xref: /linux/drivers/scsi/st.c (revision 3b27d13940c3710a1128527c43719cb0bb05d73b)
1 /*
2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
3    file Documentation/scsi/st.txt for more information.
4 
5    History:
6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
7    Contribution and ideas from several people including (in alphabetical
8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
10    Michael Schaefer, J"org Weule, and Eric Youngdale.
11 
12    Copyright 1992 - 2010 Kai Makisara
13    email Kai.Makisara@kolumbus.fi
14 
15    Some small formal changes - aeb, 950809
16 
17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
18  */
19 
20 static const char *verstr = "20101219";
21 
22 #include <linux/module.h>
23 
24 #include <linux/fs.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/mm.h>
28 #include <linux/init.h>
29 #include <linux/string.h>
30 #include <linux/slab.h>
31 #include <linux/errno.h>
32 #include <linux/mtio.h>
33 #include <linux/cdrom.h>
34 #include <linux/ioctl.h>
35 #include <linux/fcntl.h>
36 #include <linux/spinlock.h>
37 #include <linux/blkdev.h>
38 #include <linux/moduleparam.h>
39 #include <linux/cdev.h>
40 #include <linux/idr.h>
41 #include <linux/delay.h>
42 #include <linux/mutex.h>
43 
44 #include <asm/uaccess.h>
45 #include <asm/dma.h>
46 
47 #include <scsi/scsi.h>
48 #include <scsi/scsi_dbg.h>
49 #include <scsi/scsi_device.h>
50 #include <scsi/scsi_driver.h>
51 #include <scsi/scsi_eh.h>
52 #include <scsi/scsi_host.h>
53 #include <scsi/scsi_ioctl.h>
54 #include <scsi/sg.h>
55 
56 
57 /* The driver prints some debugging information on the console if DEBUG
58    is defined and non-zero. */
59 #define DEBUG 1
60 #define NO_DEBUG 0
61 
62 #define ST_DEB_MSG  KERN_NOTICE
63 #if DEBUG
64 /* The message level for the debug messages is currently set to KERN_NOTICE
65    so that people can easily see the messages. Later when the debugging messages
66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
67 #define DEB(a) a
68 #define DEBC(a) if (debugging) { a ; }
69 #else
70 #define DEB(a)
71 #define DEBC(a)
72 #endif
73 
74 #define ST_KILOBYTE 1024
75 
76 #include "st_options.h"
77 #include "st.h"
78 
79 static int buffer_kbs;
80 static int max_sg_segs;
81 static int try_direct_io = TRY_DIRECT_IO;
82 static int try_rdio = 1;
83 static int try_wdio = 1;
84 static int debug_flag;
85 
86 static struct class st_sysfs_class;
87 static const struct attribute_group *st_dev_groups[];
88 
89 MODULE_AUTHOR("Kai Makisara");
90 MODULE_DESCRIPTION("SCSI tape (st) driver");
91 MODULE_LICENSE("GPL");
92 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
93 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
94 
95 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
96  * of sysfs parameters (which module_param doesn't yet support).
97  * Sysfs parameters defined explicitly later.
98  */
99 module_param_named(buffer_kbs, buffer_kbs, int, 0);
100 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
101 module_param_named(max_sg_segs, max_sg_segs, int, 0);
102 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
103 module_param_named(try_direct_io, try_direct_io, int, 0);
104 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
105 module_param_named(debug_flag, debug_flag, int, 0);
106 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
107 
108 
109 /* Extra parameters for testing */
110 module_param_named(try_rdio, try_rdio, int, 0);
111 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
112 module_param_named(try_wdio, try_wdio, int, 0);
113 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
114 
115 #ifndef MODULE
116 static int write_threshold_kbs;  /* retained for compatibility */
117 static struct st_dev_parm {
118 	char *name;
119 	int *val;
120 } parms[] __initdata = {
121 	{
122 		"buffer_kbs", &buffer_kbs
123 	},
124 	{       /* Retained for compatibility with 2.4 */
125 		"write_threshold_kbs", &write_threshold_kbs
126 	},
127 	{
128 		"max_sg_segs", NULL
129 	},
130 	{
131 		"try_direct_io", &try_direct_io
132 	},
133 	{
134 		"debug_flag", &debug_flag
135 	}
136 };
137 #endif
138 
139 /* Restrict the number of modes so that names for all are assigned */
140 #if ST_NBR_MODES > 16
141 #error "Maximum number of modes is 16"
142 #endif
143 /* Bit reversed order to get same names for same minors with all
144    mode counts */
145 static const char *st_formats[] = {
146 	"",  "r", "k", "s", "l", "t", "o", "u",
147 	"m", "v", "p", "x", "a", "y", "q", "z"};
148 
149 /* The default definitions have been moved to st_options.h */
150 
151 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
152 
153 /* The buffer size should fit into the 24 bits for length in the
154    6-byte SCSI read and write commands. */
155 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
156 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
157 #endif
158 
159 static int debugging = DEBUG;
160 
161 #define MAX_RETRIES 0
162 #define MAX_WRITE_RETRIES 0
163 #define MAX_READY_RETRIES 0
164 #define NO_TAPE  NOT_READY
165 
166 #define ST_TIMEOUT (900 * HZ)
167 #define ST_LONG_TIMEOUT (14000 * HZ)
168 
169 /* Remove mode bits and auto-rewind bit (7) */
170 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
171     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
172 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
173 
174 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
175 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
176   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
177 
178 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
179    24 bits) */
180 #define SET_DENS_AND_BLK 0x10001
181 
182 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
183 static int st_max_sg_segs = ST_MAX_SG;
184 
185 static int modes_defined;
186 
187 static int enlarge_buffer(struct st_buffer *, int, int);
188 static void clear_buffer(struct st_buffer *);
189 static void normalize_buffer(struct st_buffer *);
190 static int append_to_buffer(const char __user *, struct st_buffer *, int);
191 static int from_buffer(struct st_buffer *, char __user *, int);
192 static void move_buffer_data(struct st_buffer *, int);
193 
194 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
195 			      unsigned long, size_t, int);
196 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
197 
198 static int st_probe(struct device *);
199 static int st_remove(struct device *);
200 
201 static int do_create_sysfs_files(void);
202 static void do_remove_sysfs_files(void);
203 
204 static struct scsi_driver st_template = {
205 	.gendrv = {
206 		.name		= "st",
207 		.owner		= THIS_MODULE,
208 		.probe		= st_probe,
209 		.remove		= st_remove,
210 	},
211 };
212 
213 static int st_compression(struct scsi_tape *, int);
214 
215 static int find_partition(struct scsi_tape *);
216 static int switch_partition(struct scsi_tape *);
217 
218 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
219 
220 static void scsi_tape_release(struct kref *);
221 
222 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
223 
224 static DEFINE_MUTEX(st_ref_mutex);
225 static DEFINE_SPINLOCK(st_index_lock);
226 static DEFINE_SPINLOCK(st_use_lock);
227 static DEFINE_IDR(st_index_idr);
228 
229 
230 
231 #include "osst_detect.h"
232 #ifndef SIGS_FROM_OSST
233 #define SIGS_FROM_OSST \
234 	{"OnStream", "SC-", "", "osst"}, \
235 	{"OnStream", "DI-", "", "osst"}, \
236 	{"OnStream", "DP-", "", "osst"}, \
237 	{"OnStream", "USB", "", "osst"}, \
238 	{"OnStream", "FW-", "", "osst"}
239 #endif
240 
241 static struct scsi_tape *scsi_tape_get(int dev)
242 {
243 	struct scsi_tape *STp = NULL;
244 
245 	mutex_lock(&st_ref_mutex);
246 	spin_lock(&st_index_lock);
247 
248 	STp = idr_find(&st_index_idr, dev);
249 	if (!STp) goto out;
250 
251 	kref_get(&STp->kref);
252 
253 	if (!STp->device)
254 		goto out_put;
255 
256 	if (scsi_device_get(STp->device))
257 		goto out_put;
258 
259 	goto out;
260 
261 out_put:
262 	kref_put(&STp->kref, scsi_tape_release);
263 	STp = NULL;
264 out:
265 	spin_unlock(&st_index_lock);
266 	mutex_unlock(&st_ref_mutex);
267 	return STp;
268 }
269 
270 static void scsi_tape_put(struct scsi_tape *STp)
271 {
272 	struct scsi_device *sdev = STp->device;
273 
274 	mutex_lock(&st_ref_mutex);
275 	kref_put(&STp->kref, scsi_tape_release);
276 	scsi_device_put(sdev);
277 	mutex_unlock(&st_ref_mutex);
278 }
279 
280 struct st_reject_data {
281 	char *vendor;
282 	char *model;
283 	char *rev;
284 	char *driver_hint; /* Name of the correct driver, NULL if unknown */
285 };
286 
287 static struct st_reject_data reject_list[] = {
288 	/* {"XXX", "Yy-", "", NULL},  example */
289 	SIGS_FROM_OSST,
290 	{NULL, }};
291 
292 /* If the device signature is on the list of incompatible drives, the
293    function returns a pointer to the name of the correct driver (if known) */
294 static char * st_incompatible(struct scsi_device* SDp)
295 {
296 	struct st_reject_data *rp;
297 
298 	for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
299 		if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
300 		    !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
301 		    !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
302 			if (rp->driver_hint)
303 				return rp->driver_hint;
304 			else
305 				return "unknown";
306 		}
307 	return NULL;
308 }
309 
310 
311 static inline char *tape_name(struct scsi_tape *tape)
312 {
313 	return tape->disk->disk_name;
314 }
315 
316 #define st_printk(prefix, t, fmt, a...) \
317 	sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
318 #ifdef DEBUG
319 #define DEBC_printk(t, fmt, a...) \
320 	if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
321 #else
322 #define DEBC_printk(t, fmt, a...)
323 #endif
324 
325 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
326 {
327 	const u8 *ucp;
328 	const u8 *sense = SRpnt->sense;
329 
330 	s->have_sense = scsi_normalize_sense(SRpnt->sense,
331 				SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
332 	s->flags = 0;
333 
334 	if (s->have_sense) {
335 		s->deferred = 0;
336 		s->remainder_valid =
337 			scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
338 		switch (sense[0] & 0x7f) {
339 		case 0x71:
340 			s->deferred = 1;
341 		case 0x70:
342 			s->fixed_format = 1;
343 			s->flags = sense[2] & 0xe0;
344 			break;
345 		case 0x73:
346 			s->deferred = 1;
347 		case 0x72:
348 			s->fixed_format = 0;
349 			ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
350 			s->flags = ucp ? (ucp[3] & 0xe0) : 0;
351 			break;
352 		}
353 	}
354 }
355 
356 
357 /* Convert the result to success code */
358 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
359 {
360 	int result = SRpnt->result;
361 	u8 scode;
362 	DEB(const char *stp;)
363 	char *name = tape_name(STp);
364 	struct st_cmdstatus *cmdstatp;
365 
366 	if (!result)
367 		return 0;
368 
369 	cmdstatp = &STp->buffer->cmdstat;
370 	st_analyze_sense(SRpnt, cmdstatp);
371 
372 	if (cmdstatp->have_sense)
373 		scode = STp->buffer->cmdstat.sense_hdr.sense_key;
374 	else
375 		scode = 0;
376 
377 	DEB(
378 	if (debugging) {
379 		st_printk(ST_DEB_MSG, STp,
380 			    "Error: %x, cmd: %x %x %x %x %x %x\n", result,
381 			    SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
382 			    SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
383 		if (cmdstatp->have_sense)
384 			__scsi_print_sense(STp->device, name,
385 					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
386 	} ) /* end DEB */
387 	if (!debugging) { /* Abnormal conditions for tape */
388 		if (!cmdstatp->have_sense)
389 			st_printk(KERN_WARNING, STp,
390 			       "Error %x (driver bt 0x%x, host bt 0x%x).\n",
391 			       result, driver_byte(result), host_byte(result));
392 		else if (cmdstatp->have_sense &&
393 			 scode != NO_SENSE &&
394 			 scode != RECOVERED_ERROR &&
395 			 /* scode != UNIT_ATTENTION && */
396 			 scode != BLANK_CHECK &&
397 			 scode != VOLUME_OVERFLOW &&
398 			 SRpnt->cmd[0] != MODE_SENSE &&
399 			 SRpnt->cmd[0] != TEST_UNIT_READY) {
400 
401 			__scsi_print_sense(STp->device, name,
402 					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
403 		}
404 	}
405 
406 	if (cmdstatp->fixed_format &&
407 	    STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
408 		if (STp->cln_sense_value)
409 			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
410 					       STp->cln_sense_mask) == STp->cln_sense_value);
411 		else
412 			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
413 					       STp->cln_sense_mask) != 0);
414 	}
415 	if (cmdstatp->have_sense &&
416 	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
417 		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
418 
419 	STp->pos_unknown |= STp->device->was_reset;
420 
421 	if (cmdstatp->have_sense &&
422 	    scode == RECOVERED_ERROR
423 #if ST_RECOVERED_WRITE_FATAL
424 	    && SRpnt->cmd[0] != WRITE_6
425 	    && SRpnt->cmd[0] != WRITE_FILEMARKS
426 #endif
427 	    ) {
428 		STp->recover_count++;
429 		STp->recover_reg++;
430 
431 		DEB(
432 		if (debugging) {
433 			if (SRpnt->cmd[0] == READ_6)
434 				stp = "read";
435 			else if (SRpnt->cmd[0] == WRITE_6)
436 				stp = "write";
437 			else
438 				stp = "ioctl";
439 			st_printk(ST_DEB_MSG, STp,
440 				  "Recovered %s error (%d).\n",
441 				  stp, STp->recover_count);
442 		} ) /* end DEB */
443 
444 		if (cmdstatp->flags == 0)
445 			return 0;
446 	}
447 	return (-EIO);
448 }
449 
450 static struct st_request *st_allocate_request(struct scsi_tape *stp)
451 {
452 	struct st_request *streq;
453 
454 	streq = kzalloc(sizeof(*streq), GFP_KERNEL);
455 	if (streq)
456 		streq->stp = stp;
457 	else {
458 		st_printk(KERN_ERR, stp,
459 			  "Can't get SCSI request.\n");
460 		if (signal_pending(current))
461 			stp->buffer->syscall_result = -EINTR;
462 		else
463 			stp->buffer->syscall_result = -EBUSY;
464 	}
465 
466 	return streq;
467 }
468 
469 static void st_release_request(struct st_request *streq)
470 {
471 	kfree(streq);
472 }
473 
474 static void st_do_stats(struct scsi_tape *STp, struct request *req)
475 {
476 	ktime_t now;
477 
478 	now = ktime_get();
479 	if (req->cmd[0] == WRITE_6) {
480 		now = ktime_sub(now, STp->stats->write_time);
481 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
482 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
483 		atomic64_inc(&STp->stats->write_cnt);
484 		if (req->errors) {
485 			atomic64_add(atomic_read(&STp->stats->last_write_size)
486 				- STp->buffer->cmdstat.residual,
487 				&STp->stats->write_byte_cnt);
488 			if (STp->buffer->cmdstat.residual > 0)
489 				atomic64_inc(&STp->stats->resid_cnt);
490 		} else
491 			atomic64_add(atomic_read(&STp->stats->last_write_size),
492 				&STp->stats->write_byte_cnt);
493 	} else if (req->cmd[0] == READ_6) {
494 		now = ktime_sub(now, STp->stats->read_time);
495 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
496 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
497 		atomic64_inc(&STp->stats->read_cnt);
498 		if (req->errors) {
499 			atomic64_add(atomic_read(&STp->stats->last_read_size)
500 				- STp->buffer->cmdstat.residual,
501 				&STp->stats->read_byte_cnt);
502 			if (STp->buffer->cmdstat.residual > 0)
503 				atomic64_inc(&STp->stats->resid_cnt);
504 		} else
505 			atomic64_add(atomic_read(&STp->stats->last_read_size),
506 				&STp->stats->read_byte_cnt);
507 	} else {
508 		now = ktime_sub(now, STp->stats->other_time);
509 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
510 		atomic64_inc(&STp->stats->other_cnt);
511 	}
512 	atomic64_dec(&STp->stats->in_flight);
513 }
514 
515 static void st_scsi_execute_end(struct request *req, int uptodate)
516 {
517 	struct st_request *SRpnt = req->end_io_data;
518 	struct scsi_tape *STp = SRpnt->stp;
519 	struct bio *tmp;
520 
521 	STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
522 	STp->buffer->cmdstat.residual = req->resid_len;
523 
524 	st_do_stats(STp, req);
525 
526 	tmp = SRpnt->bio;
527 	if (SRpnt->waiting)
528 		complete(SRpnt->waiting);
529 
530 	blk_rq_unmap_user(tmp);
531 	__blk_put_request(req->q, req);
532 }
533 
534 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
535 			   int data_direction, void *buffer, unsigned bufflen,
536 			   int timeout, int retries)
537 {
538 	struct request *req;
539 	struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
540 	int err = 0;
541 	int write = (data_direction == DMA_TO_DEVICE);
542 	struct scsi_tape *STp = SRpnt->stp;
543 
544 	req = blk_get_request(SRpnt->stp->device->request_queue, write,
545 			      GFP_KERNEL);
546 	if (IS_ERR(req))
547 		return DRIVER_ERROR << 24;
548 
549 	blk_rq_set_block_pc(req);
550 	req->cmd_flags |= REQ_QUIET;
551 
552 	mdata->null_mapped = 1;
553 
554 	if (bufflen) {
555 		err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
556 				      GFP_KERNEL);
557 		if (err) {
558 			blk_put_request(req);
559 			return DRIVER_ERROR << 24;
560 		}
561 	}
562 
563 	atomic64_inc(&STp->stats->in_flight);
564 	if (cmd[0] == WRITE_6) {
565 		atomic_set(&STp->stats->last_write_size, bufflen);
566 		STp->stats->write_time = ktime_get();
567 	} else if (cmd[0] == READ_6) {
568 		atomic_set(&STp->stats->last_read_size, bufflen);
569 		STp->stats->read_time = ktime_get();
570 	} else {
571 		STp->stats->other_time = ktime_get();
572 	}
573 
574 	SRpnt->bio = req->bio;
575 	req->cmd_len = COMMAND_SIZE(cmd[0]);
576 	memset(req->cmd, 0, BLK_MAX_CDB);
577 	memcpy(req->cmd, cmd, req->cmd_len);
578 	req->sense = SRpnt->sense;
579 	req->sense_len = 0;
580 	req->timeout = timeout;
581 	req->retries = retries;
582 	req->end_io_data = SRpnt;
583 
584 	blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
585 	return 0;
586 }
587 
588 /* Do the scsi command. Waits until command performed if do_wait is true.
