xref: /linux/drivers/scsi/st.c (revision d195c39052d1da278a00a6744ce59c383b67b191)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
4    file Documentation/scsi/st.rst for more information.
5 
6    History:
7    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
8    Contribution and ideas from several people including (in alphabetical
9    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
10    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
11    Michael Schaefer, J"org Weule, and Eric Youngdale.
12 
13    Copyright 1992 - 2016 Kai Makisara
14    email Kai.Makisara@kolumbus.fi
15 
16    Some small formal changes - aeb, 950809
17 
18    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
19  */
20 
21 static const char *verstr = "20160209";
22 
23 #include <linux/module.h>
24 
25 #include <linux/compat.h>
26 #include <linux/fs.h>
27 #include <linux/kernel.h>
28 #include <linux/sched/signal.h>
29 #include <linux/mm.h>
30 #include <linux/init.h>
31 #include <linux/string.h>
32 #include <linux/slab.h>
33 #include <linux/errno.h>
34 #include <linux/mtio.h>
35 #include <linux/cdrom.h>
36 #include <linux/ioctl.h>
37 #include <linux/fcntl.h>
38 #include <linux/spinlock.h>
39 #include <linux/blkdev.h>
40 #include <linux/moduleparam.h>
41 #include <linux/cdev.h>
42 #include <linux/idr.h>
43 #include <linux/delay.h>
44 #include <linux/mutex.h>
45 
46 #include <linux/uaccess.h>
47 #include <asm/dma.h>
48 #include <asm/unaligned.h>
49 
50 #include <scsi/scsi.h>
51 #include <scsi/scsi_dbg.h>
52 #include <scsi/scsi_device.h>
53 #include <scsi/scsi_driver.h>
54 #include <scsi/scsi_eh.h>
55 #include <scsi/scsi_host.h>
56 #include <scsi/scsi_ioctl.h>
57 #include <scsi/sg.h>
58 
59 
60 /* The driver prints some debugging information on the console if DEBUG
61    is defined and non-zero. */
62 #define DEBUG 1
63 #define NO_DEBUG 0
64 
65 #define ST_DEB_MSG  KERN_NOTICE
66 #if DEBUG
67 /* The message level for the debug messages is currently set to KERN_NOTICE
68    so that people can easily see the messages. Later when the debugging messages
69    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
70 #define DEB(a) a
71 #define DEBC(a) if (debugging) { a ; }
72 #else
73 #define DEB(a)
74 #define DEBC(a)
75 #endif
76 
77 #define ST_KILOBYTE 1024
78 
79 #include "st_options.h"
80 #include "st.h"
81 
82 static int buffer_kbs;
83 static int max_sg_segs;
84 static int try_direct_io = TRY_DIRECT_IO;
85 static int try_rdio = 1;
86 static int try_wdio = 1;
87 static int debug_flag;
88 
89 static struct class st_sysfs_class;
90 static const struct attribute_group *st_dev_groups[];
91 static const struct attribute_group *st_drv_groups[];
92 
93 MODULE_AUTHOR("Kai Makisara");
94 MODULE_DESCRIPTION("SCSI tape (st) driver");
95 MODULE_LICENSE("GPL");
96 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
97 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
98 
99 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
100  * of sysfs parameters (which module_param doesn't yet support).
101  * Sysfs parameters defined explicitly later.
102  */
103 module_param_named(buffer_kbs, buffer_kbs, int, 0);
104 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
105 module_param_named(max_sg_segs, max_sg_segs, int, 0);
106 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
107 module_param_named(try_direct_io, try_direct_io, int, 0);
108 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
109 module_param_named(debug_flag, debug_flag, int, 0);
110 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
111 
112 
113 /* Extra parameters for testing */
114 module_param_named(try_rdio, try_rdio, int, 0);
115 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
116 module_param_named(try_wdio, try_wdio, int, 0);
117 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
118 
119 #ifndef MODULE
120 static int write_threshold_kbs;  /* retained for compatibility */
121 static struct st_dev_parm {
122 	char *name;
123 	int *val;
124 } parms[] __initdata = {
125 	{
126 		"buffer_kbs", &buffer_kbs
127 	},
128 	{       /* Retained for compatibility with 2.4 */
129 		"write_threshold_kbs", &write_threshold_kbs
130 	},
131 	{
132 		"max_sg_segs", NULL
133 	},
134 	{
135 		"try_direct_io", &try_direct_io
136 	},
137 	{
138 		"debug_flag", &debug_flag
139 	}
140 };
141 #endif
142 
143 /* Restrict the number of modes so that names for all are assigned */
144 #if ST_NBR_MODES > 16
145 #error "Maximum number of modes is 16"
146 #endif
147 /* Bit reversed order to get same names for same minors with all
148    mode counts */
149 static const char *st_formats[] = {
150 	"",  "r", "k", "s", "l", "t", "o", "u",
151 	"m", "v", "p", "x", "a", "y", "q", "z"};
152 
153 /* The default definitions have been moved to st_options.h */
154 
155 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
156 
157 /* The buffer size should fit into the 24 bits for length in the
158    6-byte SCSI read and write commands. */
159 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
160 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
161 #endif
162 
163 static int debugging = DEBUG;
164 
165 #define MAX_RETRIES 0
166 #define MAX_WRITE_RETRIES 0
167 #define MAX_READY_RETRIES 0
168 #define NO_TAPE  NOT_READY
169 
170 #define ST_TIMEOUT (900 * HZ)
171 #define ST_LONG_TIMEOUT (14000 * HZ)
172 
173 /* Remove mode bits and auto-rewind bit (7) */
174 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
175 	(iminor(x) & ((1 << ST_MODE_SHIFT)-1)))
176 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
177 
178 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
179 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
180   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
181 
182 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
183    24 bits) */
184 #define SET_DENS_AND_BLK 0x10001
185 
186 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
187 static int st_max_sg_segs = ST_MAX_SG;
188 
189 static int modes_defined;
190 
