244 			mtop->mt_count++;
5245 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5246 			"bsf in eof: count=%ld, op=%x\n",
5247 			mtop->mt_count, mtop->mt_op);
5248 
5249 		}
5250 
5251 		if (st_check_density_or_wfm(dev, 1, 0, STEPBACK)) {
5252 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5253 			    "st_ioctl : EIO : MTBSF : check den wfm");
5254 			return (EIO);
5255 		}
5256 
5257 		if (mtop->mt_count <= 0) {
5258 			/*
5259 			 * for a negative count, we need to step forward
5260 			 * first and then step back again
5261 			 */
5262 			mtop->mt_count = -mtop->mt_count+1;
5263 			goto fspace;
5264 		}
5265 
5266 bspace:
5267 	{
5268 		int skip_cnt, end_at_eof;
5269 
5270 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5271 		    "bspace: count=%lx, eof=%x\n", mtop->mt_count,
5272 			un->un_eof);
5273 		/*
5274 		 * Backspace files (MTNBSF):
5275 		 *
5276 		 *	For tapes that can backspace, backspace
5277 		 *	count+1 filemarks and then run forward over
5278 		 *	a filemark
5279 		 *
5280 		 *	For tapes that can't backspace,
5281 		 *		calculate desired filenumber
5282 		 *		(un->un_fileno - count), rewind,
5283 		 *		and then space forward this amount
5284 		 *
5285 		 * Backspace filemarks (MTBSF)
5286 		 *
5287 		 *	For tapes that can backspace, backspace count
5288 		 *	filemarks
5289 		 *
5290 		 *	For tapes that can't backspace, calculate
5291 		 *	desired filenumber (un->un_fileno - count),
5292 		 *	add 1, rewind, space forward this amount,
5293 		 *	and mark state as ST_EOF_PENDING appropriately.
5294 		 */
5295 
5296 		if (mtop->mt_op == MTBSF) {
5297 			end_at_eof = 1;
5298 		} else {
5299 			end_at_eof = 0;
5300 		}
5301 
5302 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5303 		    "bspace: mt_op=%x, count=%lx, fileno=%x, blkno=%lx\n",
5304 		    mtop->mt_op, mtop->mt_count, un->un_fileno, un->un_blkno);
5305 
5306 		/*
5307 		 * Handle the simple case of BOT
5308 		 * playing a role in these cmds.
5309 		 * We do this by calculating the
5310 		 * ending file number. If the ending
5311 		 * file is < BOT, rewind and set an
5312 		 * error and mark resid appropriately.
5313 		 * If we're backspacing a file (not a
5314 		 * filemark) and the target file is
5315 		 * the first file on the tape, just
5316 		 * rewind.
5317 		 */
5318 
5319 		tmp = un->un_fileno - mtop->mt_count;
5320 		if ((end_at_eof && tmp < 0) || (end_at_eof == 0 && tmp <= 0)) {
5321 			if (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD)) {
5322 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5323 				    "st_ioctl : EIO : bspace : end_at_eof && "
5324 				    "tmp < 0");
5325 				rval = EIO;
5326 			}
5327 			if (tmp < 0) {
5328 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5329 				    "st_ioctl : EIO : bspace : tmp < 0");
5330 				rval = EIO;
5331 				un->un_err_resid = -tmp;
5332 				un->un_status = SUN_KEY_BOT;
5333 			}
5334 			break;
5335 		}
5336 
5337 		if (un->un_dp->options & ST_BSF) {
5338 			skip_cnt = 1 - end_at_eof;
5339 			/*
5340 			 * If we are going to end up at the beginning
5341 			 * of the file, we have to space one extra file
5342 			 * first, and then space forward later.
5343 			 */
5344 			tmp = -(mtop->mt_count + skip_cnt);
5345 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5346 			    "skip_cnt=%x, tmp=%x\n", skip_cnt, tmp);
5347 			if (st_cmd(dev, SCMD_SPACE, Fmk(tmp), SYNC_CMD)) {
5348 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5349 				    "st_ioctl : EIO : bspace : can't space "
5350 				    "tmp");
5351 				rval = EIO;
5352 			}
5353 		} else {
5354 			if (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD)) {
5355 				rval = EIO;
5356 			} else {
5357 				skip_cnt = tmp + end_at_eof;
5358 			}
5359 		}
5360 
5361 		/*
5362 		 * If we have to space forward, do so...
5363 		 */
5364 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5365 		    "space forward skip_cnt=%x, rval=%x\n", skip_cnt, rval);
5366 		if (rval == 0 && skip_cnt) {
5367 			if (st_cmd(dev, SCMD_SPACE, Fmk(skip_cnt), SYNC_CMD)) {
5368 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5369 				    "st_ioctl : EIO : bspace : can't space "
5370 				    "skip_cnt");
5371 				rval = EIO;
5372 			} else if (end_at_eof) {
5373 				/*
5374 				 * If we had to space forward, and we're
5375 				 * not a tape that can backspace, mark state
5376 				 * as if we'd just seen a filemark during a
5377 				 * a read.
5378 				 */
5379 				if ((un->un_dp->options & ST_BSF) == 0) {
5380 					un->un_eof = ST_EOF_PENDING;
5381 					un->un_fileno -= 1;
5382 					un->un_blkno = INF;
5383 				}
5384 			}
5385 		}
5386 
5387 		if (rval != 0) {
5388 			un->un_fileno = -1;
5389 		}
5390 		break;
5391 	}
5392 
5393 	case MTNBSF:
5394 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5395 		    "nbsf: count=%lx, eof=%x\n", mtop->mt_count,
5396 			un->un_eof);
5397 		/*
5398 		 * backward space file to beginning of file
5399 		 *
5400 		 * If a negative count (which implies a forward space op)
5401 		 * is specified, and we're at logical or physical eot,
5402 		 * bounce the request.
5403 		 */
5404 
5405 		if (un->un_eof >= ST_EOT && mtop->mt_count < 0) {
5406 			un->un_err_resid = mtop->mt_count;
5407 			un->un_status = SUN_KEY_EOT;
5408 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5409 			    "st_ioctl : EIO : > EOT and count < 0");
5410 			return (EIO);
5411 		}
5412 		/*
5413 		 * physical tape position may not be what we've been
5414 		 * telling the user; adjust the request accordingly
5415 		 */
5416 		if (IN_EOF(un)) {
5417 			un->un_fileno++;
5418 			un->un_blkno = 0;
5419 			mtop->mt_count++;
5420 		}
5421 
5422 		if (st_check_density_or_wfm(dev, 1, 0, STEPBACK)) {
5423 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5424 			    "st_ioctl : EIO : MTNBSF check den and wfm");
5425 			return (EIO);
5426 		}
5427 
5428 mtnbsf:
5429 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5430 		    "mtnbsf: count=%lx, eof=%x\n", mtop->mt_count,
5431 			un->un_eof);
5432 		if (mtop->mt_count <= 0) {
5433 			mtop->mt_op = MTFSF;
5434 			mtop->mt_count = -mtop->mt_count;
5435 			goto fspace;
5436 		}
5437 		goto bspace;
5438 
5439 	case MTBSR:
5440 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5441 		    "bsr: count=%lx, eof=%x\n", mtop->mt_count,
5442 			un->un_eof);
5443 		/*
5444 		 * backward space into inter-record gap
5445 		 *
5446 		 * If a negative count (which implies a forward space op)
5447 		 * is specified, and we're at logical or physical eot,
5448 		 * bounce the request.
5449 		 */
5450 		if (un->un_eof >= ST_EOT && mtop->mt_count < 0) {
5451 			un->un_err_resid = mtop->mt_count;
5452 			un->un_status = SUN_KEY_EOT;
5453 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5454 			    "st_ioctl : EIO : MTBSR > EOT");
5455 			return (EIO);
5456 		}
5457 
5458 		if (mtop->mt_count == 0) {
5459 			un->un_err_fileno = un->un_fileno;
5460 			un->un_err_blkno = un->un_blkno;
5461 			un->un_err_resid = 0;
5462 			if (IN_EOF(un) && SVR4_BEHAVIOR) {
5463 				un->un_status = SUN_KEY_EOF;
5464 			}
5465 			return (0);
5466 		}
5467 
5468 		/*
5469 		 * physical tape position may not be what we've been
5470 		 * telling the user; adjust the position accordingly.
5471 		 * bsr can not skip filemarks and continue to skip records
5472 		 * therefore if we are logically before the filemark but
5473 		 * physically at the EOT side of the filemark, we need to step
5474 		 * back; this allows fsr N where N > number of blocks in file
5475 		 * followed by bsr 1 to position at the beginning of last block
5476 		 */
5477 		if (IN_EOF(un)) {
5478 			int blkno = un->un_blkno;
5479 			int fileno = un->un_fileno;
5480 			uchar_t lastop = un->un_lastop;
5481 			if (st_cmd(dev, SCMD_SPACE, Fmk((-1)), SYNC_CMD)
5482 			    == -1) {
5483 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5484 				    "st_write_fm : EIO : MTBSR can't space");
5485 				return (EIO);
5486 			}
5487 
5488 			un->un_blkno = blkno;
5489 			un->un_fileno = fileno;
5490 			un->un_lastop = lastop;
5491 		}
5492 
5493 		un->un_eof = ST_NO_EOF;
5494 
5495 		if (st_check_density_or_wfm(dev, 1, 0, STEPBACK)) {
5496 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5497 			    "st_ioctl : EIO : MTBSR : can't set density or "
5498 			    "wfm");
5499 			return (EIO);
5500 		}
5501 
5502 		mtop->mt_count = -mtop->mt_count;
5503 		goto space_records;
5504 
5505 	case MTSRSZ:
5506 
5507 		/*
5508 		 * Set record-size to that sent by user
5509 		 * Check to see if there is reason that the requested
5510 		 * block size should not be set.
5511 		 */
5512 
5513 		/* If requesting variable block size is it ok? */
5514 		if ((mtop->mt_count == 0) &&
5515 		    ((un->un_dp->options & ST_VARIABLE) == 0)) {
5516 			return (ENOTTY);
5517 		}
5518 
5519 		/*
5520 		 * If requested block size is not variable "0",
5521 		 * is it less then minimum.
5522 		 */
5523 		if ((mtop->mt_count != 0) &&
5524 		    (mtop->mt_count < un->un_minbsize)) {
5525 			return (EINVAL);
5526 		}
5527 
5528 		/* Is the requested block size more then maximum */
5529 		if ((mtop->mt_count > min(un->un_maxbsize, un->un_maxdma)) &&
5530 		    (un->un_maxbsize != 0)) {
5531 			return (EINVAL);
5532 		}
5533 
5534 		/* Is requested block size a modulus the device likes */
5535 		if ((mtop->mt_count % un->un_data_mod) != 0) {
5536 			return (EINVAL);
5537 		}
5538 
5539 		if (st_change_block_size(dev, (uint32_t)mtop->mt_count) != 0) {
5540 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5541 			    "st_ioctl : MTSRSZ : EIO : cant set block size");
5542 			return (EIO);
5543 		}
5544 
5545 		return (0);
5546 
5547 	case MTGRSZ:
5548 	{
5549 #ifdef _MULTI_DATAMODEL
5550 	/*
5551 	 * For use when a 32 bit app makes a call into a
5552 	 * 64 bit ioctl
5553 	 */
5554 	struct mtop32	mtop_32_for_64;
5555 #endif /* _MULTI_DATAMODEL */
5556 
5557 
5558 		/*
5559 		 * Get record-size to the user
5560 		 */
5561 		mtop->mt_count = un->un_bsize;
5562 
5563 #ifdef _MULTI_DATAMODEL
5564 		switch (ddi_model_convert_from(flag & FMODELS)) {
5565 		case DDI_MODEL_ILP32:
5566 			/*
5567 			 * Convert 64 bit back to 32 bit before doing
5568 			 * copyout. This is what the ILP32 app expects.
5569 			 */
5570 			mtop_32_for_64.mt_op = mtop->mt_op;
5571 			mtop_32_for_64.mt_count = mtop->mt_count;
5572 
5573 			if (ddi_copyout(&mtop_32_for_64, (void *)arg,
5574 			    sizeof (struct mtop32), flag)) {
5575 				return (EFAULT);
5576 			}
5577 			break;
5578 
5579 		case DDI_MODEL_NONE:
5580 			if (ddi_copyout(mtop, (void *)arg,
5581 			    sizeof (struct mtop), flag)) {
5582 				return (EFAULT);
5583 			}
5584 			break;
5585 		}
5586 #else /* ! _MULTI_DATAMODE */
5587 		if (ddi_copyout(mtop, (void *)arg, sizeof (struct mtop), flag))
5588 			return (EFAULT);
5589 
5590 #endif /* _MULTI_DATAMODE */
5591 
5592 		return (0);
5593 	}
5594 	default:
5595 		rval = ENOTTY;
5596 	}
5597 
5598 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5599 	    "st_ioctl: fileno=%x, blkno=%lx, un_eof=%x\n", un->un_fileno,
5600 	    un->un_blkno, un->un_eof);
5601 
5602 	if (un->un_fileno < 0) {
5603 		un->un_density_known = 0;
5604 	}
5605 
5606 	ASSERT(mutex_owned(ST_MUTEX));
5607 	return (rval);
5608 }
5609 
5610 
5611 /*
5612  * Run a command for uscsi ioctl.
5613  * cdbspace is address space of cdb.
5614  * dataspace is address space of the uscsi data buffer.
5615  */
5616 static int
5617 st_ioctl_cmd(dev_t dev, struct uscsi_cmd *ucmd,
5618 	enum uio_seg cdbspace, enum uio_seg dataspace,
5619 	enum uio_seg rqbufspace)
5620 {
5621 	struct buf *bp;
5622 	struct uscsi_cmd *kcmd;
5623 	caddr_t kcdb;
5624 	int flag;
5625 	int err;
5626 	int rqlen;
5627 	int offline_state = 0;
5628 	char *krqbuf = NULL;
5629 
5630 	GET_SOFT_STATE(dev);
5631 
5632 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
5633 	    "st_ioctl_cmd(dev = 0x%lx)\n", dev);
5634 
5635 	ASSERT(mutex_owned(ST_MUTEX));
5636 
5637 	/*
5638 	 * We really don't know what commands are coming in here and
5639 	 * we don't want to limit the commands coming in.
5640 	 *
5641 	 * If st_tape_init() gets called from st_strategy(), then we
5642 	 * will hang the process waiting for un->un_sbuf_busy to be cleared,
5643 	 * which it never will, as we set it below.  To prevent
5644 	 * st_tape_init() from getting called, we have to set state to other
5645 	 * than ST_STATE_OFFLINE, so we choose ST_STATE_INITIALIZING, which
5646 	 * achieves this purpose already
5647 	 *
5648 	 * We use offline_state to preserve the OFFLINE state, if it exists,
5649 	 * so other entry points to the driver might have the chance to call
5650 	 * st_tape_init().
5651 	 */
5652 	if (un->un_state == ST_STATE_OFFLINE) {
5653 		un->un_laststate = ST_STATE_OFFLINE;
5654 		un->un_state = ST_STATE_INITIALIZING;
5655 		offline_state = 1;
5656 	}
5657 	/*
5658 	 * Is this a request to reset the bus?
5659 	 * If so, we need go no further.
5660 	 */
5661 	if (ucmd->uscsi_flags & (USCSI_RESET|USCSI_RESET_ALL)) {
5662 		flag = ((ucmd->uscsi_flags & USCSI_RESET_ALL)) ?
5663 			RESET_ALL : RESET_TARGET;
5664 
5665 		mutex_exit(ST_MUTEX);
5666 		err = (scsi_reset(ROUTE, flag)) ? 0 : EIO;
5667 		mutex_enter(ST_MUTEX);
5668 
5669 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
5670 			"reset %s %s\n",
5671 			(flag == RESET_ALL) ? "all" : "target",
5672 			(err == 0) ? "ok" : "failed");
5673 		/*
5674 		 * If scsi reset successful, don't write any filemarks.
5675 		 */
5676 		if (err == 0) {
5677 			un->un_fmneeded = 0;
5678 		} else {
5679 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5680 			    "st_ioctl_cmd : EIO : scsi_reset failed");
5681 		}
5682 		goto exit;
5683 	}
5684 
5685 	/*
5686 	 * First do some sanity checks for USCSI commands.
5687 	 */
5688 	if (ucmd->uscsi_cdblen <= 0) {
5689 		return (EINVAL);
5690 	}
5691 
5692 	/*
5693 	 * In order to not worry about where the uscsi structure
5694 	 * or cdb it points to came from, we kmem_alloc copies
5695 	 * of them here.  This will allow reference to the data
5696 	 * they contain long after this process has gone to
5697 	 * sleep and its kernel stack has been unmapped, etc.
5698 	 */
5699 
5700 	kcdb = kmem_alloc((size_t)ucmd->uscsi_cdblen, KM_SLEEP);
5701 	if (cdbspace == UIO_SYSSPACE) {
5702 		bcopy(ucmd->uscsi_cdb, kcdb, ucmd->uscsi_cdblen);
5703 	} else {
5704 		if (ddi_copyin(ucmd->uscsi_cdb, kcdb,
5705 		    (size_t)ucmd->uscsi_cdblen, 0)) {
5706 			kmem_free(kcdb, (size_t)ucmd->uscsi_cdblen);
5707 			err = EFAULT;
5708 			goto exit;
5709 		}
5710 	}
5711 
5712 	kcmd = kmem_alloc(sizeof (struct uscsi_cmd), KM_SLEEP);
5713 	bcopy(ucmd, kcmd, sizeof (struct uscsi_cmd));
5714 	kcmd->uscsi_cdb = kcdb;
5715 
5716 	flag = (kcmd->uscsi_flags & USCSI_READ) ? B_READ : B_WRITE;
5717 
5718 #ifdef STDEBUG
5719 	if (st_debug > 6) {
5720 		st_clean_print(ST_DEVINFO, st_label, SCSI_DEBUG,
5721 		    "uscsi cdb", kcdb, kcmd->uscsi_cdblen);
5722 		if (kcmd->uscsi_buflen) {
5723 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5724 			"uscsi %s of %ld bytes %s %s space\n",
5725 			(flag == B_READ) ? rd_str : wr_str,
5726 			kcmd->uscsi_buflen,
5727 			(flag == B_READ) ? "to" : "from",
5728 			(dataspace == UIO_SYSSPACE) ? "system" : "user");
5729 		}
5730 	}
5731 #endif /* ST_DEBUG */
5732 
5733 	/*
5734 	 * Initialize Request Sense buffering, if requested.
5735 	 * For user processes, allocate a kernel copy of the sense buffer
5736 	 */
5737 	if ((kcmd->uscsi_flags & USCSI_RQENABLE) &&
5738 			kcmd->uscsi_rqlen && kcmd->uscsi_rqbuf) {
5739 		if (rqbufspace == UIO_USERSPACE) {
5740 			krqbuf = kmem_alloc(SENSE_LENGTH, KM_SLEEP);
5741 		}
5742 		kcmd->uscsi_rqlen = SENSE_LENGTH;
5743 		kcmd->uscsi_rqresid = SENSE_LENGTH;
5744 	} else {
5745 		kcmd->uscsi_rqlen = 0;
5746 		kcmd->uscsi_rqresid = 0;
5747 	}
5748 
5749 	/*
5750 	 * Get buffer resources...
5751 	 */
5752 	while (un->un_sbuf_busy)
5753 		cv_wait(&un->un_sbuf_cv, ST_MUTEX);
5754 	un->un_sbuf_busy = 1;
5755 
5756 	un->un_srqbufp = krqbuf;
5757 	bp = un->un_sbufp;
5758 	bzero(bp, sizeof (buf_t));
5759 
5760 	/*
5761 	 * Force asynchronous mode, if necessary.
5762 	 */
5763 	if (ucmd->uscsi_flags & USCSI_ASYNC) {
5764 		mutex_exit(ST_MUTEX);
5765 		if (scsi_ifgetcap(ROUTE, "synchronous", 1) == 1) {
5766 			if (scsi_ifsetcap(ROUTE, "synchronous", 0, 1) == 1) {
5767 				ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
5768 				    "forced async ok\n");
5769 			} else {
5770 				ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
5771 				    "forced async failed\n");
5772 				err = EINVAL;
5773 				mutex_enter(ST_MUTEX);
5774 				goto done;
5775 			}
5776 		}
5777 		mutex_enter(ST_MUTEX);
5778 	}
5779 
5780 	/*
5781 	 * Re-enable synchronous mode, if requested
5782 	 */
5783 	if (ucmd->uscsi_flags & USCSI_SYNC) {
5784 		mutex_exit(ST_MUTEX);
5785 		if (scsi_ifgetcap(ROUTE, "synchronous", 1) == 0) {
5786 			int i = scsi_ifsetcap(ROUTE, "synchronous", 1, 1);
5787 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
5788 				"re-enabled sync %s\n",
5789 				(i == 1) ? "ok" : "failed");
5790 		}
5791 		mutex_enter(ST_MUTEX);
5792 	}
5793 
5794 	if (kcmd->uscsi_buflen) {
5795 		/*
5796 		 * We're going to do actual I/O.
5797 		 * Set things up for physio.
5798 		 */
5799 		struct iovec aiov;
5800 		struct uio auio;
5801 		struct uio *uio = &auio;
5802 
5803 		bzero(&auio, sizeof (struct uio));
5804 		bzero(&aiov, sizeof (struct iovec));
5805 		aiov.iov_base = kcmd->uscsi_bufaddr;
5806 		aiov.iov_len = kcmd->uscsi_buflen;
5807 
5808 		uio->uio_iov = &aiov;
5809 		uio->uio_iovcnt = 1;
5810 		uio->uio_resid = aiov.iov_len;
5811 		uio->uio_segflg = dataspace;
5812 
5813 		/*
5814 		 * Let physio do the rest...
5815 		 */
5816 		bp->b_forw = (struct buf *)(uintptr_t)kcdb[0];
5817 		bp->b_back = (struct buf *)kcmd;
5818 
5819 		mutex_exit(ST_MUTEX);
5820 		err = physio(st_strategy, bp, dev, flag, st_uscsi_minphys, uio);
5821 		mutex_enter(ST_MUTEX);
5822 	} else {
5823 		/*
5824 		 * Mimic physio
5825 		 */
5826 		bp->b_forw = (struct buf *)(uintptr_t)kcdb[0];
5827 		bp->b_back = (struct buf *)kcmd;
5828 		bp->b_flags = B_BUSY | flag;
5829 		bp->b_edev = dev;
5830 		bp->b_dev = cmpdev(dev);
5831 		bp->b_bcount = 0;
5832 		bp->b_blkno = 0;
5833 		bp->b_resid = 0;
5834 		mutex_exit(ST_MUTEX);
5835 		(void) st_strategy(bp);
5836 
5837 		/*
5838 		 * BugTraq #4260046
5839 		 * ----------------
5840 		 * See comments in st_cmd.
5841 		 */
5842 
5843 		err = biowait(bp);
5844 		mutex_enter(ST_MUTEX);
5845 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5846 		    "st_ioctl_cmd: biowait returns %d\n", err);
5847 	}
5848 
5849 	/*
5850 	 * Copy status from kernel copy of uscsi_cmd to user copy
5851 	 * of uscsi_cmd - this was saved in st_done_and_mutex_exit()
5852 	 */
5853 	ucmd->uscsi_status = kcmd->uscsi_status;
5854 
5855 done:
5856 	ucmd->uscsi_resid = bp->b_resid;
5857 
5858 	/*
5859 	 * Update the Request Sense status and resid
5860 	 */
5861 	rqlen = kcmd->uscsi_rqlen - kcmd->uscsi_rqresid;
5862 	rqlen = min(((int)ucmd->uscsi_rqlen), rqlen);
5863 	ucmd->uscsi_rqresid = ucmd->uscsi_rqlen - rqlen;
5864 	ucmd->uscsi_rqstatus = kcmd->uscsi_rqstatus;
5865 	/*
5866 	 * Copy out the sense data for user processes
5867 	 */
5868 	if (ucmd->uscsi_rqbuf && rqlen && rqbufspace == UIO_USERSPACE) {
5869 		if (copyout(krqbuf, ucmd->uscsi_rqbuf, rqlen)) {
5870 			err = EFAULT;
5871 		}
5872 	}
5873 
5874 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5875 	    "st_ioctl_cmd status is 0x%x, resid is 0x%lx\n",
5876 	    ucmd->uscsi_status, ucmd->uscsi_resid);
5877 	if (DEBUGGING && (rqlen != 0)) {
5878 		int i, n, len;
5879 		char *data = krqbuf;
5880 		scsi_log(ST_DEVINFO, st_label, SCSI_DEBUG,
5881 			"rqstatus=0x%x	rqlen=0x%x  rqresid=0x%x\n",
5882 			ucmd->uscsi_rqstatus, ucmd->uscsi_rqlen,
5883 			ucmd->uscsi_rqresid);
5884 		len = (int)ucmd->uscsi_rqlen - ucmd->uscsi_rqresid;
5885 		for (i = 0; i < len; i += 16) {
5886 			n = min(16, len-1);
5887 			st_clean_print(ST_DEVINFO, st_label, CE_NOTE,
5888 				"  ", &data[i], n);
5889 		}
5890 	}
5891 
5892 exit_free:
5893 	/*
5894 	 * Free resources
5895 	 */
5896 	un->un_sbuf_busy = 0;
5897 	un->un_srqbufp = NULL;
5898 	cv_signal(&un->un_sbuf_cv);
5899 
5900 	if (krqbuf) {
5901 		kmem_free(krqbuf, SENSE_LENGTH);
5902 	}
5903 	kmem_free(kcdb, kcmd->uscsi_cdblen);
5904 	kmem_free(kcmd, sizeof (struct uscsi_cmd));
5905 
5906 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5907 	    "st_ioctl_cmd returns 0x%x\n", err);
5908 
5909 
5910 exit:
5911 	/* don't lose offline state */
5912 	if (offline_state)
5913 		un->un_state = ST_STATE_OFFLINE;
5914 
5915 	ASSERT(mutex_owned(ST_MUTEX));
5916 	return (err);
5917 }
5918 
5919 static int
5920 st_write_fm(dev_t dev, int wfm)
5921 {
5922 	int i;
5923 
5924 	GET_SOFT_STATE(dev);
5925 
5926 	ASSERT(mutex_owned(ST_MUTEX));
5927 
5928 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
5929 	    "st_write_fm(dev = 0x%lx, wfm = %d)\n", dev, wfm);
5930 
5931 	/*
5932 	 * write one filemark at the time after EOT
5933 	 */
5934 	if (un->un_eof >= ST_EOT) {
5935 		for (i = 0; i < wfm; i++) {
5936 			if (st_cmd(dev, SCMD_WRITE_FILE_MARK, 1, SYNC_CMD)) {
5937 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5938 				    "st_write_fm : EIO : write EOT file mark");
5939 				return (EIO);
5940 			}
5941 		}
5942 	} else if (st_cmd(dev, SCMD_WRITE_FILE_MARK, wfm, SYNC_CMD)) {
5943 		ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
5944 		    "st_write_fm : EIO : write file mark");
5945 		return (EIO);
5946 	}
5947 
5948 	ASSERT(mutex_owned(ST_MUTEX));
5949 	return (0);
5950 }
5951 
5952 #ifdef STDEBUG
5953 static void
5954 start_dump(struct scsi_tape *un, struct buf *bp)
5955 {
5956 	struct scsi_pkt *pkt = BP_PKT(bp);
5957 	uchar_t *cdbp = (uchar_t *)pkt->pkt_cdbp;
5958 
5959 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5960 	    "st_start: cmd=0x%p count=%ld resid=%ld flags=0x%x pkt=0x%p\n",
5961 	    (void *)bp->b_forw, bp->b_bcount,
5962 	    bp->b_resid, bp->b_flags, (void *)BP_PKT(bp));
5963 
5964 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
5965 	    "st_start: cdb %x %x %x %x %x %x, fileno=%d, blk=%ld\n",
5966 	    cdbp[0], cdbp[1], cdbp[2],
5967 	    cdbp[3], cdbp[4], cdbp[5], un->un_fileno,
5968 	    un->un_blkno);
5969 }
5970 #endif
5971 
5972 
5973 /*
5974  * Command start && done functions
5975  */
5976 
5977 /*
5978  * st_start()
5979  *
5980  * Called from:
5981  *  st_strategy() to start a command.
5982  *  st_runout() to retry when scsi_pkt allocation fails on previous attempt(s).
5983  *  st_attach() when resuming from power down state.
5984  *  st_start_restart() to retry transport when device was previously busy.
5985  *  st_done_and_mutex_exit() to start the next command when previous is done.
5986  *
5987  * On entry:
5988  *  scsi_pkt may or may not be allocated.
5989  *
5990  */
5991 static void
5992 st_start(struct scsi_tape *un)
5993 {
5994 	struct buf *bp;
5995 	int status;
5996 
5997 	ASSERT(mutex_owned(ST_MUTEX));
5998 
5999 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6000 	    "st_start(): dev = 0x%lx\n", un->un_dev);
6001 
6002 	if ((bp = un->un_quef) == NULL) {
6003 		return;
6004 	}
6005 
6006 	ASSERT((bp->b_flags & B_DONE) == 0);
6007 
6008 	/*
6009 	 * Don't send more than un_throttle commands to the HBA
6010 	 */
6011 	if ((un->un_throttle <= 0) || (un->un_ncmds >= un->un_throttle)) {
6012 		return;
6013 	}
6014 
6015 	/*
6016 	 * If the buf has no scsi_pkt call st_make_cmd() to get one and
6017 	 * build the command.
6018 	 */
6019 	if (BP_PKT(bp) == NULL) {
6020 		ASSERT((bp->b_flags & B_DONE) == 0);
6021 		st_make_cmd(un, bp, st_runout);
6022 		ASSERT((bp->b_flags & B_DONE) == 0);
6023 		status = geterror(bp);
6024 
6025 		/*
6026 		 * Some HBA's don't call bioerror() to set an error.
6027 		 * And geterror() returns zero if B_ERROR is not set.
6028 		 * So if we get zero we must check b_error.
6029 		 */
6030 		if (status == 0 && bp->b_error != 0) {
6031 			status = bp->b_error;
6032 			bioerror(bp, status);
6033 		}
6034 
6035 		/*
6036 		 * Some HBA's convert DDI_DMA_NORESOURCES into ENOMEM.
6037 		 * In tape ENOMEM has special meaning so we'll change it.
6038 		 */
6039 		if (status == ENOMEM) {
6040 			status = 0;
6041 			bioerror(bp, status);
6042 		}
6043 
6044 		/*
6045 		 * Did it fail and is it retryable?
6046 		 * If so return and wait for the callback through st_runout.
6047 		 * Also looks like scsi_init_pkt() will setup a callback even
6048 		 * if it isn't retryable.
6049 		 */
6050 		if (BP_PKT(bp) == NULL) {
6051 			if (status == 0) {
6052 				/*
6053 				 * If first attempt save state.
6054 				 */
6055 				if (un->un_state != ST_STATE_RESOURCE_WAIT) {
6056 					un->un_laststate = un->un_state;
6057 					un->un_state = ST_STATE_RESOURCE_WAIT;
6058 				}
6059 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
6060 				    "temp no resources for pkt\n");
6061 			} else {
6062 				/*
6063 				 * Unlikely that it would be retryable then not.