589    Otherwise write_behind_check() is used to check that the command
590    has finished. */
591 static struct st_request *
592 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
593 	   int bytes, int direction, int timeout, int retries, int do_wait)
594 {
595 	struct completion *waiting;
596 	struct rq_map_data *mdata = &STp->buffer->map_data;
597 	int ret;
598 
599 	/* if async, make sure there's no command outstanding */
600 	if (!do_wait && ((STp->buffer)->last_SRpnt)) {
601 		st_printk(KERN_ERR, STp,
602 			  "Async command already active.\n");
603 		if (signal_pending(current))
604 			(STp->buffer)->syscall_result = (-EINTR);
605 		else
606 			(STp->buffer)->syscall_result = (-EBUSY);
607 		return NULL;
608 	}
609 
610 	if (!SRpnt) {
611 		SRpnt = st_allocate_request(STp);
612 		if (!SRpnt)
613 			return NULL;
614 	}
615 
616 	/* If async IO, set last_SRpnt. This ptr tells write_behind_check
617 	   which IO is outstanding. It's nulled out when the IO completes. */
618 	if (!do_wait)
619 		(STp->buffer)->last_SRpnt = SRpnt;
620 
621 	waiting = &STp->wait;
622 	init_completion(waiting);
623 	SRpnt->waiting = waiting;
624 
625 	if (STp->buffer->do_dio) {
626 		mdata->page_order = 0;
627 		mdata->nr_entries = STp->buffer->sg_segs;
628 		mdata->pages = STp->buffer->mapped_pages;
629 	} else {
630 		mdata->page_order = STp->buffer->reserved_page_order;
631 		mdata->nr_entries =
632 			DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
633 		mdata->pages = STp->buffer->reserved_pages;
634 		mdata->offset = 0;
635 	}
636 
637 	memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
638 	STp->buffer->cmdstat.have_sense = 0;
639 	STp->buffer->syscall_result = 0;
640 
641 	ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
642 			      retries);
643 	if (ret) {
644 		/* could not allocate the buffer or request was too large */
645 		(STp->buffer)->syscall_result = (-EBUSY);
646 		(STp->buffer)->last_SRpnt = NULL;
647 	} else if (do_wait) {
648 		wait_for_completion(waiting);
649 		SRpnt->waiting = NULL;
650 		(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
651 	}
652 
653 	return SRpnt;
654 }
655 
656 
657 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
658    write has been correct but EOM early warning reached, -EIO if write ended in
659    error or zero if write successful. Asynchronous writes are used only in
660    variable block mode. */
661 static int write_behind_check(struct scsi_tape * STp)
662 {
663 	int retval = 0;
664 	struct st_buffer *STbuffer;
665 	struct st_partstat *STps;
666 	struct st_cmdstatus *cmdstatp;
667 	struct st_request *SRpnt;
668 
669 	STbuffer = STp->buffer;
670 	if (!STbuffer->writing)
671 		return 0;
672 
673 	DEB(
674 	if (STp->write_pending)
675 		STp->nbr_waits++;
676 	else
677 		STp->nbr_finished++;
678 	) /* end DEB */
679 
680 	wait_for_completion(&(STp->wait));
681 	SRpnt = STbuffer->last_SRpnt;
682 	STbuffer->last_SRpnt = NULL;
683 	SRpnt->waiting = NULL;
684 
685 	(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
686 	st_release_request(SRpnt);
687 
688 	STbuffer->buffer_bytes -= STbuffer->writing;
689 	STps = &(STp->ps[STp->partition]);
690 	if (STps->drv_block >= 0) {
691 		if (STp->block_size == 0)
692 			STps->drv_block++;
693 		else
694 			STps->drv_block += STbuffer->writing / STp->block_size;
695 	}
696 
697 	cmdstatp = &STbuffer->cmdstat;
698 	if (STbuffer->syscall_result) {
699 		retval = -EIO;
700 		if (cmdstatp->have_sense && !cmdstatp->deferred &&
701 		    (cmdstatp->flags & SENSE_EOM) &&
702 		    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
703 		     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
704 			/* EOM at write-behind, has all data been written? */
705 			if (!cmdstatp->remainder_valid ||
706 			    cmdstatp->uremainder64 == 0)
707 				retval = -ENOSPC;
708 		}
709 		if (retval == -EIO)
710 			STps->drv_block = -1;
711 	}
712 	STbuffer->writing = 0;
713 
714 	DEB(if (debugging && retval)
715 		    st_printk(ST_DEB_MSG, STp,
716 				"Async write error %x, return value %d.\n",
717 				STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
718 
719 	return retval;
720 }
721 
722 
723 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
724    it messes up the block number). */
725 static int cross_eof(struct scsi_tape * STp, int forward)
726 {
727 	struct st_request *SRpnt;
728 	unsigned char cmd[MAX_COMMAND_SIZE];
729 
730 	cmd[0] = SPACE;
731 	cmd[1] = 0x01;		/* Space FileMarks */
732 	if (forward) {
733 		cmd[2] = cmd[3] = 0;
734 		cmd[4] = 1;
735 	} else
736 		cmd[2] = cmd[3] = cmd[4] = 0xff;	/* -1 filemarks */
737 	cmd[5] = 0;
738 
739 	DEBC_printk(STp, "Stepping over filemark %s.\n",
740 		    forward ? "forward" : "backward");
741 
742 	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
743 			   STp->device->request_queue->rq_timeout,
744 			   MAX_RETRIES, 1);
745 	if (!SRpnt)
746 		return (STp->buffer)->syscall_result;
747 
748 	st_release_request(SRpnt);
749 	SRpnt = NULL;
750 
751 	if ((STp->buffer)->cmdstat.midlevel_result != 0)
752 		st_printk(KERN_ERR, STp,
753 			  "Stepping over filemark %s failed.\n",
754 			  forward ? "forward" : "backward");
755 
756 	return (STp->buffer)->syscall_result;
757 }
758 
759 
760 /* Flush the write buffer (never need to write if variable blocksize). */
761 static int st_flush_write_buffer(struct scsi_tape * STp)
762 {
763 	int transfer, blks;
764 	int result;
765 	unsigned char cmd[MAX_COMMAND_SIZE];
766 	struct st_request *SRpnt;
767 	struct st_partstat *STps;
768 
769 	result = write_behind_check(STp);
770 	if (result)
771 		return result;
772 
773 	result = 0;
774 	if (STp->dirty == 1) {
775 
776 		transfer = STp->buffer->buffer_bytes;
777 		DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
778 
779 		memset(cmd, 0, MAX_COMMAND_SIZE);
780 		cmd[0] = WRITE_6;
781 		cmd[1] = 1;
782 		blks = transfer / STp->block_size;
783 		cmd[2] = blks >> 16;
784 		cmd[3] = blks >> 8;
785 		cmd[4] = blks;
786 
787 		SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
788 				   STp->device->request_queue->rq_timeout,
789 				   MAX_WRITE_RETRIES, 1);
790 		if (!SRpnt)
791 			return (STp->buffer)->syscall_result;
792 
793 		STps = &(STp->ps[STp->partition]);
794 		if ((STp->buffer)->syscall_result != 0) {
795 			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
796 
797 			if (cmdstatp->have_sense && !cmdstatp->deferred &&
798 			    (cmdstatp->flags & SENSE_EOM) &&
799 			    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
800 			     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
801 			    (!cmdstatp->remainder_valid ||
802 			     cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
803 				STp->dirty = 0;
804 				(STp->buffer)->buffer_bytes = 0;
805 				if (STps->drv_block >= 0)
806 					STps->drv_block += blks;
807 				result = (-ENOSPC);
808 			} else {
809 				st_printk(KERN_ERR, STp, "Error on flush.\n");
810 				STps->drv_block = (-1);
811 				result = (-EIO);
812 			}
813 		} else {
814 			if (STps->drv_block >= 0)
815 				STps->drv_block += blks;
816 			STp->dirty = 0;
817 			(STp->buffer)->buffer_bytes = 0;
818 		}
819 		st_release_request(SRpnt);
820 		SRpnt = NULL;
821 	}
822 	return result;
823 }
824 
825 
826 /* Flush the tape buffer. The tape will be positioned correctly unless
827    seek_next is true. */
828 static int flush_buffer(struct scsi_tape *STp, int seek_next)
829 {
830 	int backspace, result;
831 	struct st_buffer *STbuffer;
832 	struct st_partstat *STps;
833 
834 	STbuffer = STp->buffer;
835 
836 	/*
837 	 * If there was a bus reset, block further access
838 	 * to this device.
839 	 */
840 	if (STp->pos_unknown)
841 		return (-EIO);
842 
843 	if (STp->ready != ST_READY)
844 		return 0;
845 	STps = &(STp->ps[STp->partition]);
846 	if (STps->rw == ST_WRITING)	/* Writing */
847 		return st_flush_write_buffer(STp);
848 
849 	if (STp->block_size == 0)
850 		return 0;
851 
852 	backspace = ((STp->buffer)->buffer_bytes +
853 		     (STp->buffer)->read_pointer) / STp->block_size -
854 	    ((STp->buffer)->read_pointer + STp->block_size - 1) /
855 	    STp->block_size;
856 	(STp->buffer)->buffer_bytes = 0;
857 	(STp->buffer)->read_pointer = 0;
858 	result = 0;
859 	if (!seek_next) {
860 		if (STps->eof == ST_FM_HIT) {
861 			result = cross_eof(STp, 0);	/* Back over the EOF hit */
862 			if (!result)
863 				STps->eof = ST_NOEOF;
864 			else {
865 				if (STps->drv_file >= 0)
866 					STps->drv_file++;
867 				STps->drv_block = 0;
868 			}
869 		}
870 		if (!result && backspace > 0)
871 			result = st_int_ioctl(STp, MTBSR, backspace);
872 	} else if (STps->eof == ST_FM_HIT) {
873 		if (STps->drv_file >= 0)
874 			STps->drv_file++;
875 		STps->drv_block = 0;
876 		STps->eof = ST_NOEOF;
877 	}
878 	return result;
879 
880 }
881 
882 /* Set the mode parameters */
883 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
884 {
885 	int set_it = 0;
886 	unsigned long arg;
887 
888 	if (!STp->density_changed &&
889 	    STm->default_density >= 0 &&
890 	    STm->default_density != STp->density) {
891 		arg = STm->default_density;
892 		set_it = 1;
893 	} else
894 		arg = STp->density;
895 	arg <<= MT_ST_DENSITY_SHIFT;
896 	if (!STp->blksize_changed &&
897 	    STm->default_blksize >= 0 &&
898 	    STm->default_blksize != STp->block_size) {
899 		arg |= STm->default_blksize;
900 		set_it = 1;
901 	} else
902 		arg |= STp->block_size;
903 	if (set_it &&
904 	    st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
905 		st_printk(KERN_WARNING, STp,
906 			  "Can't set default block size to %d bytes "
907 			  "and density %x.\n",
908 			  STm->default_blksize, STm->default_density);
909 		if (modes_defined)
910 			return (-EINVAL);
911 	}
912 	return 0;
913 }
914 
915 
916 /* Lock or unlock the drive door. Don't use when st_request allocated. */
917 static int do_door_lock(struct scsi_tape * STp, int do_lock)
918 {
919 	int retval;
920 
921 	DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
922 
923 	retval = scsi_set_medium_removal(STp->device,
924 			do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
925 	if (!retval)
926 		STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
927 	else
928 		STp->door_locked = ST_LOCK_FAILS;
929 	return retval;
930 }
931 
932 
933 /* Set the internal state after reset */
934 static void reset_state(struct scsi_tape *STp)
935 {
936 	int i;
937 	struct st_partstat *STps;
938 
939 	STp->pos_unknown = 0;
940 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
941 		STps = &(STp->ps[i]);
942 		STps->rw = ST_IDLE;
943 		STps->eof = ST_NOEOF;
944 		STps->at_sm = 0;
945 		STps->last_block_valid = 0;
946 		STps->drv_block = -1;
947 		STps->drv_file = -1;
948 	}
949 	if (STp->can_partitions) {
950 		STp->partition = find_partition(STp);
951 		if (STp->partition < 0)
952 			STp->partition = 0;
953 		STp->new_partition = STp->partition;
954 	}
955 }
956 
957 /* Test if the drive is ready. Returns either one of the codes below or a negative system
958    error code. */
959 #define CHKRES_READY       0
960 #define CHKRES_NEW_SESSION 1
961 #define CHKRES_NOT_READY   2
962 #define CHKRES_NO_TAPE     3
963 
964 #define MAX_ATTENTIONS    10
965 
966 static int test_ready(struct scsi_tape *STp, int do_wait)
967 {
968 	int attentions, waits, max_wait, scode;
969 	int retval = CHKRES_READY, new_session = 0;
970 	unsigned char cmd[MAX_COMMAND_SIZE];
971 	struct st_request *SRpnt = NULL;
972 	struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
973 
974 	max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
975 
976 	for (attentions=waits=0; ; ) {
977 		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
978 		cmd[0] = TEST_UNIT_READY;
979 		SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
980 				   STp->long_timeout, MAX_READY_RETRIES, 1);
981 
982 		if (!SRpnt) {
983 			retval = (STp->buffer)->syscall_result;
984 			break;
985 		}
986 
987 		if (cmdstatp->have_sense) {
988 
989 			scode = cmdstatp->sense_hdr.sense_key;
990 
991 			if (scode == UNIT_ATTENTION) { /* New media? */
992 				new_session = 1;
993 				if (attentions < MAX_ATTENTIONS) {
994 					attentions++;
995 					continue;
996 				}
997 				else {
998 					retval = (-EIO);
999 					break;
1000 				}
1001 			}
1002 
1003 			if (scode == NOT_READY) {
1004 				if (waits < max_wait) {
1005 					if (msleep_interruptible(1000)) {
1006 						retval = (-EINTR);
1007 						break;
1008 					}
1009 					waits++;
1010 					continue;
1011 				}
1012 				else {
1013 					if ((STp->device)->scsi_level >= SCSI_2 &&
1014 					    cmdstatp->sense_hdr.asc == 0x3a)	/* Check ASC */
1015 						retval = CHKRES_NO_TAPE;
1016 					else
1017 						retval = CHKRES_NOT_READY;
1018 					break;
1019 				}
1020 			}
1021 		}
1022 
1023 		retval = (STp->buffer)->syscall_result;
1024 		if (!retval)
1025 			retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1026 		break;
1027 	}
1028 
1029 	if (SRpnt != NULL)
1030 		st_release_request(SRpnt);
1031 	return retval;
1032 }
1033 
1034 
1035 /* See if the drive is ready and gather information about the tape. Return values:
1036    < 0   negative error code from errno.h
1037    0     drive ready
1038    1     drive not ready (possibly no tape)
1039 */
1040 static int check_tape(struct scsi_tape *STp, struct file *filp)
1041 {
1042 	int i, retval, new_session = 0, do_wait;
1043 	unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1044 	unsigned short st_flags = filp->f_flags;
1045 	struct st_request *SRpnt = NULL;
1046 	struct st_modedef *STm;
1047 	struct st_partstat *STps;
1048 	struct inode *inode = file_inode(filp);
1049 	int mode = TAPE_MODE(inode);
1050 
1051 	STp->ready = ST_READY;
1052 
1053 	if (mode != STp->current_mode) {
1054 		DEBC_printk(STp, "Mode change from %d to %d.\n",
1055 			    STp->current_mode, mode);
1056 		new_session = 1;
1057 		STp->current_mode = mode;
1058 	}
1059 	STm = &(STp->modes[STp->current_mode]);
1060 
1061 	saved_cleaning = STp->cleaning_req;
1062 	STp->cleaning_req = 0;
1063 
1064 	do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1065 	retval = test_ready(STp, do_wait);
1066 
1067 	if (retval < 0)
1068 	    goto err_out;
1069 
1070 	if (retval == CHKRES_NEW_SESSION) {
1071 		STp->pos_unknown = 0;
1072 		STp->partition = STp->new_partition = 0;
1073 		if (STp->can_partitions)
1074 			STp->nbr_partitions = 1; /* This guess will be updated later
1075                                                     if necessary */
1076 		for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1077 			STps = &(STp->ps[i]);
1078 			STps->rw = ST_IDLE;
1079 			STps->eof = ST_NOEOF;
1080 			STps->at_sm = 0;
1081 			STps->last_block_valid = 0;
1082 			STps->drv_block = 0;
1083 			STps->drv_file = 0;
1084 		}
1085 		new_session = 1;
1086 	}
1087 	else {
1088 		STp->cleaning_req |= saved_cleaning;
1089 
1090 		if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1091 			if (retval == CHKRES_NO_TAPE)
1092 				STp->ready = ST_NO_TAPE;
1093 			else
1094 				STp->ready = ST_NOT_READY;
1095 
1096 			STp->density = 0;	/* Clear the erroneous "residue" */
1097 			STp->write_prot = 0;
1098 			STp->block_size = 0;
1099 			STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1100 			STp->partition = STp->new_partition = 0;
1101 			STp->door_locked = ST_UNLOCKED;
1102 			return CHKRES_NOT_READY;
1103 		}
1104 	}
1105 
1106 	if (STp->omit_blklims)
1107 		STp->min_block = STp->max_block = (-1);
1108 	else {
1109 		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1110 		cmd[0] = READ_BLOCK_LIMITS;
1111 
1112 		SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1113 				   STp->device->request_queue->rq_timeout,
1114 				   MAX_READY_RETRIES, 1);
1115 		if (!SRpnt) {
1116 			retval = (STp->buffer)->syscall_result;
1117 			goto err_out;
1118 		}
1119 
1120 		if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1121 			STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1122 			    ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1123 			STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1124 			    (STp->buffer)->b_data[5];
1125 			if ( DEB( debugging || ) !STp->inited)
1126 				st_printk(KERN_INFO, STp,
1127 					  "Block limits %d - %d bytes.\n",
1128 					  STp->min_block, STp->max_block);
1129 		} else {
1130 			STp->min_block = STp->max_block = (-1);
1131 			DEBC_printk(STp, "Can't read block limits.\n");
1132 		}
1133 	}
1134 
1135 	memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1136 	cmd[0] = MODE_SENSE;
1137 	cmd[4] = 12;
1138 
1139 	SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1140 			   STp->device->request_queue->rq_timeout,
1141 			   MAX_READY_RETRIES, 1);
1142 	if (!SRpnt) {
1143 		retval = (STp->buffer)->syscall_result;
1144 		goto err_out;
1145 	}
1146 
1147 	if ((STp->buffer)->syscall_result != 0) {
1148 		DEBC_printk(STp, "No Mode Sense.\n");
1149 		STp->block_size = ST_DEFAULT_BLOCK;	/* Educated guess (?) */
1150 		(STp->buffer)->syscall_result = 0;	/* Prevent error propagation */
1151 		STp->drv_write_prot = 0;
1152 	} else {
1153 		DEBC_printk(STp,"Mode sense. Length %d, "
1154 			    "medium %x, WBS %x, BLL %d\n",
1155 			    (STp->buffer)->b_data[0],
1156 			    (STp->buffer)->b_data[1],
1157 			    (STp->buffer)->b_data[2],
1158 			    (STp->buffer)->b_data[3]);
1159 
1160 		if ((STp->buffer)->b_data[3] >= 8) {
1161 			STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1162 			STp->density = (STp->buffer)->b_data[4];
1163 			STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1164 			    (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1165 			DEBC_printk(STp, "Density %x, tape length: %x, "
1166 				    "drv buffer: %d\n",
1167 				    STp->density,
1168 				    (STp->buffer)->b_data[5] * 65536 +
1169 				    (STp->buffer)->b_data[6] * 256 +
1170 				    (STp->buffer)->b_data[7],
1171 				    STp->drv_buffer);
1172 		}
1173 		STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1174 		if (!STp->drv_buffer && STp->immediate_filemark) {
1175 			st_printk(KERN_WARNING, STp,
1176 				  "non-buffered tape: disabling "
1177 				  "writing immediate filemarks\n");
1178 			STp->immediate_filemark = 0;
1179 		}
1180 	}
1181 	st_release_request(SRpnt);
1182 	SRpnt = NULL;
1183 	STp->inited = 1;
1184 
1185 	if (STp->block_size > 0)
1186 		(STp->buffer)->buffer_blocks =
1187 			(STp->buffer)->buffer_size / STp->block_size;
1188 	else
1189 		(STp->buffer)->buffer_blocks = 1;
1190 	(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1191 
1192 	DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1193 		    STp->block_size, (STp->buffer)->buffer_size,
1194 		    (STp->buffer)->buffer_blocks);
1195 
1196 	if (STp->drv_write_prot) {
1197 		STp->write_prot = 1;
1198 
1199 		DEBC_printk(STp, "Write protected\n");
1200 
1201 		if (do_wait &&
1202 		    ((st_flags & O_ACCMODE) == O_WRONLY ||
1203 		     (st_flags & O_ACCMODE) == O_RDWR)) {
1204 			retval = (-EROFS);
1205 			goto err_out;
1206 		}
1207 	}
1208 
1209 	if (STp->can_partitions && STp->nbr_partitions < 1) {
1210 		/* This code is reached when the device is opened for the first time
1211 		   after the driver has been initialized with tape in the drive and the
1212 		   partition support has been enabled. */
1213 		DEBC_printk(STp, "Updating partition number in status.\n");
1214 		if ((STp->partition = find_partition(STp)) < 0) {
1215 			retval = STp->partition;
1216 			goto err_out;
1217 		}
1218 		STp->new_partition = STp->partition;
1219 		STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1220 	}
1221 
1222 	if (new_session) {	/* Change the drive parameters for the new mode */
1223 		STp->density_changed = STp->blksize_changed = 0;