191 static int enlarge_buffer(struct st_buffer *, int, int);
192 static void clear_buffer(struct st_buffer *);
193 static void normalize_buffer(struct st_buffer *);
194 static int append_to_buffer(const char __user *, struct st_buffer *, int);
195 static int from_buffer(struct st_buffer *, char __user *, int);
196 static void move_buffer_data(struct st_buffer *, int);
197 
198 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
199 			      unsigned long, size_t, int);
200 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
201 
202 static int st_probe(struct device *);
203 static int st_remove(struct device *);
204 
205 static struct scsi_driver st_template = {
206 	.gendrv = {
207 		.name		= "st",
208 		.owner		= THIS_MODULE,
209 		.probe		= st_probe,
210 		.remove		= st_remove,
211 		.groups		= st_drv_groups,
212 	},
213 };
214 
215 static int st_compression(struct scsi_tape *, int);
216 
217 static int find_partition(struct scsi_tape *);
218 static int switch_partition(struct scsi_tape *);
219 
220 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
221 
222 static void scsi_tape_release(struct kref *);
223 
224 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
225 
226 static DEFINE_MUTEX(st_ref_mutex);
227 static DEFINE_SPINLOCK(st_index_lock);
228 static DEFINE_SPINLOCK(st_use_lock);
229 static DEFINE_IDR(st_index_idr);
230 
231 
232 
233 #ifndef SIGS_FROM_OSST
234 #define SIGS_FROM_OSST \
235 	{"OnStream", "SC-", "", "osst"}, \
236 	{"OnStream", "DI-", "", "osst"}, \
237 	{"OnStream", "DP-", "", "osst"}, \
238 	{"OnStream", "USB", "", "osst"}, \
239 	{"OnStream", "FW-", "", "osst"}
240 #endif
241 
242 static struct scsi_tape *scsi_tape_get(int dev)
243 {
244 	struct scsi_tape *STp = NULL;
245 
246 	mutex_lock(&st_ref_mutex);
247 	spin_lock(&st_index_lock);
248 
249 	STp = idr_find(&st_index_idr, dev);
250 	if (!STp) goto out;
251 
252 	kref_get(&STp->kref);
253 
254 	if (!STp->device)
255 		goto out_put;
256 
257 	if (scsi_device_get(STp->device))
258 		goto out_put;
259 
260 	goto out;
261 
262 out_put:
263 	kref_put(&STp->kref, scsi_tape_release);
264 	STp = NULL;
265 out:
266 	spin_unlock(&st_index_lock);
267 	mutex_unlock(&st_ref_mutex);
268 	return STp;
269 }
270 
271 static void scsi_tape_put(struct scsi_tape *STp)
272 {
273 	struct scsi_device *sdev = STp->device;
274 
275 	mutex_lock(&st_ref_mutex);
276 	kref_put(&STp->kref, scsi_tape_release);
277 	scsi_device_put(sdev);
278 	mutex_unlock(&st_ref_mutex);
279 }
280 
281 struct st_reject_data {
282 	char *vendor;
283 	char *model;
284 	char *rev;
285 	char *driver_hint; /* Name of the correct driver, NULL if unknown */
286 };
287 
288 static struct st_reject_data reject_list[] = {
289 	/* {"XXX", "Yy-", "", NULL},  example */
290 	SIGS_FROM_OSST,
291 	{NULL, }};
292 
293 /* If the device signature is on the list of incompatible drives, the
294    function returns a pointer to the name of the correct driver (if known) */
295 static char * st_incompatible(struct scsi_device* SDp)
296 {
297 	struct st_reject_data *rp;
298 
299 	for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
300 		if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
301 		    !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
302 		    !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
303 			if (rp->driver_hint)
304 				return rp->driver_hint;
305 			else
306 				return "unknown";
307 		}
308 	return NULL;
309 }
310 
311 
312 static inline char *tape_name(struct scsi_tape *tape)
313 {
314 	return tape->disk->disk_name;
315 }
316 
317 #define st_printk(prefix, t, fmt, a...) \
318 	sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
319 #ifdef DEBUG
320 #define DEBC_printk(t, fmt, a...) \
321 	if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
322 #else
323 #define DEBC_printk(t, fmt, a...)
324 #endif
325 
326 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
327 {
328 	const u8 *ucp;
329 	const u8 *sense = SRpnt->sense;
330 
331 	s->have_sense = scsi_normalize_sense(SRpnt->sense,
332 				SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
333 	s->flags = 0;
334 
335 	if (s->have_sense) {
336 		s->deferred = 0;
337 		s->remainder_valid =
338 			scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
339 		switch (sense[0] & 0x7f) {
340 		case 0x71:
341 			s->deferred = 1;
342 			/* fall through */
343 		case 0x70:
344 			s->fixed_format = 1;
345 			s->flags = sense[2] & 0xe0;
346 			break;
347 		case 0x73:
348 			s->deferred = 1;
349 			/* fall through */
350 		case 0x72:
351 			s->fixed_format = 0;
352 			ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
353 			s->flags = ucp ? (ucp[3] & 0xe0) : 0;
354 			break;
355 		}
356 	}
357 }
358 
359 
360 /* Convert the result to success code */
361 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
362 {
363 	int result = SRpnt->result;
364 	u8 scode;
365 	DEB(const char *stp;)
366 	char *name = tape_name(STp);
367 	struct st_cmdstatus *cmdstatp;
368 
369 	if (!result)
370 		return 0;
371 
372 	cmdstatp = &STp->buffer->cmdstat;
373 	st_analyze_sense(SRpnt, cmdstatp);
374 
375 	if (cmdstatp->have_sense)
376 		scode = STp->buffer->cmdstat.sense_hdr.sense_key;
377 	else
378 		scode = 0;
379 
380 	DEB(
381 	if (debugging) {
382 		st_printk(ST_DEB_MSG, STp,
383 			    "Error: %x, cmd: %x %x %x %x %x %x\n", result,
384 			    SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
385 			    SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
386 		if (cmdstatp->have_sense)
387 			__scsi_print_sense(STp->device, name,
388 					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
389 	} ) /* end DEB */
390 	if (!debugging) { /* Abnormal conditions for tape */
391 		if (!cmdstatp->have_sense)
392 			st_printk(KERN_WARNING, STp,
393 			       "Error %x (driver bt 0x%x, host bt 0x%x).\n",
394 			       result, driver_byte(result), host_byte(result));
395 		else if (cmdstatp->have_sense &&
396 			 scode != NO_SENSE &&
397 			 scode != RECOVERED_ERROR &&
398 			 /* scode != UNIT_ATTENTION && */
399 			 scode != BLANK_CHECK &&