6064 				 */
6065 				if (un->un_state == ST_STATE_RESOURCE_WAIT) {
6066 					un->un_state = un->un_laststate;
6067 				}
6068 				scsi_log(ST_DEVINFO, st_label, SCSI_DEBUG,
6069 				    "perm no resources for pkt errno = 0x%x\n",
6070 				    status);
6071 			}
6072 			return;
6073 		}
6074 		/*
6075 		 * Worked this time set the state back.
6076 		 */
6077 		if (un->un_state == ST_STATE_RESOURCE_WAIT) {
6078 			un->un_state = un->un_laststate;
6079 		}
6080 	}
6081 
6082 	/*
6083 	 * move from waitq to runq
6084 	 */
6085 	un->un_quef = bp->b_actf;
6086 	if (un->un_quel == bp) {
6087 		/*
6088 		 *  For the case of queue having one
6089 		 *  element, set the tail pointer to
6090 		 *  point to the element.
6091 		 */
6092 		un->un_quel = bp->b_actf;
6093 	}
6094 
6095 	bp->b_actf = NULL;
6096 
6097 	if (un->un_runqf) {
6098 		un->un_runql->b_actf = bp;
6099 	} else {
6100 		un->un_runqf = bp;
6101 	}
6102 	un->un_runql = bp;
6103 
6104 
6105 #ifdef STDEBUG
6106 	start_dump(un, bp);
6107 #endif
6108 
6109 	/* could not get here if throttle was zero */
6110 	un->un_last_throttle = un->un_throttle;
6111 	un->un_throttle = 0;	/* so nothing else will come in here */
6112 	un->un_ncmds++;
6113 
6114 	ST_DO_KSTATS(bp, kstat_waitq_to_runq);
6115 
6116 	mutex_exit(ST_MUTEX);
6117 
6118 	status = scsi_transport(BP_PKT(bp));
6119 
6120 	mutex_enter(ST_MUTEX);
6121 
6122 	if (un->un_last_throttle) {
6123 		un->un_throttle = un->un_last_throttle;
6124 	}
6125 
6126 	if (status != TRAN_ACCEPT) {
6127 		ST_DO_KSTATS(bp, kstat_runq_back_to_waitq);
6128 		mutex_exit(ST_MUTEX);
6129 
6130 		if (status == TRAN_BUSY) {
6131 			/* if too many retries, fail the transport */
6132 			if (st_handle_start_busy(un, bp,
6133 			    ST_TRAN_BUSY_TIMEOUT) == 0)
6134 				goto done;
6135 		}
6136 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
6137 		    "transport rejected\n");
6138 		bp->b_resid = bp->b_bcount;
6139 
6140 
6141 #ifndef __lock_lint
6142 		/*
6143 		 * warlock doesn't understand this potential
6144 		 * recursion?
6145 		 */
6146 		mutex_enter(ST_MUTEX);
6147 		ST_DO_KSTATS(bp, kstat_waitq_exit);
6148 		ST_DO_ERRSTATS(un, st_transerrs);
6149 		st_bioerror(bp, EIO);
6150 		SET_PE_FLAG(un);
6151 		st_done_and_mutex_exit(un, bp);
6152 #endif
6153 	} else {
6154 		un->un_tran_retry_ct = 0;
6155 		mutex_exit(ST_MUTEX);
6156 	}
6157 
6158 done:
6159 
6160 	mutex_enter(ST_MUTEX);
6161 }
6162 
6163 /*
6164  * if the transport is busy, then put this bp back on the waitq
6165  */
6166 static int
6167 st_handle_start_busy(struct scsi_tape *un, struct buf *bp,
6168     clock_t timeout_interval)
6169 {
6170 	struct buf *last_quef, *runq_bp;
6171 	int rval = 0;
6172 
6173 	mutex_enter(ST_MUTEX);
6174 
6175 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6176 	    "st_handle_start_busy()\n");
6177 
6178 	/*
6179 	 * Check to see if we hit the retry timeout and one last check for
6180 	 * making sure this is the last on the runq, if it is not, we have
6181 	 * to fail
6182 	 */
6183 	if (((int)un->un_tran_retry_ct++ > st_retry_count) ||
6184 	    (un->un_runql != bp)) {
6185 		rval = -1;
6186 		goto exit;
6187 	}
6188 
6189 	/* put the bp back on the waitq */
6190 	if (un->un_quef) {
6191 		last_quef = un->un_quef;
6192 		un->un_quef = bp;
6193 		bp->b_actf = last_quef;
6194 	} else  {
6195 		bp->b_actf = NULL;
6196 		un->un_quef = bp;
6197 		un->un_quel = bp;
6198 	}
6199 
6200 	/*
6201 	 * Decrement un_ncmds so that this
6202 	 * gets thru' st_start() again.
6203 	 */
6204 	un->un_ncmds--;
6205 
6206 	/*
6207 	 * since this is an error case, we won't have to do
6208 	 * this list walking much.  We've already made sure this bp was the
6209 	 * last on the runq
6210 	 */
6211 	runq_bp = un->un_runqf;
6212 
6213 	if (un->un_runqf == bp) {
6214 		un->un_runqf = NULL;
6215 		un->un_runql = NULL;
6216 	} else {
6217 		while (runq_bp) {
6218 			if (runq_bp->b_actf == bp) {
6219 				runq_bp->b_actf = NULL;
6220 				un->un_runql = runq_bp;
6221 				break;
6222 			}
6223 			runq_bp = runq_bp->b_actf;
6224 		}
6225 	}
6226 
6227 
6228 	/*
6229 	 * send a marker pkt, if appropriate
6230 	 */
6231 	st_hba_unflush(un);
6232 
6233 	/*
6234 	 * all queues are aligned, we are just waiting to
6235 	 * transport, don't alloc any more buf p's, when
6236 	 * st_start is reentered.
6237 	 */
6238 	(void) timeout(st_start_restart, un, timeout_interval);
6239 
6240 exit:
6241 	mutex_exit(ST_MUTEX);
6242 	return (rval);
6243 }
6244 
6245 
6246 
6247 /*
6248  * st_runout a callback that is called what a resource allocatation failed
6249  */
6250 static int
6251 st_runout(caddr_t arg)
6252 {
6253 	struct scsi_tape *un = (struct scsi_tape *)arg;
6254 	struct buf *bp;
6255 
6256 	ASSERT(un != NULL);
6257 
6258 	mutex_enter(ST_MUTEX);
6259 
6260 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_runout()\n");
6261 
6262 	bp = un->un_quef;
6263 
6264 	/*
6265 	 * failed scsi_init_pkt(). If errno is zero its retryable.
6266 	 */
6267 	if ((bp != NULL) && (geterror(bp) != 0)) {
6268 
6269 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
6270 		    "errors after pkt alloc (b_flags=0x%x, b_error=0x%x)\n",
6271 		    bp->b_flags, geterror(bp));
6272 		ASSERT((bp->b_flags & B_DONE) == 0);
6273 
6274 		un->un_quef = bp->b_actf;
6275 		if (un->un_quel == bp) {
6276 			/*
6277 			 *  For the case of queue having one
6278 			 *  element, set the tail pointer to
6279 			 *  point to the element.
6280 			 */
6281 			un->un_quel = bp->b_actf;
6282 		}
6283 		mutex_exit(ST_MUTEX);
6284 		bp->b_actf = NULL;
6285 
6286 		ASSERT((bp->b_flags & B_DONE) == 0);
6287 
6288 		/*
6289 		 * Set resid, Error already set, then unblock calling thread.
6290 		 */
6291 		bp->b_resid = bp->b_bcount;
6292 		biodone(bp);
6293 	} else {
6294 		/*
6295 		 * Try Again
6296 		 */
6297 		st_start(un);
6298 		mutex_exit(ST_MUTEX);
6299 	}
6300 
6301 	/*
6302 	 * Comments courtesy of sd.c
6303 	 * The scsi_init_pkt routine allows for the callback function to
6304 	 * return a 0 indicating the callback should be rescheduled or a 1
6305 	 * indicating not to reschedule. This routine always returns 1
6306 	 * because the driver always provides a callback function to
6307 	 * scsi_init_pkt. This results in a callback always being scheduled
6308 	 * (via the scsi_init_pkt callback implementation) if a resource
6309 	 * failure occurs.
6310 	 */
6311 
6312 	return (1);
6313 }
6314 
6315 /*
6316  * st_done_and_mutex_exit()
6317  *	- remove bp from runq
6318  *	- start up the next request
6319  *	- if this was an asynch bp, clean up
6320  *	- exit with released mutex
6321  */
6322 static void
6323 st_done_and_mutex_exit(struct scsi_tape *un, struct buf *bp)
6324 {
6325 	struct buf *runqbp, *prevbp;
6326 	int	pe_flagged = 0;
6327 
6328 	ASSERT(MUTEX_HELD(&un->un_sd->sd_mutex));
6329 #if !defined(lint)
6330 	_NOTE(LOCK_RELEASED_AS_SIDE_EFFECT(&un->un_sd->sd_mutex))
6331 #endif
6332 	ASSERT(mutex_owned(ST_MUTEX));
6333 
6334 	/*
6335 	 * if bp is still on the runq (anywhere), then remove it
6336 	 */
6337 	prevbp = NULL;
6338 	for (runqbp = un->un_runqf; runqbp != 0; runqbp = runqbp->b_actf) {
6339 		if (runqbp == bp) {
6340 			if (runqbp == un->un_runqf) {
6341 				un->un_runqf = bp->b_actf;
6342 			} else {
6343 				prevbp->b_actf = bp->b_actf;
6344 			}
6345 			if (un->un_runql == bp) {
6346 				un->un_runql = prevbp;
6347 			}
6348 			break;
6349 		}
6350 		prevbp = runqbp;
6351 	}
6352 	bp->b_actf = NULL;
6353 
6354 	un->un_ncmds--;
6355 	cv_signal(&un->un_queue_cv);
6356 
6357 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6358 	"st_done_and_mutex_exit(): cmd=0x%x count=%ld resid=%ld  flags=0x%x\n",
6359 		(int)*((caddr_t)(BP_PKT(bp))->pkt_cdbp),
6360 		bp->b_bcount, bp->b_resid, bp->b_flags);
6361 
6362 
6363 	/*
6364 	 * update kstats with transfer count info
6365 	 */
6366 	if (un->un_stats && (bp != un->un_sbufp) && IS_RW(bp)) {
6367 		uint32_t n_done =  bp->b_bcount - bp->b_resid;
6368 		if (bp->b_flags & B_READ) {
6369 			IOSP->reads++;
6370 			IOSP->nread += n_done;
6371 		} else {
6372 			IOSP->writes++;
6373 			IOSP->nwritten += n_done;
6374 		}
6375 	}
6376 
6377 	/*
6378 	 * Start the next one before releasing resources on this one, if
6379 	 * there is something on the queue and persistent errors has not been
6380 	 * flagged
6381 	 */
6382 
6383 	if ((pe_flagged = IS_PE_FLAG_SET(un)) != 0) {
6384 		un->un_last_resid = bp->b_resid;
6385 		un->un_last_count = bp->b_bcount;
6386 	}
6387 
6388 	if (un->un_pwr_mgmt == ST_PWR_SUSPENDED) {
6389 		cv_broadcast(&un->un_tape_busy_cv);
6390 	} else if (un->un_quef && un->un_throttle && !pe_flagged) {
6391 		st_start(un);
6392 	}
6393 
6394 	if (bp == un->un_sbufp && (bp->b_flags & B_ASYNC)) {
6395 		/*
6396 		 * Since we marked this ourselves as ASYNC,
6397 		 * there isn't anybody around waiting for
6398 		 * completion any more.
6399 		 */
6400 		uchar_t com = (uchar_t)(uintptr_t)bp->b_forw;
6401 		if (com == SCMD_READ || com == SCMD_WRITE) {
6402 			bp->b_un.b_addr = (caddr_t)0;
6403 		}
6404 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
6405 		    "st_done_and_mutex_exit(async): freeing pkt\n");
6406 		scsi_destroy_pkt(BP_PKT(bp));
6407 		un->un_sbuf_busy = 0;
6408 		cv_signal(&un->un_sbuf_cv);
6409 		mutex_exit(ST_MUTEX);
6410 		return;
6411 	}
6412 
6413 	if (bp == un->un_sbufp && BP_UCMD(bp)) {
6414 		/*
6415 		 * Copy status from scsi_pkt to uscsi_cmd
6416 		 * since st_ioctl_cmd needs it
6417 		 */
6418 		BP_UCMD(bp)->uscsi_status = SCBP_C(BP_PKT(bp));
6419 	}
6420 
6421 
6422 #ifdef STDEBUG
6423 	if ((st_debug >= 4) &&
6424 	    (((un->un_blkno % 100) == 0) || IS_PE_FLAG_SET(un))) {
6425 
6426 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
6427 		    "st_d_a_m_exit(): ncmds = %d, thr = %d, "
6428 		    "un_errno = %d, un_pe = %d\n",
6429 		    un->un_ncmds, un->un_throttle, un->un_errno,
6430 		    un->un_persist_errors);
6431 	}
6432 
6433 #endif
6434 
6435 	mutex_exit(ST_MUTEX);
6436 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
6437 	    "st_done_and_mutex_exit: freeing pkt\n");
6438 
6439 	scsi_destroy_pkt(BP_PKT(bp));
6440 
6441 	biodone(bp);
6442 
6443 	/*
6444 	 * now that we biodoned that command, if persistent errors have been
6445 	 * flagged, flush the waitq
6446 	 */
6447 	if (pe_flagged)
6448 		st_flush(un);
6449 }
6450 
6451 
6452 /*
6453  * Tape error, flush tape driver queue.
6454  */
6455 static void
6456 st_flush(struct scsi_tape *un)
6457 {
6458 	struct buf *bp;
6459 
6460 	mutex_enter(ST_MUTEX);
6461 
6462 	ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
6463 	    "st_flush(), ncmds = %d, quef = 0x%p\n",
6464 	    un->un_ncmds, (void *)un->un_quef);
6465 
6466 	/*
6467 	 * if we still have commands outstanding, wait for them to come in
6468 	 * before flushing the queue, and make sure there is a queue
6469 	 */
6470 	if (un->un_ncmds || !un->un_quef)
6471 		goto exit;
6472 
6473 	/*
6474 	 * we have no more commands outstanding, so let's deal with special
6475 	 * cases in the queue for EOM and FM. If we are here, and un_errno
6476 	 * is 0, then we know there was no error and we return a 0 read or
6477 	 * write before showing errors
6478 	 */
6479 
6480 	/* Flush the wait queue. */
6481 	while ((bp = un->un_quef) != NULL) {
6482 		un->un_quef = bp->b_actf;
6483 
6484 		bp->b_resid = bp->b_bcount;
6485 
6486 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
6487 		    "st_flush() : blkno=%ld, err=%d, b_bcount=%ld\n",
6488 		    un->un_blkno, un->un_errno, bp->b_bcount);
6489 
6490 		st_set_pe_errno(un);
6491 
6492 		bioerror(bp, un->un_errno);
6493 
6494 		mutex_exit(ST_MUTEX);
6495 		/* it should have one, but check anyway */
6496 		if (BP_PKT(bp)) {
6497 			scsi_destroy_pkt(BP_PKT(bp));
6498 		}
6499 		biodone(bp);
6500 		mutex_enter(ST_MUTEX);
6501 	}
6502 
6503 	/*
6504 	 * It's not a bad practice to reset the
6505 	 * waitq tail pointer to NULL.
6506 	 */
6507 	un->un_quel = NULL;
6508 
6509 exit:
6510 	/* we mucked with the queue, so let others know about it */
6511 	cv_signal(&un->un_queue_cv);
6512 	mutex_exit(ST_MUTEX);
6513 }
6514 
6515 
6516 /*
6517  * Utility functions
6518  */
6519 static int
6520 st_determine_generic(dev_t dev)
6521 {
6522 	int bsize;
6523 	static char *cart = "0.25 inch cartridge";
6524 	char *sizestr;
6525 
6526 	GET_SOFT_STATE(dev);
6527 
6528 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6529 	    "st_determine_generic(dev = 0x%lx)\n", dev);
6530 
6531 	ASSERT(mutex_owned(ST_MUTEX));
6532 
6533 	if (st_modesense(un)) {
6534 		return (-1);
6535 	}
6536 
6537 	bsize = (un->un_mspl->high_bl << 16)	|
6538 		(un->un_mspl->mid_bl << 8)	|
6539 		(un->un_mspl->low_bl);
6540 
6541 	if (bsize == 0) {
6542 		un->un_dp->options |= ST_VARIABLE;
6543 		un->un_dp->bsize = 0;
6544 		un->un_bsize = 0;
6545 	} else if (bsize > ST_MAXRECSIZE_FIXED) {
6546 		/*
6547 		 * record size of this device too big.
6548 		 * try and convert it to variable record length.
6549 		 *
6550 		 */
6551 		un->un_dp->options |= ST_VARIABLE;
6552 		if (st_change_block_size(dev, 0) != 0) {
6553 			ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
6554 			    "Fixed Record Size %d is too large\n", bsize);
6555 			ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
6556 			    "Cannot switch to variable record size\n");
6557 			un->un_dp->options &= ~ST_VARIABLE;
6558 			return (-1);
6559 		}
6560 	} else if (st_change_block_size(dev, 0) == 0) {
6561 		/*
6562 		 * If the drive was set to a non zero block size,
6563 		 * See if it can be set to a zero block size.
6564 		 * If it works, ST_VARIABLE so user can set it as they want.
6565 		 */
6566 		un->un_dp->options |= ST_VARIABLE;
6567 		un->un_dp->bsize = 0;
6568 		un->un_bsize = 0;
6569 	} else {
6570 		un->un_dp->bsize = bsize;
6571 		un->un_bsize = bsize;
6572 	}
6573 
6574 
6575 	switch (un->un_mspl->density) {
6576 	default:
6577 	case 0x0:
6578 		/*
6579 		 * default density, cannot determine any other
6580 		 * information.
6581 		 */
6582 		sizestr = "Unknown type- assuming 0.25 inch cartridge";
6583 		un->un_dp->type = ST_TYPE_DEFAULT;
6584 		un->un_dp->options |= (ST_AUTODEN_OVERRIDE|ST_QIC);
6585 		break;
6586 	case 0x1:
6587 	case 0x2:
6588 	case 0x3:
6589 	case 0x6:
6590 		/*
6591 		 * 1/2" reel
6592 		 */
6593 		sizestr = "0.50 inch reel";
6594 		un->un_dp->type = ST_TYPE_REEL;
6595 		un->un_dp->options |= ST_REEL;
6596 		un->un_dp->densities[0] = 0x1;
6597 		un->un_dp->densities[1] = 0x2;
6598 		un->un_dp->densities[2] = 0x6;
6599 		un->un_dp->densities[3] = 0x3;
6600 		break;
6601 	case 0x4:
6602 	case 0x5:
6603 	case 0x7:
6604 	case 0x0b:
6605 
6606 		/*
6607 		 * Quarter inch.
6608 		 */
6609 		sizestr = cart;
6610 		un->un_dp->type = ST_TYPE_DEFAULT;
6611 		un->un_dp->options |= ST_QIC;
6612 
6613 		un->un_dp->densities[1] = 0x4;
6614 		un->un_dp->densities[2] = 0x5;
6615 		un->un_dp->densities[3] = 0x7;
6616 		un->un_dp->densities[0] = 0x0b;
6617 		break;
6618 
6619 	case 0x0f:
6620 	case 0x10:
6621 	case 0x11:
6622 	case 0x12:
6623 		/*
6624 		 * QIC-120, QIC-150, QIC-320, QIC-600
6625 		 */
6626 		sizestr = cart;
6627 		un->un_dp->type = ST_TYPE_DEFAULT;
6628 		un->un_dp->options |= ST_QIC;
6629 		un->un_dp->densities[0] = 0x0f;
6630 		un->un_dp->densities[1] = 0x10;
6631 		un->un_dp->densities[2] = 0x11;
6632 		un->un_dp->densities[3] = 0x12;
6633 		break;
6634 
6635 	case 0x09:
6636 	case 0x0a:
6637 	case 0x0c:
6638 	case 0x0d:
6639 		/*
6640 		 * 1/2" cartridge tapes. Include HI-TC.
6641 		 */
6642 		sizestr = cart;
6643 		sizestr[2] = '5';
6644 		sizestr[3] = '0';
6645 		un->un_dp->type = ST_TYPE_HIC;
6646 		un->un_dp->densities[0] = 0x09;
6647 		un->un_dp->densities[1] = 0x0a;
6648 		un->un_dp->densities[2] = 0x0c;
6649 		un->un_dp->densities[3] = 0x0d;
6650 		break;
6651 
6652 	case 0x13:
6653 			/* DDS-2/DDS-3 scsi spec densities */
6654 	case 0x24:
6655 	case 0x25:
6656 	case 0x26:
6657 		sizestr = "DAT Data Storage (DDS)";
6658 		un->un_dp->type = ST_TYPE_DAT;
6659 		un->un_dp->options |= ST_AUTODEN_OVERRIDE;
6660 		break;
6661 
6662 	case 0x14:
6663 		/*
6664 		 * Helical Scan (Exabyte) devices
6665 		 */
6666 		sizestr = "8mm helical scan cartridge";
6667 		un->un_dp->type = ST_TYPE_EXABYTE;
6668 		un->un_dp->options |= ST_AUTODEN_OVERRIDE;
6669 		break;
6670 	}
6671 
6672 	/*
6673 	 * Assume LONG ERASE, BSF and BSR
6674 	 */
6675 
6676 	un->un_dp->options |= (ST_LONG_ERASE|ST_UNLOADABLE|ST_BSF|
6677 				ST_BSR|ST_KNOWS_EOD);
6678 
6679 	/*
6680 	 * Only if mode sense data says no buffered write, set NOBUF
6681 	 */
6682 	if (un->un_mspl->bufm == 0)
6683 		un->un_dp->options |= ST_NOBUF;
6684 
6685 	/*
6686 	 * set up large read and write retry counts
6687 	 */
6688 
6689 	un->un_dp->max_rretries = un->un_dp->max_wretries = 1000;
6690 
6691 	/*
6692 	 * If this is a 0.50 inch reel tape, and
6693 	 * it is *not* variable mode, try and
6694 	 * set it to variable record length
6695 	 * mode.
6696 	 */
6697 	if ((un->un_dp->options & ST_REEL) && un->un_bsize != 0 &&
6698 	    (un->un_dp->options & ST_VARIABLE)) {
6699 		if (st_change_block_size(dev, 0) == 0) {
6700 			un->un_dp->bsize = 0;
6701 			un->un_mspl->high_bl = un->un_mspl->mid_bl =
6702 			    un->un_mspl->low_bl = 0;
6703 		}
6704 	}
6705 
6706 	/*
6707 	 * Write to console about type of device found
6708 	 */
6709 	ST_DEBUG6(ST_DEVINFO, st_label, CE_NOTE,
6710 	    "Generic Drive, Vendor=%s\n\t%s", un->un_dp->name,
6711 	    sizestr);
6712 	if (un->un_dp->options & ST_VARIABLE) {
6713 		scsi_log(ST_DEVINFO, st_label, CE_NOTE,
6714 		    "!Variable record length I/O\n");
6715 	} else {
6716 		scsi_log(ST_DEVINFO, st_label, CE_NOTE,
6717 		    "!Fixed record length (%d byte blocks) I/O\n",
6718 		    un->un_dp->bsize);
6719 	}
6720 	ASSERT(mutex_owned(ST_MUTEX));
6721 	return (0);
6722 }
6723 
6724 static int
6725 st_determine_density(dev_t dev, int rw)
6726 {
6727 	int rval = 0;
6728 
6729 	GET_SOFT_STATE(dev);
6730 
6731 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6732 	    "st_determine_density(dev = 0x%lx, rw = %s)\n",
6733 	    dev, (rw == B_WRITE ? wr_str: rd_str));
6734 
6735 	ASSERT(mutex_owned(ST_MUTEX));
6736 
6737 	/*
6738 	 * If we're past BOT, density is determined already.
6739 	 */
6740 	if (un->un_fileno > 0 || (un->un_fileno == 0 && un->un_blkno != 0)) {
6741 		/*
6742 		 * XXX: put in a bitch message about attempting to
6743 		 * XXX: change density past BOT.
6744 		 */
6745 		goto exit;
6746 	}
6747 
6748 	/*
6749 	 * If we're going to be writing, we set the density
6750 	 */
6751 	if (rw == 0 || rw == B_WRITE) {
6752 		/* un_curdens is used as an index into densities table */
6753 		un->un_curdens = MT_DENSITY(un->un_dev);
6754 		if (st_set_density(dev)) {
6755 			rval = -1;
6756 		}
6757 		goto exit;
6758 	}
6759 
6760 	/*
6761 	 * If density is known already,
6762 	 * we don't have to get it again.(?)
6763 	 */
6764 	if (!un->un_density_known) {
6765 		if (st_get_density(dev)) {
6766 			rval = -1;
6767 		}
6768 	}
6769 
6770 exit:
6771 	ASSERT(mutex_owned(ST_MUTEX));
6772 	return (rval);
6773 }
6774 
6775 
6776 /*
6777  * Try to determine density. We do this by attempting to read the
6778  * first record off the tape, cycling through the available density
6779  * codes as we go.
6780  */
6781 
6782 static int
6783 st_get_density(dev_t dev)
6784 {
6785 	int succes = 0, rval = -1, i;
6786 	uint_t size;
6787 	uchar_t dens, olddens;
6788 
6789 	GET_SOFT_STATE(dev);
6790 
6791 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6792 	    "st_get_density(dev = 0x%lx)\n", dev);
6793 
6794 	ASSERT(mutex_owned(ST_MUTEX));
6795 
6796 	/*
6797 	 * If Auto Density override is enabled The drive has
6798 	 * only one density and there is no point in attempting
6799 	 * find the correct one.
6800 	 *
6801 	 * Since most modern drives auto detect the density
6802 	 * and format of the recorded media before they come
6803 	 * ready. What this function does is a legacy behavior
6804 	 * and modern drives not only don't need it, The backup
6805 	 * utilities that do positioning via uscsi find the un-
6806 	 * expected rewinds problematic.
6807 	 *
6808 	 * The drives that need this are old reel to reel devices.
6809 	 * I took a swag and said they must be scsi-1 or older.
6810 	 * I don't beleave there will any of the newer devices
6811 	 * that need this. There will be some scsi-1 devices that
6812 	 * don't need this but I don't think they will be using the
6813 	 * BIG aftermarket backup and restore utilitys.
6814 	 */
6815 	if ((un->un_dp->options & ST_AUTODEN_OVERRIDE) ||
6816 	    (un->un_sd->sd_inq->inq_ansi > 1)) {
6817 		un->un_density_known = 1;
6818 		rval = 0;
6819 		goto exit;
6820 	}
6821 
6822 	/*
6823 	 * This will only work on variable record length tapes
6824 	 * if and only if all variable record length tapes autodensity
6825 	 * select.
6826 	 */
6827 	size = (unsigned)(un->un_dp->bsize ? un->un_dp->bsize : SECSIZE);
6828 	un->un_tmpbuf = kmem_alloc(size, KM_SLEEP);
6829 
6830 	/*
6831 	 * Start at the specified density
6832 	 */
6833 
6834 	dens = olddens = un->un_curdens = MT_DENSITY(un->un_dev);
6835 
6836 	for (i = 0; i < NDENSITIES; i++, ((un->un_curdens == NDENSITIES - 1) ?
6837 					(un->un_curdens = 0) :
6838 					(un->un_curdens += 1))) {
6839 		/*
6840 		 * If we've done this density before,
6841 		 * don't bother to do it again.
6842 		 */
6843 		dens = un->un_dp->densities[un->un_curdens];
6844 		if (i > 0 && dens == olddens)
6845 			continue;
6846 		olddens = dens;
6847 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
6848 		    "trying density 0x%x\n", dens);
6849 		if (st_set_density(dev)) {
6850 			continue;
6851 		}
6852 
6853 		/*
6854 		 * XXX - the creates lots of headaches and slowdowns - must
6855 		 * fix.
6856 		 */
6857 		succes = (st_cmd(dev, SCMD_READ, (int)size, SYNC_CMD) == 0);
6858 		if (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD)) {
6859 			break;
6860 		}
6861 		if (succes) {
6862 			st_init(un);
6863 			rval = 0;
6864 			un->un_density_known = 1;
6865 			break;
6866 		}
6867 	}
6868 	kmem_free(un->un_tmpbuf, size);
6869 	un->un_tmpbuf = 0;
6870 
6871 exit:
6872 	ASSERT(mutex_owned(ST_MUTEX));
6873 	return (rval);
6874 }
6875 
6876 static int
6877 st_set_density(dev_t dev)
6878 {
6879 	int rval = 0;
6880 
6881 	GET_SOFT_STATE(dev);
6882 
6883 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6884 	    "st_set_density(dev = 0x%lx): density = 0x%x\n", dev,
6885 	    un->un_dp->densities[un->un_curdens]);
6886 
6887 	ASSERT(mutex_owned(ST_MUTEX));
6888 
6889 	un->un_mspl->density = un->un_dp->densities[un->un_curdens];
6890 
6891 	if ((un->un_dp->options & ST_AUTODEN_OVERRIDE) == 0) {
6892 		/*
6893 		 * If auto density override is not set, Use mode select
6894 		 * to set density and compression.
6895 		 */
6896 		if (st_modeselect(un)) {
6897 			rval = -1;
6898 		}
6899 	} else if ((un->un_dp->options & ST_MODE_SEL_COMP) != 0) {
6900 		/*
6901 		 * If auto density and mode select compression are set,
6902 		 * This is a drive with one density code but compression
6903 		 * can be enabled or disabled.
6904 		 * Set compression but no need to set density.
6905 		 */
6906 		rval = st_set_compression(un);
6907 		if ((rval != 0) && (rval != EALREADY)) {
6908 			rval = -1;
6909 		} else {
6910 			rval = 0;
6911 		}
6912 	}
6913 
6914 	/* If sucessful set density and/or compression, mark density known */
6915 	if (rval == 0) {
6916 		un->un_density_known = 1;
6917 	}
6918 
6919 	ASSERT(mutex_owned(ST_MUTEX));
6920 	return (rval);
6921 }
6922 
6923 static int
6924 st_loadtape(dev_t dev)
6925 {
6926 	int rval = 0;
6927 
6928 	GET_SOFT_STATE(dev);
6929 
6930 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6931 	    "st_loadtape(dev = 0x%lx)\n", dev);
6932 
6933 	ASSERT(mutex_owned(ST_MUTEX));
6934 
6935 	/*
6936 	 * 'LOAD' the tape to BOT by rewinding
6937 	 */
6938 	if (st_cmd(dev, SCMD_REWIND, 1, SYNC_CMD)) {
6939 		rval = -1;
6940 	} else {
6941 		st_init(un);
6942 		un->un_density_known = 0;
6943 	}
6944 
6945 	ASSERT(mutex_owned(ST_MUTEX));
6946 	return (rval);
6947 }
6948 
6949 
6950 /*
6951  * Note: QIC devices aren't so smart.  If you try to append
6952  * after EOM, the write can fail because the device doesn't know
6953  * it's at EOM.	 In that case, issue a read.  The read should fail
6954  * because there's no data, but the device knows it's at EOM,
6955  * so a subsequent write should succeed.  To further confuse matters,
6956  * the target returns the same error if the tape is positioned
6957  * such that a write would overwrite existing data.  That's why
6958  * we have to do the append test.  A read in the middle of
6959  * recorded data would succeed, thus indicating we're attempting
6960  * something illegal.