1224 		STp->compression_changed = 0;
1225 		if (!(STm->defaults_for_writes) &&
1226 		    (retval = set_mode_densblk(STp, STm)) < 0)
1227 		    goto err_out;
1228 
1229 		if (STp->default_drvbuffer != 0xff) {
1230 			if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1231 				st_printk(KERN_WARNING, STp,
1232 					  "Can't set default drive "
1233 					  "buffering to %d.\n",
1234 					  STp->default_drvbuffer);
1235 		}
1236 	}
1237 
1238 	return CHKRES_READY;
1239 
1240  err_out:
1241 	return retval;
1242 }
1243 
1244 
1245 /* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1246    module count. */
1247 static int st_open(struct inode *inode, struct file *filp)
1248 {
1249 	int i, retval = (-EIO);
1250 	int resumed = 0;
1251 	struct scsi_tape *STp;
1252 	struct st_partstat *STps;
1253 	int dev = TAPE_NR(inode);
1254 
1255 	/*
1256 	 * We really want to do nonseekable_open(inode, filp); here, but some
1257 	 * versions of tar incorrectly call lseek on tapes and bail out if that
1258 	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1259 	 */
1260 	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1261 
1262 	if (!(STp = scsi_tape_get(dev))) {
1263 		return -ENXIO;
1264 	}
1265 
1266 	filp->private_data = STp;
1267 
1268 	spin_lock(&st_use_lock);
1269 	if (STp->in_use) {
1270 		spin_unlock(&st_use_lock);
1271 		scsi_tape_put(STp);
1272 		DEBC_printk(STp, "Device already in use.\n");
1273 		return (-EBUSY);
1274 	}
1275 
1276 	STp->in_use = 1;
1277 	spin_unlock(&st_use_lock);
1278 	STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1279 
1280 	if (scsi_autopm_get_device(STp->device) < 0) {
1281 		retval = -EIO;
1282 		goto err_out;
1283 	}
1284 	resumed = 1;
1285 	if (!scsi_block_when_processing_errors(STp->device)) {
1286 		retval = (-ENXIO);
1287 		goto err_out;
1288 	}
1289 
1290 	/* See that we have at least a one page buffer available */
1291 	if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1292 		st_printk(KERN_WARNING, STp,
1293 			  "Can't allocate one page tape buffer.\n");
1294 		retval = (-EOVERFLOW);
1295 		goto err_out;
1296 	}
1297 
1298 	(STp->buffer)->cleared = 0;
1299 	(STp->buffer)->writing = 0;
1300 	(STp->buffer)->syscall_result = 0;
1301 
1302 	STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1303 
1304 	STp->dirty = 0;
1305 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1306 		STps = &(STp->ps[i]);
1307 		STps->rw = ST_IDLE;
1308 	}
1309 	STp->try_dio_now = STp->try_dio;
1310 	STp->recover_count = 0;
1311 	DEB( STp->nbr_waits = STp->nbr_finished = 0;
1312 	     STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1313 
1314 	retval = check_tape(STp, filp);
1315 	if (retval < 0)
1316 		goto err_out;
1317 	if ((filp->f_flags & O_NONBLOCK) == 0 &&
1318 	    retval != CHKRES_READY) {
1319 		if (STp->ready == NO_TAPE)
1320 			retval = (-ENOMEDIUM);
1321 		else
1322 			retval = (-EIO);
1323 		goto err_out;
1324 	}
1325 	return 0;
1326 
1327  err_out:
1328 	normalize_buffer(STp->buffer);
1329 	spin_lock(&st_use_lock);
1330 	STp->in_use = 0;
1331 	spin_unlock(&st_use_lock);
1332 	if (resumed)
1333 		scsi_autopm_put_device(STp->device);
1334 	scsi_tape_put(STp);
1335 	return retval;
1336 
1337 }
1338 
1339 
1340 /* Flush the tape buffer before close */
1341 static int st_flush(struct file *filp, fl_owner_t id)
1342 {
1343 	int result = 0, result2;
1344 	unsigned char cmd[MAX_COMMAND_SIZE];
1345 	struct st_request *SRpnt;
1346 	struct scsi_tape *STp = filp->private_data;
1347 	struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1348 	struct st_partstat *STps = &(STp->ps[STp->partition]);
1349 
1350 	if (file_count(filp) > 1)
1351 		return 0;
1352 
1353 	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1354 		result = st_flush_write_buffer(STp);
1355 		if (result != 0 && result != (-ENOSPC))
1356 			goto out;
1357 	}
1358 
1359 	if (STp->can_partitions &&
1360 	    (result2 = switch_partition(STp)) < 0) {
1361 		DEBC_printk(STp, "switch_partition at close failed.\n");
1362 		if (result == 0)
1363 			result = result2;
1364 		goto out;
1365 	}
1366 
1367 	DEBC( if (STp->nbr_requests)
1368 		st_printk(KERN_DEBUG, STp,
1369 			  "Number of r/w requests %d, dio used in %d, "
1370 			  "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1371 			  STp->nbr_pages));
1372 
1373 	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1374 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1375 
1376 #if DEBUG
1377 		DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1378 			    STp->nbr_waits, STp->nbr_finished);
1379 #endif
1380 		memset(cmd, 0, MAX_COMMAND_SIZE);
1381 		cmd[0] = WRITE_FILEMARKS;
1382 		if (STp->immediate_filemark)
1383 			cmd[1] = 1;
1384 		cmd[4] = 1 + STp->two_fm;
1385 
1386 		SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1387 				   STp->device->request_queue->rq_timeout,
1388 				   MAX_WRITE_RETRIES, 1);
1389 		if (!SRpnt) {
1390 			result = (STp->buffer)->syscall_result;
1391 			goto out;
1392 		}
1393 
1394 		if (STp->buffer->syscall_result == 0 ||
1395 		    (cmdstatp->have_sense && !cmdstatp->deferred &&
1396 		     (cmdstatp->flags & SENSE_EOM) &&
1397 		     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1398 		      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1399 		     (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1400 			/* Write successful at EOM */
1401 			st_release_request(SRpnt);
1402 			SRpnt = NULL;
1403 			if (STps->drv_file >= 0)
1404 				STps->drv_file++;
1405 			STps->drv_block = 0;
1406 			if (STp->two_fm)
1407 				cross_eof(STp, 0);
1408 			STps->eof = ST_FM;
1409 		}
1410 		else { /* Write error */
1411 			st_release_request(SRpnt);
1412 			SRpnt = NULL;
1413 			st_printk(KERN_ERR, STp,
1414 				  "Error on write filemark.\n");
1415 			if (result == 0)
1416 				result = (-EIO);
1417 		}
1418 
1419 		DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1420 	} else if (!STp->rew_at_close) {
1421 		STps = &(STp->ps[STp->partition]);
1422 		if (!STm->sysv || STps->rw != ST_READING) {
1423 			if (STp->can_bsr)
1424 				result = flush_buffer(STp, 0);
1425 			else if (STps->eof == ST_FM_HIT) {
1426 				result = cross_eof(STp, 0);
1427 				if (result) {
1428 					if (STps->drv_file >= 0)
1429 						STps->drv_file++;
1430 					STps->drv_block = 0;
1431 					STps->eof = ST_FM;
1432 				} else
1433 					STps->eof = ST_NOEOF;
1434 			}
1435 		} else if ((STps->eof == ST_NOEOF &&
1436 			    !(result = cross_eof(STp, 1))) ||
1437 			   STps->eof == ST_FM_HIT) {
1438 			if (STps->drv_file >= 0)
1439 				STps->drv_file++;
1440 			STps->drv_block = 0;
1441 			STps->eof = ST_FM;
1442 		}
1443 	}
1444 
1445       out:
1446 	if (STp->rew_at_close) {
1447 		result2 = st_int_ioctl(STp, MTREW, 1);
1448 		if (result == 0)
1449 			result = result2;
1450 	}
1451 	return result;
1452 }
1453 
1454 
1455 /* Close the device and release it. BKL is not needed: this is the only thread
1456    accessing this tape. */
1457 static int st_release(struct inode *inode, struct file *filp)
1458 {
1459 	int result = 0;
1460 	struct scsi_tape *STp = filp->private_data;
1461 
1462 	if (STp->door_locked == ST_LOCKED_AUTO)
1463 		do_door_lock(STp, 0);
1464 
1465 	normalize_buffer(STp->buffer);
1466 	spin_lock(&st_use_lock);
1467 	STp->in_use = 0;
1468 	spin_unlock(&st_use_lock);
1469 	scsi_autopm_put_device(STp->device);
1470 	scsi_tape_put(STp);
1471 
1472 	return result;
1473 }
1474 
1475 /* The checks common to both reading and writing */
1476 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1477 {
1478 	ssize_t retval = 0;
1479 
1480 	/*
1481 	 * If we are in the middle of error recovery, don't let anyone
1482 	 * else try and use this device.  Also, if error recovery fails, it
1483 	 * may try and take the device offline, in which case all further
1484 	 * access to the device is prohibited.
1485 	 */
1486 	if (!scsi_block_when_processing_errors(STp->device)) {
1487 		retval = (-ENXIO);
1488 		goto out;
1489 	}
1490 
1491 	if (STp->ready != ST_READY) {
1492 		if (STp->ready == ST_NO_TAPE)
1493 			retval = (-ENOMEDIUM);
1494 		else
1495 			retval = (-EIO);
1496 		goto out;
1497 	}
1498 
1499 	if (! STp->modes[STp->current_mode].defined) {
1500 		retval = (-ENXIO);
1501 		goto out;
1502 	}
1503 
1504 
1505 	/*
1506 	 * If there was a bus reset, block further access
1507 	 * to this device.
1508 	 */
1509 	if (STp->pos_unknown) {
1510 		retval = (-EIO);
1511 		goto out;
1512 	}
1513 
1514 	if (count == 0)
1515 		goto out;
1516 
1517 	DEB(
1518 	if (!STp->in_use) {
1519 		st_printk(ST_DEB_MSG, STp,
1520 			  "Incorrect device.\n");
1521 		retval = (-EIO);
1522 		goto out;
1523 	} ) /* end DEB */
1524 
1525 	if (STp->can_partitions &&
1526 	    (retval = switch_partition(STp)) < 0)
1527 		goto out;
1528 
1529 	if (STp->block_size == 0 && STp->max_block > 0 &&
1530 	    (count < STp->min_block || count > STp->max_block)) {
1531 		retval = (-EINVAL);
1532 		goto out;
1533 	}
1534 
1535 	if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1536 	    !do_door_lock(STp, 1))
1537 		STp->door_locked = ST_LOCKED_AUTO;
1538 
1539  out:
1540 	return retval;
1541 }
1542 
1543 
1544 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1545 			   size_t count, int is_read)
1546 {
1547 	int i, bufsize, retval = 0;
1548 	struct st_buffer *STbp = STp->buffer;
1549 
1550 	if (is_read)
1551 		i = STp->try_dio_now && try_rdio;
1552 	else
1553 		i = STp->try_dio_now && try_wdio;
1554 
1555 	if (i && ((unsigned long)buf & queue_dma_alignment(
1556 					STp->device->request_queue)) == 0) {
1557 		i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1558 				       count, (is_read ? READ : WRITE));
1559 		if (i > 0) {
1560 			STbp->do_dio = i;
1561 			STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1562 		}
1563 		else
1564 			STbp->do_dio = 0;  /* fall back to buffering with any error */
1565 		STbp->sg_segs = STbp->do_dio;
1566 		DEB(
1567 		     if (STbp->do_dio) {
1568 			STp->nbr_dio++;
1569 			STp->nbr_pages += STbp->do_dio;
1570 		     }
1571 		)
1572 	} else
1573 		STbp->do_dio = 0;
1574 	DEB( STp->nbr_requests++; )
1575 
1576 	if (!STbp->do_dio) {
1577 		if (STp->block_size)
1578 			bufsize = STp->block_size > st_fixed_buffer_size ?
1579 				STp->block_size : st_fixed_buffer_size;
1580 		else {
1581 			bufsize = count;
1582 			/* Make sure that data from previous user is not leaked even if
1583 			   HBA does not return correct residual */
1584 			if (is_read && STp->sili && !STbp->cleared)
1585 				clear_buffer(STbp);
1586 		}
1587 
1588 		if (bufsize > STbp->buffer_size &&
1589 		    !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1590 			st_printk(KERN_WARNING, STp,
1591 				  "Can't allocate %d byte tape buffer.\n",
1592 				  bufsize);
1593 			retval = (-EOVERFLOW);
1594 			goto out;
1595 		}
1596 		if (STp->block_size)
1597 			STbp->buffer_blocks = bufsize / STp->block_size;
1598 	}
1599 
1600  out:
1601 	return retval;
1602 }
1603 
1604 
1605 /* Can be called more than once after each setup_buffer() */
1606 static void release_buffering(struct scsi_tape *STp, int is_read)
1607 {
1608 	struct st_buffer *STbp;
1609 
1610 	STbp = STp->buffer;
1611 	if (STbp->do_dio) {
1612 		sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1613 		STbp->do_dio = 0;
1614 		STbp->sg_segs = 0;
1615 	}
1616 }
1617 
1618 
1619 /* Write command */
1620 static ssize_t
1621 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1622 {
1623 	ssize_t total;
1624 	ssize_t i, do_count, blks, transfer;
1625 	ssize_t retval;
1626 	int undone, retry_eot = 0, scode;
1627 	int async_write;
1628 	unsigned char cmd[MAX_COMMAND_SIZE];
1629 	const char __user *b_point;
1630 	struct st_request *SRpnt = NULL;
1631 	struct scsi_tape *STp = filp->private_data;
1632 	struct st_modedef *STm;
1633 	struct st_partstat *STps;
1634 	struct st_buffer *STbp;
1635 
1636 	if (mutex_lock_interruptible(&STp->lock))
1637 		return -ERESTARTSYS;
1638 
1639 	retval = rw_checks(STp, filp, count);
1640 	if (retval || count == 0)
1641 		goto out;
1642 
1643 	/* Write must be integral number of blocks */
1644 	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1645 		st_printk(KERN_WARNING, STp,
1646 			  "Write not multiple of tape block size.\n");
1647 		retval = (-EINVAL);
1648 		goto out;
1649 	}
1650 
1651 	STm = &(STp->modes[STp->current_mode]);
1652 	STps = &(STp->ps[STp->partition]);
1653 
1654 	if (STp->write_prot) {
1655 		retval = (-EACCES);
1656 		goto out;
1657 	}
1658 
1659 
1660 	if (STps->rw == ST_READING) {
1661 		retval = flush_buffer(STp, 0);
1662 		if (retval)
1663 			goto out;
1664 		STps->rw = ST_WRITING;
1665 	} else if (STps->rw != ST_WRITING &&
1666 		   STps->drv_file == 0 && STps->drv_block == 0) {
1667 		if ((retval = set_mode_densblk(STp, STm)) < 0)
1668 			goto out;
1669 		if (STm->default_compression != ST_DONT_TOUCH &&
1670 		    !(STp->compression_changed)) {
1671 			if (st_compression(STp, (STm->default_compression == ST_YES))) {
1672 				st_printk(KERN_WARNING, STp,
1673 					  "Can't set default compression.\n");
1674 				if (modes_defined) {
1675 					retval = (-EINVAL);
1676 					goto out;
1677 				}
1678 			}
1679 		}
1680 	}
1681 
1682 	STbp = STp->buffer;
1683 	i = write_behind_check(STp);
1684 	if (i) {
1685 		if (i == -ENOSPC)
1686 			STps->eof = ST_EOM_OK;
1687 		else
1688 			STps->eof = ST_EOM_ERROR;
1689 	}
1690 
1691 	if (STps->eof == ST_EOM_OK) {
1692 		STps->eof = ST_EOD_1;  /* allow next write */
1693 		retval = (-ENOSPC);
1694 		goto out;
1695 	}
1696 	else if (STps->eof == ST_EOM_ERROR) {
1697 		retval = (-EIO);
1698 		goto out;
1699 	}
1700 
1701 	/* Check the buffer readability in cases where copy_user might catch
1702 	   the problems after some tape movement. */
1703 	if (STp->block_size != 0 &&
1704 	    !STbp->do_dio &&
1705 	    (copy_from_user(&i, buf, 1) != 0 ||
1706 	     copy_from_user(&i, buf + count - 1, 1) != 0)) {
1707 		retval = (-EFAULT);
1708 		goto out;
1709 	}
1710 
1711 	retval = setup_buffering(STp, buf, count, 0);
1712 	if (retval)
1713 		goto out;
1714 
1715 	total = count;
1716 
1717 	memset(cmd, 0, MAX_COMMAND_SIZE);
1718 	cmd[0] = WRITE_6;
1719 	cmd[1] = (STp->block_size != 0);
1720 
1721 	STps->rw = ST_WRITING;
1722 
1723 	b_point = buf;
1724 	while (count > 0 && !retry_eot) {
1725 
1726 		if (STbp->do_dio) {
1727 			do_count = count;
1728 		}
1729 		else {
1730 			if (STp->block_size == 0)
1731 				do_count = count;
1732 			else {
1733 				do_count = STbp->buffer_blocks * STp->block_size -
1734 					STbp->buffer_bytes;
1735 				if (do_count > count)
1736 					do_count = count;
1737 			}
1738 
1739 			i = append_to_buffer(b_point, STbp, do_count);
1740 			if (i) {
1741 				retval = i;
1742 				goto out;
1743 			}
1744 		}
1745 		count -= do_count;
1746 		b_point += do_count;
1747 
1748 		async_write = STp->block_size == 0 && !STbp->do_dio &&
1749 			STm->do_async_writes && STps->eof < ST_EOM_OK;
1750 
1751 		if (STp->block_size != 0 && STm->do_buffer_writes &&
1752 		    !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1753 		    STbp->buffer_bytes < STbp->buffer_size) {
1754 			STp->dirty = 1;
1755 			/* Don't write a buffer that is not full enough. */
1756 			if (!async_write && count == 0)
1757 				break;
1758 		}
1759 
1760 	retry_write:
1761 		if (STp->block_size == 0)
1762 			blks = transfer = do_count;
1763 		else {
1764 			if (!STbp->do_dio)
1765 				blks = STbp->buffer_bytes;
1766 			else
1767 				blks = do_count;
1768 			blks /= STp->block_size;
1769 			transfer = blks * STp->block_size;
1770 		}
1771 		cmd[2] = blks >> 16;
1772 		cmd[3] = blks >> 8;
1773 		cmd[4] = blks;
1774 
1775 		SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1776 				   STp->device->request_queue->rq_timeout,
1777 				   MAX_WRITE_RETRIES, !async_write);
1778 		if (!SRpnt) {
1779 			retval = STbp->syscall_result;
1780 			goto out;
1781 		}
1782 		if (async_write && !STbp->syscall_result) {
1783 			STbp->writing = transfer;
1784 			STp->dirty = !(STbp->writing ==
1785 				       STbp->buffer_bytes);
1786 			SRpnt = NULL;  /* Prevent releasing this request! */
1787 			DEB( STp->write_pending = 1; )
1788 			break;
1789 		}
1790 
1791 		if (STbp->syscall_result != 0) {
1792 			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1793 
1794 			DEBC_printk(STp, "Error on write:\n");
1795 			if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1796 				scode = cmdstatp->sense_hdr.sense_key;
1797 				if (cmdstatp->remainder_valid)
1798 					undone = (int)cmdstatp->uremainder64;
1799 				else if (STp->block_size == 0 &&
1800 					 scode == VOLUME_OVERFLOW)
1801 					undone = transfer;
1802 				else
1803 					undone = 0;
1804 				if (STp->block_size != 0)
1805 					undone *= STp->block_size;
1806 				if (undone <= do_count) {
1807 					/* Only data from this write is not written */
1808 					count += undone;
1809 					b_point -= undone;
1810 					do_count -= undone;
1811 					if (STp->block_size)
1812 						blks = (transfer - undone) / STp->block_size;
1813 					STps->eof = ST_EOM_OK;
1814 					/* Continue in fixed block mode if all written
1815 					   in this request but still something left to write
1816 					   (retval left to zero)
1817 					*/
1818 					if (STp->block_size == 0 ||
1819 					    undone > 0 || count == 0)
1820 						retval = (-ENOSPC); /* EOM within current request */
1821 					DEBC_printk(STp, "EOM with %d "
1822 						    "bytes unwritten.\n",
1823 						    (int)count);
1824 				} else {
1825 					/* EOT within data buffered earlier (possible only
1826 					   in fixed block mode without direct i/o) */
1827 					if (!retry_eot && !cmdstatp->deferred &&
1828 					    (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1829 						move_buffer_data(STp->buffer, transfer - undone);
1830 						retry_eot = 1;
1831 						if (STps->drv_block >= 0) {
1832 							STps->drv_block += (transfer - undone) /
1833 								STp->block_size;
1834 						}
1835 						STps->eof = ST_EOM_OK;
1836 						DEBC_printk(STp, "Retry "
1837 							    "write of %d "
1838 							    "bytes at EOM.\n",
1839 							    STp->buffer->buffer_bytes);
1840 						goto retry_write;
1841 					}
1842 					else {
1843 						/* Either error within data buffered by driver or
1844 						   failed retry */
1845 						count -= do_count;
1846 						blks = do_count = 0;
1847 						STps->eof = ST_EOM_ERROR;
1848 						STps->drv_block = (-1); /* Too cautious? */
1849 						retval = (-EIO);	/* EOM for old data */
1850 						DEBC_printk(STp, "EOM with "
1851 							    "lost data.\n");
1852 					}
1853 				}
1854 			} else {
1855 				count += do_count;
1856 				STps->drv_block = (-1);		/* Too cautious? */
1857 				retval = STbp->syscall_result;
1858 			}
1859 
1860 		}
1861 
1862 		if (STps->drv_block >= 0) {
1863 			if (STp->block_size == 0)
1864 				STps->drv_block += (do_count > 0);
1865 			else
1866 				STps->drv_block += blks;
1867 		}
1868 
1869 		STbp->buffer_bytes = 0;
1870 		STp->dirty = 0;
1871 
1872 		if (retval || retry_eot) {
1873 			if (count < total)
1874 				retval = total - count;
1875 			goto out;
1876 		}
1877 	}
1878 
1879 	if (STps->eof == ST_EOD_1)
1880 		STps->eof = ST_EOM_OK;
1881 	else if (STps->eof != ST_EOM_OK)
1882 		STps->eof = ST_NOEOF;
1883 	retval = total - count;
1884 
1885  out:
1886 	if (SRpnt != NULL)
1887 		st_release_request(SRpnt);
1888 	release_buffering(STp, 0);
1889 	mutex_unlock(&STp->lock);
1890 
1891 	return retval;
1892 }
1893 
1894 /* Read data from the tape. Returns zero in the normal case, one if the
1895    eof status has changed, and the negative error code in case of a
1896    fatal error. Otherwise updates the buffer and the eof state.