400 			 scode != VOLUME_OVERFLOW &&
401 			 SRpnt->cmd[0] != MODE_SENSE &&
402 			 SRpnt->cmd[0] != TEST_UNIT_READY) {
403 
404 			__scsi_print_sense(STp->device, name,
405 					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
406 		}
407 	}
408 
409 	if (cmdstatp->fixed_format &&
410 	    STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
411 		if (STp->cln_sense_value)
412 			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
413 					       STp->cln_sense_mask) == STp->cln_sense_value);
414 		else
415 			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
416 					       STp->cln_sense_mask) != 0);
417 	}
418 	if (cmdstatp->have_sense &&
419 	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
420 		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
421 
422 	STp->pos_unknown |= STp->device->was_reset;
423 
424 	if (cmdstatp->have_sense &&
425 	    scode == RECOVERED_ERROR
426 #if ST_RECOVERED_WRITE_FATAL
427 	    && SRpnt->cmd[0] != WRITE_6
428 	    && SRpnt->cmd[0] != WRITE_FILEMARKS
429 #endif
430 	    ) {
431 		STp->recover_count++;
432 		STp->recover_reg++;
433 
434 		DEB(
435 		if (debugging) {
436 			if (SRpnt->cmd[0] == READ_6)
437 				stp = "read";
438 			else if (SRpnt->cmd[0] == WRITE_6)
439 				stp = "write";
440 			else
441 				stp = "ioctl";
442 			st_printk(ST_DEB_MSG, STp,
443 				  "Recovered %s error (%d).\n",
444 				  stp, STp->recover_count);
445 		} ) /* end DEB */
446 
447 		if (cmdstatp->flags == 0)
448 			return 0;
449 	}
450 	return (-EIO);
451 }
452 
453 static struct st_request *st_allocate_request(struct scsi_tape *stp)
454 {
455 	struct st_request *streq;
456 
457 	streq = kzalloc(sizeof(*streq), GFP_KERNEL);
458 	if (streq)
459 		streq->stp = stp;
460 	else {
461 		st_printk(KERN_ERR, stp,
462 			  "Can't get SCSI request.\n");
463 		if (signal_pending(current))
464 			stp->buffer->syscall_result = -EINTR;
465 		else
466 			stp->buffer->syscall_result = -EBUSY;
467 	}
468 
469 	return streq;
470 }
471 
472 static void st_release_request(struct st_request *streq)
473 {
474 	kfree(streq);
475 }
476 
477 static void st_do_stats(struct scsi_tape *STp, struct request *req)
478 {
479 	ktime_t now;
480 
481 	now = ktime_get();
482 	if (scsi_req(req)->cmd[0] == WRITE_6) {
483 		now = ktime_sub(now, STp->stats->write_time);
484 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
485 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
486 		atomic64_inc(&STp->stats->write_cnt);
487 		if (scsi_req(req)->result) {
488 			atomic64_add(atomic_read(&STp->stats->last_write_size)
489 				- STp->buffer->cmdstat.residual,
490 				&STp->stats->write_byte_cnt);
491 			if (STp->buffer->cmdstat.residual > 0)
492 				atomic64_inc(&STp->stats->resid_cnt);
493 		} else
494 			atomic64_add(atomic_read(&STp->stats->last_write_size),
495 				&STp->stats->write_byte_cnt);
496 	} else if (scsi_req(req)->cmd[0] == READ_6) {
497 		now = ktime_sub(now, STp->stats->read_time);
498 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
499 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
500 		atomic64_inc(&STp->stats->read_cnt);
501 		if (scsi_req(req)->result) {
502 			atomic64_add(atomic_read(&STp->stats->last_read_size)
503 				- STp->buffer->cmdstat.residual,
504 				&STp->stats->read_byte_cnt);
505 			if (STp->buffer->cmdstat.residual > 0)
506 				atomic64_inc(&STp->stats->resid_cnt);
507 		} else
508 			atomic64_add(atomic_read(&STp->stats->last_read_size),
509 				&STp->stats->read_byte_cnt);
510 	} else {
511 		now = ktime_sub(now, STp->stats->other_time);
512 		atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
513 		atomic64_inc(&STp->stats->other_cnt);
514 	}
515 	atomic64_dec(&STp->stats->in_flight);
516 }
517 
518 static void st_scsi_execute_end(struct request *req, blk_status_t status)
519 {
520 	struct st_request *SRpnt = req->end_io_data;
521 	struct scsi_request *rq = scsi_req(req);
522 	struct scsi_tape *STp = SRpnt->stp;
523 	struct bio *tmp;
524 
525 	STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
526 	STp->buffer->cmdstat.residual = rq->resid_len;
527 
528 	st_do_stats(STp, req);
529 
530 	tmp = SRpnt->bio;
531 	if (rq->sense_len)
532 		memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
533 	if (SRpnt->waiting)
534 		complete(SRpnt->waiting);
535 
536 	blk_rq_unmap_user(tmp);
537 	blk_put_request(req);
538 }
539 
540 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
541 			   int data_direction, void *buffer, unsigned bufflen,
542 			   int timeout, int retries)
543 {
544 	struct request *req;
545 	struct scsi_request *rq;
546 	struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
547 	int err = 0;
548 	struct scsi_tape *STp = SRpnt->stp;
549 
550 	req = blk_get_request(SRpnt->stp->device->request_queue,
551 			data_direction == DMA_TO_DEVICE ?
552 			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
553 	if (IS_ERR(req))
554 		return DRIVER_ERROR << 24;
555 	rq = scsi_req(req);
556 	req->rq_flags |= RQF_QUIET;
557 
558 	mdata->null_mapped = 1;
559 
560 	if (bufflen) {
561 		err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
562 				      GFP_KERNEL);
563 		if (err) {
564 			blk_put_request(req);
565 			return DRIVER_ERROR << 24;
566 		}
567 	}
568 
569 	atomic64_inc(&STp->stats->in_flight);
570 	if (cmd[0] == WRITE_6) {
571 		atomic_set(&STp->stats->last_write_size, bufflen);
572 		STp->stats->write_time = ktime_get();
573 	} else if (cmd[0] == READ_6) {
574 		atomic_set(&STp->stats->last_read_size, bufflen);
575 		STp->stats->read_time = ktime_get();
576 	} else {
577 		STp->stats->other_time = ktime_get();
578 	}
579 
580 	SRpnt->bio = req->bio;
581 	rq->cmd_len = COMMAND_SIZE(cmd[0]);
582 	memset(rq->cmd, 0, BLK_MAX_CDB);
583 	memcpy(rq->cmd, cmd, rq->cmd_len);
584 	req->timeout = timeout;
585 	rq->retries = retries;
586 	req->end_io_data = SRpnt;
587 
588 	blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
589 	return 0;
590 }
591 
592 /* Do the scsi command. Waits until command performed if do_wait is true.