6961  */
6962 
6963 void bp_mapin(struct buf *bp);
6964 
6965 static void
6966 st_test_append(struct buf *bp)
6967 {
6968 	dev_t dev = bp->b_edev;
6969 	struct scsi_tape *un;
6970 	uchar_t status;
6971 	unsigned bcount;
6972 
6973 	un = ddi_get_soft_state(st_state, MTUNIT(dev));
6974 
6975 	ASSERT(mutex_owned(ST_MUTEX));
6976 
6977 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
6978 	    "st_test_append(): fileno %d\n", un->un_fileno);
6979 
6980 	un->un_laststate = un->un_state;
6981 	un->un_state = ST_STATE_APPEND_TESTING;
6982 	un->un_test_append = 0;
6983 
6984 	/*
6985 	 * first, map in the buffer, because we're doing a double write --
6986 	 * first into the kernel, then onto the tape.
6987 	 */
6988 	bp_mapin(bp);
6989 
6990 	/*
6991 	 * get a copy of the data....
6992 	 */
6993 	un->un_tmpbuf = kmem_alloc((unsigned)bp->b_bcount, KM_SLEEP);
6994 	bcopy(bp->b_un.b_addr, un->un_tmpbuf, (uint_t)bp->b_bcount);
6995 
6996 	/*
6997 	 * attempt the write..
6998 	 */
6999 
7000 	if (st_cmd(dev, (int)SCMD_WRITE, (int)bp->b_bcount, SYNC_CMD) == 0) {
7001 success:
7002 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7003 		    "append write succeeded\n");
7004 		bp->b_resid = un->un_sbufp->b_resid;
7005 		mutex_exit(ST_MUTEX);
7006 		bcount = (unsigned)bp->b_bcount;
7007 		biodone(bp);
7008 		mutex_enter(ST_MUTEX);
7009 		un->un_laststate = un->un_state;
7010 		un->un_state = ST_STATE_OPEN;
7011 		kmem_free(un->un_tmpbuf, bcount);
7012 		un->un_tmpbuf = NULL;
7013 		return;
7014 	}
7015 
7016 	/*
7017 	 * The append failed. Do a short read. If that fails,  we are at EOM
7018 	 * so we can retry the write command. If that succeeds, than we're
7019 	 * all screwed up (the controller reported a real error).
7020 	 *
7021 	 * XXX: should the dummy read be > SECSIZE? should it be the device's
7022 	 * XXX: block size?
7023 	 *
7024 	 */
7025 	status = un->un_status;
7026 	un->un_status = 0;
7027 	(void) st_cmd(dev, SCMD_READ, SECSIZE, SYNC_CMD);
7028 	if (un->un_status == KEY_BLANK_CHECK) {
7029 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7030 		    "append at EOM\n");
7031 		/*
7032 		 * Okay- the read failed. We should actually have confused
7033 		 * the controller enough to allow writing. In any case, the
7034 		 * i/o is on its own from here on out.
7035 		 */
7036 		un->un_laststate = un->un_state;
7037 		un->un_state = ST_STATE_OPEN;
7038 		bcopy(bp->b_un.b_addr, un->un_tmpbuf, (uint_t)bp->b_bcount);
7039 		if (st_cmd(dev, (int)SCMD_WRITE, (int)bp->b_bcount,
7040 		    SYNC_CMD) == 0) {
7041 			goto success;
7042 		}
7043 	}
7044 
7045 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7046 	    "append write failed- not at EOM\n");
7047 	bp->b_resid = bp->b_bcount;
7048 	st_bioerror(bp, EIO);
7049 
7050 	ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
7051 	    "st_test_append : EIO : append write failed - not at EOM");
7052 
7053 	/*
7054 	 * backspace one record to get back to where we were
7055 	 */
7056 	if (st_cmd(dev, SCMD_SPACE, Blk(-1), SYNC_CMD)) {
7057 		un->un_fileno = -1;
7058 	}
7059 
7060 	un->un_err_resid = bp->b_resid;
7061 	un->un_status = status;
7062 
7063 	/*
7064 	 * Note: biodone will do a bp_mapout()
7065 	 */
7066 	mutex_exit(ST_MUTEX);
7067 	bcount = (unsigned)bp->b_bcount;
7068 	biodone(bp);
7069 	mutex_enter(ST_MUTEX);
7070 	un->un_laststate = un->un_state;
7071 	un->un_state = ST_STATE_OPEN_PENDING_IO;
7072 	kmem_free(un->un_tmpbuf, bcount);
7073 	un->un_tmpbuf = NULL;
7074 }
7075 
7076 /*
7077  * Special command handler
7078  */
7079 
7080 /*
7081  * common st_cmd code. The fourth parameter states
7082  * whether the caller wishes to await the results
7083  * Note the release of the mutex during most of the function
7084  */
7085 static int
7086 st_cmd(dev_t dev, int com, int count, int wait)
7087 {
7088 	struct buf *bp;
7089 	int err;
7090 
7091 	GET_SOFT_STATE(dev);
7092 
7093 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
7094 	    "st_cmd(dev = 0x%lx, com = 0x%x, count = %x, wait = %d)\n",
7095 	    dev, com, count, wait);
7096 
7097 	ASSERT(MUTEX_HELD(&un->un_sd->sd_mutex));
7098 	ASSERT(mutex_owned(ST_MUTEX));
7099 
7100 #ifdef STDEBUG
7101 	if (st_debug)
7102 		st_debug_cmds(un, com, count, wait);
7103 #endif
7104 
7105 	while (un->un_sbuf_busy)
7106 		cv_wait(&un->un_sbuf_cv, ST_MUTEX);
7107 	un->un_sbuf_busy = 1;
7108 
7109 	bp = un->un_sbufp;
7110 	bzero(bp, sizeof (buf_t));
7111 
7112 	bp->b_flags = (wait) ? B_BUSY : B_BUSY|B_ASYNC;
7113 
7114 	/*
7115 	 * Set count to the actual size of the data tranfer.
7116 	 * For commands with no data transfer, set bp->b_bcount
7117 	 * to the value to be used when constructing the
7118 	 * cdb in st_make_cmd().
7119 	 */
7120 	switch (com) {
7121 	case SCMD_READ:
7122 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7123 		    "special read %d\n", count);
7124 		bp->b_flags |= B_READ;
7125 		bp->b_un.b_addr = un->un_tmpbuf;
7126 		break;
7127 
7128 	case SCMD_WRITE:
7129 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7130 		    "special write %d\n", count);
7131 		bp->b_un.b_addr = un->un_tmpbuf;
7132 		break;
7133 
7134 	case SCMD_WRITE_FILE_MARK:
7135 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7136 		    "write %d file marks\n", count);
7137 		bp->b_bcount = count;
7138 		count = 0;
7139 		break;
7140 
7141 	case SCMD_REWIND:
7142 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "rewind\n");
7143 		bp->b_bcount = 0;
7144 		count = 0;
7145 		break;
7146 
7147 	case SCMD_SPACE:
7148 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "space\n");
7149 		bp->b_bcount = count;
7150 		count = 0;
7151 		break;
7152 
7153 	case SCMD_RESERVE:
7154 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "reserve");
7155 		bp->b_bcount = 0;
7156 		count = 0;
7157 		break;
7158 
7159 	case SCMD_RELEASE:
7160 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "release");
7161 		bp->b_bcount = 0;
7162 		count = 0;
7163 		break;
7164 
7165 	case SCMD_LOAD:
7166 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7167 		    "%s tape\n", (count) ? "load" : "unload");
7168 		bp->b_bcount = count;
7169 		count = 0;
7170 		break;
7171 
7172 	case SCMD_ERASE:
7173 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7174 		    "erase tape\n");
7175 		bp->b_bcount = 0;
7176 		count = 0;
7177 		break;
7178 
7179 	case SCMD_MODE_SENSE:
7180 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7181 		    "mode sense\n");
7182 		bp->b_flags |= B_READ;
7183 		bp->b_un.b_addr = (caddr_t)(un->un_mspl);
7184 		break;
7185 
7186 	case SCMD_MODE_SELECT:
7187 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7188 		    "mode select\n");
7189 		bp->b_un.b_addr = (caddr_t)(un->un_mspl);
7190 		break;
7191 
7192 	case SCMD_READ_BLKLIM:
7193 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7194 		    "read block limits\n");
7195 		bp->b_flags |= B_READ;
7196 		bp->b_un.b_addr = (caddr_t)(un->un_rbl);
7197 		break;
7198 
7199 	case SCMD_TEST_UNIT_READY:
7200 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7201 		    "test unit ready\n");
7202 		bp->b_bcount = 0;
7203 		count = 0;
7204 		break;
7205 	default:
7206 		ST_DEBUG(ST_DEVINFO, st_label, CE_PANIC,
7207 		    "Unhandled scsi command 0x%x in st_cmd()\n", com);
7208 	}
7209 
7210 	mutex_exit(ST_MUTEX);
7211 
7212 	if (count > 0) {
7213 		/*
7214 		 * We're going to do actual I/O.
7215 		 * Set things up for physio.
7216 		 */
7217 		struct iovec aiov;
7218 		struct uio auio;
7219 		struct uio *uio = &auio;
7220 
7221 		bzero(&auio, sizeof (struct uio));
7222 		bzero(&aiov, sizeof (struct iovec));
7223 		aiov.iov_base = bp->b_un.b_addr;
7224 		aiov.iov_len = count;
7225 
7226 		uio->uio_iov = &aiov;
7227 		uio->uio_iovcnt = 1;
7228 		uio->uio_resid = aiov.iov_len;
7229 		uio->uio_segflg = UIO_SYSSPACE;
7230 
7231 		/*
7232 		 * Let physio do the rest...
7233 		 */
7234 		bp->b_forw = (struct buf *)(uintptr_t)com;
7235 		bp->b_back = NULL;
7236 		err = physio(st_strategy, bp, dev,
7237 			(bp->b_flags & B_READ) ? B_READ : B_WRITE,
7238 			st_minphys, uio);
7239 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7240 		    "st_cmd: physio returns %d\n", err);
7241 	} else {
7242 		/*
7243 		 * Mimic physio
7244 		 */
7245 		bp->b_forw = (struct buf *)(uintptr_t)com;
7246 		bp->b_back = NULL;
7247 		bp->b_edev = dev;
7248 		bp->b_dev = cmpdev(dev);
7249 		bp->b_blkno = 0;
7250 		bp->b_resid = 0;
7251 		(void) st_strategy(bp);
7252 		if (!wait) {
7253 			/*
7254 			 * This is an async command- the caller won't wait
7255 			 * and doesn't care about errors.
7256 			 */
7257 			mutex_enter(ST_MUTEX);
7258 			return (0);
7259 		}
7260 
7261 		/*
7262 		 * BugTraq #4260046
7263 		 * ----------------
7264 		 * Restore Solaris 2.5.1 behavior, namely call biowait
7265 		 * unconditionally. The old comment said...
7266 		 *
7267 		 * "if strategy was flagged with  persistent errors, we would
7268 		 *  have an error here, and the bp would never be sent, so we
7269 		 *  don't want to wait on a bp that was never sent...or hang"
7270 		 *
7271 		 * The new rationale, courtesy of Chitrank...
7272 		 *
7273 		 * "we should unconditionally biowait() here because
7274 		 *  st_strategy() will do a biodone() in the persistent error
7275 		 *  case and the following biowait() will return immediately.
7276 		 *  If not, in the case of "errors after pkt alloc" in
7277 		 *  st_start(), we will not biowait here which will cause the
7278 		 *  next biowait() to return immediately which will cause
7279 		 *  us to send out the next command. In the case where both of
7280 		 *  these use the sbuf, when the first command completes we'll
7281 		 *  free the packet attached to sbuf and the same pkt will
7282 		 *  get freed again when we complete the second command.
7283 		 *  see esc 518987.  BTW, it is necessary to do biodone() in
7284 		 *  st_start() for the pkt alloc failure case because physio()
7285 		 *  does biowait() and will hang if we don't do biodone()"
7286 		 */
7287 
7288 		err = biowait(bp);
7289 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7290 		    "st_cmd: biowait returns %d\n", err);
7291 	}
7292 	mutex_enter(ST_MUTEX);
7293 
7294 	un->un_sbuf_busy = 0;
7295 	cv_signal(&un->un_sbuf_cv);
7296 	return (err);
7297 }
7298 
7299 static int
7300 st_set_compression(struct scsi_tape *un)
7301 {
7302 	int rval;
7303 	int turn_compression_on;
7304 	minor_t minor;
7305 
7306 	/*
7307 	 * Drive either dosn't have compression or it is controlled with
7308 	 * special density codes. Return ENOTTY so caller
7309 	 * knows nothing was done.
7310 	 */
7311 	if ((un->un_dp->options & ST_MODE_SEL_COMP) == 0) {
7312 		un->un_comp_page = 0;
7313 		return (ENOTTY);
7314 	}
7315 
7316 	/* set compression based on minor node opened */
7317 	minor = MT_DENSITY(un->un_dev);
7318 
7319 	/*
7320 	 * If this the compression density or
7321 	 * the drive has two densities and uses mode select for
7322 	 * control of compression turn on compression for MT_DENSITY2
7323 	 * as well.
7324 	 */
7325 	if ((minor == ST_COMPRESSION_DENSITY) ||
7326 	    (minor == MT_DENSITY(MT_DENSITY2)) &&
7327 	    (un->un_dp->densities[0] == un->un_dp->densities[1]) &&
7328 	    (un->un_dp->densities[2] == un->un_dp->densities[3]) &&
7329 	    (un->un_dp->densities[0] != un->un_dp->densities[2])) {
7330 
7331 		turn_compression_on = 1;
7332 	} else {
7333 		turn_compression_on = 0;
7334 	}
7335 
7336 	un->un_mspl->high_bl = (uchar_t)(un->un_bsize >> 16);
7337 	un->un_mspl->mid_bl  = (uchar_t)(un->un_bsize >> 8);
7338 	un->un_mspl->low_bl  = (uchar_t)(un->un_bsize);
7339 
7340 	/*
7341 	 * Need to determine which page does the device use for compression.
7342 	 * First try the data compression page. If this fails try the device
7343 	 * configuration page
7344 	 */
7345 
7346 	if ((un->un_comp_page & ST_DEV_DATACOMP_PAGE) == ST_DEV_DATACOMP_PAGE) {
7347 		rval = st_set_datacomp_page(un, turn_compression_on);
7348 		if (rval == EALREADY) {
7349 			return (rval);
7350 		}
7351 		if (rval != 0) {
7352 			if (un->un_status == KEY_ILLEGAL_REQUEST) {
7353 				/*
7354 				 * This device does not support data
7355 				 * compression page
7356 				 */
7357 				un->un_comp_page = ST_DEV_CONFIG_PAGE;
7358 			} else if (un->un_state >= ST_STATE_OPEN) {
7359 				un->un_fileno = -1;
7360 				rval = EIO;
7361 			} else {
7362 				rval = -1;
7363 			}
7364 		} else {
7365 			un->un_comp_page = ST_DEV_DATACOMP_PAGE;
7366 		}
7367 	}
7368 
7369 	if ((un->un_comp_page & ST_DEV_CONFIG_PAGE) == ST_DEV_CONFIG_PAGE) {
7370 		rval = st_set_devconfig_page(un, turn_compression_on);
7371 		if (rval == EALREADY) {
7372 			return (rval);
7373 		}
7374 		if (rval != 0) {
7375 			if (un->un_status == KEY_ILLEGAL_REQUEST) {
7376 				/*
7377 				 * This device does not support
7378 				 * compression at all advice the
7379 				 * user and unset ST_MODE_SEL_COMP
7380 				 */
7381 				un->un_dp->options &= ~ST_MODE_SEL_COMP;
7382 				un->un_comp_page = 0;
7383 				scsi_log(ST_DEVINFO, st_label, CE_NOTE,
7384 				    "Device Does Not Support Compression\n");
7385 			} else if (un->un_state >= ST_STATE_OPEN) {
7386 				un->un_fileno = -1;
7387 				rval = EIO;
7388 			} else {
7389 				rval = -1;
7390 			}
7391 		}
7392 	}
7393 
7394 	return (rval);
7395 }
7396 
7397 /*
7398  * set or unset compression thru device configuration page.
7399  */
7400 static int
7401 st_set_devconfig_page(struct scsi_tape *un, int compression_on)
7402 {
7403 	unsigned char cflag;
7404 	int rval = 0;
7405 
7406 	ASSERT(mutex_owned(ST_MUTEX));
7407 
7408 	/*
7409 	 * Figure what to set compression flag to.
7410 	 */
7411 	if (compression_on) {
7412 		/* They have selected a compression node */
7413 		if (un->un_dp->type == ST_TYPE_FUJI) {
7414 			cflag = 0x84;   /* use EDRC */
7415 		} else {
7416 			cflag = ST_DEV_CONFIG_DEF_COMP;
7417 		}
7418 	} else {
7419 		cflag = ST_DEV_CONFIG_NO_COMP;
7420 	}
7421 
7422 	/*
7423 	 * If compression is already set the way it was requested.
7424 	 * And if this not the first time we has tried.
7425 	 */
7426 	if ((cflag == un->un_mspl->page.dev.comp_alg) &&
7427 	    (un->un_comp_page == ST_DEV_DATACOMP_PAGE)) {
7428 		return (EALREADY);
7429 	}
7430 
7431 	un->un_mspl->page.dev.comp_alg = cflag;
7432 	/*
7433 	 * need to send mode select even if correct compression is
7434 	 * already set since need to set density code
7435 	 */
7436 
7437 #ifdef STDEBUG
7438 	if (st_debug >= 6) {
7439 		st_clean_print(ST_DEVINFO, st_label, SCSI_DEBUG,
7440 		    "st_set_devconfig_page: sense data for mode select",
7441 		    (char *)un->un_mspl, sizeof (struct seq_mode));
7442 	}
7443 #endif
7444 	rval = st_gen_mode_select(un, un->un_mspl, sizeof (struct seq_mode));
7445 
7446 	return (rval);
7447 }
7448 
7449 /*
7450  * set/reset compression bit thru data compression page
7451  */
7452 static int
7453 st_set_datacomp_page(struct scsi_tape *un, int compression_on)
7454 {
7455 	int compression_on_already;
7456 	int rval = 0;
7457 
7458 	ASSERT(mutex_owned(ST_MUTEX));
7459 
7460 	/*
7461 	 * If drive is not capable of compression (at this time)
7462 	 * return EALREADY so caller doesn't think that this page
7463 	 * is not supported. This check is for drives that can
7464 	 * disable compression from the front panel or configuration.
7465 	 * I doubt that a drive that supports this page is not really
7466 	 * capable of compression.
7467 	 */
7468 	if (un->un_mspl->page.comp.dcc == 0) {
7469 		return (EALREADY);
7470 	}
7471 
7472 	/* See if compression currently turned on */
7473 	if (un->un_mspl->page.comp.dce) {
7474 		compression_on_already = 1;
7475 	} else {
7476 		compression_on_already = 0;
7477 	}
7478 
7479 	/*
7480 	 * If compression is already set the way it was requested.
7481 	 * And if this not the first time we has tried.
7482 	 */
7483 	if ((compression_on == compression_on_already) &&
7484 	    (un->un_comp_page == ST_DEV_DATACOMP_PAGE)) {
7485 		return (EALREADY);
7486 	}
7487 
7488 	/*
7489 	 * if we are already set to the appropriate compression
7490 	 * mode, don't set it again
7491 	 */
7492 	if (compression_on) {
7493 		/* compression selected */
7494 		un->un_mspl->page.comp.dce = 1;
7495 	} else {
7496 		un->un_mspl->page.comp.dce = 0;
7497 	}
7498 
7499 
7500 #ifdef STDEBUG
7501 	if (st_debug >= 6) {
7502 		st_clean_print(ST_DEVINFO, st_label, SCSI_DEBUG,
7503 		    "st_set_datacomp_page: sense data for mode select",
7504 		    (char *)un->un_mspl, sizeof (struct seq_mode));
7505 	}
7506 #endif
7507 	rval = st_gen_mode_select(un, un->un_mspl, sizeof (struct seq_mode));
7508 
7509 	return (rval);
7510 }
7511 
7512 static int
7513 st_modesense(struct scsi_tape *un)
7514 {
7515 	int rval;
7516 	uchar_t page;
7517 
7518 	page = un->un_comp_page;
7519 
7520 	switch (page) {
7521 	case ST_DEV_DATACOMP_PAGE:
7522 	case ST_DEV_CONFIG_PAGE: /* fall through */
7523 		rval = st_gen_mode_sense(un, page, un->un_mspl,
7524 		    sizeof (struct seq_mode));
7525 		break;
7526 
7527 	case ST_DEV_DATACOMP_PAGE | ST_DEV_CONFIG_PAGE:
7528 		if (un->un_dp->options & ST_MODE_SEL_COMP) {
7529 			page = ST_DEV_DATACOMP_PAGE;
7530 			rval = st_gen_mode_sense(un, page, un->un_mspl,
7531 			    sizeof (struct seq_mode));
7532 			if (rval == 0 && un->un_mspl->page_code == page) {
7533 				un->un_comp_page = page;
7534 				break;
7535 			}
7536 			page = ST_DEV_CONFIG_PAGE;
7537 			rval = st_gen_mode_sense(un, page, un->un_mspl,
7538 			    sizeof (struct seq_mode));
7539 			if (rval == 0 && un->un_mspl->page_code == page) {
7540 				un->un_comp_page = page;
7541 				break;
7542 			}
7543 			un->un_dp->options &= ~ST_MODE_SEL_COMP;
7544 			un->un_comp_page = 0;
7545 		} else {
7546 			un->un_comp_page = 0;
7547 		}
7548 
7549 	default:	/* fall through */
7550 		rval = st_cmd(un->un_dev, SCMD_MODE_SENSE, MSIZE, SYNC_CMD);
7551 	}
7552 	return (rval);
7553 }
7554 
7555 static int
7556 st_modeselect(struct scsi_tape *un)
7557 {
7558 	int rval = 0;
7559 	int ix;
7560 
7561 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
7562 	    "st_modeselect(dev = 0x%lx): density = 0x%x\n",
7563 	    un->un_dev, un->un_mspl->density);
7564 
7565 	ASSERT(mutex_owned(ST_MUTEX));
7566 
7567 	/*
7568 	 * The parameter list should be the same for all of the
7569 	 * cases that follow so set them here
7570 	 *
7571 	 * Try mode select first if if fails set fields manually
7572 	 */
7573 	rval = st_modesense(un);
7574 	if (rval != 0) {
7575 		ST_DEBUG3(ST_DEVINFO, st_label, CE_WARN,
7576 		    "st_modeselect: First mode sense failed\n");
7577 		un->un_mspl->bd_len  = 8;
7578 		un->un_mspl->high_nb = 0;
7579 		un->un_mspl->mid_nb  = 0;
7580 		un->un_mspl->low_nb  = 0;
7581 	}
7582 	un->un_mspl->high_bl = (uchar_t)(un->un_bsize >> 16);
7583 	un->un_mspl->mid_bl  = (uchar_t)(un->un_bsize >> 8);
7584 	un->un_mspl->low_bl  = (uchar_t)(un->un_bsize);
7585 
7586 
7587 	/*
7588 	 * If configured to use a specific density code for a media type.
7589 	 * curdens is previously set by the minor node opened.
7590 	 * If the media type doesn't match the minor node we change it so it
7591 	 * looks like the correct one was opened.
7592 	 */
7593 	if (un->un_dp->options & ST_KNOWS_MEDIA) {
7594 		uchar_t best;
7595 
7596 		for (best = 0xff, ix = 0; ix < NDENSITIES; ix++) {
7597 			if (un->un_mspl->media_type ==
7598 			    un->un_dp->mediatype[ix]) {
7599 				best = ix;
7600 				/*
7601 				 * It matches but it might not be the only one.
7602 				 * Use the highest matching media type but not
7603 				 * to exceed the density selected by the open.
7604 				 */
7605 				if (ix < un->un_curdens) {
7606 					continue;
7607 				}
7608 				un->un_curdens = ix;
7609 				break;
7610 			}
7611 		}
7612 		/* If a match was found best will not be 0xff any more */
7613 		if (best < NDENSITIES) {
7614 			ST_DEBUG3(ST_DEVINFO, st_label, CE_WARN,
7615 			    "found media 0x%X using density 0x%X\n",
7616 			    un->un_mspl->media_type,
7617 			    un->un_dp->densities[best]);
7618 		}
7619 
7620 		un->un_mspl->density = un->un_dp->densities[best];
7621 
7622 	} else {
7623 		/* Otherwise set density based on minor node opened */
7624 		un->un_mspl->density = un->un_dp->densities[un->un_curdens];
7625 	}
7626 
7627 	if (un->un_dp->options & ST_NOBUF) {
7628 		un->un_mspl->bufm = 0;
7629 	} else {
7630 		un->un_mspl->bufm = 1;
7631 	}
7632 
7633 	rval = st_set_compression(un);
7634 
7635 	/*
7636 	 * If st_set_compression returned invalid or already it
7637 	 * found no need to do the mode select.
7638 	 * So do it here.
7639 	 */
7640 	if ((rval == ENOTTY) || (rval == EALREADY)) {
7641 
7642 		/* Zero non-writeable fields */
7643 		un->un_mspl->data_len = 0;
7644 		un->un_mspl->media_type = 0;
7645 		un->un_mspl->wp = 0;
7646 
7647 		/* need to set the density code */
7648 		rval = st_cmd(un->un_dev, SCMD_MODE_SELECT, MSIZE, SYNC_CMD);
7649 		if (rval != 0) {
7650 			if (un->un_state >= ST_STATE_OPEN) {
7651 				ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
7652 				    "unable to set tape mode\n");
7653 				un->un_fileno = -1;
7654 				rval = EIO;
7655 			} else {
7656 				rval = -1;
7657 			}
7658 		}
7659 	}
7660 
7661 	/*
7662 	 * The spec recommends to send a mode sense after a mode select
7663 	 */
7664 	(void) st_modesense(un);
7665 
7666 	ASSERT(mutex_owned(ST_MUTEX));
7667 
7668 	return (rval);
7669 }
7670 
7671 /*
7672  * st_gen_mode_sense
7673  *
7674  * generic mode sense.. it allows for any page
7675  */
7676 static int
7677 st_gen_mode_sense(struct scsi_tape *un, int page, struct seq_mode *page_data,
7678     int page_size)
7679 {
7680 
7681 	int r;
7682 	char	cdb[CDB_GROUP0];
7683 	struct uscsi_cmd *com;
7684 
7685 	com = kmem_zalloc(sizeof (*com), KM_SLEEP);
7686 
7687 	bzero(cdb, CDB_GROUP0);
7688 	cdb[0] = SCMD_MODE_SENSE;
7689 	cdb[2] = (char)page;
7690 	cdb[4] = (char)page_size;
7691 
7692 	com->uscsi_cdb = cdb;
7693 	com->uscsi_cdblen = CDB_GROUP0;
7694 	com->uscsi_bufaddr = (caddr_t)page_data;
7695 	com->uscsi_buflen = page_size;
7696 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
7697 	com->uscsi_flags = USCSI_DIAGNOSE | USCSI_SILENT |
7698 			    USCSI_READ | USCSI_RQENABLE;
7699 
7700 	r = st_ioctl_cmd(un->un_dev, com, UIO_SYSSPACE, UIO_SYSSPACE,
7701 		UIO_SYSSPACE);
7702 	kmem_free(com, sizeof (*com));
7703 	return (r);
7704 }
7705 
7706 /*
7707  * st_gen_mode_select
7708  *
7709  * generic mode select.. it allows for any page
7710  */
7711 static int
7712 st_gen_mode_select(struct scsi_tape *un, struct seq_mode *page_data,
7713     int page_size)
7714 {
7715 
7716 	int r;
7717 	char cdb[CDB_GROUP0];
7718 	struct uscsi_cmd *com;
7719 
7720 	/* Zero non-writeable fields */
7721 	page_data->data_len = 0;
7722 	page_data->media_type = 0;
7723 	page_data->wp = 0;
7724 
7725 	/*
7726 	 * If mode select has any page data, zero the ps (Page Savable) bit.
7727 	 */
7728 	if (page_size > MSIZE) {
7729 		page_data->ps = 0;
7730 	}
7731 
7732 
7733 	com = kmem_zalloc(sizeof (*com), KM_SLEEP);
7734 
7735 	/*
7736 	 * then, do a mode select to set what ever info
7737 	 */
7738 	bzero(cdb, CDB_GROUP0);
7739 	cdb[0] = SCMD_MODE_SELECT;
7740 	cdb[1] = 0x10;		/* set PF bit for many third party drives */
7741 	cdb[4] = (char)page_size;
7742 
7743 	com->uscsi_cdb = cdb;
7744 	com->uscsi_cdblen = CDB_GROUP0;
7745 	com->uscsi_bufaddr = (caddr_t)page_data;
7746 	com->uscsi_buflen = page_size;
7747 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
7748 	com->uscsi_flags = USCSI_DIAGNOSE | USCSI_SILENT
7749 		| USCSI_WRITE | USCSI_RQENABLE;
7750 
7751 	r = st_ioctl_cmd(un->un_dev, com, UIO_SYSSPACE, UIO_SYSSPACE,
7752 		UIO_SYSSPACE);
7753 
7754 	kmem_free(com, sizeof (*com));
7755 	return (r);
7756 }
7757 
7758 /*
7759  * Changes devices blocksize and bsize to requested blocksize nblksz.
7760  * Returns returned value from first failed call or zero on success.