1897 
1898    Does release user buffer mapping if it is set.
1899 */
1900 static long read_tape(struct scsi_tape *STp, long count,
1901 		      struct st_request ** aSRpnt)
1902 {
1903 	int transfer, blks, bytes;
1904 	unsigned char cmd[MAX_COMMAND_SIZE];
1905 	struct st_request *SRpnt;
1906 	struct st_modedef *STm;
1907 	struct st_partstat *STps;
1908 	struct st_buffer *STbp;
1909 	int retval = 0;
1910 
1911 	if (count == 0)
1912 		return 0;
1913 
1914 	STm = &(STp->modes[STp->current_mode]);
1915 	STps = &(STp->ps[STp->partition]);
1916 	if (STps->eof == ST_FM_HIT)
1917 		return 1;
1918 	STbp = STp->buffer;
1919 
1920 	if (STp->block_size == 0)
1921 		blks = bytes = count;
1922 	else {
1923 		if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1924 			blks = (STp->buffer)->buffer_blocks;
1925 			bytes = blks * STp->block_size;
1926 		} else {
1927 			bytes = count;
1928 			if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1929 				bytes = (STp->buffer)->buffer_size;
1930 			blks = bytes / STp->block_size;
1931 			bytes = blks * STp->block_size;
1932 		}
1933 	}
1934 
1935 	memset(cmd, 0, MAX_COMMAND_SIZE);
1936 	cmd[0] = READ_6;
1937 	cmd[1] = (STp->block_size != 0);
1938 	if (!cmd[1] && STp->sili)
1939 		cmd[1] |= 2;
1940 	cmd[2] = blks >> 16;
1941 	cmd[3] = blks >> 8;
1942 	cmd[4] = blks;
1943 
1944 	SRpnt = *aSRpnt;
1945 	SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1946 			   STp->device->request_queue->rq_timeout,
1947 			   MAX_RETRIES, 1);
1948 	release_buffering(STp, 1);
1949 	*aSRpnt = SRpnt;
1950 	if (!SRpnt)
1951 		return STbp->syscall_result;
1952 
1953 	STbp->read_pointer = 0;
1954 	STps->at_sm = 0;
1955 
1956 	/* Something to check */
1957 	if (STbp->syscall_result) {
1958 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1959 
1960 		retval = 1;
1961 		DEBC_printk(STp,
1962 			    "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1963 			    SRpnt->sense[0], SRpnt->sense[1],
1964 			    SRpnt->sense[2], SRpnt->sense[3],
1965 			    SRpnt->sense[4], SRpnt->sense[5],
1966 			    SRpnt->sense[6], SRpnt->sense[7]);
1967 		if (cmdstatp->have_sense) {
1968 
1969 			if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1970 				cmdstatp->flags &= 0xcf;	/* No need for EOM in this case */
1971 
1972 			if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1973 				/* Compute the residual count */
1974 				if (cmdstatp->remainder_valid)
1975 					transfer = (int)cmdstatp->uremainder64;
1976 				else
1977 					transfer = 0;
1978 				if (STp->block_size == 0 &&
1979 				    cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR)
1980 					transfer = bytes;
1981 
1982 				if (cmdstatp->flags & SENSE_ILI) {	/* ILI */
1983 					if (STp->block_size == 0 &&
1984 					    transfer < 0) {
1985 						st_printk(KERN_NOTICE, STp,
1986 							  "Failed to read %d "
1987 							  "byte block with %d "
1988 							  "byte transfer.\n",
1989 							  bytes - transfer,
1990 							  bytes);
1991 						if (STps->drv_block >= 0)
1992 							STps->drv_block += 1;
1993 						STbp->buffer_bytes = 0;
1994 						return (-ENOMEM);
1995 					} else if (STp->block_size == 0) {
1996 						STbp->buffer_bytes = bytes - transfer;
1997 					} else {
1998 						st_release_request(SRpnt);
1999 						SRpnt = *aSRpnt = NULL;
2000 						if (transfer == blks) {	/* We did not get anything, error */
2001 							st_printk(KERN_NOTICE, STp,
2002 								  "Incorrect "
2003 								  "block size.\n");
2004 							if (STps->drv_block >= 0)
2005 								STps->drv_block += blks - transfer + 1;
2006 							st_int_ioctl(STp, MTBSR, 1);
2007 							return (-EIO);
2008 						}
2009 						/* We have some data, deliver it */
2010 						STbp->buffer_bytes = (blks - transfer) *
2011 						    STp->block_size;
2012 						DEBC_printk(STp, "ILI but "
2013 							    "enough data "
2014 							    "received %ld "
2015 							    "%d.\n", count,
2016 							    STbp->buffer_bytes);
2017 						if (STps->drv_block >= 0)
2018 							STps->drv_block += 1;
2019 						if (st_int_ioctl(STp, MTBSR, 1))
2020 							return (-EIO);
2021 					}
2022 				} else if (cmdstatp->flags & SENSE_FMK) {	/* FM overrides EOM */
2023 					if (STps->eof != ST_FM_HIT)
2024 						STps->eof = ST_FM_HIT;
2025 					else
2026 						STps->eof = ST_EOD_2;
2027 					if (STp->block_size == 0)
2028 						STbp->buffer_bytes = 0;
2029 					else
2030 						STbp->buffer_bytes =
2031 						    bytes - transfer * STp->block_size;
2032 					DEBC_printk(STp, "EOF detected (%d "
2033 						    "bytes read).\n",
2034 						    STbp->buffer_bytes);
2035 				} else if (cmdstatp->flags & SENSE_EOM) {
2036 					if (STps->eof == ST_FM)
2037 						STps->eof = ST_EOD_1;
2038 					else
2039 						STps->eof = ST_EOM_OK;
2040 					if (STp->block_size == 0)
2041 						STbp->buffer_bytes = bytes - transfer;
2042 					else
2043 						STbp->buffer_bytes =
2044 						    bytes - transfer * STp->block_size;
2045 
2046 					DEBC_printk(STp, "EOM detected (%d "
2047 						    "bytes read).\n",
2048 						    STbp->buffer_bytes);
2049 				}
2050 			}
2051 			/* end of EOF, EOM, ILI test */
2052 			else {	/* nonzero sense key */
2053 				DEBC_printk(STp, "Tape error while reading.\n");
2054 				STps->drv_block = (-1);
2055 				if (STps->eof == ST_FM &&
2056 				    cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2057 					DEBC_printk(STp, "Zero returned for "
2058 						    "first BLANK CHECK "
2059 						    "after EOF.\n");
2060 					STps->eof = ST_EOD_2;	/* First BLANK_CHECK after FM */
2061 				} else	/* Some other extended sense code */
2062 					retval = (-EIO);
2063 			}
2064 
2065 			if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2066 				STbp->buffer_bytes = 0;
2067 		}
2068 		/* End of extended sense test */
2069 		else {		/* Non-extended sense */
2070 			retval = STbp->syscall_result;
2071 		}
2072 
2073 	}
2074 	/* End of error handling */
2075 	else {			/* Read successful */
2076 		STbp->buffer_bytes = bytes;
2077 		if (STp->sili) /* In fixed block mode residual is always zero here */
2078 			STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2079 	}
2080 
2081 	if (STps->drv_block >= 0) {
2082 		if (STp->block_size == 0)
2083 			STps->drv_block++;
2084 		else
2085 			STps->drv_block += STbp->buffer_bytes / STp->block_size;
2086 	}
2087 	return retval;
2088 }
2089 
2090 
2091 /* Read command */
2092 static ssize_t
2093 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2094 {
2095 	ssize_t total;
2096 	ssize_t retval = 0;
2097 	ssize_t i, transfer;
2098 	int special, do_dio = 0;
2099 	struct st_request *SRpnt = NULL;
2100 	struct scsi_tape *STp = filp->private_data;
2101 	struct st_modedef *STm;
2102 	struct st_partstat *STps;
2103 	struct st_buffer *STbp = STp->buffer;
2104 
2105 	if (mutex_lock_interruptible(&STp->lock))
2106 		return -ERESTARTSYS;
2107 
2108 	retval = rw_checks(STp, filp, count);
2109 	if (retval || count == 0)
2110 		goto out;
2111 
2112 	STm = &(STp->modes[STp->current_mode]);
2113 	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2114 		if (!STm->do_read_ahead) {
2115 			retval = (-EINVAL);	/* Read must be integral number of blocks */
2116 			goto out;
2117 		}
2118 		STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2119 	}
2120 
2121 	STps = &(STp->ps[STp->partition]);
2122 	if (STps->rw == ST_WRITING) {
2123 		retval = flush_buffer(STp, 0);
2124 		if (retval)
2125 			goto out;
2126 		STps->rw = ST_READING;
2127 	}
2128 	DEB(
2129 	if (debugging && STps->eof != ST_NOEOF)
2130 		st_printk(ST_DEB_MSG, STp,
2131 			  "EOF/EOM flag up (%d). Bytes %d\n",
2132 			  STps->eof, STbp->buffer_bytes);
2133 	) /* end DEB */
2134 
2135 	retval = setup_buffering(STp, buf, count, 1);
2136 	if (retval)
2137 		goto out;
2138 	do_dio = STbp->do_dio;
2139 
2140 	if (STbp->buffer_bytes == 0 &&
2141 	    STps->eof >= ST_EOD_1) {
2142 		if (STps->eof < ST_EOD) {
2143 			STps->eof += 1;
2144 			retval = 0;
2145 			goto out;
2146 		}
2147 		retval = (-EIO);	/* EOM or Blank Check */
2148 		goto out;
2149 	}
2150 
2151 	if (do_dio) {
2152 		/* Check the buffer writability before any tape movement. Don't alter
2153 		   buffer data. */
2154 		if (copy_from_user(&i, buf, 1) != 0 ||
2155 		    copy_to_user(buf, &i, 1) != 0 ||
2156 		    copy_from_user(&i, buf + count - 1, 1) != 0 ||
2157 		    copy_to_user(buf + count - 1, &i, 1) != 0) {
2158 			retval = (-EFAULT);
2159 			goto out;
2160 		}
2161 	}
2162 
2163 	STps->rw = ST_READING;
2164 
2165 
2166 	/* Loop until enough data in buffer or a special condition found */
2167 	for (total = 0, special = 0; total < count && !special;) {
2168 
2169 		/* Get new data if the buffer is empty */
2170 		if (STbp->buffer_bytes == 0) {
2171 			special = read_tape(STp, count - total, &SRpnt);
2172 			if (special < 0) {	/* No need to continue read */
2173 				retval = special;
2174 				goto out;
2175 			}
2176 		}
2177 
2178 		/* Move the data from driver buffer to user buffer */
2179 		if (STbp->buffer_bytes > 0) {
2180 			DEB(
2181 			if (debugging && STps->eof != ST_NOEOF)
2182 				st_printk(ST_DEB_MSG, STp,
2183 					  "EOF up (%d). Left %d, needed %d.\n",
2184 					  STps->eof, STbp->buffer_bytes,
2185 					  (int)(count - total));
2186 			) /* end DEB */
2187 			transfer = STbp->buffer_bytes < count - total ?
2188 			    STbp->buffer_bytes : count - total;
2189 			if (!do_dio) {
2190 				i = from_buffer(STbp, buf, transfer);
2191 				if (i) {
2192 					retval = i;
2193 					goto out;
2194 				}
2195 			}
2196 			buf += transfer;
2197 			total += transfer;
2198 		}
2199 
2200 		if (STp->block_size == 0)
2201 			break;	/* Read only one variable length block */
2202 
2203 	}			/* for (total = 0, special = 0;
2204                                    total < count && !special; ) */
2205 
2206 	/* Change the eof state if no data from tape or buffer */
2207 	if (total == 0) {
2208 		if (STps->eof == ST_FM_HIT) {
2209 			STps->eof = ST_FM;
2210 			STps->drv_block = 0;
2211 			if (STps->drv_file >= 0)
2212 				STps->drv_file++;
2213 		} else if (STps->eof == ST_EOD_1) {
2214 			STps->eof = ST_EOD_2;
2215 			STps->drv_block = 0;
2216 			if (STps->drv_file >= 0)
2217 				STps->drv_file++;
2218 		} else if (STps->eof == ST_EOD_2)
2219 			STps->eof = ST_EOD;
2220 	} else if (STps->eof == ST_FM)
2221 		STps->eof = ST_NOEOF;
2222 	retval = total;
2223 
2224  out:
2225 	if (SRpnt != NULL) {
2226 		st_release_request(SRpnt);
2227 		SRpnt = NULL;
2228 	}
2229 	if (do_dio) {
2230 		release_buffering(STp, 1);
2231 		STbp->buffer_bytes = 0;
2232 	}
2233 	mutex_unlock(&STp->lock);
2234 
2235 	return retval;
2236 }
2237 
2238 
2239 
2240 DEB(
2241 /* Set the driver options */
2242 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2243 {
2244 	if (debugging) {
2245 		st_printk(KERN_INFO, STp,
2246 			  "Mode %d options: buffer writes: %d, "
2247 			  "async writes: %d, read ahead: %d\n",
2248 			  STp->current_mode, STm->do_buffer_writes,
2249 			  STm->do_async_writes, STm->do_read_ahead);
2250 		st_printk(KERN_INFO, STp,
2251 			  "    can bsr: %d, two FMs: %d, "
2252 			  "fast mteom: %d, auto lock: %d,\n",
2253 			  STp->can_bsr, STp->two_fm, STp->fast_mteom,
2254 			  STp->do_auto_lock);
2255 		st_printk(KERN_INFO, STp,
2256 			  "    defs for wr: %d, no block limits: %d, "
2257 			  "partitions: %d, s2 log: %d\n",
2258 			  STm->defaults_for_writes, STp->omit_blklims,
2259 			  STp->can_partitions, STp->scsi2_logical);
2260 		st_printk(KERN_INFO, STp,
2261 			  "    sysv: %d nowait: %d sili: %d "
2262 			  "nowait_filemark: %d\n",
2263 			  STm->sysv, STp->immediate, STp->sili,
2264 			  STp->immediate_filemark);
2265 		st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2266 	}
2267 }
2268 	)
2269 
2270 
2271 static int st_set_options(struct scsi_tape *STp, long options)
2272 {
2273 	int value;
2274 	long code;
2275 	struct st_modedef *STm;
2276 	struct cdev *cd0, *cd1;
2277 	struct device *d0, *d1;
2278 
2279 	STm = &(STp->modes[STp->current_mode]);
2280 	if (!STm->defined) {
2281 		cd0 = STm->cdevs[0];
2282 		cd1 = STm->cdevs[1];
2283 		d0  = STm->devs[0];
2284 		d1  = STm->devs[1];
2285 		memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2286 		STm->cdevs[0] = cd0;
2287 		STm->cdevs[1] = cd1;
2288 		STm->devs[0]  = d0;
2289 		STm->devs[1]  = d1;
2290 		modes_defined = 1;
2291 		DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2292 			    STp->current_mode);
2293 	}
2294 
2295 	code = options & MT_ST_OPTIONS;
2296 	if (code == MT_ST_BOOLEANS) {
2297 		STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2298 		STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2299 		STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2300 		STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2301 		STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2302 		STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2303 		STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2304 		STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2305 		STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2306 		if ((STp->device)->scsi_level >= SCSI_2)
2307 			STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2308 		STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2309 		STp->immediate = (options & MT_ST_NOWAIT) != 0;
2310 		STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2311 		STm->sysv = (options & MT_ST_SYSV) != 0;
2312 		STp->sili = (options & MT_ST_SILI) != 0;
2313 		DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2314 		     st_log_options(STp, STm); )
2315 	} else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2316 		value = (code == MT_ST_SETBOOLEANS);
2317 		if ((options & MT_ST_BUFFER_WRITES) != 0)
2318 			STm->do_buffer_writes = value;
2319 		if ((options & MT_ST_ASYNC_WRITES) != 0)
2320 			STm->do_async_writes = value;
2321 		if ((options & MT_ST_DEF_WRITES) != 0)
2322 			STm->defaults_for_writes = value;
2323 		if ((options & MT_ST_READ_AHEAD) != 0)
2324 			STm->do_read_ahead = value;
2325 		if ((options & MT_ST_TWO_FM) != 0)
2326 			STp->two_fm = value;
2327 		if ((options & MT_ST_FAST_MTEOM) != 0)
2328 			STp->fast_mteom = value;
2329 		if ((options & MT_ST_AUTO_LOCK) != 0)
2330 			STp->do_auto_lock = value;
2331 		if ((options & MT_ST_CAN_BSR) != 0)
2332 			STp->can_bsr = value;
2333 		if ((options & MT_ST_NO_BLKLIMS) != 0)
2334 			STp->omit_blklims = value;
2335 		if ((STp->device)->scsi_level >= SCSI_2 &&
2336 		    (options & MT_ST_CAN_PARTITIONS) != 0)
2337 			STp->can_partitions = value;
2338 		if ((options & MT_ST_SCSI2LOGICAL) != 0)
2339 			STp->scsi2_logical = value;
2340 		if ((options & MT_ST_NOWAIT) != 0)
2341 			STp->immediate = value;
2342 		if ((options & MT_ST_NOWAIT_EOF) != 0)
2343 			STp->immediate_filemark = value;
2344 		if ((options & MT_ST_SYSV) != 0)
2345 			STm->sysv = value;
2346 		if ((options & MT_ST_SILI) != 0)
2347 			STp->sili = value;
2348 		DEB(
2349 		if ((options & MT_ST_DEBUGGING) != 0)
2350 			debugging = value;
2351 			st_log_options(STp, STm); )
2352 	} else if (code == MT_ST_WRITE_THRESHOLD) {
2353 		/* Retained for compatibility */
2354 	} else if (code == MT_ST_DEF_BLKSIZE) {
2355 		value = (options & ~MT_ST_OPTIONS);
2356 		if (value == ~MT_ST_OPTIONS) {
2357 			STm->default_blksize = (-1);
2358 			DEBC_printk(STp, "Default block size disabled.\n");
2359 		} else {
2360 			STm->default_blksize = value;
2361 			DEBC_printk(STp,"Default block size set to "
2362 				    "%d bytes.\n", STm->default_blksize);
2363 			if (STp->ready == ST_READY) {
2364 				STp->blksize_changed = 0;
2365 				set_mode_densblk(STp, STm);
2366 			}
2367 		}
2368 	} else if (code == MT_ST_TIMEOUTS) {
2369 		value = (options & ~MT_ST_OPTIONS);
2370 		if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2371 			STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2372 			DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2373 				    (value & ~MT_ST_SET_LONG_TIMEOUT));
2374 		} else {
2375 			blk_queue_rq_timeout(STp->device->request_queue,
2376 					     value * HZ);
2377 			DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2378 				    value);
2379 		}
2380 	} else if (code == MT_ST_SET_CLN) {
2381 		value = (options & ~MT_ST_OPTIONS) & 0xff;
2382 		if (value != 0 &&
2383 			(value < EXTENDED_SENSE_START ||
2384 				value >= SCSI_SENSE_BUFFERSIZE))
2385 			return (-EINVAL);
2386 		STp->cln_mode = value;
2387 		STp->cln_sense_mask = (options >> 8) & 0xff;
2388 		STp->cln_sense_value = (options >> 16) & 0xff;
2389 		st_printk(KERN_INFO, STp,
2390 			  "Cleaning request mode %d, mask %02x, value %02x\n",
2391 			  value, STp->cln_sense_mask, STp->cln_sense_value);
2392 	} else if (code == MT_ST_DEF_OPTIONS) {
2393 		code = (options & ~MT_ST_CLEAR_DEFAULT);
2394 		value = (options & MT_ST_CLEAR_DEFAULT);
2395 		if (code == MT_ST_DEF_DENSITY) {
2396 			if (value == MT_ST_CLEAR_DEFAULT) {
2397 				STm->default_density = (-1);
2398 				DEBC_printk(STp,
2399 					    "Density default disabled.\n");
2400 			} else {
2401 				STm->default_density = value & 0xff;
2402 				DEBC_printk(STp, "Density default set to %x\n",
2403 					    STm->default_density);
2404 				if (STp->ready == ST_READY) {
2405 					STp->density_changed = 0;
2406 					set_mode_densblk(STp, STm);
2407 				}
2408 			}
2409 		} else if (code == MT_ST_DEF_DRVBUFFER) {
2410 			if (value == MT_ST_CLEAR_DEFAULT) {
2411 				STp->default_drvbuffer = 0xff;
2412 				DEBC_printk(STp,
2413 					    "Drive buffer default disabled.\n");
2414 			} else {
2415 				STp->default_drvbuffer = value & 7;
2416 				DEBC_printk(STp,
2417 					    "Drive buffer default set to %x\n",
2418 					    STp->default_drvbuffer);
2419 				if (STp->ready == ST_READY)
2420 					st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2421 			}
2422 		} else if (code == MT_ST_DEF_COMPRESSION) {
2423 			if (value == MT_ST_CLEAR_DEFAULT) {
2424 				STm->default_compression = ST_DONT_TOUCH;
2425 				DEBC_printk(STp,
2426 					    "Compression default disabled.\n");
2427 			} else {
2428 				if ((value & 0xff00) != 0) {
2429 					STp->c_algo = (value & 0xff00) >> 8;
2430 					DEBC_printk(STp, "Compression "
2431 						    "algorithm set to 0x%x.\n",
2432 						    STp->c_algo);
2433 				}
2434 				if ((value & 0xff) != 0xff) {
2435 					STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2436 					DEBC_printk(STp, "Compression default "
2437 						    "set to %x\n",
2438 						    (value & 1));
2439 					if (STp->ready == ST_READY) {
2440 						STp->compression_changed = 0;
2441 						st_compression(STp, (STm->default_compression == ST_YES));
2442 					}
2443 				}
2444 			}
2445 		}
2446 	} else
2447 		return (-EIO);
2448 
2449 	return 0;
2450 }
2451 
2452 #define MODE_HEADER_LENGTH  4
2453 
2454 /* Mode header and page byte offsets */
2455 #define MH_OFF_DATA_LENGTH     0
2456 #define MH_OFF_MEDIUM_TYPE     1
2457 #define MH_OFF_DEV_SPECIFIC    2
2458 #define MH_OFF_BDESCS_LENGTH   3
2459 #define MP_OFF_PAGE_NBR        0
2460 #define MP_OFF_PAGE_LENGTH     1
2461 
2462 /* Mode header and page bit masks */
2463 #define MH_BIT_WP              0x80
2464 #define MP_MSK_PAGE_NBR        0x3f
2465 
2466 /* Don't return block descriptors */
2467 #define MODE_SENSE_OMIT_BDESCS 0x08
2468 
2469 #define MODE_SELECT_PAGE_FORMAT 0x10
2470 
2471 /* Read a mode page into the tape buffer. The block descriptors are included
2472    if incl_block_descs is true. The page control is ored to the page number
2473    parameter, if necessary. */
2474 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2475 {
2476 	unsigned char cmd[MAX_COMMAND_SIZE];
2477 	struct st_request *SRpnt;
2478 
2479 	memset(cmd, 0, MAX_COMMAND_SIZE);
2480 	cmd[0] = MODE_SENSE;
2481 	if (omit_block_descs)
2482 		cmd[1] = MODE_SENSE_OMIT_BDESCS;
2483 	cmd[2] = page;
2484 	cmd[4] = 255;
2485 
2486 	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2487 			   STp->device->request_queue->rq_timeout, 0, 1);
2488 	if (SRpnt == NULL)
2489 		return (STp->buffer)->syscall_result;
2490 
2491 	st_release_request(SRpnt);
2492 
2493 	return STp->buffer->syscall_result;
2494 }
2495 
2496 
2497 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2498    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2499 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2500 {
2501 	int pgo;
2502 	unsigned char cmd[MAX_COMMAND_SIZE];
2503 	struct st_request *SRpnt;
2504 	int timeout;
2505 
2506 	memset(cmd, 0, MAX_COMMAND_SIZE);
2507 	cmd[0] = MODE_SELECT;
2508 	cmd[1] = MODE_SELECT_PAGE_FORMAT;
2509 	pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2510 	cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2511 
2512 	/* Clear reserved fields */
2513 	(STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2514 	(STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2515 	(STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2516 	(STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2517 
2518 	timeout = slow ?