593    Otherwise write_behind_check() is used to check that the command
594    has finished. */
595 static struct st_request *
596 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
597 	   int bytes, int direction, int timeout, int retries, int do_wait)
598 {
599 	struct completion *waiting;
600 	struct rq_map_data *mdata = &STp->buffer->map_data;
601 	int ret;
602 
603 	/* if async, make sure there's no command outstanding */
604 	if (!do_wait && ((STp->buffer)->last_SRpnt)) {
605 		st_printk(KERN_ERR, STp,
606 			  "Async command already active.\n");
607 		if (signal_pending(current))
608 			(STp->buffer)->syscall_result = (-EINTR);
609 		else
610 			(STp->buffer)->syscall_result = (-EBUSY);
611 		return NULL;
612 	}
613 
614 	if (!SRpnt) {
615 		SRpnt = st_allocate_request(STp);
616 		if (!SRpnt)
617 			return NULL;
618 	}
619 
620 	/* If async IO, set last_SRpnt. This ptr tells write_behind_check
621 	   which IO is outstanding. It's nulled out when the IO completes. */
622 	if (!do_wait)
623 		(STp->buffer)->last_SRpnt = SRpnt;
624 
625 	waiting = &STp->wait;
626 	init_completion(waiting);
627 	SRpnt->waiting = waiting;
628 
629 	if (STp->buffer->do_dio) {
630 		mdata->page_order = 0;
631 		mdata->nr_entries = STp->buffer->sg_segs;
632 		mdata->pages = STp->buffer->mapped_pages;
633 	} else {
634 		mdata->page_order = STp->buffer->reserved_page_order;
635 		mdata->nr_entries =
636 			DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
637 		mdata->pages = STp->buffer->reserved_pages;
638 		mdata->offset = 0;
639 	}
640 
641 	memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
642 	STp->buffer->cmdstat.have_sense = 0;
643 	STp->buffer->syscall_result = 0;
644 
645 	ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
646 			      retries);
647 	if (ret) {
648 		/* could not allocate the buffer or request was too large */
649 		(STp->buffer)->syscall_result = (-EBUSY);
650 		(STp->buffer)->last_SRpnt = NULL;
651 	} else if (do_wait) {
652 		wait_for_completion(waiting);
653 		SRpnt->waiting = NULL;
654 		(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
655 	}
656 
657 	return SRpnt;
658 }
659 
660 
661 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
662    write has been correct but EOM early warning reached, -EIO if write ended in
663    error or zero if write successful. Asynchronous writes are used only in
664    variable block mode. */
665 static int write_behind_check(struct scsi_tape * STp)
666 {
667 	int retval = 0;
668 	struct st_buffer *STbuffer;
669 	struct st_partstat *STps;
670 	struct st_cmdstatus *cmdstatp;
671 	struct st_request *SRpnt;
672 
673 	STbuffer = STp->buffer;
674 	if (!STbuffer->writing)
675 		return 0;
676 
677 	DEB(
678 	if (STp->write_pending)
679 		STp->nbr_waits++;
680 	else
681 		STp->nbr_finished++;
682 	) /* end DEB */
683 
684 	wait_for_completion(&(STp->wait));
685 	SRpnt = STbuffer->last_SRpnt;
686 	STbuffer->last_SRpnt = NULL;
687 	SRpnt->waiting = NULL;
688 
689 	(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
690 	st_release_request(SRpnt);
691 
692 	STbuffer->buffer_bytes -= STbuffer->writing;
693 	STps = &(STp->ps[STp->partition]);
694 	if (STps->drv_block >= 0) {
695 		if (STp->block_size == 0)
696 			STps->drv_block++;
697 		else
698 			STps->drv_block += STbuffer->writing / STp->block_size;
699 	}
700 
701 	cmdstatp = &STbuffer->cmdstat;
702 	if (STbuffer->syscall_result) {
703 		retval = -EIO;
704 		if (cmdstatp->have_sense && !cmdstatp->deferred &&
705 		    (cmdstatp->flags & SENSE_EOM) &&
706 		    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
707 		     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
708 			/* EOM at write-behind, has all data been written? */
709 			if (!cmdstatp->remainder_valid ||
710 			    cmdstatp->uremainder64 == 0)
711 				retval = -ENOSPC;
712 		}
713 		if (retval == -EIO)
714 			STps->drv_block = -1;
715 	}
716 	STbuffer->writing = 0;
717 
718 	DEB(if (debugging && retval)
719 		    st_printk(ST_DEB_MSG, STp,
720 				"Async write error %x, return value %d.\n",
721 				STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
722 
723 	return retval;
724 }
725 
726 
727 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
728    it messes up the block number). */
729 static int cross_eof(struct scsi_tape * STp, int forward)
730 {
731 	struct st_request *SRpnt;
732 	unsigned char cmd[MAX_COMMAND_SIZE];
733 
734 	cmd[0] = SPACE;
735 	cmd[1] = 0x01;		/* Space FileMarks */
736 	if (forward) {
737 		cmd[2] = cmd[3] = 0;
738 		cmd[4] = 1;
739 	} else
740 		cmd[2] = cmd[3] = cmd[4] = 0xff;	/* -1 filemarks */
741 	cmd[5] = 0;
742 
743 	DEBC_printk(STp, "Stepping over filemark %s.\n",
744 		    forward ? "forward" : "backward");
745 
746 	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
747 			   STp->device->request_queue->rq_timeout,
748 			   MAX_RETRIES, 1);
749 	if (!SRpnt)
750 		return (STp->buffer)->syscall_result;
751 
752 	st_release_request(SRpnt);
753 	SRpnt = NULL;
754 
755 	if ((STp->buffer)->cmdstat.midlevel_result != 0)
756 		st_printk(KERN_ERR, STp,
757 			  "Stepping over filemark %s failed.\n",
758 			  forward ? "forward" : "backward");
759 
760 	return (STp->buffer)->syscall_result;
761 }
762 
763 
764 /* Flush the write buffer (never need to write if variable blocksize). */
765 static int st_flush_write_buffer(struct scsi_tape * STp)
766 {
767 	int transfer, blks;
768 	int result;
769 	unsigned char cmd[MAX_COMMAND_SIZE];
770 	struct st_request *SRpnt;
771 	struct st_partstat *STps;
772 
773 	result = write_behind_check(STp);
774 	if (result)
775 		return result;
776 
777 	result = 0;
778 	if (STp->dirty == 1) {
779 
780 		transfer = STp->buffer->buffer_bytes;
781 		DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
782 
783 		memset(cmd, 0, MAX_COMMAND_SIZE);
784 		cmd[0] = WRITE_6;
785 		cmd[1] = 1;
786 		blks = transfer / STp->block_size;
787 		cmd[2] = blks >> 16;
788 		cmd[3] = blks >> 8;
789 		cmd[4] = blks;
790 
791 		SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
792 				   STp->device->request_queue->rq_timeout,
793 				   MAX_WRITE_RETRIES, 1);
794 		if (!SRpnt)
795 			return (STp->buffer)->syscall_result;
796 
797 		STps = &(STp->ps[STp->partition]);
798 		if ((STp->buffer)->syscall_result != 0) {
799 			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
800 
801 			if (cmdstatp->have_sense && !cmdstatp->deferred &&
802 			    (cmdstatp->flags & SENSE_EOM) &&
803 			    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
804 			     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
805 			    (!cmdstatp->remainder_valid ||
806 			     cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
807 				STp->dirty = 0;
808 				(STp->buffer)->buffer_bytes = 0;
809 				if (STps->drv_block >= 0)
810 					STps->drv_block += blks;
811 				result = (-ENOSPC);
812 			} else {
813 				st_printk(KERN_ERR, STp, "Error on flush.\n");
814 				STps->drv_block = (-1);
815 				result = (-EIO);
816 			}
817 		} else {
818 			if (STps->drv_block >= 0)
819 				STps->drv_block += blks;
820 			STp->dirty = 0;
821 			(STp->buffer)->buffer_bytes = 0;
822 		}
823 		st_release_request(SRpnt);
824 		SRpnt = NULL;
825 	}
826 	return result;
827 }
828 
829 
830 /* Flush the tape buffer. The tape will be positioned correctly unless
831    seek_next is true. */
832 static int flush_buffer(struct scsi_tape *STp, int seek_next)
833 {
834 	int backspace, result;
835 	struct st_partstat *STps;
836 
837 	/*
838 	 * If there was a bus reset, block further access
839 	 * to this device.