7761  */
7762 static int
7763 st_change_block_size(dev_t dev, uint32_t nblksz)
7764 {
7765 	struct seq_mode *current;
7766 	int rval;
7767 	uint32_t oldblksz;
7768 
7769 	GET_SOFT_STATE(dev);
7770 
7771 	current = kmem_zalloc(MSIZE, KM_SLEEP);
7772 
7773 	/* Read current settings */
7774 	rval = st_gen_mode_sense(un, 0, current, MSIZE);
7775 	if (rval != 0) {
7776 		scsi_log(ST_DEVINFO, st_label, SCSI_DEBUG,
7777 		    "mode sense for change block size failed: rval = %d", rval);
7778 		goto finish;
7779 	}
7780 
7781 	/* Figure the current block size */
7782 	oldblksz =
7783 	    (current->high_bl << 16) |
7784 	    (current->mid_bl << 8) |
7785 	    (current->low_bl);
7786 
7787 	/* If current block size is the same as requested were done */
7788 	if (oldblksz == nblksz) {
7789 		un->un_bsize = nblksz;
7790 		rval = 0;
7791 		goto finish;
7792 	}
7793 
7794 	/* Change to requested block size */
7795 	current->high_bl = (uchar_t)(nblksz >> 16);
7796 	current->mid_bl  = (uchar_t)(nblksz >> 8);
7797 	current->low_bl  = (uchar_t)(nblksz);
7798 
7799 	/* Attempt to change block size */
7800 	rval = st_gen_mode_select(un, current, MSIZE);
7801 	if (rval != 0) {
7802 		scsi_log(ST_DEVINFO, st_label, SCSI_DEBUG,
7803 		    "Set new block size failed: rval = %d", rval);
7804 		goto finish;
7805 	}
7806 
7807 	/* Read back and verify setting */
7808 	rval = st_modesense(un);
7809 	if (rval == 0) {
7810 		un->un_bsize =
7811 		    (un->un_mspl->high_bl << 16) |
7812 		    (un->un_mspl->mid_bl << 8) |
7813 		    (un->un_mspl->low_bl);
7814 
7815 		if (un->un_bsize != nblksz) {
7816 			scsi_log(ST_DEVINFO, st_label, SCSI_DEBUG,
7817 			    "Blocksize set does not equal requested blocksize"
7818 			    "(read: %u requested: %u)\n", nblksz, un->un_bsize);
7819 			rval = EIO;
7820 		}
7821 	}
7822 finish:
7823 	kmem_free(current, MSIZE);
7824 	return (rval);
7825 }
7826 
7827 
7828 static void
7829 st_init(struct scsi_tape *un)
7830 {
7831 	ASSERT(mutex_owned(ST_MUTEX));
7832 
7833 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
7834 	"st_init(): dev = 0x%lx, will reset fileno, blkno, eof\n", un->un_dev);
7835 
7836 	un->un_blkno = 0;
7837 	un->un_fileno = 0;
7838 	un->un_lastop = ST_OP_NIL;
7839 	un->un_eof = ST_NO_EOF;
7840 	un->un_pwr_mgmt = ST_PWR_NORMAL;
7841 	if (st_error_level != SCSI_ERR_ALL) {
7842 		if (DEBUGGING) {
7843 			st_error_level = SCSI_ERR_ALL;
7844 		} else {
7845 			st_error_level = SCSI_ERR_RETRYABLE;
7846 		}
7847 	}
7848 }
7849 
7850 
7851 static void
7852 st_make_cmd(struct scsi_tape *un, struct buf *bp, int (*func)(caddr_t))
7853 {
7854 	struct scsi_pkt *pkt;
7855 	struct uscsi_cmd *ucmd;
7856 	int count, tval = 0;
7857 	int flags = 0;
7858 	uchar_t com;
7859 	char fixbit;
7860 
7861 	ASSERT(mutex_owned(ST_MUTEX));
7862 
7863 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
7864 	    "st_make_cmd(): dev = 0x%lx\n", un->un_dev);
7865 
7866 
7867 	/*
7868 	 * fixbit is for setting the Fixed Mode and Suppress Incorrect
7869 	 * Length Indicator bits on read/write commands, for setting
7870 	 * the Long bit on erase commands, and for setting the Code
7871 	 * Field bits on space commands.
7872 	 * XXX why do we set lastop here?
7873 	 */
7874 
7875 	if (bp != un->un_sbufp) {		/* regular raw I/O */
7876 		int stat_size = (un->un_arq_enabled ?
7877 			sizeof (struct scsi_arq_status) : 1);
7878 		pkt = scsi_init_pkt(ROUTE, NULL, bp,
7879 		    CDB_GROUP0, stat_size, 0, 0, func, (caddr_t)un);
7880 		if (pkt == NULL) {
7881 			goto exit;
7882 		}
7883 		SET_BP_PKT(bp, pkt);
7884 		if (un->un_bsize == 0) {
7885 			count = bp->b_bcount;
7886 			fixbit = 0;
7887 		} else {
7888 			count = bp->b_bcount / un->un_bsize;
7889 			fixbit = 1;
7890 		}
7891 		if (bp->b_flags & B_READ) {
7892 			com = SCMD_READ;
7893 			un->un_lastop = ST_OP_READ;
7894 			if ((un->un_bsize == 0) && /* Not Fixed Block */
7895 			    (un->un_dp->options & ST_READ_IGNORE_ILI)) {
7896 				fixbit = 2;
7897 			}
7898 		} else {
7899 			com = SCMD_WRITE;
7900 			un->un_lastop = ST_OP_WRITE;
7901 		}
7902 
7903 		tval = un->un_dp->io_timeout;
7904 
7905 		/*
7906 		 * For really large xfers, increase timeout
7907 		 */
7908 		if (bp->b_bcount > (10 * ONE_MEG))
7909 			tval *= bp->b_bcount/(10 * ONE_MEG);
7910 
7911 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7912 		    "%s %ld amt 0x%lx\n", (com == SCMD_WRITE) ?
7913 		    wr_str: rd_str, un->un_blkno, bp->b_bcount);
7914 
7915 	} else if ((ucmd = BP_UCMD(bp)) != NULL) {
7916 		/*
7917 		 * uscsi - build command, allocate scsi resources
7918 		 */
7919 		st_make_uscsi_cmd(un, ucmd, bp, func);
7920 		goto exit;
7921 
7922 	} else {				/* special I/O */
7923 		struct buf *allocbp = NULL;
7924 		int stat_size = (un->un_arq_enabled ?
7925 			sizeof (struct scsi_arq_status) : 1);
7926 
7927 
7928 		com = (uchar_t)(uintptr_t)bp->b_forw;
7929 		count = bp->b_bcount;
7930 
7931 		switch (com) {
7932 		case SCMD_READ:
7933 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7934 			    "special read %d\n", count);
7935 			if (un->un_bsize == 0) {
7936 				fixbit = 2;	/* suppress SILI */
7937 			} else {
7938 				fixbit = 1;	/* Fixed Block Mode */
7939 				count /= un->un_bsize;
7940 			}
7941 			allocbp = bp;
7942 			un->un_lastop = ST_OP_READ;
7943 			tval = un->un_dp->io_timeout;
7944 			break;
7945 
7946 		case SCMD_WRITE:
7947 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7948 			    "special write %d\n", count);
7949 			if (un->un_bsize != 0) {
7950 				fixbit = 1;	/* Fixed Block Mode */
7951 				count /= un->un_bsize;
7952 			} else {
7953 				fixbit = 0;
7954 			}
7955 			allocbp = bp;
7956 			un->un_lastop = ST_OP_WRITE;
7957 			tval = un->un_dp->io_timeout;
7958 			break;
7959 
7960 		case SCMD_WRITE_FILE_MARK:
7961 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7962 			    "write %d file marks\n", count);
7963 			un->un_lastop = ST_OP_WEOF;
7964 			fixbit = 0;
7965 			tval = un->un_dp->io_timeout;
7966 			break;
7967 
7968 		case SCMD_REWIND:
7969 			fixbit = 0;
7970 			count = 0;
7971 			un->un_lastop = ST_OP_CTL;
7972 			tval = un->un_dp->rewind_timeout;
7973 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7974 			    "rewind\n");
7975 			break;
7976 
7977 		case SCMD_SPACE:
7978 			fixbit = Isfmk(count);
7979 			count = (int)space_cnt(count);
7980 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7981 			    "space %d %s from file %d blk %ld\n",
7982 			    count, (fixbit) ? "filemarks" : "records",
7983 			    un->un_fileno, un->un_blkno);
7984 			un->un_lastop = ST_OP_CTL;
7985 			tval = un->un_dp->space_timeout;
7986 			break;
7987 
7988 		case SCMD_LOAD:
7989 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
7990 			    "%s tape\n", (count & 1) ? "load" : "unload");
7991 			fixbit = 0;
7992 
7993 			/* Loading or Unloading */
7994 			if (count & 1) {
7995 				tval = un->un_dp->load_timeout;
7996 			} else {
7997 				tval = un->un_dp->unload_timeout;
7998 			}
7999 			/* Is Retension requested */
8000 			if (count & 2) {
8001 				tval += un->un_dp->rewind_timeout;
8002 			}
8003 			un->un_lastop = ST_OP_CTL;
8004 			break;
8005 
8006 		case SCMD_ERASE:
8007 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8008 			    "erase tape\n");
8009 			count = 0;
8010 			/*
8011 			 * We support long erase only
8012 			 */
8013 			fixbit = 1;
8014 			tval = un->un_dp->erase_timeout;
8015 			un->un_lastop = ST_OP_CTL;
8016 			break;
8017 
8018 		case SCMD_MODE_SENSE:
8019 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8020 			    "mode sense\n");
8021 			allocbp = bp;
8022 			fixbit = 0;
8023 			tval = un->un_dp->non_motion_timeout;
8024 			break;
8025 
8026 		case SCMD_MODE_SELECT:
8027 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8028 			    "mode select\n");
8029 			allocbp = bp;
8030 			fixbit = 0;
8031 			tval = un->un_dp->non_motion_timeout;
8032 			break;
8033 
8034 		case SCMD_RESERVE:
8035 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8036 			    "reserve\n");
8037 			fixbit = 0;
8038 			tval = un->un_dp->non_motion_timeout;
8039 			break;
8040 
8041 		case SCMD_RELEASE:
8042 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8043 			    "release\n");
8044 			fixbit = 0;
8045 			tval = un->un_dp->non_motion_timeout;
8046 			break;
8047 
8048 		case SCMD_READ_BLKLIM:
8049 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8050 			    "read block limits\n");
8051 			allocbp = bp;
8052 			fixbit = count = 0;
8053 			tval = un->un_dp->non_motion_timeout;
8054 			break;
8055 
8056 		case SCMD_TEST_UNIT_READY:
8057 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8058 			    "test unit ready\n");
8059 			fixbit = 0;
8060 			tval = un->un_dp->non_motion_timeout;
8061 			break;
8062 		default:
8063 			ST_DEBUG(ST_DEVINFO, st_label, CE_PANIC,
8064 			    "Unhandled scsi command 0x%x in st_make_cmd()\n",
8065 			    com);
8066 		}
8067 		pkt = scsi_init_pkt(ROUTE, NULL, allocbp,
8068 			CDB_GROUP0, stat_size, 0, 0, func, (caddr_t)un);
8069 		if (pkt == NULL) {
8070 			goto exit;
8071 		}
8072 		if (allocbp)
8073 			ASSERT(geterror(allocbp) == 0);
8074 
8075 	}
8076 
8077 	(void) scsi_setup_cdb((union scsi_cdb *)pkt->pkt_cdbp,
8078 	    com, 0, (uint_t)count, 0);
8079 	FILL_SCSI1_LUN(un->un_sd, pkt);
8080 	/*
8081 	 * Initialize the SILI/Fixed bits of the byte 1 of cdb.
8082 	 */
8083 	((union scsi_cdb *)(pkt->pkt_cdbp))->t_code = fixbit;
8084 	pkt->pkt_flags = flags;
8085 
8086 	/*
8087 	 * If ST_SHORT_FILEMARKS bit is ON for EXABYTE
8088 	 * device, set the Vendor Unique bit to
8089 	 * write Short File Mark.
8090 	 */
8091 	if (com == SCMD_WRITE_FILE_MARK &&
8092 		un->un_dp->options & ST_SHORT_FILEMARKS) {
8093 		switch (un->un_dp->type) {
8094 		case ST_TYPE_EXB8500:
8095 		case ST_TYPE_EXABYTE:
8096 			/*
8097 			 * Now the Vendor Unique bit 7 in Byte 5 of CDB
8098 			 * is set to to write Short File Mark
8099 			 */
8100 			((union scsi_cdb *)pkt->pkt_cdbp)->g0_vu_1 = 1;
8101 			break;
8102 
8103 		default:
8104 			/*
8105 			 * Well, if ST_SHORT_FILEMARKS is set for other
8106 			 * tape drives, it is just ignored
8107 			 */
8108 			break;
8109 		}
8110 	}
8111 	ASSERT(tval);
8112 	pkt->pkt_time = tval;
8113 	pkt->pkt_comp = st_intr;
8114 	pkt->pkt_private = (opaque_t)bp;
8115 	SET_BP_PKT(bp, pkt);
8116 
8117 exit:
8118 	ASSERT(mutex_owned(ST_MUTEX));
8119 }
8120 
8121 
8122 /*
8123  * Build a command based on a uscsi command;
8124  */
8125 static void
8126 st_make_uscsi_cmd(struct scsi_tape *un, struct uscsi_cmd *ucmd,
8127     struct buf *bp, int (*func)(caddr_t))
8128 {
8129 	struct scsi_pkt *pkt;
8130 	caddr_t cdb;
8131 	int	cdblen;
8132 	int stat_size;
8133 
8134 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
8135 	    "st_make_uscsi_cmd(): dev = 0x%lx\n", un->un_dev);
8136 
8137 	if (ucmd->uscsi_flags & USCSI_RQENABLE) {
8138 		stat_size = (un->un_arq_enabled ?
8139 		    sizeof (struct scsi_arq_status) : 1);
8140 	} else {
8141 		stat_size = 1;
8142 	}
8143 
8144 	ASSERT(mutex_owned(ST_MUTEX));
8145 
8146 	un->un_lastop = ST_OP_CTL;	/* usual */
8147 
8148 	cdb = ucmd->uscsi_cdb;
8149 	cdblen = ucmd->uscsi_cdblen;
8150 
8151 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8152 	    "st_make_uscsi_cmd: buflen=%ld bcount=%ld\n",
8153 		ucmd->uscsi_buflen, bp->b_bcount);
8154 	pkt = scsi_init_pkt(ROUTE, NULL,
8155 		(bp->b_bcount > 0) ? bp : NULL,
8156 		cdblen, stat_size, 0, 0, func, (caddr_t)un);
8157 	if (pkt == NULL) {
8158 		goto exit;
8159 	}
8160 
8161 	bcopy(cdb, pkt->pkt_cdbp, (uint_t)cdblen);
8162 
8163 #ifdef STDEBUG
8164 	if (st_debug >= 6) {
8165 		st_clean_print(ST_DEVINFO, st_label, SCSI_DEBUG,
8166 		    "pkt_cdbp", (char *)cdb, cdblen);
8167 	}
8168 #endif
8169 
8170 	if (ucmd->uscsi_flags & USCSI_SILENT) {
8171 		pkt->pkt_flags |= FLAG_SILENT;
8172 	}
8173 
8174 	pkt->pkt_time = ucmd->uscsi_timeout;
8175 	pkt->pkt_comp = st_intr;
8176 	pkt->pkt_private = (opaque_t)bp;
8177 	SET_BP_PKT(bp, pkt);
8178 exit:
8179 	ASSERT(mutex_owned(ST_MUTEX));
8180 }
8181 
8182 
8183 /*
8184  * restart cmd currently at the head of the runq
8185  *
8186  * If scsi_transport() succeeds or the retries
8187  * count exhausted, restore the throttle that was
8188  * zeroed out in st_handle_intr_busy().
8189  *
8190  */
8191 static void
8192 st_intr_restart(void *arg)
8193 {
8194 	struct scsi_tape *un = arg;
8195 	struct buf *bp;
8196 	int status = TRAN_ACCEPT;
8197 
8198 	mutex_enter(ST_MUTEX);
8199 
8200 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
8201 		"st_intr_restart(), un = 0x%p\n", (void *)un);
8202 
8203 	un->un_hib_tid = 0;
8204 
8205 	/*
8206 	 * move from waitq to runq, if there is anything on the waitq
8207 	 */
8208 	if ((bp = un->un_quef) == NULL) {
8209 		mutex_exit(ST_MUTEX);
8210 		return;
8211 	}
8212 
8213 	/*
8214 	 * Here we know :
8215 	 *	throttle = 0, via st_handle_intr_busy
8216 	 */
8217 
8218 	if (un->un_quel == bp) {
8219 		un->un_quel = NULL;
8220 		un->un_quef = NULL;	/* we know it's the first one */
8221 	} else {
8222 		un->un_quef = bp->b_actf;
8223 	}
8224 	bp->b_actf = NULL;
8225 
8226 	if (un->un_runqf) {
8227 		/*
8228 		 * not good, we don't want to requeue something after
8229 		 * another.
8230 		 */
8231 		mutex_exit(ST_MUTEX);
8232 		goto done_error;
8233 	} else {
8234 		un->un_runqf = bp;
8235 		un->un_runql = bp;
8236 	}
8237 
8238 	ST_DO_KSTATS(bp, kstat_waitq_to_runq);
8239 
8240 	mutex_exit(ST_MUTEX);
8241 
8242 	status = scsi_transport(BP_PKT(bp));
8243 
8244 	mutex_enter(ST_MUTEX);
8245 
8246 	if (status != TRAN_ACCEPT) {
8247 		ST_DO_KSTATS(bp, kstat_runq_back_to_waitq);
8248 		mutex_exit(ST_MUTEX);
8249 
8250 		if (status == TRAN_BUSY) {
8251 			if (st_handle_intr_busy(un, bp,
8252 			    ST_TRAN_BUSY_TIMEOUT) == 0)
8253 				return;	/* timeout is setup again */
8254 		}
8255 
8256 	} else {
8257 		un->un_tran_retry_ct = 0;
8258 		if (un->un_last_throttle) {
8259 			un->un_throttle = un->un_last_throttle;
8260 		}
8261 		mutex_exit(ST_MUTEX);
8262 		return;
8263 	}
8264 
8265 done_error:
8266 	ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
8267 	    "restart transport rejected\n");
8268 	bp->b_resid = bp->b_bcount;
8269 
8270 #ifndef __lock_lint
8271 	/*
8272 	 * warlock doesn't understand this potential
8273 	 * recursion?
8274 	 */
8275 	mutex_enter(ST_MUTEX);
8276 	if (un->un_last_throttle) {
8277 		un->un_throttle = un->un_last_throttle;
8278 	}
8279 	if (status != TRAN_ACCEPT)
8280 		ST_DO_ERRSTATS(un, st_transerrs);
8281 	ST_DO_KSTATS(bp, kstat_waitq_exit);
8282 	SET_PE_FLAG(un);
8283 	st_bioerror(bp, EIO);
8284 	st_done_and_mutex_exit(un, bp);
8285 #endif
8286 	ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
8287 	    "busy restart aborted\n");
8288 }
8289 
8290 /*
8291  * st_check_media():
8292  * Periodically check the media state using scsi_watch service;
8293  * this service calls back after TUR and possibly request sense
8294  * the callback handler (st_media_watch_cb()) decodes the request sense
8295  * data (if any)
8296  */
8297 
8298 static int
8299 st_check_media(dev_t dev, enum mtio_state state)
8300 {
8301 	int rval = 0;
8302 	enum mtio_state	prev_state;
8303 	opaque_t token = NULL;
8304 
8305 	GET_SOFT_STATE(dev);
8306 
8307 	mutex_enter(ST_MUTEX);
8308 
8309 	ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8310 		"st_check_media:state=%x, mediastate=%x\n",
8311 		state, un->un_mediastate);
8312 
8313 	prev_state = un->un_mediastate;
8314 
8315 	/*
8316 	 * is there anything to do?
8317 	 */
8318 retry:
8319 	if (state == un->un_mediastate || un->un_mediastate == MTIO_NONE) {
8320 		/*
8321 		 * submit the request to the scsi_watch service;
8322 		 * scsi_media_watch_cb() does the real work
8323 		 */
8324 		mutex_exit(ST_MUTEX);
8325 		token = scsi_watch_request_submit(ST_SCSI_DEVP,
8326 			st_check_media_time, SENSE_LENGTH,
8327 			st_media_watch_cb, (caddr_t)dev);
8328 		if (token == NULL) {
8329 			rval = EAGAIN;
8330 			goto done;
8331 		}
8332 		mutex_enter(ST_MUTEX);
8333 
8334 		un->un_swr_token = token;
8335 		un->un_specified_mediastate = state;
8336 
8337 		/*
8338 		 * now wait for media change
8339 		 * we will not be signalled unless mediastate == state but it
8340 		 * still better to test for this condition, since there
8341 		 * is a 5 sec cv_broadcast delay when
8342 		 *  mediastate == MTIO_INSERTED
8343 		 */
8344 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8345 			"st_check_media:waiting for media state change\n");
8346 		while (un->un_mediastate == state) {
8347 			if (cv_wait_sig(&un->un_state_cv, ST_MUTEX) == 0) {
8348 				mutex_exit(ST_MUTEX);
8349 				ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8350 				    "st_check_media:waiting for media state "
8351 				    "was interrupted\n");
8352 				rval = EINTR;
8353 				goto done;
8354 			}
8355 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8356 			    "st_check_media:received signal, state=%x\n",
8357 			    un->un_mediastate);
8358 		}
8359 	}
8360 
8361 	/*
8362 	 * if we transitioned to MTIO_INSERTED, media has really been
8363 	 * inserted.  If TUR fails, it is probably a exabyte slow spin up.
8364 	 * Reset and retry the state change.  If everything is ok, replay
8365 	 * the open() logic.
8366 	 */
8367 	if ((un->un_mediastate == MTIO_INSERTED) &&
8368 	    (un->un_state == ST_STATE_OFFLINE)) {
8369 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8370 		    "st_check_media: calling st_cmd to confirm inserted\n");
8371 
8372 		/*
8373 		 * set this early so that TUR will make it through strategy
8374 		 * without triggering a st_tape_init().  We needed it set
8375 		 * before calling st_tape_init() ourselves anyway.  If TUR
8376 		 * fails, set it back
8377 		 */
8378 		un->un_state = ST_STATE_INITIALIZING;
8379 		/*
8380 		 * If we haven't done/checked reservation on the
8381 		 * tape unit do it now.
8382 		 */
8383 		if (ST_RESERVE_SUPPORTED(un) &&
8384 			!(un->un_rsvd_status & ST_INIT_RESERVE)) {
8385 				if (rval = st_tape_reservation_init(dev)) {
8386 					mutex_exit(ST_MUTEX);
8387 					goto done;
8388 				}
8389 		}
8390 
8391 		if (st_cmd(dev, SCMD_TEST_UNIT_READY, 0, SYNC_CMD)) {
8392 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8393 			    "st_check_media: TUR failed, going to retry\n");
8394 			un->un_mediastate = prev_state;
8395 			un->un_state = ST_STATE_OFFLINE;
8396 			goto retry;
8397 		}
8398 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8399 		    "st_check_media: media inserted\n");
8400 
8401 		/* this also rewinds the tape */
8402 		rval = st_tape_init(dev);
8403 		if (rval != 0) {
8404 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8405 			    "st_check_media : OFFLINE init failure ");
8406 			un->un_state = ST_STATE_OFFLINE;
8407 			un->un_fileno = -1;
8408 		} else {
8409 			un->un_state = ST_STATE_OPEN_PENDING_IO;
8410 			un->un_fileno = 0;
8411 			un->un_blkno = 0;
8412 		}
8413 	} else if ((un->un_mediastate == MTIO_EJECTED) &&
8414 		(un->un_state != ST_STATE_OFFLINE)) {
8415 		/*
8416 		 * supported devices must be rewound before ejection
8417 		 * rewind resets fileno & blkno
8418 		 */
8419 		un->un_laststate = un->un_state;
8420 		un->un_state = ST_STATE_OFFLINE;
8421 	}
8422 	mutex_exit(ST_MUTEX);
8423 done:
8424 	if (token) {
8425 		(void) scsi_watch_request_terminate(token,
8426 				SCSI_WATCH_TERMINATE_WAIT);
8427 		mutex_enter(ST_MUTEX);
8428 		un->un_swr_token = (opaque_t)NULL;
8429 		mutex_exit(ST_MUTEX);
8430 	}
8431 
8432 	ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG, "st_check_media: done\n");
8433 
8434 	return (rval);
8435 }
8436 
8437 /*
8438  * st_media_watch_cb() is called by scsi_watch_thread for
8439  * verifying the request sense data (if any)
8440  */
8441 static int
8442 st_media_watch_cb(caddr_t arg, struct scsi_watch_result *resultp)
8443 {
8444 	struct scsi_status *statusp = resultp->statusp;
8445 	struct scsi_extended_sense *sensep = resultp->sensep;
8446 	uchar_t actual_sense_length = resultp->actual_sense_length;
8447 	struct scsi_tape *un;
8448 	enum mtio_state state = MTIO_NONE;
8449 	int instance;
8450 	dev_t dev = (dev_t)arg;
8451 
8452 	instance = MTUNIT(dev);
8453 	if ((un = ddi_get_soft_state(st_state, instance)) == NULL) {
8454 		return (-1);
8455 	}
8456 
8457 	mutex_enter(ST_MUTEX);
8458 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
8459 		"st_media_watch_cb: status=%x, sensep=%p, len=%x\n",
8460 			*((char *)statusp), (void *)sensep,
8461 			actual_sense_length);
8462 
8463 	/*
8464 	 * if there was a check condition then sensep points to valid
8465 	 * sense data
8466 	 * if status was not a check condition but a reservation or busy
8467 	 * status then the new state is MTIO_NONE
8468 	 */
8469 	if (sensep) {
8470 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8471 		    "st_media_watch_cb: KEY=%x, ASC=%x, ASCQ=%x\n",
8472 		    sensep->es_key, sensep->es_add_code, sensep->es_qual_code);
8473 
8474 		switch (un->un_dp->type) {
8475 		default:
8476 			ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8477 	    "st_media_watch_cb: unknown drive type %d, default to ST_TYPE_HP\n",
8478 	    un->un_dp->type);
8479 		/* FALLTHROUGH */
8480 
8481 		case ST_TYPE_STC3490:	/* STK 4220 1/2" cartridge */
8482 		case ST_TYPE_FUJI:	/* 1/2" cartridge */
8483 		case ST_TYPE_HP:	/* HP 88780 1/2" reel */
8484 			if (un->un_dp->type == ST_TYPE_FUJI) {
8485 				ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8486 				    "st_media_watch_cb: ST_TYPE_FUJI\n");
8487 			} else {
8488 				ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8489 				    "st_media_watch_cb: ST_TYPE_HP\n");
8490 			}
8491 			switch (sensep->es_key) {
8492 			case KEY_UNIT_ATTENTION:
8493 				/* not ready to ready transition */
8494 				/* hp/es_qual_code == 80 on>off>on */
8495 				/* hp/es_qual_code == 0 on>off>unld>ld>on */
8496 				if (sensep->es_add_code == 0x28) {
8497 					state = MTIO_INSERTED;
8498 				}
8499 				break;
8500 			case KEY_NOT_READY:
8501 				/* in process, rewinding or loading */
8502 				if ((sensep->es_add_code == 0x04) &&
8503 				    (sensep->es_qual_code == 0x00)) {
8504 					state = MTIO_EJECTED;
8505 				}
8506 				break;
8507 			}
8508 			break;
8509 
8510 		case ST_TYPE_EXB8500:	/* Exabyte 8500 */
8511 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8512 			    "st_media_watch_cb: ST_TYPE_EXB8500\n");
8513 			switch (sensep->es_key) {
8514 			case KEY_UNIT_ATTENTION:
8515 				/* operator medium removal request */
8516 				if ((sensep->es_add_code == 0x5a) &&
8517 				    (sensep->es_qual_code == 0x01)) {
8518 					state = MTIO_EJECTED;
8519 				/* not ready to ready transition */
8520 				} else if ((sensep->es_add_code == 0x28) &&
8521 				    (sensep->es_qual_code == 0x00)) {
8522 					state = MTIO_INSERTED;
8523 				}
8524 				break;
8525 			case KEY_NOT_READY:
8526 				/* medium not present */
8527 				if (sensep->es_add_code == 0x3a) {
8528 					state = MTIO_EJECTED;
8529 				}
8530 				break;
8531 			}
8532 			break;
8533 		case ST_TYPE_EXABYTE:	/* Exabyte 8200 */
8534 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8535 			    "st_media_watch_cb: ST_TYPE_EXABYTE\n");
8536 			switch (sensep->es_key) {
8537 			case KEY_NOT_READY:
8538 				if ((sensep->es_add_code == 0x04) &&
8539 				    (sensep->es_qual_code == 0x00)) {
8540 					/* volume not mounted? */
8541 					state = MTIO_EJECTED;
8542 				} else if (sensep->es_add_code == 0x3a) {
8543 					state = MTIO_EJECTED;
8544 				}
8545 				break;
8546 			case KEY_UNIT_ATTENTION:
8547 				state = MTIO_EJECTED;
8548 				break;
8549 			}
8550 			break;
8551 
8552 		case ST_TYPE_DLT:		/* quantum DLT4xxx */
8553 			switch (sensep->es_key) {
8554 			case KEY_UNIT_ATTENTION:
8555 				if (sensep->es_add_code == 0x28) {
8556 					state = MTIO_INSERTED;
8557 				}
8558 				break;
8559 			case KEY_NOT_READY:
8560 				if (sensep->es_add_code == 0x04) {
8561 					/* in transition but could be either */
8562 					state = un->un_specified_mediastate;
8563 				} else if ((sensep->es_add_code == 0x3a) &&
8564 				    (sensep->es_qual_code == 0x00)) {
8565 					state = MTIO_EJECTED;
8566 				}
8567 				break;
8568 			}
8569 			break;
8570 		}
8571 	} else if (*((char *)statusp) == STATUS_GOOD) {
8572 		state = MTIO_INSERTED;
8573 	}
8574 
8575 	ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8576 		"st_media_watch_cb:state=%x, specified=%x\n",
8577 		state, un->un_specified_mediastate);
8578 
8579 	/*
8580 	 * now signal the waiting thread if this is *not* the specified state;
8581 	 * delay the signal if the state is MTIO_INSERTED
8582 	 * to allow the target to recover
8583 	 */
8584 	if (state != un->un_specified_mediastate) {
8585 		un->un_mediastate = state;
8586 		if (state == MTIO_INSERTED) {
8587 			/*
8588 			 * delay the signal to give the drive a chance
8589 			 * to do what it apparently needs to do
8590 			 */
8591 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8592 			    "st_media_watch_cb:delayed cv_broadcast\n");
8593 			un->un_delay_tid = timeout(st_delayed_cv_broadcast,
8594 			    un, drv_usectohz((clock_t)MEDIA_ACCESS_DELAY));
8595 		} else {
8596 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
8597 				"st_media_watch_cb:immediate cv_broadcast\n");
8598 			cv_broadcast(&un->un_state_cv);
8599 		}
8600 	}
8601 	mutex_exit(ST_MUTEX);
8602 	return (0);
8603 }
8604 
8605 /*
8606  * delayed cv_broadcast to allow for target to recover
8607  * from media insertion
8608  */
8609 static void
8610 st_delayed_cv_broadcast(void *arg)
8611 {
8612 	struct scsi_tape *un = arg;
8613 
8614 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
8615 		"st_delayed_cv_broadcast:delayed cv_broadcast\n");
8616 
8617 	mutex_enter(ST_MUTEX);
8618 	cv_broadcast(&un->un_state_cv);
8619 	mutex_exit(ST_MUTEX);
8620 }
8621 
8622 /*
8623  * restart cmd currently at the start of the waitq
8624  */
8625 static void
8626 st_start_restart(void *arg)
8627 {
8628 	struct scsi_tape *un = arg;
8629 
8630 	ASSERT(un != NULL);
8631 
8632 	mutex_enter(ST_MUTEX);
8633 
8634 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
8635 		"st_tran_restart()\n");
8636 
8637 	if (un->un_quef) {
8638 		st_start(un);
8639 	}
8640 
8641 	mutex_exit(ST_MUTEX);
8642 }
8643 
8644 
8645 /*
8646  * Command completion processing
8647  *
8648  */
8649 static void
8650 st_intr(struct scsi_pkt *pkt)
8651 {
8652 	struct scsi_tape *un;
8653 	struct buf *last_runqf;
8654 	struct buf *bp;
8655 	int action = COMMAND_DONE;
8656 	clock_t	timout;
8657 	int	status;
8658 
8659 	bp = (struct buf *)pkt->pkt_private;
8660 	un = ddi_get_soft_state(st_state, MTUNIT(bp->b_edev));
8661 
8662 	mutex_enter(ST_MUTEX);
8663 
8664 	un->un_rqs_state &= ~(ST_RQS_ERROR);
8665 
8666 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_intr()\n");
8667 
8668 	if (pkt->pkt_reason != CMD_CMPLT) {
8669 
8670 		/* If device has gone away not much else to do */
8671 		if (pkt->pkt_reason == CMD_DEV_GONE) {
8672 			action = COMMAND_DONE_ERROR;
8673 		} else if (un->un_state == ST_STATE_SENSING) {
8674 			ST_DO_ERRSTATS(un, st_transerrs);
8675 			action = COMMAND_DONE_ERROR;
8676 		} else {
8677 			action = st_handle_incomplete(un, bp);
8678 		}
8679 	/*
8680 	 * At this point we know that the command was successfully
8681 	 * completed. Now what?