2519 		STp->long_timeout : STp->device->request_queue->rq_timeout;
2520 	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2521 			   timeout, 0, 1);
2522 	if (SRpnt == NULL)
2523 		return (STp->buffer)->syscall_result;
2524 
2525 	st_release_request(SRpnt);
2526 
2527 	return STp->buffer->syscall_result;
2528 }
2529 
2530 
2531 #define COMPRESSION_PAGE        0x0f
2532 #define COMPRESSION_PAGE_LENGTH 16
2533 
2534 #define CP_OFF_DCE_DCC          2
2535 #define CP_OFF_C_ALGO           7
2536 
2537 #define DCE_MASK  0x80
2538 #define DCC_MASK  0x40
2539 #define RED_MASK  0x60
2540 
2541 
2542 /* Control the compression with mode page 15. Algorithm not changed if zero.
2543 
2544    The block descriptors are read and written because Sony SDT-7000 does not
2545    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2546    Including block descriptors should not cause any harm to other drives. */
2547 
2548 static int st_compression(struct scsi_tape * STp, int state)
2549 {
2550 	int retval;
2551 	int mpoffs;  /* Offset to mode page start */
2552 	unsigned char *b_data = (STp->buffer)->b_data;
2553 
2554 	if (STp->ready != ST_READY)
2555 		return (-EIO);
2556 
2557 	/* Read the current page contents */
2558 	retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2559 	if (retval) {
2560 		DEBC_printk(STp, "Compression mode page not supported.\n");
2561 		return (-EIO);
2562 	}
2563 
2564 	mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2565 	DEBC_printk(STp, "Compression state is %d.\n",
2566 		    (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2567 
2568 	/* Check if compression can be changed */
2569 	if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2570 		DEBC_printk(STp, "Compression not supported.\n");
2571 		return (-EIO);
2572 	}
2573 
2574 	/* Do the change */
2575 	if (state) {
2576 		b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2577 		if (STp->c_algo != 0)
2578 			b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2579 	}
2580 	else {
2581 		b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2582 		if (STp->c_algo != 0)
2583 			b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2584 	}
2585 
2586 	retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2587 	if (retval) {
2588 		DEBC_printk(STp, "Compression change failed.\n");
2589 		return (-EIO);
2590 	}
2591 	DEBC_printk(STp, "Compression state changed to %d.\n", state);
2592 
2593 	STp->compression_changed = 1;
2594 	return 0;
2595 }
2596 
2597 
2598 /* Process the load and unload commands (does unload if the load code is zero) */
2599 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2600 {
2601 	int retval = (-EIO), timeout;
2602 	unsigned char cmd[MAX_COMMAND_SIZE];
2603 	struct st_partstat *STps;
2604 	struct st_request *SRpnt;
2605 
2606 	if (STp->ready != ST_READY && !load_code) {
2607 		if (STp->ready == ST_NO_TAPE)
2608 			return (-ENOMEDIUM);
2609 		else
2610 			return (-EIO);
2611 	}
2612 
2613 	memset(cmd, 0, MAX_COMMAND_SIZE);
2614 	cmd[0] = START_STOP;
2615 	if (load_code)
2616 		cmd[4] |= 1;
2617 	/*
2618 	 * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2619 	 */
2620 	if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2621 	    && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2622 		DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2623 			    (cmd[4]) ? "" : "un",
2624 			    load_code - MT_ST_HPLOADER_OFFSET);
2625 		cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2626 	}
2627 	if (STp->immediate) {
2628 		cmd[1] = 1;	/* Don't wait for completion */
2629 		timeout = STp->device->request_queue->rq_timeout;
2630 	}
2631 	else
2632 		timeout = STp->long_timeout;
2633 
2634 	DEBC(
2635 		if (!load_code)
2636 			st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2637 		else
2638 			st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2639 		);
2640 
2641 	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2642 			   timeout, MAX_RETRIES, 1);
2643 	if (!SRpnt)
2644 		return (STp->buffer)->syscall_result;
2645 
2646 	retval = (STp->buffer)->syscall_result;
2647 	st_release_request(SRpnt);
2648 
2649 	if (!retval) {	/* SCSI command successful */
2650 
2651 		if (!load_code) {
2652 			STp->rew_at_close = 0;
2653 			STp->ready = ST_NO_TAPE;
2654 		}
2655 		else {
2656 			STp->rew_at_close = STp->autorew_dev;
2657 			retval = check_tape(STp, filp);
2658 			if (retval > 0)
2659 				retval = 0;
2660 		}
2661 	}
2662 	else {
2663 		STps = &(STp->ps[STp->partition]);
2664 		STps->drv_file = STps->drv_block = (-1);
2665 	}
2666 
2667 	return retval;
2668 }
2669 
2670 #if DEBUG
2671 #define ST_DEB_FORWARD  0
2672 #define ST_DEB_BACKWARD 1
2673 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2674 {
2675 	s32 sc;
2676 
2677 	if (!debugging)
2678 		return;
2679 
2680 	sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2681 	sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2682 	if (direction)
2683 		sc = -sc;
2684 	st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2685 		  direction ? "backward" : "forward", sc, units);
2686 }
2687 #else
2688 #define ST_DEB_FORWARD  0
2689 #define ST_DEB_BACKWARD 1
2690 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2691 #endif
2692 
2693 
2694 /* Internal ioctl function */
2695 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2696 {
2697 	int timeout;
2698 	long ltmp;
2699 	int ioctl_result;
2700 	int chg_eof = 1;
2701 	unsigned char cmd[MAX_COMMAND_SIZE];
2702 	struct st_request *SRpnt;
2703 	struct st_partstat *STps;
2704 	int fileno, blkno, at_sm, undone;
2705 	int datalen = 0, direction = DMA_NONE;
2706 
2707 	WARN_ON(STp->buffer->do_dio != 0);
2708 	if (STp->ready != ST_READY) {
2709 		if (STp->ready == ST_NO_TAPE)
2710 			return (-ENOMEDIUM);
2711 		else
2712 			return (-EIO);
2713 	}
2714 	timeout = STp->long_timeout;
2715 	STps = &(STp->ps[STp->partition]);
2716 	fileno = STps->drv_file;
2717 	blkno = STps->drv_block;
2718 	at_sm = STps->at_sm;
2719 
2720 	memset(cmd, 0, MAX_COMMAND_SIZE);
2721 	switch (cmd_in) {
2722 	case MTFSFM:
2723 		chg_eof = 0;	/* Changed from the FSF after this */
2724 	case MTFSF:
2725 		cmd[0] = SPACE;
2726 		cmd[1] = 0x01;	/* Space FileMarks */
2727 		cmd[2] = (arg >> 16);
2728 		cmd[3] = (arg >> 8);
2729 		cmd[4] = arg;
2730 		deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2731 		if (fileno >= 0)
2732 			fileno += arg;
2733 		blkno = 0;
2734 		at_sm &= (arg == 0);
2735 		break;
2736 	case MTBSFM:
2737 		chg_eof = 0;	/* Changed from the FSF after this */
2738 	case MTBSF:
2739 		cmd[0] = SPACE;
2740 		cmd[1] = 0x01;	/* Space FileMarks */
2741 		ltmp = (-arg);
2742 		cmd[2] = (ltmp >> 16);
2743 		cmd[3] = (ltmp >> 8);
2744 		cmd[4] = ltmp;
2745 		deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2746 		if (fileno >= 0)
2747 			fileno -= arg;
2748 		blkno = (-1);	/* We can't know the block number */
2749 		at_sm &= (arg == 0);
2750 		break;
2751 	case MTFSR:
2752 		cmd[0] = SPACE;
2753 		cmd[1] = 0x00;	/* Space Blocks */
2754 		cmd[2] = (arg >> 16);
2755 		cmd[3] = (arg >> 8);
2756 		cmd[4] = arg;
2757 		deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2758 		if (blkno >= 0)
2759 			blkno += arg;
2760 		at_sm &= (arg == 0);
2761 		break;
2762 	case MTBSR:
2763 		cmd[0] = SPACE;
2764 		cmd[1] = 0x00;	/* Space Blocks */
2765 		ltmp = (-arg);
2766 		cmd[2] = (ltmp >> 16);
2767 		cmd[3] = (ltmp >> 8);
2768 		cmd[4] = ltmp;
2769 		deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2770 		if (blkno >= 0)
2771 			blkno -= arg;
2772 		at_sm &= (arg == 0);
2773 		break;
2774 	case MTFSS:
2775 		cmd[0] = SPACE;
2776 		cmd[1] = 0x04;	/* Space Setmarks */
2777 		cmd[2] = (arg >> 16);
2778 		cmd[3] = (arg >> 8);
2779 		cmd[4] = arg;
2780 		deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2781 		if (arg != 0) {
2782 			blkno = fileno = (-1);
2783 			at_sm = 1;
2784 		}
2785 		break;
2786 	case MTBSS:
2787 		cmd[0] = SPACE;
2788 		cmd[1] = 0x04;	/* Space Setmarks */
2789 		ltmp = (-arg);
2790 		cmd[2] = (ltmp >> 16);
2791 		cmd[3] = (ltmp >> 8);
2792 		cmd[4] = ltmp;
2793 		deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2794 		if (arg != 0) {
2795 			blkno = fileno = (-1);
2796 			at_sm = 1;
2797 		}
2798 		break;
2799 	case MTWEOF:
2800 	case MTWEOFI:
2801 	case MTWSM:
2802 		if (STp->write_prot)
2803 			return (-EACCES);
2804 		cmd[0] = WRITE_FILEMARKS;
2805 		if (cmd_in == MTWSM)
2806 			cmd[1] = 2;
2807 		if (cmd_in == MTWEOFI ||
2808 		    (cmd_in == MTWEOF && STp->immediate_filemark))
2809 			cmd[1] |= 1;
2810 		cmd[2] = (arg >> 16);
2811 		cmd[3] = (arg >> 8);
2812 		cmd[4] = arg;
2813 		timeout = STp->device->request_queue->rq_timeout;
2814 		DEBC(
2815 			if (cmd_in != MTWSM)
2816 				st_printk(ST_DEB_MSG, STp,
2817 					  "Writing %d filemarks.\n",
2818 					  cmd[2] * 65536 +
2819 					  cmd[3] * 256 +
2820 					  cmd[4]);
2821 			else
2822 				st_printk(ST_DEB_MSG, STp,
2823 					  "Writing %d setmarks.\n",
2824 					  cmd[2] * 65536 +
2825 					  cmd[3] * 256 +
2826 					  cmd[4]);
2827 		)
2828 		if (fileno >= 0)
2829 			fileno += arg;
2830 		blkno = 0;
2831 		at_sm = (cmd_in == MTWSM);
2832 		break;
2833 	case MTREW:
2834 		cmd[0] = REZERO_UNIT;
2835 		if (STp->immediate) {
2836 			cmd[1] = 1;	/* Don't wait for completion */
2837 			timeout = STp->device->request_queue->rq_timeout;
2838 		}
2839 		DEBC_printk(STp, "Rewinding tape.\n");
2840 		fileno = blkno = at_sm = 0;
2841 		break;
2842 	case MTNOP:
2843 		DEBC_printk(STp, "No op on tape.\n");
2844 		return 0;	/* Should do something ? */
2845 		break;
2846 	case MTRETEN:
2847 		cmd[0] = START_STOP;
2848 		if (STp->immediate) {
2849 			cmd[1] = 1;	/* Don't wait for completion */
2850 			timeout = STp->device->request_queue->rq_timeout;
2851 		}
2852 		cmd[4] = 3;
2853 		DEBC_printk(STp, "Retensioning tape.\n");
2854 		fileno = blkno = at_sm = 0;
2855 		break;
2856 	case MTEOM:
2857 		if (!STp->fast_mteom) {
2858 			/* space to the end of tape */
2859 			ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2860 			fileno = STps->drv_file;
2861 			if (STps->eof >= ST_EOD_1)
2862 				return 0;
2863 			/* The next lines would hide the number of spaced FileMarks
2864 			   That's why I inserted the previous lines. I had no luck
2865 			   with detecting EOM with FSF, so we go now to EOM.