840 	 */
841 	if (STp->pos_unknown)
842 		return (-EIO);
843 
844 	if (STp->ready != ST_READY)
845 		return 0;
846 	STps = &(STp->ps[STp->partition]);
847 	if (STps->rw == ST_WRITING)	/* Writing */
848 		return st_flush_write_buffer(STp);
849 
850 	if (STp->block_size == 0)
851 		return 0;
852 
853 	backspace = ((STp->buffer)->buffer_bytes +
854 		     (STp->buffer)->read_pointer) / STp->block_size -
855 	    ((STp->buffer)->read_pointer + STp->block_size - 1) /
856 	    STp->block_size;
857 	(STp->buffer)->buffer_bytes = 0;
858 	(STp->buffer)->read_pointer = 0;
859 	result = 0;
860 	if (!seek_next) {
861 		if (STps->eof == ST_FM_HIT) {
862 			result = cross_eof(STp, 0);	/* Back over the EOF hit */
863 			if (!result)
864 				STps->eof = ST_NOEOF;
865 			else {
866 				if (STps->drv_file >= 0)
867 					STps->drv_file++;
868 				STps->drv_block = 0;
869 			}
870 		}
871 		if (!result && backspace > 0)
872 			result = st_int_ioctl(STp, MTBSR, backspace);
873 	} else if (STps->eof == ST_FM_HIT) {
874 		if (STps->drv_file >= 0)
875 			STps->drv_file++;
876 		STps->drv_block = 0;
877 		STps->eof = ST_NOEOF;
878 	}
879 	return result;
880 
881 }
882 
883 /* Set the mode parameters */
884 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
885 {
886 	int set_it = 0;
887 	unsigned long arg;
888 
889 	if (!STp->density_changed &&
890 	    STm->default_density >= 0 &&
891 	    STm->default_density != STp->density) {
892 		arg = STm->default_density;
893 		set_it = 1;
894 	} else
895 		arg = STp->density;
896 	arg <<= MT_ST_DENSITY_SHIFT;
897 	if (!STp->blksize_changed &&
898 	    STm->default_blksize >= 0 &&
899 	    STm->default_blksize != STp->block_size) {
900 		arg |= STm->default_blksize;
901 		set_it = 1;
902 	} else
903 		arg |= STp->block_size;
904 	if (set_it &&
905 	    st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
906 		st_printk(KERN_WARNING, STp,
907 			  "Can't set default block size to %d bytes "
908 			  "and density %x.\n",
909 			  STm->default_blksize, STm->default_density);
910 		if (modes_defined)
911 			return (-EINVAL);
912 	}
913 	return 0;
914 }
915 
916 
917 /* Lock or unlock the drive door. Don't use when st_request allocated. */
918 static int do_door_lock(struct scsi_tape * STp, int do_lock)
919 {
920 	int retval;
921 
922 	DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
923 
924 	retval = scsi_set_medium_removal(STp->device,
925 			do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
926 	if (!retval)
927 		STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
928 	else
929 		STp->door_locked = ST_LOCK_FAILS;
930 	return retval;
931 }
932 
933 
934 /* Set the internal state after reset */
935 static void reset_state(struct scsi_tape *STp)
936 {
937 	int i;
938 	struct st_partstat *STps;
939 
940 	STp->pos_unknown = 0;
941 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
942 		STps = &(STp->ps[i]);
943 		STps->rw = ST_IDLE;
944 		STps->eof = ST_NOEOF;
945 		STps->at_sm = 0;
946 		STps->last_block_valid = 0;
947 		STps->drv_block = -1;
948 		STps->drv_file = -1;
949 	}
950 	if (STp->can_partitions) {
951 		STp->partition = find_partition(STp);
952 		if (STp->partition < 0)
953 			STp->partition = 0;
954 		STp->new_partition = STp->partition;
955 	}
956 }
957 
958 /* Test if the drive is ready. Returns either one of the codes below or a negative system
959    error code. */
960 #define CHKRES_READY       0
961 #define CHKRES_NEW_SESSION 1
962 #define CHKRES_NOT_READY   2
963 #define CHKRES_NO_TAPE     3
964 
965 #define MAX_ATTENTIONS    10
966 
967 static int test_ready(struct scsi_tape *STp, int do_wait)
968 {
969 	int attentions, waits, max_wait, scode;
970 	int retval = CHKRES_READY, new_session = 0;
971 	unsigned char cmd[MAX_COMMAND_SIZE];
972 	struct st_request *SRpnt = NULL;
973 	struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
974 
975 	max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
976 
977 	for (attentions=waits=0; ; ) {
978 		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
979 		cmd[0] = TEST_UNIT_READY;
980 		SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
981 				   STp->long_timeout, MAX_READY_RETRIES, 1);
982 
983 		if (!SRpnt) {
984 			retval = (STp->buffer)->syscall_result;
985 			break;
986 		}
987 
988 		if (cmdstatp->have_sense) {
989 
990 			scode = cmdstatp->sense_hdr.sense_key;
991 
992 			if (scode == UNIT_ATTENTION) { /* New media? */
993 				new_session = 1;
994 				if (attentions < MAX_ATTENTIONS) {
995 					attentions++;
996 					continue;
997 				}
998 				else {
999 					retval = (-EIO);
1000 					break;
1001 				}
1002 			}
1003 
1004 			if (scode == NOT_READY) {
1005 				if (waits < max_wait) {
1006 					if (msleep_interruptible(1000)) {
1007 						retval = (-EINTR);
1008 						break;
1009 					}
1010 					waits++;
1011 					continue;
1012 				}
1013 				else {
1014 					if ((STp->device)->scsi_level >= SCSI_2 &&
1015 					    cmdstatp->sense_hdr.asc == 0x3a)	/* Check ASC */
1016 						retval = CHKRES_NO_TAPE;
1017 					else
1018 						retval = CHKRES_NOT_READY;
1019 					break;
1020 				}
1021 			}
1022 		}
1023 
1024 		retval = (STp->buffer)->syscall_result;
1025 		if (!retval)
1026 			retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1027 		break;
1028 	}
1029 
1030 	if (SRpnt != NULL)
1031 		st_release_request(SRpnt);
1032 	return retval;
1033 }
1034 
1035 
1036 /* See if the drive is ready and gather information about the tape. Return values:
1037    < 0   negative error code from errno.h
1038    0     drive ready
1039    1     drive not ready (possibly no tape)
1040 */
1041 static int check_tape(struct scsi_tape *STp, struct file *filp)
1042 {
1043 	int i, retval, new_session = 0, do_wait;
1044 	unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1045 	unsigned short st_flags = filp->f_flags;
1046 	struct st_request *SRpnt = NULL;
1047 	struct st_modedef *STm;
1048 	struct st_partstat *STps;
1049 	struct inode *inode = file_inode(filp);
1050 	int mode = TAPE_MODE(inode);
1051 
1052 	STp->ready = ST_READY;
1053 
1054 	if (mode != STp->current_mode) {
1055 		DEBC_printk(STp, "Mode change from %d to %d.\n",
1056 			    STp->current_mode, mode);
1057 		new_session = 1;
1058 		STp->current_mode = mode;
1059 	}
1060 	STm = &(STp->modes[STp->current_mode]);
1061 
1062 	saved_cleaning = STp->cleaning_req;
1063 	STp->cleaning_req = 0;
1064 
1065 	do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1066 	retval = test_ready(STp, do_wait);
1067 
1068 	if (retval < 0)
1069 	    goto err_out;
1070 
1071 	if (retval == CHKRES_NEW_SESSION) {
1072 		STp->pos_unknown = 0;