8682 	 */
8683 	} else if (un->un_arq_enabled &&
8684 	    (pkt->pkt_state & STATE_ARQ_DONE)) {
8685 		/*
8686 		 * the transport layer successfully completed an autorqsense
8687 		 */
8688 		action = st_handle_autosense(un, bp);
8689 
8690 	} else if (un->un_state == ST_STATE_SENSING) {
8691 		/*
8692 		 * okay. We were running a REQUEST SENSE. Find
8693 		 * out what to do next.
8694 		 * some actions are based on un_state, hence
8695 		 * restore the state st was in before ST_STATE_SENSING.
8696 		 */
8697 		un->un_state = un->un_laststate;
8698 		action = st_handle_sense(un, bp);
8699 		/*
8700 		 * set pkt back to original packet in case we will have
8701 		 * to requeue it
8702 		 */
8703 		pkt = BP_PKT(bp);
8704 	} else  if ((SCBP(pkt)->sts_busy) || (SCBP(pkt)->sts_chk)) {
8705 		/*
8706 		 * Okay, we weren't running a REQUEST SENSE. Call a routine
8707 		 * to see if the status bits we're okay. If a request sense
8708 		 * is to be run, that will happen.
8709 		 */
8710 		action = st_check_error(un, pkt);
8711 	}
8712 
8713 	if (un->un_pwr_mgmt == ST_PWR_SUSPENDED) {
8714 		switch (action) {
8715 			case QUE_COMMAND:
8716 				/*
8717 				 * return cmd to head to the queue
8718 				 * since we are suspending so that
8719 				 * it gets restarted during resume
8720 				 */
8721 				if (un->un_runqf) {
8722 					last_runqf = un->un_runqf;
8723 					un->un_runqf = bp;
8724 					bp->b_actf = last_runqf;
8725 				} else {
8726 					bp->b_actf = NULL;
8727 					un->un_runqf = bp;
8728 					un->un_runql = bp;
8729 				}
8730 				action = JUST_RETURN;
8731 				break;
8732 
8733 			case QUE_SENSE:
8734 				action = COMMAND_DONE_ERROR;
8735 				break;
8736 
8737 			default:
8738 				break;
8739 		}
8740 	}
8741 
8742 	/*
8743 	 * Restore old state if we were sensing.
8744 	 */
8745 	if (un->un_state == ST_STATE_SENSING && action != QUE_SENSE) {
8746 		un->un_state = un->un_laststate;
8747 	}
8748 
8749 	ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
8750 	    "st_intr: pkt=%p, bp=%p, action=%x, status=%x\n",
8751 	    (void *)pkt, (void *)bp, action, SCBP_C(pkt));
8752 
8753 
8754 	switch (action) {
8755 	case COMMAND_DONE_EACCES:
8756 		/* this is to report a reservation conflict */
8757 		st_bioerror(bp, EACCES);
8758 		ST_DEBUG(ST_DEVINFO, st_label, SCSI_DEBUG,
8759 			"Reservation Conflict \n");
8760 
8761 		/*FALLTHROUGH*/
8762 	case COMMAND_DONE_ERROR:
8763 		if (un->un_eof < ST_EOT_PENDING &&
8764 		    un->un_state >= ST_STATE_OPEN) {
8765 			/*
8766 			 * all errors set state of the tape to 'unknown'
8767 			 * unless we're at EOT or are doing append testing.
8768 			 * If sense key was illegal request, preserve state.
8769 			 */
8770 			if (un->un_status != KEY_ILLEGAL_REQUEST) {
8771 				un->un_fileno = -1;
8772 			}
8773 		}
8774 		un->un_err_resid = bp->b_resid = bp->b_bcount;
8775 		/*
8776 		 * since we have an error (COMMAND_DONE_ERROR), we want to
8777 		 * make sure an error ocurrs, so make sure at least EIO is
8778 		 * returned
8779 		 */
8780 		if (geterror(bp) == 0)
8781 			st_bioerror(bp, EIO);
8782 
8783 		SET_PE_FLAG(un);
8784 		if (!(un->un_rqs_state & ST_RQS_ERROR) &&
8785 		    (un->un_errno == EIO)) {
8786 			un->un_rqs_state &= ~(ST_RQS_VALID);
8787 		}
8788 		goto done;
8789 
8790 	case COMMAND_DONE_ERROR_RECOVERED:
8791 		un->un_err_resid = bp->b_resid = bp->b_bcount;
8792 		ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
8793 		    "st_intr(): COMMAND_DONE_ERROR_RECOVERED");
8794 		if (geterror(bp) == 0)
8795 			st_bioerror(bp, EIO);
8796 		SET_PE_FLAG(un);
8797 		if (!(un->un_rqs_state & ST_RQS_ERROR) &&
8798 		    (un->un_errno == EIO)) {
8799 			un->un_rqs_state &= ~(ST_RQS_VALID);
8800 		}
8801 		/*FALLTHROUGH*/
8802 	case COMMAND_DONE:
8803 		st_set_state(un);
8804 done:
8805 		ST_DO_KSTATS(bp, kstat_runq_exit);
8806 		st_done_and_mutex_exit(un, bp);
8807 		return;
8808 
8809 	case QUE_SENSE:
8810 		if ((un->un_ncmds > 1) && !un->un_flush_on_errors)
8811 			goto sense_error;
8812 
8813 		if (un->un_state != ST_STATE_SENSING) {
8814 			un->un_laststate = un->un_state;
8815 			un->un_state = ST_STATE_SENSING;
8816 		}
8817 
8818 		un->un_rqs->pkt_private = (opaque_t)bp;
8819 		bzero(ST_RQSENSE, SENSE_LENGTH);
8820 
8821 		if (un->un_throttle) {
8822 			un->un_last_throttle = un->un_throttle;
8823 			un->un_throttle = 0;
8824 		}
8825 
8826 		mutex_exit(ST_MUTEX);
8827 
8828 		/*
8829 		 * never retry this, some other command will have nuked the
8830 		 * sense, anyway
8831 		 */
8832 		status = scsi_transport(un->un_rqs);
8833 
8834 		mutex_enter(ST_MUTEX);
8835 
8836 		if (un->un_last_throttle) {
8837 			un->un_throttle = un->un_last_throttle;
8838 		}
8839 
8840 		if (status == TRAN_ACCEPT) {
8841 			mutex_exit(ST_MUTEX);
8842 			return;
8843 		}
8844 		if (status != TRAN_BUSY)
8845 			ST_DO_ERRSTATS(un, st_transerrs);
8846 sense_error:
8847 		un->un_fileno = -1;
8848 		st_bioerror(bp, EIO);
8849 		SET_PE_FLAG(un);
8850 		goto done;
8851 
8852 	case QUE_BUSY_COMMAND:
8853 		/* longish timeout */
8854 		timout = ST_STATUS_BUSY_TIMEOUT;
8855 		goto que_it_up;
8856 
8857 	case QUE_COMMAND:
8858 		/* short timeout */
8859 		timout = ST_TRAN_BUSY_TIMEOUT;
8860 que_it_up:
8861 		/*
8862 		 * let st_handle_intr_busy put this bp back on waitq and make
8863 		 * checks to see if it is ok to requeue the command.
8864 		 */
8865 		ST_DO_KSTATS(bp, kstat_runq_back_to_waitq);
8866 
8867 		/*
8868 		 * Save the throttle before setting up the timeout
8869 		 */
8870 		if (un->un_throttle) {
8871 			un->un_last_throttle = un->un_throttle;
8872 		}
8873 		mutex_exit(ST_MUTEX);
8874 		if (st_handle_intr_busy(un, bp, timout) == 0)
8875 			return;		/* timeout is setup again */
8876 
8877 		mutex_enter(ST_MUTEX);
8878 		un->un_fileno = -1;
8879 		un->un_err_resid = bp->b_resid = bp->b_bcount;
8880 		st_bioerror(bp, EIO);
8881 		SET_PE_FLAG(un);
8882 		goto done;
8883 
8884 	case QUE_LAST_COMMAND:
8885 
8886 		if ((un->un_ncmds > 1) && !un->un_flush_on_errors) {
8887 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
8888 			    "un_ncmds: %d can't retry cmd \n", un->un_ncmds);
8889 			goto last_command_error;
8890 		}
8891 		mutex_exit(ST_MUTEX);
8892 		if (st_handle_intr_retry_lcmd(un, bp) == 0)
8893 			return;
8894 		mutex_enter(ST_MUTEX);
8895 last_command_error:
8896 		un->un_err_resid = bp->b_resid = bp->b_bcount;
8897 		un->un_fileno = -1;
8898 		st_bioerror(bp, EIO);
8899 		SET_PE_FLAG(un);
8900 		goto done;
8901 
8902 	case JUST_RETURN:
8903 	default:
8904 		ST_DO_KSTATS(bp, kstat_runq_back_to_waitq);
8905 		mutex_exit(ST_MUTEX);
8906 		return;
8907 	}
8908 	/*NOTREACHED*/
8909 }
8910 
8911 static int
8912 st_handle_incomplete(struct scsi_tape *un, struct buf *bp)
8913 {
8914 	static char *fail = "SCSI transport failed: reason '%s': %s\n";
8915 	int rval = COMMAND_DONE_ERROR;
8916 	struct scsi_pkt *pkt = (un->un_state == ST_STATE_SENSING) ?
8917 			un->un_rqs : BP_PKT(bp);
8918 	int result;
8919 
8920 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
8921 		"st_handle_incomplete(): dev = 0x%lx\n", un->un_dev);
8922 
8923 	ASSERT(mutex_owned(ST_MUTEX));
8924 
8925 	switch (pkt->pkt_reason) {
8926 	case CMD_INCOMPLETE:	/* tran stopped with not normal state */
8927 		/*
8928 		 * this occurs when accessing a powered down drive, no
8929 		 * need to complain; just fail the open
8930 		 */
8931 #ifdef STDEBUG
8932 		if (st_debug >= 1) {
8933 			st_clean_print(ST_DEVINFO, st_label, CE_WARN,
8934 			    "Failed CDB", (char *)pkt->pkt_cdbp, CDB_SIZE);
8935 		}
8936 
8937 #endif
8938 		/*
8939 		 * if we have commands outstanding in HBA, and a command
8940 		 * comes back incomplete, we're hosed, so reset target
8941 		 * If we have the bus, but cmd_incomplete, we probably just
8942 		 * have a failed selection, so don't reset the target, just
8943 		 * requeue the command and try again
8944 		 */
8945 		if ((un->un_ncmds > 1) || (pkt->pkt_state != STATE_GOT_BUS)) {
8946 			goto reset_target;
8947 		}
8948 
8949 		/*
8950 		 * Retry selection a couple more times if we're
8951 		 * open.  If opening, we only try just once to
8952 		 * reduce probe time for nonexistant devices.
8953 		 */
8954 		if ((un->un_laststate > ST_STATE_OPENING) &&
8955 		    ((int)un->un_retry_ct < st_selection_retry_count)) {
8956 			rval = QUE_COMMAND;
8957 		}
8958 		ST_DO_ERRSTATS(un, st_transerrs);
8959 		break;
8960 
8961 	case CMD_ABORTED:
8962 		/*
8963 		 * most likely this is caused by flush-on-error support. If
8964 		 * it was not there, the we're in trouble.
8965 		 */
8966 		if (!un->un_flush_on_errors) {
8967 			un->un_status = SUN_KEY_FATAL;
8968 			goto reset_target;
8969 		}
8970 
8971 		st_set_pe_errno(un);
8972 		bioerror(bp, un->un_errno);
8973 		if (un->un_errno)
8974 			return (COMMAND_DONE_ERROR);
8975 		else
8976 			return (COMMAND_DONE);
8977 
8978 	case CMD_TIMEOUT:	/* Command timed out */
8979 		un->un_status = SUN_KEY_TIMEOUT;
8980 
8981 		/*FALLTHROUGH*/
8982 	default:
8983 reset_target:
8984 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
8985 		    "transport completed with %s\n",
8986 		    scsi_rname(pkt->pkt_reason));
8987 		ST_DO_ERRSTATS(un, st_transerrs);
8988 		if ((pkt->pkt_state & STATE_GOT_TARGET) &&
8989 		    ((pkt->pkt_statistics & (STAT_BUS_RESET | STAT_DEV_RESET |
8990 			STAT_ABORTED)) == 0)) {
8991 
8992 			mutex_exit(ST_MUTEX);
8993 
8994 			result = scsi_reset(ROUTE, RESET_TARGET);
8995 			/*
8996 			 * if target reset fails, then pull the chain
8997 			 */
8998 			if (result == 0) {
8999 				result = scsi_reset(ROUTE, RESET_ALL);
9000 			}
9001 			mutex_enter(ST_MUTEX);
9002 
9003 			if ((result == 0) && (un->un_state >= ST_STATE_OPEN)) {
9004 				/* no hope left to recover */
9005 				scsi_log(ST_DEVINFO, st_label, CE_WARN,
9006 				    "recovery by resets failed\n");
9007 				return (rval);
9008 			}
9009 		}
9010 	}
9011 
9012 	if ((pkt->pkt_reason == CMD_RESET) || (pkt->pkt_statistics &
9013 		(STAT_BUS_RESET | STAT_DEV_RESET))) {
9014 		if ((un->un_rsvd_status & ST_RESERVE)) {
9015 			un->un_rsvd_status |= ST_LOST_RESERVE;
9016 			ST_DEBUG3(ST_DEVINFO, st_label, CE_WARN,
9017 				"Lost Reservation\n");
9018 		}
9019 	}
9020 
9021 	if ((int)un->un_retry_ct++ < st_retry_count) {
9022 		if (un->un_pwr_mgmt == ST_PWR_SUSPENDED) {
9023 			rval = QUE_COMMAND;
9024 		} else if (bp == un->un_sbufp) {
9025 			switch ((uchar_t)(uintptr_t)bp->b_forw) {
9026 			case SCMD_MODE_SENSE:
9027 			case SCMD_MODE_SELECT:
9028 			case SCMD_READ_BLKLIM:
9029 			case SCMD_REWIND:
9030 			case SCMD_LOAD:
9031 			case SCMD_TEST_UNIT_READY:
9032 				/*
9033 				 * These commands can be rerun with impunity
9034 				 */
9035 				rval = QUE_COMMAND;
9036 				break;
9037 
9038 			default:
9039 				break;
9040 			}
9041 		}
9042 	} else {
9043 		rval = COMMAND_DONE_ERROR;
9044 	}
9045 
9046 	if (un->un_state >= ST_STATE_OPEN) {
9047 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
9048 		    fail, scsi_rname(pkt->pkt_reason),
9049 		    (rval == COMMAND_DONE_ERROR)?
9050 		    "giving up" : "retrying command");
9051 	}
9052 	return (rval);
9053 }
9054 
9055 /*
9056  * if the device is busy, then put this bp back on the waitq, on the
9057  * interrupt thread, where we want the head of the queue and not the
9058  * end
9059  *
9060  * The callers of this routine should take measures to save the
9061  * un_throttle in un_last_throttle which will be restored in
9062  * st_intr_restart(). The only exception should be st_intr_restart()
9063  * calling this routine for which the saving is already done.
9064  */
9065 static int
9066 st_handle_intr_busy(struct scsi_tape *un, struct buf *bp,
9067 	clock_t timeout_interval)
9068 {
9069 	struct buf *last_quef;
9070 	int rval = 0;
9071 
9072 	mutex_enter(ST_MUTEX);
9073 
9074 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9075 	    "st_handle_intr_busy(), un = 0x%p\n", (void *)un);
9076 
9077 	/*
9078 	 * Check to see if we hit the retry timeout. We check to make sure
9079 	 * this is the first one on the runq and make sure we have not
9080 	 * queued up any more, so this one has to be the last on the list
9081 	 * also. If it is not, we have to fail.  If it is not the first, but
9082 	 * is the last we are in trouble anyway, as we are in the interrupt
9083 	 * context here.
9084 	 */
9085 	if (((int)un->un_tran_retry_ct++ > st_retry_count) ||
9086 	    ((un->un_runqf != bp) && (un->un_runql != bp))) {
9087 		rval = -1;
9088 		goto exit;
9089 	}
9090 
9091 	/* put the bp back on the waitq */
9092 	if (un->un_quef) {
9093 		last_quef = un->un_quef;
9094 		un->un_quef = bp;
9095 		bp->b_actf = last_quef;
9096 	} else  {
9097 		bp->b_actf = NULL;
9098 		un->un_quef = bp;
9099 		un->un_quel = bp;
9100 	}
9101 
9102 	/*
9103 	 * We know that this is the first and last on the runq at this time,
9104 	 * so we just nullify those two queues
9105 	 */
9106 	un->un_runqf = NULL;
9107 	un->un_runql = NULL;
9108 
9109 	/*
9110 	 * We don't want any other commands being started in the mean time.
9111 	 * If start had just released mutex after putting something on the
9112 	 * runq, we won't even get here.
9113 	 */
9114 	un->un_throttle = 0;
9115 
9116 	/*
9117 	 * send a marker pkt, if appropriate
9118 	 */
9119 	st_hba_unflush(un);
9120 
9121 	/*
9122 	 * all queues are aligned, we are just waiting to
9123 	 * transport
9124 	 */
9125 	un->un_hib_tid = timeout(st_intr_restart, un, timeout_interval);
9126 
9127 exit:
9128 	mutex_exit(ST_MUTEX);
9129 	return (rval);
9130 }
9131 
9132 static int
9133 st_handle_sense(struct scsi_tape *un, struct buf *bp)
9134 {
9135 	struct scsi_pkt *rqpkt = un->un_rqs;
9136 	int rval = COMMAND_DONE_ERROR;
9137 	int amt;
9138 
9139 	ASSERT(mutex_owned(ST_MUTEX));
9140 
9141 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9142 		"st_handle_sense()\n");
9143 
9144 	if (SCBP(rqpkt)->sts_busy) {
9145 		ST_DEBUG4(ST_DEVINFO, st_label, CE_WARN,
9146 		    "busy unit on request sense\n");
9147 		if ((int)un->un_retry_ct++ < st_retry_count) {
9148 			rval = QUE_BUSY_COMMAND;
9149 		}
9150 		return (rval);
9151 	} else if (SCBP(rqpkt)->sts_chk) {
9152 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9153 		    "Check Condition on REQUEST SENSE\n");
9154 		return (rval);
9155 	}
9156 
9157 	/* was there enough data? */
9158 	amt = (int)SENSE_LENGTH - rqpkt->pkt_resid;
9159 	if ((rqpkt->pkt_state & STATE_XFERRED_DATA) == 0 ||
9160 	    (amt < SUN_MIN_SENSE_LENGTH)) {
9161 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9162 		    "REQUEST SENSE couldn't get sense data\n");
9163 		return (rval);
9164 	}
9165 	return (st_decode_sense(un, bp, amt, SCBP(rqpkt)));
9166 }
9167 
9168 static int
9169 st_handle_autosense(struct scsi_tape *un, struct buf *bp)
9170 {
9171 	struct scsi_pkt *pkt = BP_PKT(bp);
9172 	struct scsi_arq_status *arqstat =
9173 	    (struct scsi_arq_status *)pkt->pkt_scbp;
9174 	int rval = COMMAND_DONE_ERROR;
9175 	int amt;
9176 
9177 	ASSERT(mutex_owned(ST_MUTEX));
9178 
9179 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9180 		"st_handle_autosense()\n");
9181 
9182 	if (arqstat->sts_rqpkt_status.sts_busy) {
9183 		ST_DEBUG4(ST_DEVINFO, st_label, CE_WARN,
9184 		    "busy unit on request sense\n");
9185 		/*
9186 		 * we return QUE_SENSE so st_intr will setup the SENSE cmd.
9187 		 * the disadvantage is that we do not have any delay for the
9188 		 * second retry of rqsense and we have to keep a packet around
9189 		 */
9190 		return (QUE_SENSE);
9191 
9192 	} else if (arqstat->sts_rqpkt_reason != CMD_CMPLT) {
9193 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9194 		    "transport error on REQUEST SENSE\n");
9195 		if ((arqstat->sts_rqpkt_state & STATE_GOT_TARGET) &&
9196 		    ((arqstat->sts_rqpkt_statistics &
9197 		    (STAT_BUS_RESET | STAT_DEV_RESET | STAT_ABORTED)) == 0)) {
9198 			mutex_exit(ST_MUTEX);
9199 			if (scsi_reset(ROUTE, RESET_TARGET) == 0) {
9200 				/*
9201 				 * if target reset fails, then pull the chain
9202 				 */
9203 				if (scsi_reset(ROUTE, RESET_ALL) == 0) {
9204 					ST_DEBUG6(ST_DEVINFO, st_label,
9205 					    CE_WARN,
9206 					    "recovery by resets failed\n");
9207 				}
9208 			}
9209 			mutex_enter(ST_MUTEX);
9210 		}
9211 		return (rval);
9212 
9213 	} else if (arqstat->sts_rqpkt_status.sts_chk) {
9214 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9215 		    "Check Condition on REQUEST SENSE\n");
9216 		return (rval);
9217 	}
9218 
9219 
9220 	/* was there enough data? */
9221 	amt = (int)SENSE_LENGTH - arqstat->sts_rqpkt_resid;
9222 	if ((arqstat->sts_rqpkt_state & STATE_XFERRED_DATA) == 0 ||
9223 	    (amt < SUN_MIN_SENSE_LENGTH)) {
9224 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9225 		    "REQUEST SENSE couldn't get sense data\n");
9226 		return (rval);
9227 	}
9228 
9229 	bcopy(&arqstat->sts_sensedata, ST_RQSENSE, SENSE_LENGTH);
9230 
9231 	return (st_decode_sense(un, bp, amt, &arqstat->sts_rqpkt_status));
9232 }
9233 
9234 static int
9235 st_decode_sense(struct scsi_tape *un, struct buf *bp,  int amt,
9236 	struct scsi_status *statusp)
9237 {
9238 	struct scsi_pkt *pkt = BP_PKT(bp);
9239 	int rval = COMMAND_DONE_ERROR;
9240 	long resid;
9241 	struct scsi_extended_sense *sensep = ST_RQSENSE;
9242 	int severity;
9243 	int get_error;
9244 
9245 	ASSERT(mutex_owned(ST_MUTEX));
9246 
9247 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9248 		"st_decode_sense()\n");
9249 
9250 	/*
9251 	 * For uscsi commands, squirrel away a copy of the
9252 	 * results of the Request Sense.
9253 	 */
9254 	if (USCSI_CMD(bp)) {
9255 		struct uscsi_cmd *ucmd = BP_UCMD(bp);
9256 		ucmd->uscsi_rqstatus = *(uchar_t *)statusp;
9257 		if (ucmd->uscsi_rqlen && un->un_srqbufp) {
9258 			uchar_t rqlen = min((uchar_t)amt, ucmd->uscsi_rqlen);
9259 			ucmd->uscsi_rqresid = ucmd->uscsi_rqlen - rqlen;
9260 			bcopy(ST_RQSENSE, un->un_srqbufp, rqlen);
9261 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
9262 				"st_decode_sense: stat=0x%x resid=0x%x\n",
9263 				ucmd->uscsi_rqstatus, ucmd->uscsi_rqresid);
9264 		}
9265 	}
9266 
9267 	/*
9268 	 * If the drive is an MT-02, reposition the
9269 	 * secondary error code into the proper place.
9270 	 *
9271 	 * XXX	MT-02 is non-CCS tape, so secondary error code
9272 	 * is in byte 8.  However, in SCSI-2, tape has CCS definition
9273 	 * so it's in byte 12.
9274 	 */
9275 	if (un->un_dp->type == ST_TYPE_EMULEX) {
9276 		sensep->es_code = sensep->es_add_info[0];
9277 	}
9278 
9279 	/* for normal I/O check extract the resid values. */
9280 	if (bp != un->un_sbufp) {
9281 		if (sensep->es_valid) {
9282 			resid = (sensep->es_info_1 << 24) |
9283 				(sensep->es_info_2 << 16) |
9284 				(sensep->es_info_3 << 8)  |
9285 				(sensep->es_info_4);
9286 			if (un->un_bsize) {
9287 				resid *= un->un_bsize;
9288 			}
9289 		} else if (pkt->pkt_state & STATE_XFERRED_DATA) {
9290 			resid = pkt->pkt_resid;
9291 		} else {
9292 			resid = bp->b_bcount;
9293 		}
9294 		ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9295 		    "st_handle_sense (rw): xferred bit = %d, resid=%ld (%d), "
9296 		    "pkt_resid=%ld\n", pkt->pkt_state & STATE_XFERRED_DATA,
9297 		    resid,
9298 		    (sensep->es_info_1 << 24) |
9299 		    (sensep->es_info_2 << 16) |
9300 		    (sensep->es_info_3 << 8)  |
9301 		    (sensep->es_info_4),
9302 		    pkt->pkt_resid);
9303 		/*
9304 		 * The problem is, what should we believe?
9305 		 */
9306 		if (resid && (pkt->pkt_resid == 0)) {
9307 			pkt->pkt_resid = resid;
9308 		}
9309 	} else {
9310 		/*
9311 		 * If the command is SCMD_SPACE, we need to get the
9312 		 * residual as returned in the sense data, to adjust
9313 		 * our idea of current tape position correctly
9314 		 */
9315 		if ((CDBP(pkt)->scc_cmd == SCMD_SPACE ||
9316 		    CDBP(pkt)->scc_cmd == SCMD_WRITE_FILE_MARK) &&
9317 		    (sensep->es_valid)) {
9318 			resid = (sensep->es_info_1 << 24) |
9319 			    (sensep->es_info_2 << 16) |
9320 			    (sensep->es_info_3 << 8)  |
9321 			    (sensep->es_info_4);
9322 			bp->b_resid = resid;
9323 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9324 			    "st_handle_sense(other):	resid=%ld\n",
9325 			    resid);
9326 		} else {
9327 			/*
9328 			 * If the special command is SCMD_READ,
9329 			 * the correct resid will be set later.
9330 			 */
9331 			resid = bp->b_bcount;
9332 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9333 			    "st_handle_sense(special read):  resid=%ld\n",
9334 				resid);
9335 		}
9336 	}
9337 
9338 	if ((un->un_state >= ST_STATE_OPEN) &&
9339 	    (DEBUGGING || st_error_level == SCSI_ERR_ALL)) {
9340 		st_clean_print(ST_DEVINFO, st_label, CE_NOTE,
9341 		    "Failed CDB", (char *)pkt->pkt_cdbp, CDB_SIZE);
9342 		st_clean_print(ST_DEVINFO, st_label, CE_CONT,
9343 		    "sense data", (char *)sensep, amt);
9344 		scsi_log(ST_DEVINFO, st_label, CE_CONT,
9345 		    "count 0x%lx resid 0x%lx pktresid 0x%lx\n",
9346 		    bp->b_bcount, resid, pkt->pkt_resid);
9347 	}
9348 
9349 	switch (un->un_status = sensep->es_key) {
9350 	case KEY_NO_SENSE:
9351 		severity = SCSI_ERR_INFO;
9352 		goto common;
9353 
9354 	case KEY_RECOVERABLE_ERROR:
9355 		severity = SCSI_ERR_RECOVERED;
9356 		if ((sensep->es_class == CLASS_EXTENDED_SENSE) &&
9357 		    (sensep->es_code == ST_DEFERRED_ERROR)) {
9358 		    if (un->un_dp->options &
9359 			ST_RETRY_ON_RECOVERED_DEFERRED_ERROR) {
9360 			    rval = QUE_LAST_COMMAND;
9361 			    scsi_errmsg(ST_SCSI_DEVP, pkt, st_label, severity,
9362 				un->un_blkno, un->un_err_blkno, scsi_cmds,
9363 				sensep);
9364 			    scsi_log(ST_DEVINFO, st_label, CE_CONT,
9365 				"Command will be retried\n");
9366 			} else {
9367 			    severity = SCSI_ERR_FATAL;
9368 			    rval = COMMAND_DONE_ERROR_RECOVERED;
9369 			    ST_DO_ERRSTATS(un, st_softerrs);
9370 			    scsi_errmsg(ST_SCSI_DEVP, pkt, st_label, severity,
9371 				un->un_blkno, un->un_err_blkno, scsi_cmds,
9372 				sensep);
9373 			}
9374 			break;
9375 		}
9376 common:
9377 		/*
9378 		 * XXX only want reads to be stopped by filemarks.
9379 		 * Don't want them to be stopped by EOT.  EOT matters
9380 		 * only on write.
9381 		 */
9382 		if (sensep->es_filmk && !sensep->es_eom) {
9383 			rval = COMMAND_DONE;
9384 		} else if (sensep->es_eom) {
9385 			rval = COMMAND_DONE;
9386 		} else if (sensep->es_ili) {
9387 			/*
9388 			 * Fun with variable length record devices:
9389 			 * for specifying larger blocks sizes than the
9390 			 * actual physical record size.
9391 			 */
9392 			if (un->un_bsize == 0 && resid > 0) {
9393 				/*
9394 				 * XXX! Ugly.
9395 				 * The requested blocksize is > tape blocksize,
9396 				 * so this is ok, so we just return the
9397 				 * actual size xferred.