2866 			   Joerg Weule */
2867 		} else
2868 			fileno = (-1);
2869 		cmd[0] = SPACE;
2870 		cmd[1] = 3;
2871 		DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2872 		blkno = -1;
2873 		at_sm = 0;
2874 		break;
2875 	case MTERASE:
2876 		if (STp->write_prot)
2877 			return (-EACCES);
2878 		cmd[0] = ERASE;
2879 		cmd[1] = (arg ? 1 : 0);	/* Long erase with non-zero argument */
2880 		if (STp->immediate) {
2881 			cmd[1] |= 2;	/* Don't wait for completion */
2882 			timeout = STp->device->request_queue->rq_timeout;
2883 		}
2884 		else
2885 			timeout = STp->long_timeout * 8;
2886 
2887 		DEBC_printk(STp, "Erasing tape.\n");
2888 		fileno = blkno = at_sm = 0;
2889 		break;
2890 	case MTSETBLK:		/* Set block length */
2891 	case MTSETDENSITY:	/* Set tape density */
2892 	case MTSETDRVBUFFER:	/* Set drive buffering */
2893 	case SET_DENS_AND_BLK:	/* Set density and block size */
2894 		chg_eof = 0;
2895 		if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2896 			return (-EIO);	/* Not allowed if data in buffer */
2897 		if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2898 		    (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2899 		    STp->max_block > 0 &&
2900 		    ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2901 		     (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2902 			st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2903 			return (-EINVAL);
2904 		}
2905 		cmd[0] = MODE_SELECT;
2906 		if ((STp->use_pf & USE_PF))
2907 			cmd[1] = MODE_SELECT_PAGE_FORMAT;
2908 		cmd[4] = datalen = 12;
2909 		direction = DMA_TO_DEVICE;
2910 
2911 		memset((STp->buffer)->b_data, 0, 12);
2912 		if (cmd_in == MTSETDRVBUFFER)
2913 			(STp->buffer)->b_data[2] = (arg & 7) << 4;
2914 		else
2915 			(STp->buffer)->b_data[2] =
2916 			    STp->drv_buffer << 4;
2917 		(STp->buffer)->b_data[3] = 8;	/* block descriptor length */
2918 		if (cmd_in == MTSETDENSITY) {
2919 			(STp->buffer)->b_data[4] = arg;
2920 			STp->density_changed = 1;	/* At least we tried ;-) */
2921 		} else if (cmd_in == SET_DENS_AND_BLK)
2922 			(STp->buffer)->b_data[4] = arg >> 24;
2923 		else
2924 			(STp->buffer)->b_data[4] = STp->density;
2925 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2926 			ltmp = arg & MT_ST_BLKSIZE_MASK;
2927 			if (cmd_in == MTSETBLK)
2928 				STp->blksize_changed = 1; /* At least we tried ;-) */
2929 		} else
2930 			ltmp = STp->block_size;
2931 		(STp->buffer)->b_data[9] = (ltmp >> 16);
2932 		(STp->buffer)->b_data[10] = (ltmp >> 8);
2933 		(STp->buffer)->b_data[11] = ltmp;
2934 		timeout = STp->device->request_queue->rq_timeout;
2935 		DEBC(
2936 			if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2937 				st_printk(ST_DEB_MSG, STp,
2938 					  "Setting block size to %d bytes.\n",
2939 					  (STp->buffer)->b_data[9] * 65536 +
2940 					  (STp->buffer)->b_data[10] * 256 +
2941 					  (STp->buffer)->b_data[11]);
2942 			if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2943 				st_printk(ST_DEB_MSG, STp,
2944 					  "Setting density code to %x.\n",
2945 					  (STp->buffer)->b_data[4]);
2946 			if (cmd_in == MTSETDRVBUFFER)
2947 				st_printk(ST_DEB_MSG, STp,
2948 					  "Setting drive buffer code to %d.\n",
2949 					  ((STp->buffer)->b_data[2] >> 4) & 7);
2950 		)
2951 		break;
2952 	default:
2953 		return (-ENOSYS);
2954 	}
2955 
2956 	SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2957 			   timeout, MAX_RETRIES, 1);
2958 	if (!SRpnt)
2959 		return (STp->buffer)->syscall_result;
2960 
2961 	ioctl_result = (STp->buffer)->syscall_result;
2962 
2963 	if (!ioctl_result) {	/* SCSI command successful */
2964 		st_release_request(SRpnt);
2965 		SRpnt = NULL;
2966 		STps->drv_block = blkno;
2967 		STps->drv_file = fileno;
2968 		STps->at_sm = at_sm;
2969 
2970 		if (cmd_in == MTBSFM)
2971 			ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2972 		else if (cmd_in == MTFSFM)
2973 			ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2974 
2975 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2976 			STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2977 			if (STp->block_size != 0) {
2978 				(STp->buffer)->buffer_blocks =
2979 				    (STp->buffer)->buffer_size / STp->block_size;
2980 			}
2981 			(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2982 			if (cmd_in == SET_DENS_AND_BLK)
2983 				STp->density = arg >> MT_ST_DENSITY_SHIFT;
2984 		} else if (cmd_in == MTSETDRVBUFFER)
2985 			STp->drv_buffer = (arg & 7);
2986 		else if (cmd_in == MTSETDENSITY)
2987 			STp->density = arg;
2988 
2989 		if (cmd_in == MTEOM)
2990 			STps->eof = ST_EOD;
2991 		else if (cmd_in == MTFSF)
2992 			STps->eof = ST_FM;
2993 		else if (chg_eof)
2994 			STps->eof = ST_NOEOF;
2995 
2996 		if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
2997 			STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
2998 	} else { /* SCSI command was not completely successful. Don't return
2999                     from this block without releasing the SCSI command block! */
3000 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3001 
3002 		if (cmdstatp->flags & SENSE_EOM) {
3003 			if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3004 			    cmd_in != MTBSR && cmd_in != MTBSS)
3005 				STps->eof = ST_EOM_OK;
3006 			STps->drv_block = 0;
3007 		}
3008 
3009 		if (cmdstatp->remainder_valid)
3010 			undone = (int)cmdstatp->uremainder64;
3011 		else
3012 			undone = 0;
3013 
3014 		if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3015 		    cmdstatp->have_sense &&
3016 		    (cmdstatp->flags & SENSE_EOM)) {
3017 			if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3018 			    cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3019 				ioctl_result = 0;	/* EOF(s) written successfully at EOM */
3020 				STps->eof = ST_NOEOF;
3021 			} else {  /* Writing EOF(s) failed */
3022 				if (fileno >= 0)
3023 					fileno -= undone;
3024 				if (undone < arg)
3025 					STps->eof = ST_NOEOF;
3026 			}
3027 			STps->drv_file = fileno;
3028 		} else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3029 			if (fileno >= 0)
3030 				STps->drv_file = fileno - undone;
3031 			else
3032 				STps->drv_file = fileno;
3033 			STps->drv_block = -1;
3034 			STps->eof = ST_NOEOF;
3035 		} else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3036 			if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3037 				undone = (-undone);
3038 			if (STps->drv_file >= 0)
3039 				STps->drv_file = fileno + undone;
3040 			STps->drv_block = 0;
3041 			STps->eof = ST_NOEOF;
3042 		} else if (cmd_in == MTFSR) {
3043 			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3044 				if (STps->drv_file >= 0)
3045 					STps->drv_file++;
3046 				STps->drv_block = 0;
3047 				STps->eof = ST_FM;
3048 			} else {
3049 				if (blkno >= undone)
3050 					STps->drv_block = blkno - undone;
3051 				else
3052 					STps->drv_block = (-1);
3053 				STps->eof = ST_NOEOF;
3054 			}
3055 		} else if (cmd_in == MTBSR) {
3056 			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3057 				STps->drv_file--;
3058 				STps->drv_block = (-1);
3059 			} else {
3060 				if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3061 					undone = (-undone);
3062 				if (STps->drv_block >= 0)
3063 					STps->drv_block = blkno + undone;
3064 			}
3065 			STps->eof = ST_NOEOF;
3066 		} else if (cmd_in == MTEOM) {
3067 			STps->drv_file = (-1);
3068 			STps->drv_block = (-1);
3069 			STps->eof = ST_EOD;
3070 		} else if (cmd_in == MTSETBLK ||
3071 			   cmd_in == MTSETDENSITY ||
3072 			   cmd_in == MTSETDRVBUFFER ||
3073 			   cmd_in == SET_DENS_AND_BLK) {
3074 			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3075 			    !(STp->use_pf & PF_TESTED)) {
3076 				/* Try the other possible state of Page Format if not
3077 				   already tried */
3078 				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3079 				st_release_request(SRpnt);
3080 				SRpnt = NULL;
3081 				return st_int_ioctl(STp, cmd_in, arg);
3082 			}
3083 		} else if (chg_eof)
3084 			STps->eof = ST_NOEOF;
3085 
3086 		if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3087 			STps->eof = ST_EOD;
3088 
3089 		st_release_request(SRpnt);
3090 		SRpnt = NULL;
3091 	}
3092 
3093 	return ioctl_result;
3094 }
3095 
3096 
3097 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3098    structure. */
3099 
3100 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3101 			int logical)
3102 {
3103 	int result;
3104 	unsigned char scmd[MAX_COMMAND_SIZE];
3105 	struct st_request *SRpnt;
3106 
3107 	if (STp->ready != ST_READY)
3108 		return (-EIO);
3109 
3110 	memset(scmd, 0, MAX_COMMAND_SIZE);
3111 	if ((STp->device)->scsi_level < SCSI_2) {
3112 		scmd[0] = QFA_REQUEST_BLOCK;
3113 		scmd[4] = 3;
3114 	} else {
3115 		scmd[0] = READ_POSITION;
3116 		if (!logical && !STp->scsi2_logical)
3117 			scmd[1] = 1;
3118 	}
3119 	SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3120 			   STp->device->request_queue->rq_timeout,
3121 			   MAX_READY_RETRIES, 1);
3122 	if (!SRpnt)
3123 		return (STp->buffer)->syscall_result;
3124 
3125 	if ((STp->buffer)->syscall_result != 0 ||
3126 	    (STp->device->scsi_level >= SCSI_2 &&
3127 	     ((STp->buffer)->b_data[0] & 4) != 0)) {
3128 		*block = *partition = 0;
3129 		DEBC_printk(STp, " Can't read tape position.\n");
3130 		result = (-EIO);
3131 	} else {
3132 		result = 0;
3133 		if ((STp->device)->scsi_level < SCSI_2) {
3134 			*block = ((STp->buffer)->b_data[0] << 16)
3135 			    + ((STp->buffer)->b_data[1] << 8)
3136 			    + (STp->buffer)->b_data[2];
3137 			*partition = 0;
3138 		} else {
3139 			*block = ((STp->buffer)->b_data[4] << 24)
3140 			    + ((STp->buffer)->b_data[5] << 16)
3141 			    + ((STp->buffer)->b_data[6] << 8)
3142 			    + (STp->buffer)->b_data[7];
3143 			*partition = (STp->buffer)->b_data[1];
3144 			if (((STp->buffer)->b_data[0] & 0x80) &&
3145 			    (STp->buffer)->b_data[1] == 0)	/* BOP of partition 0 */
3146 				STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3147 		}
3148 		DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3149 			    *block, *partition);
3150 	}
3151 	st_release_request(SRpnt);
3152 	SRpnt = NULL;
3153 
3154 	return result;
3155 }
3156 
3157 
3158 /* Set the tape block and partition. Negative partition means that only the
3159    block should be set in vendor specific way. */
3160 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3161 			int logical)
3162 {
3163 	struct st_partstat *STps;
3164 	int result, p;
3165 	unsigned int blk;
3166 	int timeout;
3167 	unsigned char scmd[MAX_COMMAND_SIZE];
3168 	struct st_request *SRpnt;
3169 
3170 	if (STp->ready != ST_READY)
3171 		return (-EIO);
3172 	timeout = STp->long_timeout;
3173 	STps = &(STp->ps[STp->partition]);
3174 
3175 	DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3176 		    block, partition);
3177 	DEB(if (partition < 0)
3178 		return (-EIO); )
3179 
3180 	/* Update the location at the partition we are leaving */
3181 	if ((!STp->can_partitions && partition != 0) ||
3182 	    partition >= ST_NBR_PARTITIONS)
3183 		return (-EINVAL);
3184 	if (partition != STp->partition) {
3185 		if (get_location(STp, &blk, &p, 1))
3186 			STps->last_block_valid = 0;
3187 		else {
3188 			STps->last_block_valid = 1;
3189 			STps->last_block_visited = blk;
3190 			DEBC_printk(STp, "Visited block %d for "
3191 				    "partition %d saved.\n",
3192 				    blk, STp->partition);
3193 		}
3194 	}
3195 
3196 	memset(scmd, 0, MAX_COMMAND_SIZE);
3197 	if ((STp->device)->scsi_level < SCSI_2) {
3198 		scmd[0] = QFA_SEEK_BLOCK;
3199 		scmd[2] = (block >> 16);
3200 		scmd[3] = (block >> 8);
3201 		scmd[4] = block;
3202 		scmd[5] = 0;
3203 	} else {
3204 		scmd[0] = SEEK_10;
3205 		scmd[3] = (block >> 24);
3206 		scmd[4] = (block >> 16);
3207 		scmd[5] = (block >> 8);
3208 		scmd[6] = block;
3209 		if (!logical && !STp->scsi2_logical)
3210 			scmd[1] = 4;
3211 		if (STp->partition != partition) {
3212 			scmd[1] |= 2;
3213 			scmd[8] = partition;
3214 			DEBC_printk(STp, "Trying to change partition "
3215 				    "from %d to %d\n", STp->partition,
3216 				    partition);
3217 		}
3218 	}
3219 	if (STp->immediate) {
3220 		scmd[1] |= 1;		/* Don't wait for completion */
3221 		timeout = STp->device->request_queue->rq_timeout;
3222 	}
3223 
3224 	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3225 			   timeout, MAX_READY_RETRIES, 1);
3226 	if (!SRpnt)
3227 		return (STp->buffer)->syscall_result;
3228 
3229 	STps->drv_block = STps->drv_file = (-1);
3230 	STps->eof = ST_NOEOF;
3231 	if ((STp->buffer)->syscall_result != 0) {
3232 		result = (-EIO);
3233 		if (STp->can_partitions &&
3234 		    (STp->device)->scsi_level >= SCSI_2 &&
3235 		    (p = find_partition(STp)) >= 0)
3236 			STp->partition = p;
3237 	} else {
3238 		if (STp->can_partitions) {
3239 			STp->partition = partition;
3240 			STps = &(STp->ps[partition]);
3241 			if (!STps->last_block_valid ||
3242 			    STps->last_block_visited != block) {
3243 				STps->at_sm = 0;
3244 				STps->rw = ST_IDLE;
3245 			}
3246 		} else
3247 			STps->at_sm = 0;
3248 		if (block == 0)
3249 			STps->drv_block = STps->drv_file = 0;
3250 		result = 0;
3251 	}
3252 
3253 	st_release_request(SRpnt);
3254 	SRpnt = NULL;
3255 
3256 	return result;
3257 }
3258 
3259 
3260 /* Find the current partition number for the drive status. Called from open and
3261    returns either partition number of negative error code. */
3262 static int find_partition(struct scsi_tape *STp)
3263 {
3264 	int i, partition;
3265 	unsigned int block;
3266 
3267 	if ((i = get_location(STp, &block, &partition, 1)) < 0)
3268 		return i;
3269 	if (partition >= ST_NBR_PARTITIONS)
3270 		return (-EIO);
3271 	return partition;
3272 }
3273 
3274 
3275 /* Change the partition if necessary */
3276 static int switch_partition(struct scsi_tape *STp)
3277 {
3278 	struct st_partstat *STps;
3279 
3280 	if (STp->partition == STp->new_partition)
3281 		return 0;
3282 	STps = &(STp->ps[STp->new_partition]);
3283 	if (!STps->last_block_valid)
3284 		STps->last_block_visited = 0;
3285 	return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3286 }
3287 
3288 /* Functions for reading and writing the medium partition mode page. */
3289 
3290 #define PART_PAGE   0x11
3291 #define PART_PAGE_FIXED_LENGTH 8
3292 
3293 #define PP_OFF_MAX_ADD_PARTS   2
3294 #define PP_OFF_NBR_ADD_PARTS   3
3295 #define PP_OFF_FLAGS           4
3296 #define PP_OFF_PART_UNITS      6
3297 #define PP_OFF_RESERVED        7
3298 
3299 #define PP_BIT_IDP             0x20
3300 #define PP_MSK_PSUM_MB         0x10
3301 
3302 /* Get the number of partitions on the tape. As a side effect reads the
3303    mode page into the tape buffer. */
3304 static int nbr_partitions(struct scsi_tape *STp)
3305 {
3306 	int result;
3307 
3308 	if (STp->ready != ST_READY)
3309 		return (-EIO);
3310 
3311 	result = read_mode_page(STp, PART_PAGE, 1);
3312 
3313 	if (result) {
3314 		DEBC_printk(STp, "Can't read medium partition page.\n");
3315 		result = (-EIO);
3316 	} else {
3317 		result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3318 					      PP_OFF_NBR_ADD_PARTS] + 1;
3319 		DEBC_printk(STp, "Number of partitions %d.\n", result);
3320 	}
3321 
3322 	return result;
3323 }
3324 
3325 
3326 /* Partition the tape into two partitions if size > 0 or one partition if
3327    size == 0.
3328 
3329    The block descriptors are read and written because Sony SDT-7000 does not
3330    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3331 
3332    My HP C1533A drive returns only one partition size field. This is used to
3333    set the size of partition 1. There is no size field for the default partition.
3334    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3335    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3336    The following algorithm is used to accommodate both drives: if the number of
3337    partition size fields is greater than the maximum number of additional partitions
3338    in the mode page, the second field is used. Otherwise the first field is used.
3339 
3340    For Seagate DDS drives the page length must be 8 when no partitions is defined
3341    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3342    is acceptable also to some other old drives and enforced if the first partition
3343    size field is used for the first additional partition size.
3344  */
3345 static int partition_tape(struct scsi_tape *STp, int size)
3346 {
3347 	int result;
3348 	int pgo, psd_cnt, psdo;
3349 	unsigned char *bp;
3350 
3351 	result = read_mode_page(STp, PART_PAGE, 0);
3352 	if (result) {
3353 		DEBC_printk(STp, "Can't read partition mode page.\n");
3354 		return result;
3355 	}
3356 	/* The mode page is in the buffer. Let's modify it and write it. */
3357 	bp = (STp->buffer)->b_data;
3358 	pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3359 	DEBC_printk(STp, "Partition page length is %d bytes.\n",
3360 		    bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3361 
3362 	psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3363 	psdo = pgo + PART_PAGE_FIXED_LENGTH;
3364 	if (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS]) {
3365 		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest of the tape */
3366 		psdo += 2;
3367 	}
3368 	memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3369 
3370 	DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3371 		    psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3372 		    bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3373 
3374 	if (size <= 0) {
3375 		bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3376 		if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3377 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3378 		DEBC_printk(STp, "Formatting tape with one partition.\n");
3379 	} else {
3380 		bp[psdo] = (size >> 8) & 0xff;
3381 		bp[psdo + 1] = size & 0xff;
3382 		bp[pgo + 3] = 1;
3383 		if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3384 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3385 		DEBC_printk(STp, "Formatting tape with two partitions "
3386 			    "(1 = %d MB).\n", size);
3387 	}
3388 	bp[pgo + PP_OFF_PART_UNITS] = 0;
3389 	bp[pgo + PP_OFF_RESERVED] = 0;
3390 	bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | PP_MSK_PSUM_MB;
3391 
3392 	result = write_mode_page(STp, PART_PAGE, 1);
3393 	if (result) {
3394 		st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3395 		result = (-EIO);
3396 	}
3397 
3398 	return result;
3399 }
3400 
3401 
3402 
3403 /* The ioctl command */
3404 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3405 {
3406 	int i, cmd_nr, cmd_type, bt;
3407 	int retval = 0;
3408 	unsigned int blk;
3409 	struct scsi_tape *STp = file->private_data;
3410 	struct st_modedef *STm;
3411 	struct st_partstat *STps;
3412 	void __user *p = (void __user *)arg;
3413 
3414 	if (mutex_lock_interruptible(&STp->lock))
3415 		return -ERESTARTSYS;
3416 
3417 	DEB(
3418 	if (debugging && !STp->in_use) {
3419 		st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3420 		retval = (-EIO);
3421 		goto out;
3422 	} ) /* end DEB */
3423 
3424 	STm = &(STp->modes[STp->current_mode]);
3425 	STps = &(STp->ps[STp->partition]);
3426 
3427 	/*
3428 	 * If we are in the middle of error recovery, don't let anyone
3429 	 * else try and use this device.  Also, if error recovery fails, it
3430 	 * may try and take the device offline, in which case all further
3431 	 * access to the device is prohibited.
3432 	 */
3433 	retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3434 			file->f_flags & O_NDELAY);
3435 	if (retval)
3436 		goto out;
3437 
3438 	cmd_type = _IOC_TYPE(cmd_in);
3439 	cmd_nr = _IOC_NR(cmd_in);
3440 
3441 	if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3442 		struct mtop mtc;
3443 
3444 		if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3445 			retval = (-EINVAL);
3446 			goto out;
3447 		}
3448 
3449 		i = copy_from_user(&mtc, p, sizeof(struct mtop));
3450 		if (i) {
3451 			retval = (-EFAULT);
3452 			goto out;
3453 		}
3454 
3455 		if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3456 			st_printk(KERN_WARNING, STp,
3457 				  "MTSETDRVBUFFER only allowed for root.\n");
3458 			retval = (-EPERM);
3459 			goto out;
3460 		}
3461 		if (!STm->defined &&
3462 		    (mtc.mt_op != MTSETDRVBUFFER &&
3463 		     (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3464 			retval = (-ENXIO);
3465 			goto out;
3466 		}
3467 
3468 		if (!STp->pos_unknown) {
3469 
3470 			if (STps->eof == ST_FM_HIT) {
3471 				if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3472                                     mtc.mt_op == MTEOM) {
3473 					mtc.mt_count -= 1;
3474 					if (STps->drv_file >= 0)
3475 						STps->drv_file += 1;
3476 				} else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3477 					mtc.mt_count += 1;
3478 					if (STps->drv_file >= 0)
3479 						STps->drv_file += 1;
3480 				}
3481 			}
3482 
3483 			if (mtc.mt_op == MTSEEK) {
3484 				/* Old position must be restored if partition will be
3485                                    changed */
3486 				i = !STp->can_partitions ||
3487 				    (STp->new_partition != STp->partition);
3488 			} else {
3489 				i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3490 				    mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3491 				    mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3492 				    mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3493 				    mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3494 				    mtc.mt_op == MTCOMPRESSION;
3495 			}
3496 			i = flush_buffer(STp, i);
3497 			if (i < 0) {
3498 				retval = i;
3499 				goto out;
3500 			}
3501 			if (STps->rw == ST_WRITING &&
3502 			    (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3503 			     mtc.mt_op == MTSEEK ||
3504 			     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3505 				i = st_int_ioctl(STp, MTWEOF, 1);
3506 				if (i < 0) {
3507 					retval = i;
3508 					goto out;
3509 				}
3510 				if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3511 					mtc.mt_count++;
3512 				STps->rw = ST_IDLE;
3513 			     }
3514 
3515 		} else {
3516 			/*
3517 			 * If there was a bus reset, block further access
3518 			 * to this device.  If the user wants to rewind the tape,
3519 			 * then reset the flag and allow access again.