1073 		STp->partition = STp->new_partition = 0;
1074 		if (STp->can_partitions)
1075 			STp->nbr_partitions = 1; /* This guess will be updated later
1076                                                     if necessary */
1077 		for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1078 			STps = &(STp->ps[i]);
1079 			STps->rw = ST_IDLE;
1080 			STps->eof = ST_NOEOF;
1081 			STps->at_sm = 0;
1082 			STps->last_block_valid = 0;
1083 			STps->drv_block = 0;
1084 			STps->drv_file = 0;
1085 		}
1086 		new_session = 1;
1087 	}
1088 	else {
1089 		STp->cleaning_req |= saved_cleaning;
1090 
1091 		if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1092 			if (retval == CHKRES_NO_TAPE)
1093 				STp->ready = ST_NO_TAPE;
1094 			else
1095 				STp->ready = ST_NOT_READY;
1096 
1097 			STp->density = 0;	/* Clear the erroneous "residue" */
1098 			STp->write_prot = 0;
1099 			STp->block_size = 0;
1100 			STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1101 			STp->partition = STp->new_partition = 0;
1102 			STp->door_locked = ST_UNLOCKED;
1103 			return CHKRES_NOT_READY;
1104 		}
1105 	}
1106 
1107 	if (STp->omit_blklims)
1108 		STp->min_block = STp->max_block = (-1);
1109 	else {
1110 		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1111 		cmd[0] = READ_BLOCK_LIMITS;
1112 
1113 		SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1114 				   STp->device->request_queue->rq_timeout,
1115 				   MAX_READY_RETRIES, 1);
1116 		if (!SRpnt) {
1117 			retval = (STp->buffer)->syscall_result;
1118 			goto err_out;
1119 		}
1120 
1121 		if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1122 			STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1123 			    ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1124 			STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1125 			    (STp->buffer)->b_data[5];
1126 			if ( DEB( debugging || ) !STp->inited)
1127 				st_printk(KERN_INFO, STp,
1128 					  "Block limits %d - %d bytes.\n",
1129 					  STp->min_block, STp->max_block);
1130 		} else {
1131 			STp->min_block = STp->max_block = (-1);
1132 			DEBC_printk(STp, "Can't read block limits.\n");
1133 		}
1134 	}
1135 
1136 	memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1137 	cmd[0] = MODE_SENSE;
1138 	cmd[4] = 12;
1139 
1140 	SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1141 			   STp->device->request_queue->rq_timeout,
1142 			   MAX_READY_RETRIES, 1);
1143 	if (!SRpnt) {
1144 		retval = (STp->buffer)->syscall_result;
1145 		goto err_out;
1146 	}
1147 
1148 	if ((STp->buffer)->syscall_result != 0) {
1149 		DEBC_printk(STp, "No Mode Sense.\n");
1150 		STp->block_size = ST_DEFAULT_BLOCK;	/* Educated guess (?) */
1151 		(STp->buffer)->syscall_result = 0;	/* Prevent error propagation */
1152 		STp->drv_write_prot = 0;
1153 	} else {
1154 		DEBC_printk(STp,"Mode sense. Length %d, "
1155 			    "medium %x, WBS %x, BLL %d\n",
1156 			    (STp->buffer)->b_data[0],
1157 			    (STp->buffer)->b_data[1],
1158 			    (STp->buffer)->b_data[2],
1159 			    (STp->buffer)->b_data[3]);
1160 
1161 		if ((STp->buffer)->b_data[3] >= 8) {
1162 			STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1163 			STp->density = (STp->buffer)->b_data[4];
1164 			STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1165 			    (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1166 			DEBC_printk(STp, "Density %x, tape length: %x, "
1167 				    "drv buffer: %d\n",
1168 				    STp->density,
1169 				    (STp->buffer)->b_data[5] * 65536 +
1170 				    (STp->buffer)->b_data[6] * 256 +
1171 				    (STp->buffer)->b_data[7],
1172 				    STp->drv_buffer);
1173 		}
1174 		STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1175 		if (!STp->drv_buffer && STp->immediate_filemark) {
1176 			st_printk(KERN_WARNING, STp,
1177 				  "non-buffered tape: disabling "
1178 				  "writing immediate filemarks\n");
1179 			STp->immediate_filemark = 0;
1180 		}
1181 	}
1182 	st_release_request(SRpnt);
1183 	SRpnt = NULL;
1184 	STp->inited = 1;
1185 
1186 	if (STp->block_size > 0)
1187 		(STp->buffer)->buffer_blocks =
1188 			(STp->buffer)->buffer_size / STp->block_size;
1189 	else
1190 		(STp->buffer)->buffer_blocks = 1;
1191 	(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1192 
1193 	DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1194 		    STp->block_size, (STp->buffer)->buffer_size,
1195 		    (STp->buffer)->buffer_blocks);
1196 
1197 	if (STp->drv_write_prot) {
1198 		STp->write_prot = 1;
1199 
1200 		DEBC_printk(STp, "Write protected\n");
1201 
1202 		if (do_wait &&
1203 		    ((st_flags & O_ACCMODE) == O_WRONLY ||
1204 		     (st_flags & O_ACCMODE) == O_RDWR)) {
1205 			retval = (-EROFS);
1206 			goto err_out;
1207 		}
1208 	}
1209 
1210 	if (STp->can_partitions && STp->nbr_partitions < 1) {
1211 		/* This code is reached when the device is opened for the first time
1212 		   after the driver has been initialized with tape in the drive and the
1213 		   partition support has been enabled. */
1214 		DEBC_printk(STp, "Updating partition number in status.\n");
1215 		if ((STp->partition = find_partition(STp)) < 0) {
1216 			retval = STp->partition;
1217 			goto err_out;
1218 		}
1219 		STp->new_partition = STp->partition;
1220 		STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1221 	}
1222 
1223 	if (new_session) {	/* Change the drive parameters for the new mode */
1224 		STp->density_changed = STp->blksize_changed = 0;
1225 		STp->compression_changed = 0;
1226 		if (!(STm->defaults_for_writes) &&
1227 		    (retval = set_mode_densblk(STp, STm)) < 0)
1228 		    goto err_out;
1229 
1230 		if (STp->default_drvbuffer != 0xff) {
1231 			if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1232 				st_printk(KERN_WARNING, STp,
1233 					  "Can't set default drive "
1234 					  "buffering to %d.\n",
1235 					  STp->default_drvbuffer);
1236 		}
1237 	}
1238 
1239 	return CHKRES_READY;
1240 
1241  err_out:
1242 	return retval;
1243 }
1244 
1245 
1246 /* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1247    module count. */
1248 static int st_open(struct inode *inode, struct file *filp)
1249 {
1250 	int i, retval = (-EIO);
1251 	int resumed = 0;
1252 	struct scsi_tape *STp;
1253 	struct st_partstat *STps;
1254 	int dev = TAPE_NR(inode);
1255 
1256 	/*
1257 	 * We really want to do nonseekable_open(inode, filp); here, but some
1258 	 * versions of tar incorrectly call lseek on tapes and bail out if that
1259 	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1260 	 */
1261 	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1262 
1263 	if (!(STp = scsi_tape_get(dev))) {
1264 		return -ENXIO;
1265 	}
1266 