9398 				 */
9399 				pkt->pkt_resid = resid;
9400 				rval = COMMAND_DONE;
9401 			} else if (un->un_bsize == 0 && resid < 0) {
9402 				/*
9403 				 * The requested blocksize is < tape blocksize,
9404 				 * so this is not ok, so we err with ENOMEM
9405 				 */
9406 				rval = COMMAND_DONE_ERROR_RECOVERED;
9407 				st_bioerror(bp, ENOMEM);
9408 			} else {
9409 				ST_DO_ERRSTATS(un, st_softerrs);
9410 				severity = SCSI_ERR_FATAL;
9411 				rval = COMMAND_DONE_ERROR;
9412 				st_bioerror(bp, EINVAL);
9413 			}
9414 		} else {
9415 			/*
9416 			 * we hope and pray for this just being
9417 			 * something we can ignore (ie. a
9418 			 * truly recoverable soft error)
9419 			 */
9420 			rval = COMMAND_DONE;
9421 		}
9422 		if (sensep->es_filmk) {
9423 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9424 			    "filemark\n");
9425 			un->un_status = SUN_KEY_EOF;
9426 			un->un_eof = ST_EOF_PENDING;
9427 			SET_PE_FLAG(un);
9428 		}
9429 
9430 		/*
9431 		 * ignore eom when reading, a fmk should terminate reading
9432 		 */
9433 		if ((sensep->es_eom) &&
9434 		    (CDBP(pkt)->scc_cmd != SCMD_READ)) {
9435 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "eom\n");
9436 			un->un_status = SUN_KEY_EOT;
9437 			un->un_eof = ST_EOM;
9438 			SET_PE_FLAG(un);
9439 		}
9440 
9441 		break;
9442 
9443 	case KEY_ILLEGAL_REQUEST:
9444 
9445 		if (un->un_laststate >= ST_STATE_OPEN) {
9446 			ST_DO_ERRSTATS(un, st_softerrs);
9447 			severity = SCSI_ERR_FATAL;
9448 		} else {
9449 			severity = SCSI_ERR_INFO;
9450 		}
9451 		break;
9452 
9453 	case KEY_MEDIUM_ERROR:
9454 		ST_DO_ERRSTATS(un, st_harderrs);
9455 		severity = SCSI_ERR_FATAL;
9456 
9457 		/*
9458 		 * for (buffered) writes, a medium error must be fatal
9459 		 */
9460 		if (CDBP(pkt)->scc_cmd != SCMD_WRITE) {
9461 			rval = COMMAND_DONE_ERROR_RECOVERED;
9462 		}
9463 
9464 check_keys:
9465 		/*
9466 		 * attempt to process the keys in the presence of
9467 		 * other errors
9468 		 */
9469 		if (sensep->es_ili && rval != COMMAND_DONE_ERROR) {
9470 			/*
9471 			 * Fun with variable length record devices:
9472 			 * for specifying larger blocks sizes than the
9473 			 * actual physical record size.
9474 			 */
9475 			if (un->un_bsize == 0 && resid > 0) {
9476 				/*
9477 				 * XXX! Ugly
9478 				 */
9479 				pkt->pkt_resid = resid;
9480 			} else if (un->un_bsize == 0 && resid < 0) {
9481 				st_bioerror(bp, EINVAL);
9482 			} else {
9483 				severity = SCSI_ERR_FATAL;
9484 				rval = COMMAND_DONE_ERROR;
9485 				st_bioerror(bp, EINVAL);
9486 			}
9487 		}
9488 		if (sensep->es_filmk) {
9489 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9490 			    "filemark\n");
9491 			un->un_status = SUN_KEY_EOF;
9492 			un->un_eof = ST_EOF_PENDING;
9493 			SET_PE_FLAG(un);
9494 		}
9495 
9496 		/*
9497 		 * ignore eom when reading, a fmk should terminate reading
9498 		 */
9499 		if ((sensep->es_eom) &&
9500 		    (CDBP(pkt)->scc_cmd != SCMD_READ)) {
9501 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG, "eom\n");
9502 			un->un_status = SUN_KEY_EOT;
9503 			un->un_eof = ST_EOM;
9504 			SET_PE_FLAG(un);
9505 		}
9506 
9507 		break;
9508 
9509 	case KEY_VOLUME_OVERFLOW:
9510 		ST_DO_ERRSTATS(un, st_softerrs);
9511 		un->un_eof = ST_EOM;
9512 		severity = SCSI_ERR_FATAL;
9513 		rval = COMMAND_DONE_ERROR;
9514 		goto check_keys;
9515 
9516 	case KEY_HARDWARE_ERROR:
9517 		ST_DO_ERRSTATS(un, st_harderrs);
9518 		severity = SCSI_ERR_FATAL;
9519 		rval = COMMAND_DONE_ERROR;
9520 		if (un->un_dp->options & ST_EJECT_ON_CHANGER_FAILURE)
9521 			un->un_eject_tape_on_failure = st_check_asc_ascq(un);
9522 		break;
9523 
9524 	case KEY_BLANK_CHECK:
9525 		ST_DO_ERRSTATS(un, st_softerrs);
9526 		severity = SCSI_ERR_INFO;
9527 
9528 		/*
9529 		 * if not a special request and some data was xferred then it
9530 		 * it is not an error yet
9531 		 */
9532 		if (bp != un->un_sbufp && (bp->b_flags & B_READ)) {
9533 			/*
9534 			 * no error for read with or without data xferred
9535 			 */
9536 			un->un_status = SUN_KEY_EOT;
9537 			un->un_eof = ST_EOT;
9538 			rval = COMMAND_DONE_ERROR;
9539 			SET_PE_FLAG(un);
9540 			goto check_keys;
9541 		} else if (bp != un->un_sbufp &&
9542 		    (pkt->pkt_state & STATE_XFERRED_DATA)) {
9543 			rval = COMMAND_DONE;
9544 		} else {
9545 			rval = COMMAND_DONE_ERROR_RECOVERED;
9546 		}
9547 
9548 		if (un->un_laststate >= ST_STATE_OPEN) {
9549 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9550 			    "blank check\n");
9551 			un->un_eof = ST_EOM;
9552 		}
9553 		if ((CDBP(pkt)->scc_cmd == SCMD_SPACE) &&
9554 		    (un->un_dp->options & ST_KNOWS_EOD) &&
9555 		    (severity = SCSI_ERR_INFO)) {
9556 			/*
9557 			 * we were doing a fast forward by skipping
9558 			 * multiple fmk at the time
9559 			 */
9560 			st_bioerror(bp, EIO);
9561 			severity = SCSI_ERR_RECOVERED;
9562 			rval	 = COMMAND_DONE;
9563 		}
9564 		SET_PE_FLAG(un);
9565 		goto check_keys;
9566 
9567 	case KEY_WRITE_PROTECT:
9568 		if (st_wrongtapetype(un)) {
9569 			un->un_status = SUN_KEY_WRONGMEDIA;
9570 			ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9571 		"wrong tape for writing- use DC6150 tape (or equivalent)\n");
9572 			severity = SCSI_ERR_UNKNOWN;
9573 		} else {
9574 			severity = SCSI_ERR_FATAL;
9575 		}
9576 		ST_DO_ERRSTATS(un, st_harderrs);
9577 		rval = COMMAND_DONE_ERROR;
9578 		st_bioerror(bp, EACCES);
9579 		break;
9580 
9581 	case KEY_UNIT_ATTENTION:
9582 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9583 		    "KEY_UNIT_ATTENTION : un_state = %d\n", un->un_state);
9584 
9585 		/*
9586 		 * If we have detected a Bus Reset and the tape
9587 		 * drive has been reserved.
9588 		 */
9589 		if (ST_RQSENSE->es_add_code == 0x29 &&
9590 			(un->un_rsvd_status & ST_RESERVE)) {
9591 			un->un_rsvd_status |= ST_LOST_RESERVE;
9592 			ST_DEBUG(ST_DEVINFO, st_label, CE_WARN,
9593 				"st_decode_sense: Lost Reservation\n");
9594 		}
9595 
9596 		if (un->un_state <= ST_STATE_OPENING) {
9597 			/*
9598 			 * Look, the tape isn't open yet, now determine
9599 			 * if the cause is a BUS RESET, Save the file and
9600 			 * Block positions for the callers to recover from
9601 			 * the loss of position.
9602 			 */
9603 			if ((un->un_fileno >= 0) &&
9604 			(un->un_fileno || un->un_blkno)) {
9605 				if (ST_RQSENSE->es_add_code == 0x29) {
9606 					un->un_save_fileno = un->un_fileno;
9607 					un->un_save_blkno = un->un_blkno;
9608 					un->un_restore_pos = 1;
9609 				}
9610 			}
9611 
9612 			if ((int)un->un_retry_ct++ < st_retry_count) {
9613 				rval = QUE_COMMAND;
9614 			} else {
9615 				rval = COMMAND_DONE_ERROR;
9616 			}
9617 			severity = SCSI_ERR_INFO;
9618 
9619 		} else {
9620 			/*
9621 			 * Check if it is an Unexpected Unit Attention.
9622 			 * If state is >= ST_STATE_OPEN, we have
9623 			 * already done the initialization .
9624 			 * In this case it is Fatal Error
9625 			 * since no further reading/writing
9626 			 * can be done with fileno set to < 0.
9627 			 */
9628 			if (un->un_state >= ST_STATE_OPEN) {
9629 				ST_DO_ERRSTATS(un, st_harderrs);
9630 				severity = SCSI_ERR_FATAL;
9631 			} else {
9632 				severity = SCSI_ERR_INFO;
9633 			}
9634 			rval = COMMAND_DONE_ERROR;
9635 		}
9636 		un->un_fileno = -1;
9637 
9638 		break;
9639 
9640 	case KEY_NOT_READY:
9641 		/*
9642 		 * If in process of getting ready retry.
9643 		 */
9644 		if (sensep->es_add_code  == 0x04 &&
9645 		    sensep->es_qual_code == 0x01 &&
9646 		    un->un_retry_ct++ < st_retry_count) {
9647 			rval = QUE_COMMAND;
9648 			severity = SCSI_ERR_INFO;
9649 		} else {
9650 			/* give up */
9651 			rval = COMMAND_DONE_ERROR;
9652 			severity = SCSI_ERR_FATAL;
9653 		}
9654 
9655 		/*
9656 		 * If this was an error and after device opened
9657 		 * do error stats.
9658 		 */
9659 		if (rval == COMMAND_DONE_ERROR &&
9660 		    un->un_state > ST_STATE_OPENING) {
9661 			ST_DO_ERRSTATS(un, st_harderrs);
9662 		}
9663 
9664 		if (ST_RQSENSE->es_add_code == 0x3a) {
9665 			if (st_error_level >= SCSI_ERR_FATAL)
9666 				scsi_log(ST_DEVINFO, st_label, CE_NOTE,
9667 				    "Tape not inserted in drive\n");
9668 			un->un_mediastate = MTIO_EJECTED;
9669 			cv_broadcast(&un->un_state_cv);
9670 		}
9671 		if ((un->un_dp->options & ST_EJECT_ON_CHANGER_FAILURE) &&
9672 		    (rval != QUE_COMMAND))
9673 			un->un_eject_tape_on_failure = st_check_asc_ascq(un);
9674 		break;
9675 
9676 	case KEY_ABORTED_COMMAND:
9677 
9678 		/*
9679 		 * Probably a parity error...
9680 		 * if we retry here then this may cause data to be
9681 		 * written twice or data skipped during reading
9682 		 */
9683 		ST_DO_ERRSTATS(un, st_harderrs);
9684 		severity = SCSI_ERR_FATAL;
9685 		rval = COMMAND_DONE_ERROR;
9686 		goto check_keys;
9687 
9688 	default:
9689 		/*
9690 		 * Undecoded sense key.	 Try retries and hope
9691 		 * that will fix the problem.  Otherwise, we're
9692 		 * dead.
9693 		 */
9694 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9695 		    "Unhandled Sense Key '%s'\n",
9696 		    sense_keys[un->un_status]);
9697 		ST_DO_ERRSTATS(un, st_harderrs);
9698 		severity = SCSI_ERR_FATAL;
9699 		rval = COMMAND_DONE_ERROR;
9700 		goto check_keys;
9701 	}
9702 
9703 	if ((!(pkt->pkt_flags & FLAG_SILENT) &&
9704 	    un->un_state >= ST_STATE_OPEN) && (DEBUGGING ||
9705 		(un->un_laststate > ST_STATE_OPENING) &&
9706 		(severity >= st_error_level))) {
9707 
9708 		scsi_errmsg(ST_SCSI_DEVP, pkt, st_label, severity,
9709 		    un->un_blkno, un->un_err_blkno, scsi_cmds, sensep);
9710 		if (sensep->es_filmk) {
9711 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
9712 			    "File Mark Detected\n");
9713 		}
9714 		if (sensep->es_eom) {
9715 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
9716 			    "End-of-Media Detected\n");
9717 		}
9718 		if (sensep->es_ili) {
9719 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
9720 			    "Incorrect Length Indicator Set\n");
9721 		}
9722 	}
9723 	get_error = geterror(bp);
9724 	if (((rval == COMMAND_DONE_ERROR) ||
9725 	    (rval == COMMAND_DONE_ERROR_RECOVERED)) &&
9726 	    ((get_error == EIO) || (get_error == 0))) {
9727 		un->un_rqs_state |= (ST_RQS_ERROR | ST_RQS_VALID);
9728 		bcopy(ST_RQSENSE, un->un_uscsi_rqs_buf, SENSE_LENGTH);
9729 		if (un->un_rqs_state & ST_RQS_READ) {
9730 		    un->un_rqs_state &= ~(ST_RQS_READ);
9731 		} else {
9732 		    un->un_rqs_state |= ST_RQS_OVR;
9733 		}
9734 	}
9735 
9736 	return (rval);
9737 }
9738 
9739 
9740 static int
9741 st_handle_intr_retry_lcmd(struct scsi_tape *un, struct buf *bp)
9742 {
9743 	int status = TRAN_ACCEPT;
9744 
9745 	mutex_enter(ST_MUTEX);
9746 
9747 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9748 		"st_handle_intr_rtr_lcmd(), un = 0x%p\n", (void *)un);
9749 
9750 	/*
9751 	 * Check to see if we hit the retry timeout. We check to make sure
9752 	 * this is the first one on the runq and make sure we have not
9753 	 * queued up any more, so this one has to be the last on the list
9754 	 * also. If it is not, we have to fail.  If it is not the first, but
9755 	 * is the last we are in trouble anyway, as we are in the interrupt
9756 	 * context here.
9757 	 */
9758 	if (((int)un->un_retry_ct > st_retry_count) ||
9759 	    ((un->un_runqf != bp) && (un->un_runql != bp))) {
9760 	    goto exit;
9761 	}
9762 
9763 	if (un->un_throttle) {
9764 		un->un_last_throttle = un->un_throttle;
9765 		un->un_throttle = 0;
9766 	}
9767 
9768 	/*
9769 	 * Here we know : bp is the first and last one on the runq
9770 	 * it is not necessary to put it back on the head of the
9771 	 * waitq and then move from waitq to runq. Save this queuing
9772 	 * and call scsi_transport.
9773 	 */
9774 
9775 	mutex_exit(ST_MUTEX);
9776 
9777 	status = scsi_transport(BP_PKT(bp));
9778 
9779 	mutex_enter(ST_MUTEX);
9780 
9781 	if (status == TRAN_ACCEPT) {
9782 		un->un_tran_retry_ct = 0;
9783 		if (un->un_last_throttle) {
9784 			un->un_throttle = un->un_last_throttle;
9785 		}
9786 		mutex_exit(ST_MUTEX);
9787 
9788 		ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9789 		    "restart transport \n");
9790 		return (0);
9791 	}
9792 
9793 	ST_DO_KSTATS(bp, kstat_runq_back_to_waitq);
9794 	mutex_exit(ST_MUTEX);
9795 
9796 	if (status == TRAN_BUSY) {
9797 	    if (st_handle_intr_busy(un, bp,
9798 		ST_TRAN_BUSY_TIMEOUT) == 0)
9799 		return (0);
9800 	}
9801 	ST_DEBUG6(ST_DEVINFO, st_label, CE_WARN,
9802 		"restart transport rejected\n");
9803 	mutex_enter(ST_MUTEX);
9804 	ST_DO_ERRSTATS(un, st_transerrs);
9805 	if (un->un_last_throttle) {
9806 		un->un_throttle = un->un_last_throttle;
9807 	}
9808 exit:
9809 	mutex_exit(ST_MUTEX);
9810 	return (-1);
9811 }
9812 
9813 static int
9814 st_wrongtapetype(struct scsi_tape *un)
9815 {
9816 
9817 	ASSERT(mutex_owned(ST_MUTEX));
9818 
9819 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9820 		"st_wrongtapetype()\n");
9821 
9822 	/*
9823 	 * Hack to handle  600A, 600XTD, 6150 && 660 vs. 300XL tapes...
9824 	 */
9825 	if (un->un_dp && (un->un_dp->options & ST_QIC) && un->un_mspl) {
9826 		switch (un->un_dp->type) {
9827 		case ST_TYPE_WANGTEK:
9828 		case ST_TYPE_ARCHIVE:
9829 			/*
9830 			 * If this really worked, we could go off of
9831 			 * the density codes set in the modesense
9832 			 * page. For this drive, 0x10 == QIC-120,
9833 			 * 0xf == QIC-150, and 0x5 should be for
9834 			 * both QIC-24 and, maybe, QIC-11. However,
9835 			 * the h/w doesn't do what the manual says
9836 			 * that it should, so we'll key off of
9837 			 * getting a WRITE PROTECT error AND wp *not*
9838 			 * set in the mode sense information.
9839 			 */
9840 			/*
9841 			 * XXX but we already know that status is
9842 			 * write protect, so don't check it again.
9843 			 */
9844 
9845 			if (un->un_status == KEY_WRITE_PROTECT &&
9846 			    un->un_mspl->wp == 0) {
9847 				return (1);
9848 			}
9849 			break;
9850 		default:
9851 			break;
9852 		}
9853 	}
9854 	return (0);
9855 }
9856 
9857 static int
9858 st_check_error(struct scsi_tape *un, struct scsi_pkt *pkt)
9859 {
9860 	int action;
9861 
9862 	ASSERT(mutex_owned(ST_MUTEX));
9863 
9864 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_check_error()\n");
9865 
9866 	if (SCBP_C(pkt) == STATUS_RESERVATION_CONFLICT) {
9867 		action = COMMAND_DONE_EACCES;
9868 		un->un_rsvd_status |= ST_RESERVATION_CONFLICT;
9869 	} else if (SCBP(pkt)->sts_busy) {
9870 		ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG, "unit busy\n");
9871 		if ((int)un->un_retry_ct++ < st_retry_count) {
9872 			action = QUE_BUSY_COMMAND;
9873 		} else {
9874 			ST_DEBUG2(ST_DEVINFO, st_label, CE_WARN,
9875 			    "unit busy too long\n");
9876 			mutex_exit(ST_MUTEX);
9877 			if (scsi_reset(ROUTE, RESET_TARGET) == 0) {
9878 				(void) scsi_reset(ROUTE, RESET_ALL);
9879 			}
9880 			mutex_enter(ST_MUTEX);
9881 			action = COMMAND_DONE_ERROR;
9882 		}
9883 	} else if (SCBP(pkt)->sts_chk) {
9884 		/*
9885 		 * we should only get here if the auto rqsense failed
9886 		 * thru a uscsi cmd without autorequest sense
9887 		 * so we just try again
9888 		 */
9889 		action = QUE_SENSE;
9890 	} else {
9891 		action = COMMAND_DONE;
9892 	}
9893 	return (action);
9894 }
9895 
9896 static void
9897 st_calc_bnum(struct scsi_tape *un, struct buf *bp)
9898 {
9899 	int n;
9900 
9901 	ASSERT(mutex_owned(ST_MUTEX));
9902 
9903 	if (un->un_bsize == 0) {
9904 		n = ((bp->b_bcount - bp->b_resid  == 0) ? 0 : 1);
9905 		un->un_kbytes_xferred += (bp->b_bcount - bp->b_resid)/1000;
9906 	} else {
9907 		n = ((bp->b_bcount - bp->b_resid) / un->un_bsize);
9908 	}
9909 	un->un_blkno += n;
9910 }
9911 
9912 static void
9913 st_set_state(struct scsi_tape *un)
9914 {
9915 	struct buf *bp = un->un_runqf;
9916 	struct scsi_pkt *sp = BP_PKT(bp);
9917 	struct uscsi_cmd *ucmd;
9918 
9919 	ASSERT(mutex_owned(ST_MUTEX));
9920 
9921 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
9922 	    "st_set_state(): un_eof=%x	fmneeded=%x  pkt_resid=0x%lx (%ld)\n",
9923 		un->un_eof, un->un_fmneeded, sp->pkt_resid, sp->pkt_resid);
9924 
9925 	if (bp != un->un_sbufp) {
9926 #ifdef STDEBUG
9927 		if (DEBUGGING && sp->pkt_resid) {
9928 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
9929 			    "pkt_resid %ld bcount %ld\n",
9930 			    sp->pkt_resid, bp->b_bcount);
9931 		}
9932 #endif
9933 		bp->b_resid = sp->pkt_resid;
9934 		st_calc_bnum(un, bp);
9935 		if (bp->b_flags & B_READ) {
9936 			un->un_lastop = ST_OP_READ;
9937 			un->un_fmneeded = 0;
9938 		} else {
9939 			un->un_lastop = ST_OP_WRITE;
9940 			if (un->un_dp->options & ST_REEL) {
9941 				un->un_fmneeded = 2;
9942 			} else {
9943 				un->un_fmneeded = 1;
9944 			}
9945 		}
9946 		/*
9947 		 * all is honky dory at this point, so let's
9948 		 * readjust the throttle, to increase speed, if we
9949 		 * have not throttled down.
9950 		 */
9951 		if (un->un_throttle)
9952 			un->un_throttle = un->un_max_throttle;
9953 	} else {
9954 		char saved_lastop = un->un_lastop;
9955 		uchar_t cmd = (uchar_t)(intptr_t)bp->b_forw;
9956 
9957 		un->un_lastop = ST_OP_CTL;
9958 
9959 		switch (cmd) {
9960 		case SCMD_WRITE:
9961 			bp->b_resid = sp->pkt_resid;
9962 			un->un_lastop = ST_OP_WRITE;
9963 			st_calc_bnum(un, bp);
9964 			if (un->un_dp->options & ST_REEL) {
9965 				un->un_fmneeded = 2;
9966 			} else {
9967 				un->un_fmneeded = 1;
9968 			}
9969 			break;
9970 		case SCMD_READ:
9971 			bp->b_resid = sp->pkt_resid;
9972 			un->un_lastop = ST_OP_READ;
9973 			st_calc_bnum(un, bp);
9974 			un->un_fmneeded = 0;
9975 			break;
9976 		case SCMD_WRITE_FILE_MARK:
9977 			if (un->un_eof != ST_EOM)
9978 				un->un_eof = ST_NO_EOF;
9979 			un->un_lastop = ST_OP_WEOF;
9980 			un->un_fileno += (bp->b_bcount - bp->b_resid);
9981 			un->un_blkno = 0;
9982 			if (un->un_dp->options & ST_REEL) {
9983 				un->un_fmneeded -=
9984 					(bp->b_bcount - bp->b_resid);
9985 				if (un->un_fmneeded < 0) {
9986 					un->un_fmneeded = 0;
9987 				}
9988 			} else {
9989 				un->un_fmneeded = 0;
9990 			}
9991 
9992 			break;
9993 		case SCMD_REWIND:
9994 			un->un_eof = ST_NO_EOF;
9995 			un->un_fileno = 0;
9996 			un->un_blkno = 0;
9997 			break;
9998 
9999 		case SCMD_SPACE:
10000 		{
10001 			int space_fmk, count;
10002 			long resid;
10003 
10004 			count = (int)space_cnt(bp->b_bcount);
10005 			resid = (long)space_cnt(bp->b_resid);
10006 			space_fmk = ((bp->b_bcount) & (1<<24)) ? 1 : 0;
10007 
10008 
10009 			if (count >= 0) {
10010 				if (space_fmk) {
10011 					if (un->un_eof <= ST_EOF) {
10012 						un->un_eof = ST_NO_EOF;
10013 					}
10014 					un->un_fileno += (count - resid);
10015 					un->un_blkno = 0;
10016 				} else {
10017 					un->un_blkno += count - resid;
10018 				}
10019 			} else if (count < 0) {
10020 				if (space_fmk) {
10021 					un->un_fileno -=
10022 					    ((-count) - resid);
10023 					if (un->un_fileno < 0) {
10024 						un->un_fileno = 0;
10025 						un->un_blkno = 0;
10026 					} else {
10027 						un->un_blkno = INF;
10028 					}
10029 				} else {
10030 					if (un->un_eof >= ST_EOF_PENDING) {
10031 					/*
10032 					 * we stepped back into
10033 					 * a previous file; we are not
10034 					 * making an effort to pretend that
10035 					 * we are still in the current file
10036 					 * ie. logical == physical position
10037 					 * and leave it to st_ioctl to correct
10038 					 */
10039 						if (un->un_fileno > 0) {
10040 							un->un_fileno--;
10041 							un->un_blkno = INF;
10042 						} else {
10043 							un->un_blkno = 0;
10044 						}
10045 					} else {
10046 						un->un_blkno -=
10047 						    (-count) - resid;
10048 					}
10049 				}
10050 			}
10051 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
10052 			    "aft_space rs %ld fil %d blk %ld\n",
10053 			    resid, un->un_fileno, un->un_blkno);
10054 			break;
10055 		}
10056 		case SCMD_LOAD:
10057 			if (bp->b_bcount & 0x1) {
10058 				un->un_fileno = 0;
10059 			} else {
10060 				un->un_state = ST_STATE_OFFLINE;
10061 				un->un_fileno = -1;
10062 			}
10063 			un->un_density_known = 0;
10064 			un->un_eof = ST_NO_EOF;
10065 			un->un_blkno = 0;
10066 			break;
10067 		case SCMD_ERASE:
10068 			un->un_eof = ST_NO_EOF;
10069 			un->un_blkno = 0;
10070 			un->un_fileno = 0;
10071 			break;
10072 		case SCMD_RESERVE:
10073 			un->un_rsvd_status |= ST_RESERVE;
10074 			un->un_rsvd_status &=
10075 				~(ST_RELEASE | ST_LOST_RESERVE |
10076 					ST_RESERVATION_CONFLICT);
10077 			un->un_lastop = saved_lastop;
10078 			break;
10079 		case SCMD_RELEASE:
10080 			un->un_rsvd_status |= ST_RELEASE;
10081 			un->un_rsvd_status &=
10082 				~(ST_RESERVE | ST_LOST_RESERVE |
10083 					ST_RESERVATION_CONFLICT);
10084 			un->un_lastop = saved_lastop;
10085 			break;
10086 		case SCMD_TEST_UNIT_READY:
10087 		case SCMD_READ_BLKLIM:
10088 		case SCMD_REQUEST_SENSE:
10089 		case SCMD_INQUIRY:
10090 		case SCMD_RECOVER_BUF:
10091 		case SCMD_MODE_SELECT:
10092 		case SCMD_MODE_SENSE:
10093 		case SCMD_DOORLOCK:
10094 		case SCMD_READ_POSITION:
10095 		case SCMD_READ_BUFFER:
10096 		case SCMD_REPORT_DENSITIES:
10097 		case SCMD_LOG_SELECT_G1:
10098 		case SCMD_LOG_SENSE_G1:
10099 		case SCMD_REPORT_LUNS:
10100 			un->un_lastop = saved_lastop;
10101 			break;
10102 		case SCMD_LOCATE:	/* Locate makes position unknown */
10103 		default:
10104 			/*
10105 			 * Unknown command, If was USCSI and USCSI_SILENT
10106 			 * flag was not set, set position to unknown.
10107 			 */
10108 			if ((((ucmd = BP_UCMD(bp)) != NULL) &&
10109 			    (ucmd->uscsi_flags & USCSI_SILENT) == 0)) {
10110 				ST_DEBUG2(ST_DEVINFO, st_label, CE_WARN,
10111 				    "unknown cmd 0x%X caused loss of state\n",
10112 				    cmd);
10113 			} else {
10114 				break;
10115 			}
10116 			/* FALLTHROUGH */
10117 		case SCMD_WRITE_BUFFER: /* Writes new firmware to device */
10118 			un->un_fileno = -1;
10119 			break;
10120 		}
10121 	}
10122 
10123 	/*
10124 	 * In the st driver we have a logical and physical file position.
10125 	 * Under BSD behavior, when you get a zero read, the logical position
10126 	 * is before the filemark but after the last record of the file.
10127 	 * The physical position is after the filemark. MTIOCGET should always
10128 	 * return the logical file position.
10129 	 *
10130 	 * The next read gives a silent skip to the next file.
10131 	 * Under SVR4, the logical file position remains before the filemark
10132 	 * until the file is closed or a space operation is performed.
10133 	 * Hence set err_resid and err_file before changing fileno if case
10134 	 * BSD Behaviour.
10135 	 */
10136 	un->un_err_resid = bp->b_resid;
10137 	un->un_err_fileno = un->un_fileno;
10138 	un->un_err_blkno = un->un_blkno;
10139 	un->un_retry_ct = 0;
10140 
10141 
10142 	/*
10143 	 * If we've seen a filemark via the last read operation
10144 	 * advance the file counter, but mark things such that
10145 	 * the next read operation gets a zero count. We have
10146 	 * to put this here to handle the case of sitting right
10147 	 * at the end of a tape file having seen the file mark,
10148 	 * but the tape is closed and then re-opened without
10149 	 * any further i/o. That is, the position information
10150 	 * must be updated before a close.
10151 	 */
10152 
10153 	if (un->un_lastop == ST_OP_READ && un->un_eof == ST_EOF_PENDING) {
10154 		/*
10155 		 * If we're a 1/2" tape, and we get a filemark
10156 		 * right on block 0, *AND* we were not in the
10157 		 * first file on the tape, and we've hit logical EOM.
10158 		 * We'll mark the state so that later we do the
10159 		 * right thing (in st_close(), st_strategy() or
10160 		 * st_ioctl()).
10161 		 *
10162 		 */
10163 		if ((un->un_dp->options & ST_REEL) &&
10164 			!(un->un_dp->options & ST_READ_IGNORE_EOFS) &&
10165 		    un->un_blkno == 0 && un->un_fileno > 0) {
10166 			un->un_eof = ST_EOT_PENDING;
10167 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
10168 			    "eot pending\n");
10169 			un->un_fileno++;
10170 			un->un_blkno = 0;
10171 		} else if (BSD_BEHAVIOR) {
10172 			/*
10173 			 * If the read of the filemark was a side effect
10174 			 * of reading some blocks (i.e., data was actually
10175 			 * read), then the EOF mark is pending and the
10176 			 * bump into the next file awaits the next read
10177 			 * operation (which will return a zero count), or
10178 			 * a close or a space operation, else the bump
10179 			 * into the next file occurs now.