3520 			 */
3521 			if (mtc.mt_op != MTREW &&
3522 			    mtc.mt_op != MTOFFL &&
3523 			    mtc.mt_op != MTRETEN &&
3524 			    mtc.mt_op != MTERASE &&
3525 			    mtc.mt_op != MTSEEK &&
3526 			    mtc.mt_op != MTEOM) {
3527 				retval = (-EIO);
3528 				goto out;
3529 			}
3530 			reset_state(STp);
3531 			/* remove this when the midlevel properly clears was_reset */
3532 			STp->device->was_reset = 0;
3533 		}
3534 
3535 		if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3536 		    mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3537 		    mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3538 			STps->rw = ST_IDLE;	/* Prevent automatic WEOF and fsf */
3539 
3540 		if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3541 			do_door_lock(STp, 0);	/* Ignore result! */
3542 
3543 		if (mtc.mt_op == MTSETDRVBUFFER &&
3544 		    (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3545 			retval = st_set_options(STp, mtc.mt_count);
3546 			goto out;
3547 		}
3548 
3549 		if (mtc.mt_op == MTSETPART) {
3550 			if (!STp->can_partitions ||
3551 			    mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3552 				retval = (-EINVAL);
3553 				goto out;
3554 			}
3555 			if (mtc.mt_count >= STp->nbr_partitions &&
3556 			    (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3557 				retval = (-EIO);
3558 				goto out;
3559 			}
3560 			if (mtc.mt_count >= STp->nbr_partitions) {
3561 				retval = (-EINVAL);
3562 				goto out;
3563 			}
3564 			STp->new_partition = mtc.mt_count;
3565 			retval = 0;
3566 			goto out;
3567 		}
3568 
3569 		if (mtc.mt_op == MTMKPART) {
3570 			if (!STp->can_partitions) {
3571 				retval = (-EINVAL);
3572 				goto out;
3573 			}
3574 			if ((i = st_int_ioctl(STp, MTREW, 0)) < 0 ||
3575 			    (i = partition_tape(STp, mtc.mt_count)) < 0) {
3576 				retval = i;
3577 				goto out;
3578 			}
3579 			for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3580 				STp->ps[i].rw = ST_IDLE;
3581 				STp->ps[i].at_sm = 0;
3582 				STp->ps[i].last_block_valid = 0;
3583 			}
3584 			STp->partition = STp->new_partition = 0;
3585 			STp->nbr_partitions = 1;	/* Bad guess ?-) */
3586 			STps->drv_block = STps->drv_file = 0;
3587 			retval = 0;
3588 			goto out;
3589 		}
3590 
3591 		if (mtc.mt_op == MTSEEK) {
3592 			i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3593 			if (!STp->can_partitions)
3594 				STp->ps[0].rw = ST_IDLE;
3595 			retval = i;
3596 			goto out;
3597 		}
3598 
3599 		if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3600 			retval = do_load_unload(STp, file, 0);
3601 			goto out;
3602 		}
3603 
3604 		if (mtc.mt_op == MTLOAD) {
3605 			retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3606 			goto out;
3607 		}
3608 
3609 		if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3610 			retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3611 			goto out;
3612 		}
3613 
3614 		if (STp->can_partitions && STp->ready == ST_READY &&
3615 		    (i = switch_partition(STp)) < 0) {
3616 			retval = i;
3617 			goto out;
3618 		}
3619 
3620 		if (mtc.mt_op == MTCOMPRESSION)
3621 			retval = st_compression(STp, (mtc.mt_count & 1));
3622 		else
3623 			retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3624 		goto out;
3625 	}
3626 	if (!STm->defined) {
3627 		retval = (-ENXIO);
3628 		goto out;
3629 	}
3630 
3631 	if ((i = flush_buffer(STp, 0)) < 0) {
3632 		retval = i;
3633 		goto out;
3634 	}
3635 	if (STp->can_partitions &&
3636 	    (i = switch_partition(STp)) < 0) {
3637 		retval = i;
3638 		goto out;
3639 	}
3640 
3641 	if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3642 		struct mtget mt_status;
3643 
3644 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3645 			 retval = (-EINVAL);
3646 			 goto out;
3647 		}
3648 
3649 		mt_status.mt_type = STp->tape_type;
3650 		mt_status.mt_dsreg =
3651 		    ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3652 		    ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3653 		mt_status.mt_blkno = STps->drv_block;
3654 		mt_status.mt_fileno = STps->drv_file;
3655 		if (STp->block_size != 0) {
3656 			if (STps->rw == ST_WRITING)
3657 				mt_status.mt_blkno +=
3658 				    (STp->buffer)->buffer_bytes / STp->block_size;
3659 			else if (STps->rw == ST_READING)
3660 				mt_status.mt_blkno -=
3661                                         ((STp->buffer)->buffer_bytes +
3662                                          STp->block_size - 1) / STp->block_size;
3663 		}
3664 
3665 		mt_status.mt_gstat = 0;
3666 		if (STp->drv_write_prot)
3667 			mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3668 		if (mt_status.mt_blkno == 0) {
3669 			if (mt_status.mt_fileno == 0)
3670 				mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3671 			else
3672 				mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3673 		}
3674 		mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3675 		mt_status.mt_resid = STp->partition;
3676 		if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3677 			mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3678 		else if (STps->eof >= ST_EOM_OK)
3679 			mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3680 		if (STp->density == 1)
3681 			mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3682 		else if (STp->density == 2)
3683 			mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3684 		else if (STp->density == 3)
3685 			mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3686 		if (STp->ready == ST_READY)
3687 			mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3688 		if (STp->ready == ST_NO_TAPE)
3689 			mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3690 		if (STps->at_sm)
3691 			mt_status.mt_gstat |= GMT_SM(0xffffffff);
3692 		if (STm->do_async_writes ||
3693                     (STm->do_buffer_writes && STp->block_size != 0) ||
3694 		    STp->drv_buffer != 0)
3695 			mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3696 		if (STp->cleaning_req)
3697 			mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3698 
3699 		i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3700 		if (i) {
3701 			retval = (-EFAULT);
3702 			goto out;
3703 		}
3704 
3705 		STp->recover_reg = 0;		/* Clear after read */
3706 		retval = 0;
3707 		goto out;
3708 	}			/* End of MTIOCGET */
3709 	if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3710 		struct mtpos mt_pos;
3711 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3712 			 retval = (-EINVAL);
3713 			 goto out;
3714 		}
3715 		if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3716 			retval = i;
3717 			goto out;
3718 		}
3719 		mt_pos.mt_blkno = blk;
3720 		i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3721 		if (i)
3722 			retval = (-EFAULT);
3723 		goto out;
3724 	}
3725 	mutex_unlock(&STp->lock);
3726 	switch (cmd_in) {
3727 		case SCSI_IOCTL_GET_IDLUN:
3728 		case SCSI_IOCTL_GET_BUS_NUMBER:
3729 			break;
3730 		default:
3731 			if ((cmd_in == SG_IO ||
3732 			     cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3733 			     cmd_in == CDROM_SEND_PACKET) &&
3734 			    !capable(CAP_SYS_RAWIO))
3735 				i = -EPERM;
3736 			else
3737 				i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3738 						   file->f_mode, cmd_in, p);
3739 			if (i != -ENOTTY)
3740 				return i;
3741 			break;
3742 	}
3743 	retval = scsi_ioctl(STp->device, cmd_in, p);
3744 	if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3745 		STp->rew_at_close = 0;
3746 		STp->ready = ST_NO_TAPE;
3747 	}
3748 	return retval;
3749 
3750  out:
3751 	mutex_unlock(&STp->lock);
3752 	return retval;
3753 }
3754 
3755 #ifdef CONFIG_COMPAT
3756 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3757 {
3758 	struct scsi_tape *STp = file->private_data;
3759 	struct scsi_device *sdev = STp->device;
3760 	int ret = -ENOIOCTLCMD;
3761 	if (sdev->host->hostt->compat_ioctl) {
3762 
3763 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3764 
3765 	}
3766 	return ret;
3767 }
3768 #endif
3769 
3770 
3771 
3772 /* Try to allocate a new tape buffer. Calling function must not hold
3773    dev_arr_lock. */
3774 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3775 {
3776 	struct st_buffer *tb;
3777 
3778 	tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3779 	if (!tb) {
3780 		printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3781 		return NULL;
3782 	}
3783 	tb->frp_segs = 0;
3784 	tb->use_sg = max_sg;
3785 	tb->dma = need_dma;
3786 	tb->buffer_size = 0;
3787 
3788 	tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3789 				     GFP_ATOMIC);
3790 	if (!tb->reserved_pages) {
3791 		kfree(tb);
3792 		return NULL;
3793 	}
3794 
3795 	return tb;
3796 }
3797 
3798 
3799 /* Try to allocate enough space in the tape buffer */
3800 #define ST_MAX_ORDER 6
3801 
3802 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3803 {
3804 	int segs, max_segs, b_size, order, got;
3805 	gfp_t priority;
3806 
3807 	if (new_size <= STbuffer->buffer_size)
3808 		return 1;
3809 
3810 	if (STbuffer->buffer_size <= PAGE_SIZE)
3811 		normalize_buffer(STbuffer);  /* Avoid extra segment */
3812 
3813 	max_segs = STbuffer->use_sg;
3814 
3815 	priority = GFP_KERNEL | __GFP_NOWARN;
3816 	if (need_dma)
3817 		priority |= GFP_DMA;
3818 
3819 	if (STbuffer->cleared)
3820 		priority |= __GFP_ZERO;
3821 
3822 	if (STbuffer->frp_segs) {
3823 		order = STbuffer->reserved_page_order;
3824 		b_size = PAGE_SIZE << order;
3825 	} else {
3826 		for (b_size = PAGE_SIZE, order = 0;
3827 		     order < ST_MAX_ORDER &&
3828 			     max_segs * (PAGE_SIZE << order) < new_size;
3829 		     order++, b_size *= 2)
3830 			;  /* empty */
3831 		STbuffer->reserved_page_order = order;
3832 	}
3833 	if (max_segs * (PAGE_SIZE << order) < new_size) {
3834 		if (order == ST_MAX_ORDER)
3835 			return 0;
3836 		normalize_buffer(STbuffer);
3837 		return enlarge_buffer(STbuffer, new_size, need_dma);
3838 	}
3839 
3840 	for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3841 	     segs < max_segs && got < new_size;) {
3842 		struct page *page;
3843 
3844 		page = alloc_pages(priority, order);
3845 		if (!page) {
3846 			DEB(STbuffer->buffer_size = got);
3847 			normalize_buffer(STbuffer);
3848 			return 0;
3849 		}
3850 
3851 		STbuffer->frp_segs += 1;
3852 		got += b_size;
3853 		STbuffer->buffer_size = got;
3854 		STbuffer->reserved_pages[segs] = page;
3855 		segs++;
3856 	}
3857 	STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3858 
3859 	return 1;
3860 }
3861 
3862 
3863 /* Make sure that no data from previous user is in the internal buffer */
3864 static void clear_buffer(struct st_buffer * st_bp)
3865 {
3866 	int i;
3867 
3868 	for (i=0; i < st_bp->frp_segs; i++)
3869 		memset(page_address(st_bp->reserved_pages[i]), 0,
3870 		       PAGE_SIZE << st_bp->reserved_page_order);
3871 	st_bp->cleared = 1;
3872 }
3873 
3874 
3875 /* Release the extra buffer */
3876 static void normalize_buffer(struct st_buffer * STbuffer)
3877 {
3878 	int i, order = STbuffer->reserved_page_order;
3879 
3880 	for (i = 0; i < STbuffer->frp_segs; i++) {
3881 		__free_pages(STbuffer->reserved_pages[i], order);
3882 		STbuffer->buffer_size -= (PAGE_SIZE << order);
3883 	}
3884 	STbuffer->frp_segs = 0;
3885 	STbuffer->sg_segs = 0;
3886 	STbuffer->reserved_page_order = 0;
3887 	STbuffer->map_data.offset = 0;
3888 }
3889 
3890 
3891 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3892    negative error code. */
3893 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3894 {
3895 	int i, cnt, res, offset;
3896 	int length = PAGE_SIZE << st_bp->reserved_page_order;
3897 
3898 	for (i = 0, offset = st_bp->buffer_bytes;
3899 	     i < st_bp->frp_segs && offset >= length; i++)
3900 		offset -= length;
3901 	if (i == st_bp->frp_segs) {	/* Should never happen */
3902 		printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3903 		return (-EIO);
3904 	}
3905 	for (; i < st_bp->frp_segs && do_count > 0; i++) {
3906 		struct page *page = st_bp->reserved_pages[i];
3907 		cnt = length - offset < do_count ? length - offset : do_count;
3908 		res = copy_from_user(page_address(page) + offset, ubp, cnt);
3909 		if (res)
3910 			return (-EFAULT);
3911 		do_count -= cnt;
3912 		st_bp->buffer_bytes += cnt;
3913 		ubp += cnt;
3914 		offset = 0;
3915 	}
3916 	if (do_count) /* Should never happen */
3917 		return (-EIO);
3918 
3919 	return 0;
3920 }
3921 
3922 
3923 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
3924    negative error code. */
3925 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
3926 {
3927 	int i, cnt, res, offset;
3928 	int length = PAGE_SIZE << st_bp->reserved_page_order;
3929 
3930 	for (i = 0, offset = st_bp->read_pointer;
3931 	     i < st_bp->frp_segs && offset >= length; i++)
3932 		offset -= length;
3933 	if (i == st_bp->frp_segs) {	/* Should never happen */
3934 		printk(KERN_WARNING "st: from_buffer offset overflow.\n");
3935 		return (-EIO);
3936 	}
3937 	for (; i < st_bp->frp_segs && do_count > 0; i++) {
3938 		struct page *page = st_bp->reserved_pages[i];
3939 		cnt = length - offset < do_count ? length - offset : do_count;
3940 		res = copy_to_user(ubp, page_address(page) + offset, cnt);
3941 		if (res)
3942 			return (-EFAULT);
3943 		do_count -= cnt;
3944 		st_bp->buffer_bytes -= cnt;
3945 		st_bp->read_pointer += cnt;
3946 		ubp += cnt;
3947 		offset = 0;
3948 	}
3949 	if (do_count) /* Should never happen */
3950 		return (-EIO);
3951 
3952 	return 0;
3953 }
3954 
3955 
3956 /* Move data towards start of buffer */
3957 static void move_buffer_data(struct st_buffer * st_bp, int offset)
3958 {
3959 	int src_seg, dst_seg, src_offset = 0, dst_offset;
3960 	int count, total;
3961 	int length = PAGE_SIZE << st_bp->reserved_page_order;
3962 
3963 	if (offset == 0)
3964 		return;
3965 
3966 	total=st_bp->buffer_bytes - offset;
3967 	for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
3968 		src_offset = offset;
3969 		if (src_offset < length)
3970 			break;
3971 		offset -= length;
3972 	}
3973 
3974 	st_bp->buffer_bytes = st_bp->read_pointer = total;
3975 	for (dst_seg=dst_offset=0; total > 0; ) {
3976 		struct page *dpage = st_bp->reserved_pages[dst_seg];
3977 		struct page *spage = st_bp->reserved_pages[src_seg];
3978 
3979 		count = min(length - dst_offset, length - src_offset);
3980 		memmove(page_address(dpage) + dst_offset,
3981 			page_address(spage) + src_offset, count);
3982 		src_offset += count;
3983 		if (src_offset >= length) {
3984 			src_seg++;
3985 			src_offset = 0;
3986 		}
3987 		dst_offset += count;
3988 		if (dst_offset >= length) {
3989 			dst_seg++;
3990 			dst_offset = 0;
3991 		}
3992 		total -= count;
3993 	}
3994 }
3995 
3996 /* Validate the options from command line or module parameters */
3997 static void validate_options(void)
3998 {
3999 	if (buffer_kbs > 0)
4000 		st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4001 	if (max_sg_segs >= ST_FIRST_SG)
4002 		st_max_sg_segs = max_sg_segs;
4003 }
4004 
4005 #ifndef MODULE
4006 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4007  */
4008 static int __init st_setup(char *str)
4009 {
4010 	int i, len, ints[5];
4011 	char *stp;
4012 
4013 	stp = get_options(str, ARRAY_SIZE(ints), ints);
4014 
4015 	if (ints[0] > 0) {
4016 		for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4017 			if (parms[i].val)
4018 				*parms[i].val = ints[i + 1];
4019 	} else {
4020 		while (stp != NULL) {
4021 			for (i = 0; i < ARRAY_SIZE(parms); i++) {
4022 				len = strlen(parms[i].name);
4023 				if (!strncmp(stp, parms[i].name, len) &&
4024 				    (*(stp + len) == ':' || *(stp + len) == '=')) {
4025 					if (parms[i].val)
4026 						*parms[i].val =
4027 							simple_strtoul(stp + len + 1, NULL, 0);
4028 					else
4029 						printk(KERN_WARNING "st: Obsolete parameter %s\n",
4030 						       parms[i].name);
4031 					break;
4032 				}
4033 			}
4034 			if (i >= ARRAY_SIZE(parms))
4035 				 printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4036 					stp);
4037 			stp = strchr(stp, ',');
4038 			if (stp)
4039 				stp++;
4040 		}
4041 	}
4042 
4043 	validate_options();
4044 
4045 	return 1;
4046 }
4047 
4048 __setup("st=", st_setup);
4049 
4050 #endif
4051 
4052 static const struct file_operations st_fops =
4053 {
4054 	.owner =	THIS_MODULE,
4055 	.read =		st_read,
4056 	.write =	st_write,
4057 	.unlocked_ioctl = st_ioctl,
4058 #ifdef CONFIG_COMPAT
4059 	.compat_ioctl = st_compat_ioctl,
4060 #endif
4061 	.open =		st_open,
4062 	.flush =	st_flush,
4063 	.release =	st_release,
4064 	.llseek =	noop_llseek,
4065 };
4066 
4067 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4068 {
4069 	int i, error;
4070 	dev_t cdev_devno;
4071 	struct cdev *cdev;
4072 	struct device *dev;
4073 	struct st_modedef *STm = &(tape->modes[mode]);
4074 	char name[10];
4075 	int dev_num = tape->index;
4076 
4077 	cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4078 
4079 	cdev = cdev_alloc();
4080 	if (!cdev) {
4081 		pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4082 		error = -ENOMEM;
4083 		goto out;
4084 	}
4085 	cdev->owner = THIS_MODULE;
4086 	cdev->ops = &st_fops;
4087 
4088 	error = cdev_add(cdev, cdev_devno, 1);
4089 	if (error) {
4090 		pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4091 		       rew ? "non" : "auto", mode);
4092 		pr_err("st%d: Device not attached.\n", dev_num);
4093 		goto out_free;
4094 	}
4095 	STm->cdevs[rew] = cdev;
4096 
4097 	i = mode << (4 - ST_NBR_MODE_BITS);
4098 	snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4099 		 tape->disk->disk_name, st_formats[i]);
4100 
4101 	dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4102 			    cdev_devno, &tape->modes[mode], "%s", name);
4103 	if (IS_ERR(dev)) {
4104 		pr_err("st%d: device_create failed\n", dev_num);
4105 		error = PTR_ERR(dev);
4106 		goto out_free;
4107 	}
4108 
4109 	STm->devs[rew] = dev;
4110 
4111 	return 0;
4112 out_free:
4113 	cdev_del(STm->cdevs[rew]);
4114 	STm->cdevs[rew] = NULL;
4115 out:
4116 	return error;
4117 }
4118 
4119 static int create_cdevs(struct scsi_tape *tape)
4120 {
4121 	int mode, error;
4122 	for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4123 		error = create_one_cdev(tape, mode, 0);
4124 		if (error)
4125 			return error;
4126 		error = create_one_cdev(tape, mode, 1);
4127 		if (error)
4128 			return error;
4129 	}
4130 
4131 	return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4132 				 &tape->modes[0].devs[0]->kobj, "tape");
4133 }
4134 
4135 static void remove_cdevs(struct scsi_tape *tape)
4136 {
4137 	int mode, rew;
4138 	sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4139 	for (mode = 0; mode < ST_NBR_MODES; mode++) {
4140 		struct st_modedef *STm = &(tape->modes[mode]);
4141 		for (rew = 0; rew < 2; rew++) {
4142 			if (STm->cdevs[rew])
4143 				cdev_del(STm->cdevs[rew]);
4144 			if (STm->devs[rew])
4145 				device_unregister(STm->devs[rew]);
4146 		}
4147 	}
4148 }
4149 
4150 static int st_probe(struct device *dev)
4151 {
4152 	struct scsi_device *SDp = to_scsi_device(dev);
4153 	struct gendisk *disk = NULL;
4154 	struct scsi_tape *tpnt = NULL;
4155 	struct st_modedef *STm;
4156 	struct st_partstat *STps;
4157 	struct st_buffer *buffer;
4158 	int i, error;
4159 	char *stp;
4160 
4161 	if (SDp->type != TYPE_TAPE)
4162 		return -ENODEV;
4163 	if ((stp = st_incompatible(SDp))) {
4164 		sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4165 		sdev_printk(KERN_INFO, SDp,
4166 			    "st: The suggested driver is %s.\n", stp);
4167 		return -ENODEV;
4168 	}
4169 
4170 	scsi_autopm_get_device(SDp);
4171 	i = queue_max_segments(SDp->request_queue);
4172 	if (st_max_sg_segs < i)
4173 		i = st_max_sg_segs;
4174 	buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4175 	if (buffer == NULL) {
4176 		sdev_printk(KERN_ERR, SDp,
4177 			    "st: Can't allocate new tape buffer. "
4178 			    "Device not attached.\n");
4179 		goto out;
4180 	}
4181 
4182 	disk = alloc_disk(1);
4183 	if (!disk) {
4184 		sdev_printk(KERN_ERR, SDp,
4185 			    "st: out of memory. Device not attached.\n");
4186 		goto out_buffer_free;
4187 	}
4188 
4189 	tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4190 	if (tpnt == NULL) {
4191 		sdev_printk(KERN_ERR, SDp,
4192 			    "st: Can't allocate device descriptor.\n");
4193 		goto out_put_disk;
4194 	}
4195 	kref_init(&tpnt->kref);
4196 	tpnt->disk = disk;
4197 	disk->private_data = &tpnt->driver;
4198 	disk->queue = SDp->request_queue;
4199 	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
4200 	 * take queue reference that release_disk() expects. */
4201 	if (!blk_get_queue(disk->queue))
4202 		goto out_put_disk;
4203 	tpnt->driver = &st_template;
4204 
4205 	tpnt->device = SDp;
4206 	if (SDp->scsi_level <= 2)
4207 		tpnt->tape_type = MT_ISSCSI1;
4208 	else
4209 		tpnt->tape_type = MT_ISSCSI2;
4210 
4211 	tpnt->buffer = buffer;
4212 	tpnt->buffer->last_SRpnt = NULL;
4213 
4214 	tpnt->inited = 0;
4215 	tpnt->dirty = 0;
4216 	tpnt->in_use = 0;
4217 	tpnt->drv_buffer = 1;	/* Try buffering if no mode sense */
4218 	tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4219 	tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4220 	tpnt->density = 0;
4221 	tpnt->do_auto_lock = ST_AUTO_LOCK;
4222 	tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4223 	tpnt->can_partitions = 0;
4224 	tpnt->two_fm = ST_TWO_FM;
4225 	tpnt->fast_mteom = ST_FAST_MTEOM;
4226 	tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4227 	tpnt->sili = ST_SILI;
4228 	tpnt->immediate = ST_NOWAIT;
4229 	tpnt->immediate_filemark = 0;
4230 	tpnt->default_drvbuffer = 0xff;		/* No forced buffering */
4231 	tpnt->partition = 0;
4232 	tpnt->new_partition = 0;
4233 	tpnt->nbr_partitions = 0;
4234 	blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4235 	tpnt->long_timeout = ST_LONG_TIMEOUT;
4236 	tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4237 
4238 	for (i = 0; i < ST_NBR_MODES; i++) {
4239 		STm = &(tpnt->modes[i]);
4240 		STm->defined = 0;
4241 		STm->sysv = ST_SYSV;
4242 		STm->defaults_for_writes = 0;
4243 		STm->do_async_writes = ST_ASYNC_WRITES;
4244 		STm->do_buffer_writes = ST_BUFFER_WRITES;
4245 		STm->do_read_ahead = ST_READ_AHEAD;
4246 		STm->default_compression = ST_DONT_TOUCH;
4247 		STm->default_blksize = (-1);	/* No forced size */
4248 		STm->default_density = (-1);	/* No forced density */
4249 		STm->tape = tpnt;
4250 	}
4251 
4252 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4253 		STps = &(tpnt->ps[i]);
4254 		STps->rw = ST_IDLE;
4255 		STps->eof = ST_NOEOF;
4256 		STps->at_sm = 0;
4257 		STps->last_block_valid = 0;
4258 		STps->drv_block = (-1);
4259 		STps->drv_file = (-1);
4260 	}
4261 
4262 	tpnt->current_mode = 0;
4263 	tpnt->modes[0].defined = 1;
4264 
4265 	tpnt->density_changed = tpnt->compression_changed =
4266 	    tpnt->blksize_changed = 0;
4267 	mutex_init(&tpnt->lock);
4268 
4269 	idr_preload(GFP_KERNEL);
4270 	spin_lock(&st_index_lock);
4271 	error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4272 	spin_unlock(&st_index_lock);
4273 	idr_preload_end();
4274 	if (error < 0) {
4275 		pr_warn("st: idr allocation failed: %d\n", error);
4276 		goto out_put_queue;
4277 	}
4278 	tpnt->index = error;
4279 	sprintf(disk->disk_name, "st%d", tpnt->index);
4280 	tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4281 	if (tpnt->stats == NULL) {
4282 		sdev_printk(KERN_ERR, SDp,
4283 			    "st: Can't allocate statistics.\n");
4284 		goto out_idr_remove;
4285 	}
4286 
4287 	dev_set_drvdata(dev, tpnt);
4288 
4289 
4290 	error = create_cdevs(tpnt);
4291 	if (error)
4292 		goto out_remove_devs;
4293 	scsi_autopm_put_device(SDp);
4294 
4295 	sdev_printk(KERN_NOTICE, SDp,
4296 		    "Attached scsi tape %s\n", tape_name(tpnt));
4297 	sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4298 		    tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4299 		    queue_dma_alignment(SDp->request_queue) + 1);
4300 
4301 	return 0;
4302 
4303 out_remove_devs:
4304 	remove_cdevs(tpnt);
4305 	kfree(tpnt->stats);
4306 out_idr_remove:
4307 	spin_lock(&st_index_lock);
4308 	idr_remove(&st_index_idr, tpnt->index);
4309 	spin_unlock(&st_index_lock);
4310 out_put_queue:
4311 	blk_put_queue(disk->queue);
4312 out_put_disk:
4313 	put_disk(disk);
4314 	kfree(tpnt);
4315 out_buffer_free:
4316 	kfree(buffer);
4317 out:
4318 	scsi_autopm_put_device(SDp);
4319 	return -ENODEV;
4320 };
4321 
4322 
4323 static int st_remove(struct device *dev)
4324 {
4325 	struct scsi_tape *tpnt = dev_get_drvdata(dev);
4326 	int index = tpnt->index;
4327 
4328 	scsi_autopm_get_device(to_scsi_device(dev));
4329 	remove_cdevs(tpnt);
4330 
4331 	mutex_lock(&st_ref_mutex);
4332 	kref_put(&tpnt->kref, scsi_tape_release);
4333 	mutex_unlock(&st_ref_mutex);
4334 	spin_lock(&st_index_lock);
4335 	idr_remove(&st_index_idr, index);
4336 	spin_unlock(&st_index_lock);
4337 	return 0;
4338 }
4339 
4340 /**
4341  *      scsi_tape_release - Called to free the Scsi_Tape structure
4342  *      @kref: pointer to embedded kref
4343  *
4344  *      st_ref_mutex must be held entering this routine.  Because it is
4345  *      called on last put, you should always use the scsi_tape_get()
4346  *      scsi_tape_put() helpers which manipulate the semaphore directly
4347  *      and never do a direct kref_put().