1267 	filp->private_data = STp;
1268 
1269 	spin_lock(&st_use_lock);
1270 	if (STp->in_use) {
1271 		spin_unlock(&st_use_lock);
1272 		scsi_tape_put(STp);
1273 		DEBC_printk(STp, "Device already in use.\n");
1274 		return (-EBUSY);
1275 	}
1276 
1277 	STp->in_use = 1;
1278 	spin_unlock(&st_use_lock);
1279 	STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1280 
1281 	if (scsi_autopm_get_device(STp->device) < 0) {
1282 		retval = -EIO;
1283 		goto err_out;
1284 	}
1285 	resumed = 1;
1286 	if (!scsi_block_when_processing_errors(STp->device)) {
1287 		retval = (-ENXIO);
1288 		goto err_out;
1289 	}
1290 
1291 	/* See that we have at least a one page buffer available */
1292 	if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1293 		st_printk(KERN_WARNING, STp,
1294 			  "Can't allocate one page tape buffer.\n");
1295 		retval = (-EOVERFLOW);
1296 		goto err_out;
1297 	}
1298 
1299 	(STp->buffer)->cleared = 0;
1300 	(STp->buffer)->writing = 0;
1301 	(STp->buffer)->syscall_result = 0;
1302 
1303 	STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1304 
1305 	STp->dirty = 0;
1306 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1307 		STps = &(STp->ps[i]);
1308 		STps->rw = ST_IDLE;
1309 	}
1310 	STp->try_dio_now = STp->try_dio;
1311 	STp->recover_count = 0;
1312 	DEB( STp->nbr_waits = STp->nbr_finished = 0;
1313 	     STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1314 
1315 	retval = check_tape(STp, filp);
1316 	if (retval < 0)
1317 		goto err_out;
1318 	if ((filp->f_flags & O_NONBLOCK) == 0 &&
1319 	    retval != CHKRES_READY) {
1320 		if (STp->ready == NO_TAPE)
1321 			retval = (-ENOMEDIUM);
1322 		else
1323 			retval = (-EIO);
1324 		goto err_out;
1325 	}
1326 	return 0;
1327 
1328  err_out:
1329 	normalize_buffer(STp->buffer);
1330 	spin_lock(&st_use_lock);
1331 	STp->in_use = 0;
1332 	spin_unlock(&st_use_lock);
1333 	if (resumed)
1334 		scsi_autopm_put_device(STp->device);
1335 	scsi_tape_put(STp);
1336 	return retval;
1337 
1338 }
1339 
1340 
1341 /* Flush the tape buffer before close */
1342 static int st_flush(struct file *filp, fl_owner_t id)
1343 {
1344 	int result = 0, result2;
1345 	unsigned char cmd[MAX_COMMAND_SIZE];
1346 	struct st_request *SRpnt;
1347 	struct scsi_tape *STp = filp->private_data;
1348 	struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1349 	struct st_partstat *STps = &(STp->ps[STp->partition]);
1350 
1351 	if (file_count(filp) > 1)
1352 		return 0;
1353 
1354 	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1355 		result = st_flush_write_buffer(STp);
1356 		if (result != 0 && result != (-ENOSPC))
1357 			goto out;
1358 	}
1359 
1360 	if (STp->can_partitions &&
1361 	    (result2 = switch_partition(STp)) < 0) {
1362 		DEBC_printk(STp, "switch_partition at close failed.\n");
1363 		if (result == 0)
1364 			result = result2;
1365 		goto out;
1366 	}
1367 
1368 	DEBC( if (STp->nbr_requests)
1369 		st_printk(KERN_DEBUG, STp,
1370 			  "Number of r/w requests %d, dio used in %d, "
1371 			  "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1372 			  STp->nbr_pages));
1373 
1374 	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1375 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1376 
1377 #if DEBUG
1378 		DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1379 			    STp->nbr_waits, STp->nbr_finished);
1380 #endif
1381 		memset(cmd, 0, MAX_COMMAND_SIZE);
1382 		cmd[0] = WRITE_FILEMARKS;
1383 		if (STp->immediate_filemark)
1384 			cmd[1] = 1;
1385 		cmd[4] = 1 + STp->two_fm;
1386 
1387 		SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1388 				   STp->device->request_queue->rq_timeout,
1389 				   MAX_WRITE_RETRIES, 1);
1390 		if (!SRpnt) {
1391 			result = (STp->buffer)->syscall_result;
1392 			goto out;
1393 		}
1394 
1395 		if (STp->buffer->syscall_result == 0 ||
1396 		    (cmdstatp->have_sense && !cmdstatp->deferred &&
1397 		     (cmdstatp->flags & SENSE_EOM) &&
1398 		     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1399 		      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1400 		     (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1401 			/* Write successful at EOM */
1402 			st_release_request(SRpnt);
1403 			SRpnt = NULL;
1404 			if (STps->drv_file >= 0)
1405 				STps->drv_file++;
1406 			STps->drv_block = 0;
1407 			if (STp->two_fm)
1408 				cross_eof(STp, 0);
1409 			STps->eof = ST_FM;
1410 		}
1411 		else { /* Write error */
1412 			st_release_request(SRpnt);
1413 			SRpnt = NULL;
1414 			st_printk(KERN_ERR, STp,
1415 				  "Error on write filemark.\n");
1416 			if (result == 0)
1417 				result = (-EIO);
1418 		}
1419 
1420 		DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1421 	} else if (!STp->rew_at_close) {
1422 		STps = &(STp->ps[STp->partition]);
1423 		if (!STm->sysv || STps->rw != ST_READING) {
1424 			if (STp->can_bsr)
1425 				result = flush_buffer(STp, 0);
1426 			else if (STps->eof == ST_FM_HIT) {
1427 				result = cross_eof(STp, 0);
1428 				if (result) {
1429 					if (STps->drv_file >= 0)
1430 						STps->drv_file++;
1431 					STps->drv_block = 0;
1432 					STps->eof = ST_FM;
1433 				} else
1434 					STps->eof = ST_NOEOF;
1435 			}
1436 		} else if ((STps->eof == ST_NOEOF &&
1437 			    !(result = cross_eof(STp, 1))) ||
1438 			   STps->eof == ST_FM_HIT) {
1439 			if (STps->drv_file >= 0)
1440 				STps->drv_file++;
1441 			STps->drv_block = 0;
1442 			STps->eof = ST_FM;
1443 		}
1444 	}
1445 
1446       out:
1447 	if (STp->rew_at_close) {
1448 		result2 = st_int_ioctl(STp, MTREW, 1);
1449 		if (result == 0)
1450 			result = result2;
1451 	}
1452 	return result;
1453 }
1454 
1455 
1456 /* Close the device and release it. BKL is not needed: this is the only thread
1457    accessing this tape. */
1458 static int st_release(struct inode *inode, struct file *filp)
1459 {
1460 	int result = 0;
1461 	struct scsi_tape *STp = filp->private_data;
1462 
1463 	if (STp->door_locked == ST_LOCKED_AUTO)
1464 		do_door_lock(STp, 0);
1465 
1466 	normalize_buffer(STp->buffer);
1467 	spin_lock(&st_use_lock);
1468 	STp->in_use = 0;
1469 	spin_unlock(&st_use_lock);
1470 	scsi_autopm_put_device(STp->device);
1471 	scsi_tape_put(STp);
1472 
1473 	return result;
1474 }
1475 
1476 /* The checks common to both reading and writing */
1477 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1478 {
1479 	ssize_t retval = 0;
1480 
1481 	/*
1482 	 * If we are in the middle of error recovery, don't let anyone
1483 	 * else try and use this device.  Also, if error recovery fails, it
1484 	 * may try and take the device offline, in which case all further
1485 	 * access to the device is prohibited.