10180 			 */
10181 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
10182 			    "resid=%lx, bcount=%lx\n",
10183 				bp->b_resid, bp->b_bcount);
10184 			if (bp->b_resid != bp->b_bcount) {
10185 				un->un_eof = ST_EOF;
10186 			} else {
10187 				un->un_silent_skip = 1;
10188 				un->un_eof = ST_NO_EOF;
10189 				un->un_fileno++;
10190 				un->un_save_blkno = un->un_blkno;
10191 				un->un_blkno = 0;
10192 			}
10193 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
10194 			    "eof of file %d, un_eof=%d\n",
10195 			    un->un_fileno, un->un_eof);
10196 		} else if (SVR4_BEHAVIOR) {
10197 			/*
10198 			 * If the read of the filemark was a side effect
10199 			 * of reading some blocks (i.e., data was actually
10200 			 * read), then the next read should return 0
10201 			 */
10202 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
10203 			    "resid=%lx, bcount=%lx\n",
10204 			    bp->b_resid, bp->b_bcount);
10205 			if (bp->b_resid == bp->b_bcount) {
10206 				un->un_eof = ST_EOF;
10207 			}
10208 			ST_DEBUG6(ST_DEVINFO, st_label, SCSI_DEBUG,
10209 			    "eof of file=%d, un_eof=%d\n",
10210 			    un->un_fileno, un->un_eof);
10211 		}
10212 	}
10213 }
10214 
10215 /*
10216  * set the correct un_errno, to take corner cases into consideration
10217  */
10218 static void
10219 st_set_pe_errno(struct scsi_tape *un)
10220 {
10221 	ASSERT(mutex_owned(ST_MUTEX));
10222 
10223 	/* if errno is already set, don't reset it */
10224 	if (un->un_errno)
10225 		return;
10226 
10227 	/* here un_errno == 0 */
10228 	/*
10229 	 * if the last transfer before flushing all the
10230 	 * waiting I/O's, was 0 (resid = count), then we
10231 	 * want to give the user an error on all the rest,
10232 	 * so here.  If there was a transfer, we set the
10233 	 * resid and counts to 0, and let it drop through,
10234 	 * giving a zero return.  the next I/O will then
10235 	 * give an error.
10236 	 */
10237 	if (un->un_last_resid == un->un_last_count) {
10238 		switch (un->un_eof) {
10239 		case ST_EOM:
10240 			un->un_errno = ENOMEM;
10241 			break;
10242 		case ST_EOT:
10243 		case ST_EOF:
10244 			un->un_errno = EIO;
10245 			break;
10246 		}
10247 	} else {
10248 		/*
10249 		 * we know they did not have a zero, so make
10250 		 * sure they get one
10251 		 */
10252 		un->un_last_resid = un->un_last_count = 0;
10253 	}
10254 }
10255 
10256 
10257 /*
10258  * send in a marker pkt to terminate flushing of commands by BBA (via
10259  * flush-on-errors) property.  The HBA will always return TRAN_ACCEPT
10260  */
10261 static void
10262 st_hba_unflush(struct scsi_tape *un)
10263 {
10264 	ASSERT(mutex_owned(ST_MUTEX));
10265 
10266 	if (!un->un_flush_on_errors)
10267 		return;
10268 
10269 #ifdef FLUSH_ON_ERRORS
10270 
10271 	if (!un->un_mkr_pkt) {
10272 		un->un_mkr_pkt = scsi_init_pkt(ROUTE, NULL, (struct buf *)NULL,
10273 		    NULL, 0, 0, 0, SLEEP_FUNC, NULL);
10274 
10275 		/* we slept, so it must be there */
10276 		pkt->pkt_flags |= FLAG_FLUSH_MARKER;
10277 	}
10278 
10279 	mutex_exit(ST_MUTEX);
10280 	scsi_transport(un->un_mkr_pkt);
10281 	mutex_enter(ST_MUTEX);
10282 #endif
10283 }
10284 
10285 static void
10286 st_clean_print(dev_info_t *dev, char *label, uint_t level,
10287 	char *title, char *data, int len)
10288 {
10289 	int	i;
10290 	char	buf[256];
10291 
10292 	(void) sprintf(buf, "%s: ", title);
10293 	for (i = 0; i < len; i++) {
10294 		(void) sprintf(&buf[(int)strlen(buf)], "0x%x ",
10295 			(data[i] & 0xff));
10296 	}
10297 	(void) sprintf(&buf[(int)strlen(buf)], "\n");
10298 
10299 	scsi_log(dev, label, level, "%s", buf);
10300 }
10301 
10302 /*
10303  * Conditionally enabled debugging
10304  */
10305 #ifdef	STDEBUG
10306 static void
10307 st_debug_cmds(struct scsi_tape *un, int com, int count, int wait)
10308 {
10309 	char tmpbuf[64];
10310 
10311 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10312 	    "cmd=%s count=0x%x (%d)	 %ssync\n",
10313 	    scsi_cmd_name(com, scsi_cmds, tmpbuf),
10314 	    count, count,
10315 	    wait == ASYNC_CMD ? "a" : "");
10316 }
10317 
10318 /*
10319  * Returns pointer to name of minor node name of device 'dev'.
10320  */
10321 static char *
10322 st_dev_name(dev_t dev)
10323 {
10324 	const char density[] = { 'l', 'm', 'h', 'c' };
10325 	static char name[4];
10326 	minor_t minor;
10327 	int nprt = 0;
10328 
10329 	minor = getminor(dev);
10330 	name[nprt] = density[(minor & MT_DENSITY_MASK) >> 3];
10331 
10332 	if (minor & MT_BSD) {
10333 		name[++nprt] = 'b';
10334 	}
10335 
10336 	if (minor & MT_NOREWIND) {
10337 		name[++nprt] = 'n';
10338 	}
10339 
10340 	/* NULL terminator */
10341 	name[++nprt] = 0;
10342 
10343 	return (name);
10344 }
10345 #endif	/* STDEBUG */
10346 
10347 /*
10348  * Soft error reporting, so far unique to each drive
10349  *
10350  * Currently supported: exabyte and DAT soft error reporting
10351  */
10352 static int
10353 st_report_exabyte_soft_errors(dev_t dev, int flag)
10354 {
10355 	uchar_t *sensep;
10356 	int amt;
10357 	int rval = 0;
10358 	char cdb[CDB_GROUP0], *c = cdb;
10359 	struct uscsi_cmd *com;
10360 
10361 	GET_SOFT_STATE(dev);
10362 
10363 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10364 	    "st_report_exabyte_soft_errors(dev = 0x%lx, flag = %d)\n",
10365 	    dev, flag);
10366 
10367 	ASSERT(mutex_owned(ST_MUTEX));
10368 
10369 	com = kmem_zalloc(sizeof (*com), KM_SLEEP);
10370 	sensep = kmem_zalloc(TAPE_SENSE_LENGTH, KM_SLEEP);
10371 
10372 	*c++ = SCMD_REQUEST_SENSE;
10373 	*c++ = 0;
10374 	*c++ = 0;
10375 	*c++ = 0;
10376 	*c++ = TAPE_SENSE_LENGTH;
10377 	/*
10378 	 * set CLRCNT (byte 5, bit 7 which clears the error counts)
10379 	 */
10380 	*c   = (char)0x80;
10381 
10382 	com->uscsi_cdb = cdb;
10383 	com->uscsi_cdblen = CDB_GROUP0;
10384 	com->uscsi_bufaddr = (caddr_t)sensep;
10385 	com->uscsi_buflen = TAPE_SENSE_LENGTH;
10386 	com->uscsi_flags = USCSI_DIAGNOSE | USCSI_SILENT
10387 		| USCSI_READ | USCSI_RQENABLE;
10388 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
10389 
10390 	rval = st_ioctl_cmd(dev, com, UIO_SYSSPACE, UIO_SYSSPACE,
10391 		UIO_SYSSPACE);
10392 	if (rval || com->uscsi_status) {
10393 		goto done;
10394 	}
10395 
10396 	/*
10397 	 * was there enough data?
10398 	 */
10399 	amt = (int)TAPE_SENSE_LENGTH - com->uscsi_resid;
10400 
10401 	if ((amt >= 19) && un->un_kbytes_xferred) {
10402 		uint_t count, error_rate;
10403 		uint_t rate;
10404 
10405 		if (sensep[21] & CLN) {
10406 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
10407 			    "Periodic head cleaning required");
10408 		}
10409 		if (un->un_kbytes_xferred < (EXABYTE_MIN_TRANSFER/1000))
10410 			goto done;
10411 		/*
10412 		 * check if soft error reporting needs to be done.
10413 		 */
10414 		count = sensep[16] << 16 | sensep[17] << 8 | sensep[18];
10415 		count &= 0xffffff;
10416 		error_rate = (count * 100)/un->un_kbytes_xferred;
10417 
10418 #ifdef	STDEBUG
10419 		if (st_soft_error_report_debug) {
10420 			scsi_log(ST_DEVINFO, st_label, CE_NOTE,
10421 			    "Exabyte Soft Error Report:\n");
10422 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
10423 			    "read/write error counter: %d\n", count);
10424 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
10425 			    "number of bytes transferred: %dK\n",
10426 				un->un_kbytes_xferred);
10427 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
10428 			    "error_rate: %d%%\n", error_rate);
10429 
10430 			if (amt >= 22) {
10431 				scsi_log(ST_DEVINFO, st_label, CE_CONT,
10432 				    "unit sense: 0x%b 0x%b 0x%b\n",
10433 				    sensep[19], SENSE_19_BITS,
10434 				    sensep[20], SENSE_20_BITS,
10435 				    sensep[21], SENSE_21_BITS);
10436 			}
10437 			if (amt >= 27) {
10438 				scsi_log(ST_DEVINFO, st_label, CE_CONT,
10439 				    "tracking retry counter: %d\n",
10440 				    sensep[26]);
10441 				scsi_log(ST_DEVINFO, st_label, CE_CONT,
10442 				    "read/write retry counter: %d\n",
10443 				    sensep[27]);
10444 			}
10445 		}
10446 #endif
10447 
10448 		if (flag & FWRITE) {
10449 			rate = EXABYTE_WRITE_ERROR_THRESHOLD;
10450 		} else {
10451 			rate = EXABYTE_READ_ERROR_THRESHOLD;
10452 		}
10453 		if (error_rate >= rate) {
10454 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
10455 			    "Soft error rate (%d%%) during %s was too high",
10456 			    error_rate,
10457 			    ((flag & FWRITE) ? wrg_str : rdg_str));
10458 			scsi_log(ST_DEVINFO, st_label, CE_CONT,
10459 			    "Please, replace tape cartridge\n");
10460 		}
10461 	}
10462 
10463 done:
10464 	kmem_free(com, sizeof (*com));
10465 	kmem_free(sensep, TAPE_SENSE_LENGTH);
10466 
10467 	if (rval != 0) {
10468 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
10469 		    "exabyte soft error reporting failed\n");
10470 	}
10471 	return (rval);
10472 }
10473 
10474 /*
10475  * this is very specific to Archive 4mm dat
10476  */
10477 #define	ONEGIG	(1024 * 1024 * 1024)
10478 
10479 static int
10480 st_report_dat_soft_errors(dev_t dev, int flag)
10481 {
10482 	uchar_t *sensep;
10483 	int amt, i;
10484 	int rval = 0;
10485 	char cdb[CDB_GROUP1], *c = cdb;
10486 	struct uscsi_cmd *com;
10487 
10488 	GET_SOFT_STATE(dev);
10489 
10490 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10491 	    "st_report_dat_soft_errors(dev = 0x%lx, flag = %d)\n", dev, flag);
10492 
10493 	ASSERT(mutex_owned(ST_MUTEX));
10494 
10495 	com = kmem_zalloc(sizeof (*com), KM_SLEEP);
10496 	sensep = kmem_zalloc(LOG_SENSE_LENGTH, KM_SLEEP);
10497 
10498 	*c++ = SCMD_LOG_SENSE_G1;
10499 	*c++ = 0;
10500 	*c++ = (flag & FWRITE) ? 0x42 : 0x43;
10501 	*c++ = 0;
10502 	*c++ = 0;
10503 	*c++ = 0;
10504 	*c++ = 2;
10505 	*c++ = 0;
10506 	*c++ = (char)LOG_SENSE_LENGTH;
10507 	*c   = 0;
10508 	com->uscsi_cdb    = cdb;
10509 	com->uscsi_cdblen  = CDB_GROUP1;
10510 	com->uscsi_bufaddr = (caddr_t)sensep;
10511 	com->uscsi_buflen  = LOG_SENSE_LENGTH;
10512 	com->uscsi_flags   =
10513 	    USCSI_DIAGNOSE | USCSI_SILENT | USCSI_READ | USCSI_RQENABLE;
10514 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
10515 	rval =
10516 	    st_ioctl_cmd(dev, com, UIO_SYSSPACE, UIO_SYSSPACE, UIO_SYSSPACE);
10517 	if (rval) {
10518 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
10519 		    "DAT soft error reporting failed\n");
10520 	}
10521 	if (rval || com->uscsi_status) {
10522 		goto done;
10523 	}
10524 
10525 	/*
10526 	 * was there enough data?
10527 	 */
10528 	amt = (int)LOG_SENSE_LENGTH - com->uscsi_resid;
10529 
10530 	if ((amt >= MIN_LOG_SENSE_LENGTH) && un->un_kbytes_xferred) {
10531 		int total, retries, param_code;
10532 
10533 		total = -1;
10534 		retries = -1;
10535 		amt = sensep[3] + 4;
10536 
10537 
10538 #ifdef STDEBUG
10539 		if (st_soft_error_report_debug) {
10540 			(void) printf("logsense:");
10541 			for (i = 0; i < MIN_LOG_SENSE_LENGTH; i++) {
10542 				if (i % 16 == 0) {
10543 					(void) printf("\t\n");
10544 				}
10545 				(void) printf(" %x", sensep[i]);
10546 			}
10547 			(void) printf("\n");
10548 		}
10549 #endif
10550 
10551 		/*
10552 		 * parse the param_codes
10553 		 */
10554 		if (sensep[0] == 2 || sensep[0] == 3) {
10555 			for (i = 4; i < amt; i++) {
10556 				param_code = (sensep[i++] << 8);
10557 				param_code += sensep[i++];
10558 				i++; /* skip control byte */
10559 				if (param_code == 5) {
10560 					if (sensep[i++] == 4) {
10561 						total = (sensep[i++] << 24);
10562 						total += (sensep[i++] << 16);
10563 						total += (sensep[i++] << 8);
10564 						total += sensep[i];
10565 					}
10566 				} else if (param_code == 0x8007) {
10567 					if (sensep[i++] == 2) {
10568 						retries = sensep[i++] << 8;
10569 						retries += sensep[i];
10570 					}
10571 				} else {
10572 					i += sensep[i];
10573 				}
10574 			}
10575 		}
10576 
10577 		/*
10578 		 * if the log sense returned valid numbers then determine
10579 		 * the read and write error thresholds based on the amount of
10580 		 * data transferred
10581 		 */
10582 
10583 		if (total > 0 && retries > 0) {
10584 			short normal_retries = 0;
10585 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
10586 			"total xferred (%s) =%x, retries=%x\n",
10587 				((flag & FWRITE) ? wrg_str : rdg_str),
10588 				total, retries);
10589 
10590 			if (flag & FWRITE) {
10591 				if (total <=
10592 					WRITE_SOFT_ERROR_WARNING_THRESHOLD) {
10593 					normal_retries =
10594 						DAT_SMALL_WRITE_ERROR_THRESHOLD;
10595 				} else {
10596 					normal_retries =
10597 						DAT_LARGE_WRITE_ERROR_THRESHOLD;
10598 				}
10599 			} else {
10600 				if (total <=
10601 					READ_SOFT_ERROR_WARNING_THRESHOLD) {
10602 					normal_retries =
10603 						DAT_SMALL_READ_ERROR_THRESHOLD;
10604 				} else {
10605 					normal_retries =
10606 						DAT_LARGE_READ_ERROR_THRESHOLD;
10607 				}
10608 			}
10609 
10610 			ST_DEBUG4(ST_DEVINFO, st_label, SCSI_DEBUG,
10611 			"normal retries=%d\n", normal_retries);
10612 
10613 			if (retries >= normal_retries) {
10614 				scsi_log(ST_DEVINFO, st_label, CE_WARN,
10615 				    "Soft error rate (retries = %d) during "
10616 				    "%s was too high",  retries,
10617 				    ((flag & FWRITE) ? wrg_str : rdg_str));
10618 				scsi_log(ST_DEVINFO, st_label, CE_CONT,
10619 				    "Periodic head cleaning required "
10620 				    "and/or replace tape cartridge\n");
10621 			}
10622 
10623 		} else if (total == -1 || retries == -1) {
10624 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
10625 			    "log sense parameter code does not make sense\n");
10626 		}
10627 	}
10628 
10629 	/*
10630 	 * reset all values
10631 	 */
10632 	c = cdb;
10633 	*c++ = SCMD_LOG_SELECT_G1;
10634 	*c++ = 2;	/* this resets all values */
10635 	*c++ = (char)0xc0;
10636 	*c++ = 0;
10637 	*c++ = 0;
10638 	*c++ = 0;
10639 	*c++ = 0;
10640 	*c++ = 0;
10641 	*c++ = 0;
10642 	*c   = 0;
10643 	com->uscsi_bufaddr = NULL;
10644 	com->uscsi_buflen  = 0;
10645 	com->uscsi_flags   = USCSI_DIAGNOSE | USCSI_SILENT | USCSI_RQENABLE;
10646 	rval =
10647 	    st_ioctl_cmd(dev, com, UIO_SYSSPACE, UIO_SYSSPACE, UIO_SYSSPACE);
10648 	if (rval) {
10649 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
10650 		    "DAT soft error reset failed\n");
10651 	}
10652 done:
10653 	kmem_free(com, sizeof (*com));
10654 	kmem_free(sensep, LOG_SENSE_LENGTH);
10655 	return (rval);
10656 }
10657 
10658 static int
10659 st_report_soft_errors(dev_t dev, int flag)
10660 {
10661 	GET_SOFT_STATE(dev);
10662 
10663 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10664 	    "st_report_soft_errors(dev = 0x%lx, flag = %d)\n", dev, flag);
10665 
10666 	ASSERT(mutex_owned(ST_MUTEX));
10667 
10668 	switch (un->un_dp->type) {
10669 	case ST_TYPE_EXB8500:
10670 	case ST_TYPE_EXABYTE:
10671 		return (st_report_exabyte_soft_errors(dev, flag));
10672 		/*NOTREACHED*/
10673 	case ST_TYPE_PYTHON:
10674 		return (st_report_dat_soft_errors(dev, flag));
10675 		/*NOTREACHED*/
10676 	default:
10677 		un->un_dp->options &= ~ST_SOFT_ERROR_REPORTING;
10678 		return (-1);
10679 	}
10680 }
10681 
10682 /*
10683  * persistent error routines
10684  */
10685 
10686 /*
10687  * enable persistent errors, and set the throttle appropriately, checking
10688  * for flush-on-errors capability
10689  */
10690 static void
10691 st_turn_pe_on(struct scsi_tape *un)
10692 {
10693 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_pe_on\n");
10694 	ASSERT(mutex_owned(ST_MUTEX));
10695 
10696 	un->un_persistence = 1;
10697 
10698 	/*
10699 	 * only use flush-on-errors if auto-request-sense and untagged-qing are
10700 	 * enabled.  This will simplify the error handling for request senses
10701 	 */
10702 
10703 	if (un->un_arq_enabled && un->un_untagged_qing) {
10704 		uchar_t f_o_e;
10705 
10706 		mutex_exit(ST_MUTEX);
10707 		f_o_e = (scsi_ifsetcap(ROUTE, "flush-on-errors", 1, 1) == 1) ?
10708 		    1 : 0;
10709 		mutex_enter(ST_MUTEX);
10710 
10711 		un->un_flush_on_errors = f_o_e;
10712 	} else {
10713 		un->un_flush_on_errors = 0;
10714 	}
10715 
10716 	if (un->un_flush_on_errors)
10717 		un->un_max_throttle = (uchar_t)st_max_throttle;
10718 	else
10719 		un->un_max_throttle = 1;
10720 
10721 	if (un->un_dp->options & ST_RETRY_ON_RECOVERED_DEFERRED_ERROR)
10722 		un->un_max_throttle = 1;
10723 
10724 	/* this will send a marker pkt */
10725 	CLEAR_PE(un);
10726 }
10727 
10728 /*
10729  * This turns persistent errors permanently off
10730  */
10731 static void
10732 st_turn_pe_off(struct scsi_tape *un)
10733 {
10734 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_pe_off\n");
10735 	ASSERT(mutex_owned(ST_MUTEX));
10736 
10737 	/* turn it off for good */
10738 	un->un_persistence = 0;
10739 
10740 	/* this will send a marker pkt */
10741 	CLEAR_PE(un);
10742 
10743 	/* turn off flush on error capability, if enabled */
10744 	if (un->un_flush_on_errors) {
10745 		mutex_exit(ST_MUTEX);
10746 		(void) scsi_ifsetcap(ROUTE, "flush-on-errors", 0, 1);
10747 		mutex_enter(ST_MUTEX);
10748 	}
10749 
10750 
10751 	un->un_flush_on_errors = 0;
10752 }
10753 
10754 /*
10755  * This clear persistent errors, allowing more commands through, and also
10756  * sending a marker packet.
10757  */
10758 static void
10759 st_clear_pe(struct scsi_tape *un)
10760 {
10761 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_pe_clear\n");
10762 	ASSERT(mutex_owned(ST_MUTEX));
10763 
10764 	un->un_persist_errors = 0;
10765 	un->un_throttle = un->un_last_throttle = 1;
10766 	un->un_errno = 0;
10767 	st_hba_unflush(un);
10768 }
10769 
10770 /*
10771  * This will flag persistent errors, shutting everything down, if the
10772  * application had enabled persistent errors via MTIOCPERSISTENT
10773  */
10774 static void
10775 st_set_pe_flag(struct scsi_tape *un)
10776 {
10777 	ASSERT(mutex_owned(ST_MUTEX));
10778 
10779 	if (un->un_persistence) {
10780 		ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG, "st_pe_flag\n");
10781 		un->un_persist_errors = 1;
10782 		un->un_throttle = un->un_last_throttle = 0;
10783 	}
10784 }
10785 
10786 int
10787 st_reserve_release(dev_t dev, int cmd)
10788 {
10789 	struct uscsi_cmd	uscsi_cmd;
10790 	struct uscsi_cmd	*com = &uscsi_cmd;
10791 	int			rval;
10792 	char			cdb[CDB_GROUP0];
10793 
10794 
10795 	GET_SOFT_STATE(dev);
10796 	ASSERT(mutex_owned(ST_MUTEX));
10797 
10798 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10799 		"st_reserve_release: %s \n", (cmd == ST_RELEASE)?
10800 				"Releasing":"Reserving");
10801 
10802 	bzero(cdb, CDB_GROUP0);
10803 	if (cmd == ST_RELEASE) {
10804 		cdb[0] = SCMD_RELEASE;
10805 	} else {
10806 		cdb[0] = SCMD_RESERVE;
10807 	}
10808 	bzero(com, sizeof (struct uscsi_cmd));
10809 	com->uscsi_flags = USCSI_WRITE;
10810 	com->uscsi_cdb = cdb;
10811 	com->uscsi_cdblen = CDB_GROUP0;
10812 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
10813 
10814 	rval = st_ioctl_cmd(dev, com,
10815 		UIO_SYSSPACE, UIO_SYSSPACE, UIO_SYSSPACE);
10816 
10817 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10818 		"st_reserve_release: rval(1)=%d\n", rval);
10819 
10820 	if (rval) {
10821 		if (com->uscsi_status == STATUS_RESERVATION_CONFLICT)
10822 			rval = EACCES;
10823 		/*
10824 		 * dynamically turn off reserve/release support
10825 		 * in case of drives which do not support
10826 		 * reserve/release command(ATAPI drives).
10827 		 */
10828 		if (un->un_status == KEY_ILLEGAL_REQUEST) {
10829 			if (ST_RESERVE_SUPPORTED(un)) {
10830 				un->un_dp->options |= ST_NO_RESERVE_RELEASE;
10831 				ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10832 					"Tape unit does not support "
10833 					"reserve/release \n");
10834 			}
10835 			rval = 0;
10836 		}
10837 	}
10838 	return (rval);
10839 }
10840 
10841 static int
10842 st_take_ownership(dev_t dev)
10843 {
10844 	int rval;
10845 
10846 	GET_SOFT_STATE(dev);
10847 	ASSERT(mutex_owned(ST_MUTEX));
10848 
10849 	ST_DEBUG3(ST_DEVINFO, st_label, SCSI_DEBUG,
10850 		"st_take_ownership: Entering ...\n");
10851 
10852 
10853 	rval = st_reserve_release(dev, ST_RESERVE);
10854 	/*
10855 	 * XXX -> Should reset be done only if we get EACCES.
10856 	 * .
10857 	 */
10858 	if (rval) {
10859 		mutex_exit(ST_MUTEX);
10860 		if (scsi_reset(ROUTE, RESET_TARGET) == 0) {
10861 			if (scsi_reset(ROUTE, RESET_ALL) == 0) {
10862 				mutex_enter(ST_MUTEX);
10863 				return (EIO);
10864 			}
10865 		}
10866 		mutex_enter(ST_MUTEX);
10867 		un->un_rsvd_status &=
10868 			~(ST_LOST_RESERVE | ST_RESERVATION_CONFLICT);
10869 
10870 		mutex_exit(ST_MUTEX);
10871 		delay(drv_usectohz(ST_RESERVATION_DELAY));
10872 		mutex_enter(ST_MUTEX);
10873 		/*
10874 		 * remove the check condition.
10875 		 */
10876 		(void) st_reserve_release(dev, ST_RESERVE);
10877 		if ((rval = st_reserve_release(dev, ST_RESERVE)) != 0) {
10878 			if ((st_reserve_release(dev, ST_RESERVE)) != 0) {
10879 				rval = (un->un_rsvd_status &
10880 					ST_RESERVATION_CONFLICT) ? EACCES : EIO;
10881 				return (rval);
10882 			}
10883 		}
10884 		/*
10885 		 * Set tape state to ST_STATE_OFFLINE , in case if
10886 		 * the user wants to continue and start using
10887 		 * the tape.
10888 		 */
10889 		un->un_state = ST_STATE_OFFLINE;
10890 		un->un_rsvd_status |= ST_INIT_RESERVE;
10891 	}
10892 	return (rval);
10893 }
10894 
10895 static int
10896 st_create_errstats(struct scsi_tape *un, int instance)
10897 {
10898 	char	kstatname[KSTAT_STRLEN];
10899 
10900 	/*
10901 	 * Create device error kstats
10902 	 */
10903 
10904 	if (un->un_errstats == (kstat_t *)0) {
10905 		(void) sprintf(kstatname, "st%d,err", instance);
10906 		un->un_errstats = kstat_create("sterr", instance, kstatname,
10907 			"device_error", KSTAT_TYPE_NAMED,
10908 			sizeof (struct st_errstats) / sizeof (kstat_named_t),
10909 			KSTAT_FLAG_PERSISTENT);
10910 
10911 		if (un->un_errstats) {
10912 			struct st_errstats	*stp;
10913 
10914 			stp = (struct st_errstats *)un->un_errstats->ks_data;
10915 			kstat_named_init(&stp->st_softerrs, "Soft Errors",
10916 				KSTAT_DATA_ULONG);
10917 			kstat_named_init(&stp->st_harderrs, "Hard Errors",
10918 				KSTAT_DATA_ULONG);
10919 			kstat_named_init(&stp->st_transerrs, "Transport Errors",
10920 				KSTAT_DATA_ULONG);
10921 			kstat_named_init(&stp->st_vid, "Vendor",
10922 				KSTAT_DATA_CHAR);
10923 			kstat_named_init(&stp->st_pid, "Product",
10924 				KSTAT_DATA_CHAR);
10925 			kstat_named_init(&stp->st_revision, "Revision",
10926 				KSTAT_DATA_CHAR);
10927 			kstat_named_init(&stp->st_serial, "Serial No",
10928 				KSTAT_DATA_CHAR);
10929 			un->un_errstats->ks_private = un;
10930 			un->un_errstats->ks_update = nulldev;
10931 			kstat_install(un->un_errstats);
10932 			/*
10933 			 * Fill in the static data
10934 			 */
10935 			(void) strncpy(&stp->st_vid.value.c[0],
10936 					ST_INQUIRY->inq_vid, 8);
10937 			/*
10938 			 * XXX:  Emulex MT-02 (and emulators) predates
10939 			 *	 SCSI-1 and has no vid & pid inquiry data.
10940 			 */
10941 			if (ST_INQUIRY->inq_len != 0) {
10942 				(void) strncpy(&stp->st_pid.value.c[0],
10943 					ST_INQUIRY->inq_pid, 16);
10944 				(void) strncpy(&stp->st_revision.value.c[0],
10945 					ST_INQUIRY->inq_revision, 4);
10946 				(void) strncpy(&stp->st_serial.value.c[0],
10947 					ST_INQUIRY->inq_serial, 12);
10948 			}
10949 		}
10950 	}
10951 	return (0);
10952 }
10953 
10954 static int
10955 st_validate_tapemarks(struct scsi_tape *un, int fileno, daddr_t blkno)
10956 {
10957 	dev_t 	dev;
10958 
10959 	ASSERT(MUTEX_HELD(&un->un_sd->sd_mutex));
10960 	ASSERT(mutex_owned(ST_MUTEX));
10961 
10962 	dev = un->un_dev;
10963 
10964 	scsi_log(ST_DEVINFO, st_label, CE_NOTE, "Restoring tape"
10965 	" position at fileno=%x, blkno=%lx....", fileno, blkno);
10966 
10967 	/*
10968 	 * Rewind ? Oh yeah, Fidelity has got the STK F/W changed
10969 	 * so as not to rewind tape on RESETS: Gee, Has life ever
10970 	 * been simple in tape land ?
10971 	 */
10972 	if (st_cmd(dev, SCMD_REWIND, 0, SYNC_CMD)) {
10973 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
10974 		"Failed to restore the last file and block position: In"
10975 		" this state, Tape will be loaded at BOT during next open");
10976 		un->un_fileno = -1;
10977 		return (1);
10978 	}
10979 
10980 	if (fileno) {
10981 		if (st_cmd(dev, SCMD_SPACE, Fmk(fileno), SYNC_CMD)) {
10982 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
10983 			"Failed to restore the last file position: In this "
10984 			" state, Tape will be loaded at BOT during next open");
10985 			un->un_fileno = -1;
10986 			return (2);
10987 		}
10988 	}
10989 
10990 	if (blkno) {
10991 		if (st_cmd(dev, SCMD_SPACE, Blk(blkno), SYNC_CMD)) {
10992 			scsi_log(ST_DEVINFO, st_label, CE_WARN,
10993 			"Failed to restore the last block position: In this"
10994 			" state, tape will be loaded at BOT during next open");
10995 			un->un_fileno = -1;
10996 			return (3);
10997 		}
10998 	}
10999 
11000 	return (0);
11001 }
11002 
11003 /*
11004  * check sense key, ASC, ASCQ in order to determine if the tape needs
11005  * to be ejected
11006  */
11007 
11008 static int
11009 st_check_asc_ascq(struct scsi_tape *un)
11010 {
11011 	struct scsi_extended_sense *sensep = ST_RQSENSE;
11012 	struct tape_failure_code   *code;
11013 
11014 	for (code = st_tape_failure_code; code->key != 0xff; code++) {
11015 		if ((code->key  == sensep->es_key) &&
11016 		    (code->add_code  == sensep->es_add_code) &&
11017 		    (code->qual_code == sensep->es_qual_code))
11018 			return (1);
11019 	}
11020 	return (0);
11021 }
11022 
11023 /*
11024  * st_logpage_supported() sends a Log Sense command with
11025  * page code = 0 = Supported Log Pages Page to the device,
11026  * to see whether the page 'page' is supported.