4348  **/
4349 static void scsi_tape_release(struct kref *kref)
4350 {
4351 	struct scsi_tape *tpnt = to_scsi_tape(kref);
4352 	struct gendisk *disk = tpnt->disk;
4353 
4354 	tpnt->device = NULL;
4355 
4356 	if (tpnt->buffer) {
4357 		normalize_buffer(tpnt->buffer);
4358 		kfree(tpnt->buffer->reserved_pages);
4359 		kfree(tpnt->buffer);
4360 	}
4361 
4362 	disk->private_data = NULL;
4363 	put_disk(disk);
4364 	kfree(tpnt->stats);
4365 	kfree(tpnt);
4366 	return;
4367 }
4368 
4369 static struct class st_sysfs_class = {
4370 	.name = "scsi_tape",
4371 	.dev_groups = st_dev_groups,
4372 };
4373 
4374 static int __init init_st(void)
4375 {
4376 	int err;
4377 
4378 	validate_options();
4379 
4380 	printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4381 		verstr, st_fixed_buffer_size, st_max_sg_segs);
4382 
4383 	debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4384 	if (debugging) {
4385 		printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4386 			debugging);
4387 	}
4388 
4389 	err = class_register(&st_sysfs_class);
4390 	if (err) {
4391 		pr_err("Unable register sysfs class for SCSI tapes\n");
4392 		return err;
4393 	}
4394 
4395 	err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4396 				     ST_MAX_TAPE_ENTRIES, "st");
4397 	if (err) {
4398 		printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4399 		       SCSI_TAPE_MAJOR);
4400 		goto err_class;
4401 	}
4402 
4403 	err = scsi_register_driver(&st_template.gendrv);
4404 	if (err)
4405 		goto err_chrdev;
4406 
4407 	err = do_create_sysfs_files();
4408 	if (err)
4409 		goto err_scsidrv;
4410 
4411 	return 0;
4412 
4413 err_scsidrv:
4414 	scsi_unregister_driver(&st_template.gendrv);
4415 err_chrdev:
4416 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4417 				 ST_MAX_TAPE_ENTRIES);
4418 err_class:
4419 	class_unregister(&st_sysfs_class);
4420 	return err;
4421 }
4422 
4423 static void __exit exit_st(void)
4424 {
4425 	do_remove_sysfs_files();
4426 	scsi_unregister_driver(&st_template.gendrv);
4427 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4428 				 ST_MAX_TAPE_ENTRIES);
4429 	class_unregister(&st_sysfs_class);
4430 	printk(KERN_INFO "st: Unloaded.\n");
4431 }
4432 
4433 module_init(init_st);
4434 module_exit(exit_st);
4435 
4436 
4437 /* The sysfs driver interface. Read-only at the moment */
4438 static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
4439 {
4440 	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4441 }
4442 static DRIVER_ATTR(try_direct_io, S_IRUGO, st_try_direct_io_show, NULL);
4443 
4444 static ssize_t st_fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4445 {
4446 	return snprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4447 }
4448 static DRIVER_ATTR(fixed_buffer_size, S_IRUGO, st_fixed_buffer_size_show, NULL);
4449 
4450 static ssize_t st_max_sg_segs_show(struct device_driver *ddp, char *buf)
4451 {
4452 	return snprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4453 }
4454 static DRIVER_ATTR(max_sg_segs, S_IRUGO, st_max_sg_segs_show, NULL);
4455 
4456 static ssize_t st_version_show(struct device_driver *ddd, char *buf)
4457 {
4458 	return snprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4459 }
4460 static DRIVER_ATTR(version, S_IRUGO, st_version_show, NULL);
4461 
4462 static int do_create_sysfs_files(void)
4463 {
4464 	struct device_driver *sysfs = &st_template.gendrv;
4465 	int err;
4466 
4467 	err = driver_create_file(sysfs, &driver_attr_try_direct_io);
4468 	if (err)
4469 		return err;
4470 	err = driver_create_file(sysfs, &driver_attr_fixed_buffer_size);
4471 	if (err)
4472 		goto err_try_direct_io;
4473 	err = driver_create_file(sysfs, &driver_attr_max_sg_segs);
4474 	if (err)
4475 		goto err_attr_fixed_buf;
4476 	err = driver_create_file(sysfs, &driver_attr_version);
4477 	if (err)
4478 		goto err_attr_max_sg;
4479 
4480 	return 0;
4481 
4482 err_attr_max_sg:
4483 	driver_remove_file(sysfs, &driver_attr_max_sg_segs);
4484 err_attr_fixed_buf:
4485 	driver_remove_file(sysfs, &driver_attr_fixed_buffer_size);
4486 err_try_direct_io:
4487 	driver_remove_file(sysfs, &driver_attr_try_direct_io);
4488 	return err;
4489 }
4490 
4491 static void do_remove_sysfs_files(void)
4492 {
4493 	struct device_driver *sysfs = &st_template.gendrv;
4494 
4495 	driver_remove_file(sysfs, &driver_attr_version);
4496 	driver_remove_file(sysfs, &driver_attr_max_sg_segs);
4497 	driver_remove_file(sysfs, &driver_attr_fixed_buffer_size);
4498 	driver_remove_file(sysfs, &driver_attr_try_direct_io);
4499 }
4500 
4501 /* The sysfs simple class interface */
4502 static ssize_t
4503 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4504 {
4505 	struct st_modedef *STm = dev_get_drvdata(dev);
4506 	ssize_t l = 0;
4507 
4508 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4509 	return l;
4510 }
4511 static DEVICE_ATTR_RO(defined);
4512 
4513 static ssize_t
4514 default_blksize_show(struct device *dev, struct device_attribute *attr,
4515 		     char *buf)
4516 {
4517 	struct st_modedef *STm = dev_get_drvdata(dev);
4518 	ssize_t l = 0;
4519 
4520 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4521 	return l;
4522 }
4523 static DEVICE_ATTR_RO(default_blksize);
4524 
4525 static ssize_t
4526 default_density_show(struct device *dev, struct device_attribute *attr,
4527 		     char *buf)
4528 {
4529 	struct st_modedef *STm = dev_get_drvdata(dev);
4530 	ssize_t l = 0;
4531 	char *fmt;
4532 
4533 	fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4534 	l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4535 	return l;
4536 }
4537 static DEVICE_ATTR_RO(default_density);
4538 
4539 static ssize_t
4540 default_compression_show(struct device *dev, struct device_attribute *attr,
4541 			 char *buf)
4542 {
4543 	struct st_modedef *STm = dev_get_drvdata(dev);
4544 	ssize_t l = 0;
4545 
4546 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4547 	return l;
4548 }
4549 static DEVICE_ATTR_RO(default_compression);
4550 
4551 static ssize_t
4552 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4553 {
4554 	struct st_modedef *STm = dev_get_drvdata(dev);
4555 	struct scsi_tape *STp = STm->tape;
4556 	int options;
4557 	ssize_t l = 0;
4558 
4559 	options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4560 	options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4561 	options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4562 	DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4563 	options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4564 	options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4565 	options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4566 	options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4567 	options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4568 	options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4569 	options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4570 	options |= STm->sysv ? MT_ST_SYSV : 0;
4571 	options |= STp->immediate ? MT_ST_NOWAIT : 0;
4572 	options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4573 	options |= STp->sili ? MT_ST_SILI : 0;
4574 
4575 	l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4576 	return l;
4577 }
4578 static DEVICE_ATTR_RO(options);
4579 
4580 /* Support for tape stats */
4581 
4582 /**
4583  * read_cnt_show - return read count - count of reads made from tape drive
4584  * @dev: struct device
4585  * @attr: attribute structure
4586  * @buf: buffer to return formatted data in
4587  */
4588 static ssize_t read_cnt_show(struct device *dev,
4589 	struct device_attribute *attr, char *buf)
4590 {
4591 	struct st_modedef *STm = dev_get_drvdata(dev);
4592 
4593 	return sprintf(buf, "%lld",
4594 		       (long long)atomic64_read(&STm->tape->stats->read_cnt));
4595 }
4596 static DEVICE_ATTR_RO(read_cnt);
4597 
4598 /**
4599  * read_byte_cnt_show - return read byte count - tape drives
4600  * may use blocks less than 512 bytes this gives the raw byte count of
4601  * of data read from the tape drive.
4602  * @dev: struct device
4603  * @attr: attribute structure
4604  * @buf: buffer to return formatted data in
4605  */
4606 static ssize_t read_byte_cnt_show(struct device *dev,
4607 	struct device_attribute *attr, char *buf)
4608 {
4609 	struct st_modedef *STm = dev_get_drvdata(dev);
4610 
4611 	return sprintf(buf, "%lld",
4612 		       (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4613 }
4614 static DEVICE_ATTR_RO(read_byte_cnt);
4615 
4616 /**
4617  * read_us_show - return read us - overall time spent waiting on reads in ns.
4618  * @dev: struct device
4619  * @attr: attribute structure
4620  * @buf: buffer to return formatted data in
4621  */
4622 static ssize_t read_ns_show(struct device *dev,
4623 	struct device_attribute *attr, char *buf)
4624 {
4625 	struct st_modedef *STm = dev_get_drvdata(dev);
4626 
4627 	return sprintf(buf, "%lld",
4628 		       (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4629 }
4630 static DEVICE_ATTR_RO(read_ns);
4631 
4632 /**
4633  * write_cnt_show - write count - number of user calls
4634  * to write(2) that have written data to tape.
4635  * @dev: struct device
4636  * @attr: attribute structure
4637  * @buf: buffer to return formatted data in
4638  */
4639 static ssize_t write_cnt_show(struct device *dev,
4640 	struct device_attribute *attr, char *buf)
4641 {
4642 	struct st_modedef *STm = dev_get_drvdata(dev);
4643 
4644 	return sprintf(buf, "%lld",
4645 		       (long long)atomic64_read(&STm->tape->stats->write_cnt));
4646 }
4647 static DEVICE_ATTR_RO(write_cnt);
4648 
4649 /**
4650  * write_byte_cnt_show - write byte count - raw count of
4651  * bytes written to tape.
4652  * @dev: struct device
4653  * @attr: attribute structure
4654  * @buf: buffer to return formatted data in
4655  */
4656 static ssize_t write_byte_cnt_show(struct device *dev,
4657 	struct device_attribute *attr, char *buf)
4658 {
4659 	struct st_modedef *STm = dev_get_drvdata(dev);
4660 
4661 	return sprintf(buf, "%lld",
4662 		       (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4663 }
4664 static DEVICE_ATTR_RO(write_byte_cnt);
4665 
4666 /**
4667  * write_ns_show - write ns - number of nanoseconds waiting on write
4668  * requests to complete.
4669  * @dev: struct device
4670  * @attr: attribute structure
4671  * @buf: buffer to return formatted data in
4672  */
4673 static ssize_t write_ns_show(struct device *dev,
4674 	struct device_attribute *attr, char *buf)
4675 {
4676 	struct st_modedef *STm = dev_get_drvdata(dev);
4677 
4678 	return sprintf(buf, "%lld",
4679 		       (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4680 }
4681 static DEVICE_ATTR_RO(write_ns);
4682 
4683 /**
4684  * in_flight_show - number of I/Os currently in flight -
4685  * in most cases this will be either 0 or 1. It may be higher if someone
4686  * has also issued other SCSI commands such as via an ioctl.
4687  * @dev: struct device
4688  * @attr: attribute structure
4689  * @buf: buffer to return formatted data in
4690  */
4691 static ssize_t in_flight_show(struct device *dev,
4692 	struct device_attribute *attr, char *buf)
4693 {
4694 	struct st_modedef *STm = dev_get_drvdata(dev);
4695 
4696 	return sprintf(buf, "%lld",
4697 		       (long long)atomic64_read(&STm->tape->stats->in_flight));
4698 }
4699 static DEVICE_ATTR_RO(in_flight);
4700 
4701 /**
4702  * io_ns_show - io wait ns - this is the number of ns spent
4703  * waiting on all I/O to complete. This includes tape movement commands
4704  * such as rewinding, seeking to end of file or tape, it also includes
4705  * read and write. To determine the time spent on tape movement
4706  * subtract the read and write ns from this value.
4707  * @dev: struct device
4708  * @attr: attribute structure
4709  * @buf: buffer to return formatted data in
4710  */
4711 static ssize_t io_ns_show(struct device *dev,
4712 	struct device_attribute *attr, char *buf)
4713 {
4714 	struct st_modedef *STm = dev_get_drvdata(dev);
4715 
4716 	return sprintf(buf, "%lld",
4717 		       (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4718 }
4719 static DEVICE_ATTR_RO(io_ns);
4720 
4721 /**
4722  * other_cnt_show - other io count - this is the number of
4723  * I/O requests other than read and write requests.
4724  * Typically these are tape movement requests but will include driver
4725  * tape movement. This includes only requests issued by the st driver.
4726  * @dev: struct device
4727  * @attr: attribute structure
4728  * @buf: buffer to return formatted data in
4729  */
4730 static ssize_t other_cnt_show(struct device *dev,
4731 	struct device_attribute *attr, char *buf)
4732 {
4733 	struct st_modedef *STm = dev_get_drvdata(dev);
4734 
4735 	return sprintf(buf, "%lld",
4736 		       (long long)atomic64_read(&STm->tape->stats->other_cnt));
4737 }
4738 static DEVICE_ATTR_RO(other_cnt);
4739 
4740 /**
4741  * resid_cnt_show - A count of the number of times we get a residual
4742  * count - this should indicate someone issuing reads larger than the
4743  * block size on tape.
4744  * @dev: struct device
4745  * @attr: attribute structure
4746  * @buf: buffer to return formatted data in
4747  */
4748 static ssize_t resid_cnt_show(struct device *dev,
4749 	struct device_attribute *attr, char *buf)
4750 {
4751 	struct st_modedef *STm = dev_get_drvdata(dev);
4752 
4753 	return sprintf(buf, "%lld",
4754 		       (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4755 }
4756 static DEVICE_ATTR_RO(resid_cnt);
4757 
4758 static struct attribute *st_dev_attrs[] = {
4759 	&dev_attr_defined.attr,
4760 	&dev_attr_default_blksize.attr,
4761 	&dev_attr_default_density.attr,
4762 	&dev_attr_default_compression.attr,
4763 	&dev_attr_options.attr,
4764 	NULL,
4765 };
4766 
4767 static struct attribute *st_stats_attrs[] = {
4768 	&dev_attr_read_cnt.attr,
4769 	&dev_attr_read_byte_cnt.attr,
4770 	&dev_attr_read_ns.attr,
4771 	&dev_attr_write_cnt.attr,
4772 	&dev_attr_write_byte_cnt.attr,
4773 	&dev_attr_write_ns.attr,
4774 	&dev_attr_in_flight.attr,
4775 	&dev_attr_io_ns.attr,
4776 	&dev_attr_other_cnt.attr,
4777 	&dev_attr_resid_cnt.attr,
4778 	NULL,
4779 };
4780 
4781 static struct attribute_group stats_group = {
4782 	.name = "stats",
4783 	.attrs = st_stats_attrs,
4784 };
4785 
4786 static struct attribute_group st_group = {
4787 	.attrs = st_dev_attrs,
4788 };
4789 
4790 static const struct attribute_group *st_dev_groups[] = {
4791 	&st_group,
4792 	&stats_group,
4793 	NULL,
4794 };
4795 
4796 /* The following functions may be useful for a larger audience. */
4797 static int sgl_map_user_pages(struct st_buffer *STbp,
4798 			      const unsigned int max_pages, unsigned long uaddr,
4799 			      size_t count, int rw)
4800 {
4801 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4802 	unsigned long start = uaddr >> PAGE_SHIFT;
4803 	const int nr_pages = end - start;
4804 	int res, i, j;
4805 	struct page **pages;
4806 	struct rq_map_data *mdata = &STbp->map_data;
4807 
4808 	/* User attempted Overflow! */
4809 	if ((uaddr + count) < uaddr)
4810 		return -EINVAL;
4811 
4812 	/* Too big */
4813         if (nr_pages > max_pages)
4814 		return -ENOMEM;
4815 
4816 	/* Hmm? */
4817 	if (count == 0)
4818 		return 0;
4819 
4820 	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4821 		return -ENOMEM;
4822 
4823         /* Try to fault in all of the necessary pages */
4824         /* rw==READ means read from drive, write into memory area */
4825 	res = get_user_pages_unlocked(
4826 		current,
4827 		current->mm,
4828 		uaddr,
4829 		nr_pages,
4830 		rw == READ,
4831 		0, /* don't force */
4832 		pages);
4833 
4834 	/* Errors and no page mapped should return here */
4835 	if (res < nr_pages)
4836 		goto out_unmap;
4837 
4838         for (i=0; i < nr_pages; i++) {
4839                 /* FIXME: flush superflous for rw==READ,
4840                  * probably wrong function for rw==WRITE
4841                  */
4842 		flush_dcache_page(pages[i]);
4843         }
4844 
4845 	mdata->offset = uaddr & ~PAGE_MASK;
4846 	STbp->mapped_pages = pages;
4847 
4848 	return nr_pages;
4849  out_unmap:
4850 	if (res > 0) {
4851 		for (j=0; j < res; j++)
4852 			page_cache_release(pages[j]);
4853 		res = 0;
4854 	}
4855 	kfree(pages);
4856 	return res;
4857 }
4858 
4859 
4860 /* And unmap them... */
4861 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4862 				const unsigned int nr_pages, int dirtied)
4863 {
4864 	int i;
4865 
4866 	for (i=0; i < nr_pages; i++) {
4867 		struct page *page = STbp->mapped_pages[i];
4868 
4869 		if (dirtied)
4870 			SetPageDirty(page);
4871 		/* FIXME: cache flush missing for rw==READ
4872 		 * FIXME: call the correct reference counting function
4873 		 */
4874 		page_cache_release(page);
4875 	}
4876 	kfree(STbp->mapped_pages);
4877 	STbp->mapped_pages = NULL;
4878 
4879 	return 0;
4880 }
4881