11027  * Return values are:
11028  * -1 if the Log Sense command fails
11029  * 0 if page is not supported
11030  * 1 if page is supported
11031  */
11032 
11033 static int
11034 st_logpage_supported(dev_t dev, uchar_t page)
11035 {
11036 	uchar_t *sp, *sensep;
11037 	unsigned length;
11038 	struct uscsi_cmd *com;
11039 	int rval;
11040 	char cdb[CDB_GROUP1] = {
11041 		SCMD_LOG_SENSE_G1,
11042 		0,
11043 		SUPPORTED_LOG_PAGES_PAGE,
11044 		0,
11045 		0,
11046 		0,
11047 		0,
11048 		0,
11049 		(char)LOG_SENSE_LENGTH,
11050 		0
11051 	};
11052 
11053 	GET_SOFT_STATE(dev);
11054 	ASSERT(mutex_owned(ST_MUTEX));
11055 
11056 	com = kmem_zalloc(sizeof (struct uscsi_cmd), KM_SLEEP);
11057 	sensep = kmem_zalloc(LOG_SENSE_LENGTH, KM_SLEEP);
11058 
11059 	com->uscsi_cdb = cdb;
11060 	com->uscsi_cdblen = CDB_GROUP1;
11061 	com->uscsi_bufaddr = (caddr_t)sensep;
11062 	com->uscsi_buflen = LOG_SENSE_LENGTH;
11063 	com->uscsi_flags =
11064 		USCSI_DIAGNOSE | USCSI_SILENT | USCSI_READ | USCSI_RQENABLE;
11065 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
11066 	rval = st_ioctl_cmd(dev, com, UIO_SYSSPACE, UIO_SYSSPACE, UIO_SYSSPACE);
11067 	if (rval || com->uscsi_status) {
11068 		/* uscsi-command failed */
11069 		rval = -1;
11070 	} else {
11071 
11072 		sp = sensep + 3;
11073 
11074 		for (length = *sp++; length > 0; length--, sp++) {
11075 
11076 			if (*sp == page) {
11077 				rval = 1;
11078 				break;
11079 			}
11080 		}
11081 	}
11082 	kmem_free(com, sizeof (struct uscsi_cmd));
11083 	kmem_free(sensep, LOG_SENSE_LENGTH);
11084 	return (rval);
11085 }
11086 
11087 
11088 /*
11089  * st_check_clean_bit() gets the status of the tape's cleaning bit.
11090  *
11091  * If the device does support the TapeAlert log page, then the cleaning bit
11092  * information will be read from this page. Otherwise we will see if one of
11093  * ST_CLN_TYPE_1, ST_CLN_TYPE_2 or ST_CLN_TYPE_3 is set in the properties of
11094  * the device, which means, that we can get the cleaning bit information via
11095  * a RequestSense command.
11096  * If both methods of getting cleaning bit information are not supported
11097  * st_check_clean_bit() will return with 0. Otherwise st_check_clean_bit()
11098  * returns with
11099  * - MTF_TAPE_CLN_SUPPORTED if cleaning bit is not set or
11100  * - MTF_TAPE_CLN_SUPPORTED | MTF_TAPE_HEAD_DIRTY if cleaning bit is set.
11101  * If the call to st_ioctl_cmd() to do the Log Sense or the Request Sense
11102  * command fails, or if the amount of Request Sense data is not enough, then
11103  *  st_check_clean_bit() returns with -1.
11104  */
11105 
11106 static int
11107 st_check_clean_bit(dev_t dev)
11108 {
11109 	int rval = 0;
11110 
11111 	GET_SOFT_STATE(dev);
11112 
11113 	ASSERT(mutex_owned(ST_MUTEX));
11114 
11115 	if (un->un_HeadClean & TAPE_ALERT_NOT_SUPPORTED) {
11116 		return (rval);
11117 	}
11118 
11119 	if (un->un_HeadClean == TAPE_ALERT_SUPPORT_UNKNOWN) {
11120 
11121 		rval = st_logpage_supported(dev, TAPE_SEQUENTIAL_PAGE);
11122 		if (rval == 1) {
11123 
11124 			un->un_HeadClean |= TAPE_SEQUENTIAL_SUPPORTED;
11125 		}
11126 
11127 		rval = st_logpage_supported(dev, TAPE_ALERT_PAGE);
11128 		if (rval == 1) {
11129 
11130 			un->un_HeadClean |= TAPE_ALERT_SUPPORTED;
11131 		}
11132 
11133 		if (un->un_HeadClean == TAPE_ALERT_SUPPORT_UNKNOWN) {
11134 
11135 			un->un_HeadClean = TAPE_ALERT_NOT_SUPPORTED;
11136 		}
11137 	}
11138 
11139 	rval = 0;
11140 
11141 	if (un->un_HeadClean & TAPE_SEQUENTIAL_SUPPORTED) {
11142 
11143 		rval = st_check_sequential_clean_bit(dev);
11144 	}
11145 
11146 	if ((rval <= 0) && (un->un_HeadClean & TAPE_ALERT_SUPPORTED)) {
11147 
11148 		rval = st_check_alert_clean_bit(dev);
11149 	}
11150 
11151 	if ((rval <= 0) && (un->un_dp->options & ST_CLN_MASK)) {
11152 
11153 		rval = st_check_sense_clean_bit(dev);
11154 	}
11155 
11156 	if (rval < 0) {
11157 		return (rval);
11158 	}
11159 
11160 	/*
11161 	 * If found a supported means to check need to clean.
11162 	 */
11163 	if (rval & MTF_TAPE_CLN_SUPPORTED) {
11164 
11165 		/*
11166 		 * head needs to be cleaned.
11167 		 */
11168 		if (rval & MTF_TAPE_HEAD_DIRTY) {
11169 
11170 			/*
11171 			 * Print log message only first time
11172 			 * found needing cleaned.
11173 			 */
11174 			if ((un->un_HeadClean & TAPE_PREVIOUSLY_DIRTY) == 0) {
11175 
11176 				scsi_log(ST_DEVINFO, st_label, CE_WARN,
11177 				    "Periodic head cleaning required");
11178 
11179 				un->un_HeadClean |= TAPE_PREVIOUSLY_DIRTY;
11180 			}
11181 
11182 		} else {
11183 
11184 			un->un_HeadClean &= ~TAPE_PREVIOUSLY_DIRTY;
11185 		}
11186 	}
11187 
11188 	return (rval);
11189 }
11190 
11191 
11192 static int
11193 st_check_sequential_clean_bit(dev_t dev)
11194 {
11195 	int rval;
11196 	int ix;
11197 	ushort_t parameter;
11198 	struct uscsi_cmd *cmd;
11199 	struct log_sequential_page *sp;
11200 	struct log_sequential_page_parameter *prm;
11201 	char cdb[CDB_GROUP1] = {
11202 		SCMD_LOG_SENSE_G1,
11203 		0,
11204 		TAPE_SEQUENTIAL_PAGE | CURRENT_CUMULATIVE_VALUES,
11205 		0,
11206 		0,
11207 		0,
11208 		0,
11209 		(char)(sizeof (struct log_sequential_page) >> 8),
11210 		(char)(sizeof (struct log_sequential_page)),
11211 		0
11212 	};
11213 
11214 	GET_SOFT_STATE(dev);
11215 
11216 	cmd = kmem_zalloc(sizeof (struct uscsi_cmd), KM_SLEEP);
11217 	sp  = kmem_zalloc(sizeof (struct log_sequential_page), KM_SLEEP);
11218 
11219 	cmd->uscsi_flags   =
11220 		USCSI_DIAGNOSE | USCSI_SILENT | USCSI_READ | USCSI_RQENABLE;
11221 	cmd->uscsi_timeout = un->un_dp->non_motion_timeout;
11222 	cmd->uscsi_cdb	   = cdb;
11223 	cmd->uscsi_cdblen  = CDB_GROUP1;
11224 	cmd->uscsi_bufaddr = (caddr_t)sp;
11225 	cmd->uscsi_buflen  = sizeof (struct log_sequential_page);
11226 
11227 	rval = st_ioctl_cmd(dev, cmd, UIO_SYSSPACE, UIO_SYSSPACE, UIO_SYSSPACE);
11228 
11229 	if (rval || cmd->uscsi_status || cmd->uscsi_resid) {
11230 
11231 		rval = -1;
11232 
11233 	} else if (sp->log_page.code != TAPE_SEQUENTIAL_PAGE) {
11234 
11235 		rval = -1;
11236 	}
11237 
11238 	prm = &sp->param[0];
11239 
11240 	for (ix = 0; rval == 0 && ix < TAPE_SEQUENTIAL_PAGE_PARA; ix++) {
11241 
11242 		if (prm->log_param.length == 0) {
11243 			break;
11244 		}
11245 
11246 		parameter = (((prm->log_param.pc_hi << 8) & 0xff00) +
11247 			(prm->log_param.pc_lo & 0xff));
11248 
11249 		if (parameter == SEQUENTIAL_NEED_CLN) {
11250 
11251 			rval = MTF_TAPE_CLN_SUPPORTED;
11252 			if (prm->param_value[prm->log_param.length - 1]) {
11253 
11254 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11255 					    "sequential log says head dirty\n");
11256 				rval |= MTF_TAPE_HEAD_DIRTY;
11257 			}
11258 		}
11259 		prm = (struct log_sequential_page_parameter *)
11260 			&prm->param_value[prm->log_param.length];
11261 	}
11262 
11263 	kmem_free(cmd, sizeof (struct uscsi_cmd));
11264 	kmem_free(sp,  sizeof (struct log_sequential_page));
11265 
11266 	return (rval);
11267 }
11268 
11269 
11270 static int
11271 st_check_alert_clean_bit(dev_t dev)
11272 {
11273 	struct st_tape_alert *ta;
11274 	struct uscsi_cmd *com;
11275 	unsigned ix, length;
11276 	int rval;
11277 	ushort_t parameter;
11278 	char cdb[CDB_GROUP1] = {
11279 		SCMD_LOG_SENSE_G1,
11280 		0,
11281 		TAPE_ALERT_PAGE | CURRENT_THRESHOLD_VALUES,
11282 		0,
11283 		0,
11284 		0,
11285 		0,
11286 		(char)(sizeof (struct st_tape_alert) >> 8),
11287 		(char)(sizeof (struct st_tape_alert)),
11288 		0
11289 	};
11290 
11291 	GET_SOFT_STATE(dev);
11292 
11293 	com = kmem_zalloc(sizeof (struct uscsi_cmd), KM_SLEEP);
11294 	ta  = kmem_zalloc(sizeof (struct st_tape_alert), KM_SLEEP);
11295 
11296 	com->uscsi_cdb = cdb;
11297 	com->uscsi_cdblen = CDB_GROUP1;
11298 	com->uscsi_bufaddr = (caddr_t)ta;
11299 	com->uscsi_buflen = sizeof (struct st_tape_alert);
11300 	com->uscsi_flags =
11301 		USCSI_DIAGNOSE | USCSI_SILENT | USCSI_READ | USCSI_RQENABLE;
11302 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
11303 
11304 	rval = st_ioctl_cmd(dev, com, UIO_SYSSPACE, UIO_SYSSPACE, UIO_SYSSPACE);
11305 
11306 	if (rval || com->uscsi_status || com->uscsi_resid) {
11307 
11308 		rval = -1; /* uscsi-command failed */
11309 
11310 	} else if (ta->log_page.code != TAPE_ALERT_PAGE) {
11311 
11312 		ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11313 		"Not Alert Log Page returned 0x%X\n", ta->log_page.code);
11314 		rval = -1;
11315 	}
11316 
11317 	length = (ta->log_page.length_hi << 8) + ta->log_page.length_lo;
11318 
11319 
11320 	if (length != TAPE_ALERT_PARAMETER_LENGTH) {
11321 
11322 		ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11323 		    "TapeAlert length %d\n", length);
11324 	}
11325 
11326 
11327 	for (ix = 0; ix < TAPE_ALERT_MAX_PARA; ix++) {
11328 
11329 		/*
11330 		 * if rval is bad before the first pass don't bother
11331 		 */
11332 		if (ix == 0 && rval != 0) {
11333 
11334 			break;
11335 		}
11336 
11337 		parameter = ((ta->param[ix].log_param.pc_hi << 8) +
11338 			ta->param[ix].log_param.pc_lo);
11339 
11340 		/*
11341 		 * check to see if current parameter is of interest.
11342 		 * CLEAN_FOR_ERRORS is vendor specific to 9840 9940 stk's.
11343 		 */
11344 		if ((parameter == CLEAN_NOW) ||
11345 		    (parameter == CLEAN_PERIODIC) ||
11346 		    ((parameter == CLEAN_FOR_ERRORS) &&
11347 		    (un->un_dp->type == ST_TYPE_STK9840))) {
11348 
11349 			rval = MTF_TAPE_CLN_SUPPORTED;
11350 
11351 			if (ta->param[ix].param_value & 1) {
11352 
11353 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11354 					    "alert_page drive needs clean %d\n",
11355 					    parameter);
11356 				un->un_HeadClean |= TAPE_ALERT_STILL_DIRTY;
11357 				rval |= MTF_TAPE_HEAD_DIRTY;
11358 			}
11359 
11360 		} else if (parameter == CLEANING_MEDIA) {
11361 
11362 			if (ta->param[ix].param_value & 1) {
11363 
11364 				ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11365 					    "alert_page drive was cleaned\n");
11366 				un->un_HeadClean &= ~TAPE_ALERT_STILL_DIRTY;
11367 			}
11368 		}
11369 
11370 	}
11371 
11372 	/*
11373 	 * Report it as dirty till we see it cleaned
11374 	 */
11375 	if (un->un_HeadClean & TAPE_ALERT_STILL_DIRTY) {
11376 
11377 		ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11378 			    "alert_page still dirty\n");
11379 		rval |= MTF_TAPE_HEAD_DIRTY;
11380 	}
11381 
11382 	kmem_free(com, sizeof (struct uscsi_cmd));
11383 	kmem_free(ta,  sizeof (struct st_tape_alert));
11384 
11385 	return (rval);
11386 }
11387 
11388 
11389 static int
11390 st_check_sense_clean_bit(dev_t dev)
11391 {
11392 	uchar_t *sensep;
11393 	char cdb[CDB_GROUP0];
11394 	struct uscsi_cmd *com;
11395 	ushort_t byte_pos;
11396 	uchar_t bit_mask;
11397 	unsigned length;
11398 	int index;
11399 	int rval;
11400 
11401 	GET_SOFT_STATE(dev);
11402 
11403 	/*
11404 	 * Since this tape does not support Tape Alert,
11405 	 * we now try to get the cleanbit status via
11406 	 * Request Sense.
11407 	 */
11408 
11409 	if ((un->un_dp->options & ST_CLN_MASK) == ST_CLN_TYPE_1) {
11410 
11411 		index = 0;
11412 
11413 	} else if ((un->un_dp->options & ST_CLN_MASK) == ST_CLN_TYPE_2) {
11414 
11415 		index = 1;
11416 
11417 	} else if ((un->un_dp->options & ST_CLN_MASK) == ST_CLN_TYPE_3) {
11418 
11419 		index = 2;
11420 
11421 	} else {
11422 
11423 		return (-1);
11424 	}
11425 
11426 	byte_pos  = st_cln_bit_position[index].cln_bit_byte;
11427 	bit_mask  = st_cln_bit_position[index].cln_bit_mask;
11428 	length = byte_pos + 1;
11429 
11430 	com    = kmem_zalloc(sizeof (struct uscsi_cmd), KM_SLEEP);
11431 	sensep = kmem_zalloc(length, KM_SLEEP);
11432 
11433 	cdb[0] = SCMD_REQUEST_SENSE;
11434 	cdb[1] = 0;
11435 	cdb[2] = 0;
11436 	cdb[3] = 0;
11437 	cdb[4] = (char)length;
11438 	cdb[5] = 0;
11439 
11440 	com->uscsi_cdb = cdb;
11441 	com->uscsi_cdblen = CDB_GROUP0;
11442 	com->uscsi_bufaddr = (caddr_t)sensep;
11443 	com->uscsi_buflen = length;
11444 	com->uscsi_flags =
11445 		USCSI_DIAGNOSE | USCSI_SILENT | USCSI_READ | USCSI_RQENABLE;
11446 	com->uscsi_timeout = un->un_dp->non_motion_timeout;
11447 
11448 	rval = st_ioctl_cmd(dev, com, UIO_SYSSPACE, UIO_SYSSPACE,
11449 			UIO_SYSSPACE);
11450 
11451 	if (rval || com->uscsi_status || com->uscsi_resid) {
11452 
11453 		rval = -1;
11454 
11455 	} else {
11456 
11457 		rval = MTF_TAPE_CLN_SUPPORTED;
11458 		if ((sensep[byte_pos] & bit_mask) == bit_mask) {
11459 
11460 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11461 				    "sense data says head dirty\n");
11462 			rval |= MTF_TAPE_HEAD_DIRTY;
11463 		}
11464 	}
11465 
11466 	kmem_free(com, sizeof (struct uscsi_cmd));
11467 	kmem_free(sensep, length);
11468 	return (rval);
11469 }
11470 
11471 /*
11472  * st_clear_unit_attention
11473  *
11474  *  	run test unit ready's to clear out outstanding
11475  * 	unit attentions.
11476  * 	returns zero for SUCCESS or the errno from st_cmd call
11477  */
11478 static int
11479 st_clear_unit_attentions(dev_t dev_instance, int max_trys)
11480 {
11481 	int	i    = 0;
11482 	int	rval;
11483 
11484 	do {
11485 		rval = st_cmd(dev_instance, SCMD_TEST_UNIT_READY, 0, SYNC_CMD);
11486 	} while ((rval != 0) && (rval != ENXIO) && (++i < max_trys));
11487 	return (rval);
11488 }
11489 
11490 static void
11491 st_calculate_timeouts(struct scsi_tape *un)
11492 {
11493 	if (un->un_dp->non_motion_timeout == 0) {
11494 		if (un->un_dp->options & ST_LONG_TIMEOUTS) {
11495 			un->un_dp->non_motion_timeout =
11496 				st_io_time * st_long_timeout_x;
11497 		} else {
11498 			un->un_dp->non_motion_timeout = (ushort_t)st_io_time;
11499 		}
11500 	}
11501 
11502 	if (un->un_dp->io_timeout == 0) {
11503 		if (un->un_dp->options & ST_LONG_TIMEOUTS) {
11504 			un->un_dp->io_timeout = st_io_time * st_long_timeout_x;
11505 		} else {
11506 			un->un_dp->io_timeout = (ushort_t)st_io_time;
11507 		}
11508 	}
11509 
11510 	if (un->un_dp->rewind_timeout == 0) {
11511 		if (un->un_dp->options & ST_LONG_TIMEOUTS) {
11512 			un->un_dp->rewind_timeout =
11513 				st_space_time * st_long_timeout_x;
11514 		} else {
11515 			un->un_dp->rewind_timeout = (ushort_t)st_space_time;
11516 		}
11517 	}
11518 
11519 	if (un->un_dp->space_timeout == 0) {
11520 		if (un->un_dp->options & ST_LONG_TIMEOUTS) {
11521 			un->un_dp->space_timeout =
11522 				st_space_time * st_long_timeout_x;
11523 		} else {
11524 			un->un_dp->space_timeout = (ushort_t)st_space_time;
11525 		}
11526 	}
11527 
11528 	if (un->un_dp->load_timeout == 0) {
11529 		if (un->un_dp->options & ST_LONG_TIMEOUTS) {
11530 			un->un_dp->load_timeout =
11531 				st_space_time * st_long_timeout_x;
11532 		} else {
11533 			un->un_dp->load_timeout = (ushort_t)st_space_time;
11534 		}
11535 	}
11536 
11537 	if (un->un_dp->unload_timeout == 0) {
11538 		if (un->un_dp->options & ST_LONG_TIMEOUTS) {
11539 			un->un_dp->unload_timeout =
11540 				st_space_time * st_long_timeout_x;
11541 		} else {
11542 			un->un_dp->unload_timeout = (ushort_t)st_space_time;
11543 		}
11544 	}
11545 
11546 	if (un->un_dp->erase_timeout == 0) {
11547 		if (un->un_dp->options & ST_LONG_ERASE) {
11548 			un->un_dp->erase_timeout =
11549 				st_space_time * st_long_space_time_x;
11550 		} else {
11551 			un->un_dp->erase_timeout = (ushort_t)st_space_time;
11552 		}
11553 	}
11554 }
11555 
11556 #if defined(__i386) || defined(__amd64)
11557 
11558 /*
11559  * release contig_mem and wake up waiting thread, if any
11560  */
11561 static void
11562 st_release_contig_mem(struct scsi_tape *un, struct contig_mem *cp)
11563 {
11564 	mutex_enter(ST_MUTEX);
11565 
11566 	cp->cm_next = un->un_contig_mem;
11567 	un->un_contig_mem = cp;
11568 	un->un_contig_mem_available_num++;
11569 	cv_broadcast(&un->un_contig_mem_cv);
11570 
11571 	mutex_exit(ST_MUTEX);
11572 }
11573 
11574 /*
11575  * St_get_contig_mem will return a contig_mem if there is one available
11576  * in current system. Otherwise, it will try to alloc one, if the total
11577  * number of contig_mem is within st_max_contig_mem_num.
11578  * It will sleep, if allowed by caller or return NULL, if no contig_mem
11579  * is available for now.
11580  */
11581 static struct contig_mem *
11582 st_get_contig_mem(struct scsi_tape *un, size_t len, int alloc_flags)
11583 {
11584 	size_t rlen;
11585 	struct contig_mem *cp = NULL;
11586 	ddi_acc_handle_t acc_hdl;
11587 	caddr_t addr;
11588 	int big_enough = 0;
11589 	int (*dma_alloc_cb)() = (alloc_flags == KM_SLEEP) ?
11590 		DDI_DMA_SLEEP : DDI_DMA_DONTWAIT;
11591 
11592 	/* Try to get one available contig_mem */
11593 	mutex_enter(ST_MUTEX);
11594 	if (un->un_contig_mem_available_num > 0) {
11595 		ST_GET_CONTIG_MEM_HEAD(un, cp, len, big_enough);
11596 	} else if (un->un_contig_mem_total_num < st_max_contig_mem_num) {
11597 		/*
11598 		 * we failed to get one. we're going to
11599 		 * alloc one more contig_mem for this I/O
11600 		 */
11601 		mutex_exit(ST_MUTEX);
11602 		cp = (struct contig_mem *)kmem_zalloc(
11603 		    sizeof (struct contig_mem) + biosize(),
11604 		    alloc_flags);
11605 		if (cp == NULL) {
11606 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11607 			    "alloc contig_mem failure\n");
11608 			return (NULL); /* cannot get one */
11609 		}
11610 		cp->cm_bp = (struct buf *)
11611 		    (((caddr_t)cp) + sizeof (struct contig_mem));
11612 		bioinit(cp->cm_bp);
11613 		mutex_enter(ST_MUTEX);
11614 		un->un_contig_mem_total_num++; /* one more available */
11615 	} else {
11616 		/*
11617 		 * we failed to get one and we're NOT allowed to
11618 		 * alloc more contig_mem
11619 		 */
11620 		if (alloc_flags == KM_SLEEP) {
11621 			while (un->un_contig_mem_available_num <= 0) {
11622 				cv_wait(&un->un_contig_mem_cv,
11623 				    ST_MUTEX);
11624 			}
11625 			ST_GET_CONTIG_MEM_HEAD(un, cp, len, big_enough);
11626 		} else {
11627 			mutex_exit(ST_MUTEX);
11628 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11629 			    "alloc contig_mem failure\n");
11630 			return (NULL); /* cannot get one */
11631 		}
11632 	}
11633 	mutex_exit(ST_MUTEX);
11634 
11635 	/* We need to check if this block of mem is big enough for this I/O */
11636 	if (cp->cm_len < len) {
11637 		/* not big enough, need to alloc a new one */
11638 		if (ddi_dma_mem_alloc(un->un_contig_mem_hdl, len, &st_acc_attr,
11639 			DDI_DMA_STREAMING, dma_alloc_cb, NULL,
11640 			&addr, &rlen, &acc_hdl) != DDI_SUCCESS) {
11641 			ST_DEBUG2(ST_DEVINFO, st_label, SCSI_DEBUG,
11642 			    "alloc contig_mem failure: not enough mem\n");
11643 			st_release_contig_mem(un, cp);
11644 			cp = NULL;
11645 		} else {
11646 			if (cp->cm_addr) {
11647 				/* release previous one before attach new one */
11648 				ddi_dma_mem_free(&cp->cm_acc_hdl);
11649 			}
11650 			mutex_enter(ST_MUTEX);
11651 			un->un_max_contig_mem_len =
11652 			    un->un_max_contig_mem_len >= len ?
11653 			    un->un_max_contig_mem_len : len;
11654 			mutex_exit(ST_MUTEX);
11655 
11656 			/* attach new mem to this cp */
11657 			cp->cm_addr = addr;
11658 			cp->cm_acc_hdl = acc_hdl;
11659 			cp->cm_len = len;
11660 
11661 			goto alloc_ok; /* get one usable cp */
11662 		}
11663 	} else {
11664 		goto alloc_ok; /* get one usable cp */
11665 	}
11666 
11667 	/* cannot find/alloc a usable cp, when we get here */
11668 
11669 	if ((un->un_max_contig_mem_len < len) ||
11670 	    (alloc_flags != KM_SLEEP)) {
11671 		return (NULL);
11672 	}
11673 
11674 	/*
11675 	 * we're allowed to sleep, and there is one big enough
11676 	 * contig mem in the system, which is currently in use,
11677 	 * wait for it...
11678 	 */
11679 	mutex_enter(ST_MUTEX);
11680 	big_enough = 1;
11681 	do {
11682 		cv_wait(&un->un_contig_mem_cv, ST_MUTEX);
11683 		ST_GET_CONTIG_MEM_HEAD(un, cp, len, big_enough);
11684 	} while (cp == NULL);
11685 	mutex_exit(ST_MUTEX);
11686 
11687 	/* we get the big enough contig mem, finally */
11688 
11689 alloc_ok:
11690 	/* init bp attached to this cp */
11691 	bioreset(cp->cm_bp);
11692 	cp->cm_bp->b_un.b_addr = cp->cm_addr;
11693 	cp->cm_bp->b_private = (void *)cp;
11694 
11695 	return (cp);
11696 }
11697 
11698 /*
11699  * this is the biodone func for the bp used in big block I/O
11700  */
11701 static int
11702 st_bigblk_xfer_done(struct buf *bp)
11703 {
11704 	struct contig_mem *cp;
11705 	struct buf *orig_bp;
11706 	int remapped = 0;
11707 	int ioerr;
11708 	struct scsi_tape *un;
11709 
11710 	/* sanity check */
11711 	if (bp == NULL) {
11712 		return (DDI_FAILURE);
11713 	}
11714 
11715 	un = ddi_get_soft_state(st_state, MTUNIT(bp->b_edev));
11716 	if (un == NULL) {
11717 		return (DDI_FAILURE);
11718 	}
11719 
11720 	cp = (struct contig_mem *)bp->b_private;
11721 	orig_bp = cp->cm_bp; /* get back the bp we have replaced */
11722 	cp->cm_bp = bp;
11723 
11724 	/* special handling for special I/O */
11725 	if (cp->cm_use_sbuf) {
11726 		ASSERT(un->un_sbuf_busy);
11727 		un->un_sbufp = orig_bp;
11728 		cp->cm_use_sbuf = 0;
11729 	}
11730 
11731 	orig_bp->b_resid = bp->b_resid;
11732 	ioerr = geterror(bp);
11733 	if (ioerr != 0) {
11734 		bioerror(orig_bp, ioerr);
11735 	} else if (orig_bp->b_flags & B_READ) {
11736 		/* copy data back to original bp */
11737 		if (orig_bp->b_flags & (B_PHYS | B_PAGEIO)) {
11738 			bp_mapin(orig_bp);
11739 			remapped = 1;
11740 		}
11741 		bcopy(bp->b_un.b_addr, orig_bp->b_un.b_addr,
11742 			bp->b_bcount - bp->b_resid);
11743 		if (remapped)
11744 			bp_mapout(orig_bp);
11745 	}
11746 
11747 	st_release_contig_mem(un, cp);
11748 
11749 	biodone(orig_bp);
11750 
11751 	return (DDI_SUCCESS);
11752 }
11753 
11754 /*
11755  * We use this func to replace original bp that may not be able to do I/O
11756  * in big block size with one that can
11757  */
11758 static struct buf *
11759 st_get_bigblk_bp(struct buf *bp)
11760 {
11761 	struct contig_mem *cp;
11762 	struct scsi_tape *un;
11763 	struct buf *cont_bp;
11764 	int remapped = 0;
11765 
11766 	un = ddi_get_soft_state(st_state, MTUNIT(bp->b_edev));
11767 	if (un == NULL) {
11768 		return (bp);
11769 	}
11770 
11771 	/* try to get one contig_mem */
11772 	cp = st_get_contig_mem(un, bp->b_bcount, KM_SLEEP);
11773 	if (!cp) {
11774 		scsi_log(ST_DEVINFO, st_label, CE_WARN,
11775 			"Cannot alloc contig buf for I/O for %lu blk size",
11776 			bp->b_bcount);
11777 		return (bp);
11778 	}
11779 	cont_bp = cp->cm_bp;
11780 	cp->cm_bp = bp;
11781 
11782 	/* make sure that we "are" using un_sbufp for special I/O */
11783 	if (bp == un->un_sbufp) {
11784 		ASSERT(un->un_sbuf_busy);
11785 		un->un_sbufp = cont_bp;
11786 		cp->cm_use_sbuf = 1;
11787 	}
11788 
11789 	/* clone bp */
11790 	cont_bp->b_bcount = bp->b_bcount;
11791 	cont_bp->b_resid = bp->b_resid;
11792 	cont_bp->b_iodone = st_bigblk_xfer_done;
11793 	cont_bp->b_file = bp->b_file;
11794 	cont_bp->b_offset = bp->b_offset;
11795 	cont_bp->b_dip = bp->b_dip;
11796 	cont_bp->b_error = 0;
11797 	cont_bp->b_proc = NULL;
11798 	cont_bp->b_flags = bp->b_flags & ~(B_PAGEIO | B_PHYS | B_SHADOW);
11799 	cont_bp->b_shadow = NULL;
11800 	cont_bp->b_pages = NULL;
11801 	cont_bp->b_edev = bp->b_edev;
11802 	cont_bp->b_dev = bp->b_dev;
11803 	cont_bp->b_lblkno = bp->b_lblkno;
11804 	cont_bp->b_forw = bp->b_forw;
11805 	cont_bp->b_back = bp->b_back;
11806 	cont_bp->av_forw = bp->av_forw;
11807 	cont_bp->av_back = bp->av_back;
11808 	cont_bp->b_bufsize = bp->b_bufsize;
11809 
11810 	/* get data in original bp */
11811 	if (bp->b_flags & B_WRITE) {
11812 		if (bp->b_flags & (B_PHYS | B_PAGEIO)) {
11813 			bp_mapin(bp);
11814 			remapped = 1;
11815 		}
11816 		bcopy(bp->b_un.b_addr, cont_bp->b_un.b_addr, bp->b_bcount);
11817 		if (remapped)
11818 			bp_mapout(bp);
11819 	}
11820 
11821 	return (cont_bp);
11822 }
11823 #endif
11824