1486 	 */
1487 	if (!scsi_block_when_processing_errors(STp->device)) {
1488 		retval = (-ENXIO);
1489 		goto out;
1490 	}
1491 
1492 	if (STp->ready != ST_READY) {
1493 		if (STp->ready == ST_NO_TAPE)
1494 			retval = (-ENOMEDIUM);
1495 		else
1496 			retval = (-EIO);
1497 		goto out;
1498 	}
1499 
1500 	if (! STp->modes[STp->current_mode].defined) {
1501 		retval = (-ENXIO);
1502 		goto out;
1503 	}
1504 
1505 
1506 	/*
1507 	 * If there was a bus reset, block further access
1508 	 * to this device.
1509 	 */
1510 	if (STp->pos_unknown) {
1511 		retval = (-EIO);
1512 		goto out;
1513 	}
1514 
1515 	if (count == 0)
1516 		goto out;
1517 
1518 	DEB(
1519 	if (!STp->in_use) {
1520 		st_printk(ST_DEB_MSG, STp,
1521 			  "Incorrect device.\n");
1522 		retval = (-EIO);
1523 		goto out;
1524 	} ) /* end DEB */
1525 
1526 	if (STp->can_partitions &&
1527 	    (retval = switch_partition(STp)) < 0)
1528 		goto out;
1529 
1530 	if (STp->block_size == 0 && STp->max_block > 0 &&
1531 	    (count < STp->min_block || count > STp->max_block)) {
1532 		retval = (-EINVAL);
1533 		goto out;
1534 	}
1535 
1536 	if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1537 	    !do_door_lock(STp, 1))
1538 		STp->door_locked = ST_LOCKED_AUTO;
1539 
1540  out:
1541 	return retval;
1542 }
1543 
1544 
1545 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1546 			   size_t count, int is_read)
1547 {
1548 	int i, bufsize, retval = 0;
1549 	struct st_buffer *STbp = STp->buffer;
1550 
1551 	if (is_read)
1552 		i = STp->try_dio_now && try_rdio;
1553 	else
1554 		i = STp->try_dio_now && try_wdio;
1555 
1556 	if (i && ((unsigned long)buf & queue_dma_alignment(
1557 					STp->device->request_queue)) == 0) {
1558 		i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1559 				       count, (is_read ? READ : WRITE));
1560 		if (i > 0) {
1561 			STbp->do_dio = i;
1562 			STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1563 		}
1564 		else
1565 			STbp->do_dio = 0;  /* fall back to buffering with any error */
1566 		STbp->sg_segs = STbp->do_dio;
1567 		DEB(
1568 		     if (STbp->do_dio) {
1569 			STp->nbr_dio++;
1570 			STp->nbr_pages += STbp->do_dio;
1571 		     }
1572 		)
1573 	} else
1574 		STbp->do_dio = 0;
1575 	DEB( STp->nbr_requests++; )
1576 
1577 	if (!STbp->do_dio) {
1578 		if (STp->block_size)
1579 			bufsize = STp->block_size > st_fixed_buffer_size ?
1580 				STp->block_size : st_fixed_buffer_size;
1581 		else {
1582 			bufsize = count;
1583 			/* Make sure that data from previous user is not leaked even if
1584 			   HBA does not return correct residual */
1585 			if (is_read && STp->sili && !STbp->cleared)
1586 				clear_buffer(STbp);
1587 		}
1588 
1589 		if (bufsize > STbp->buffer_size &&
1590 		    !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1591 			st_printk(KERN_WARNING, STp,
1592 				  "Can't allocate %d byte tape buffer.\n",
1593 				  bufsize);
1594 			retval = (-EOVERFLOW);
1595 			goto out;
1596 		}
1597 		if (STp->block_size)
1598 			STbp->buffer_blocks = bufsize / STp->block_size;
1599 	}
1600 
1601  out:
1602 	return retval;
1603 }
1604 
1605 
1606 /* Can be called more than once after each setup_buffer() */
1607 static void release_buffering(struct scsi_tape *STp, int is_read)
1608 {
1609 	struct st_buffer *STbp;
1610 
1611 	STbp = STp->buffer;
1612 	if (STbp->do_dio) {
1613 		sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1614 		STbp->do_dio = 0;
1615 		STbp->sg_segs = 0;
1616 	}
1617 }
1618 
1619 
1620 /* Write command */
1621 static ssize_t
1622 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1623 {
1624 	ssize_t total;
1625 	ssize_t i, do_count, blks, transfer;
1626 	ssize_t retval;
1627 	int undone, retry_eot = 0, scode;
1628 	int async_write;
1629 	unsigned char cmd[MAX_COMMAND_SIZE];
1630 	const char __user *b_point;
1631 	struct st_request *SRpnt = NULL;
1632 	struct scsi_tape *STp = filp->private_data;
1633 	struct st_modedef *STm;
1634 	struct st_partstat *STps;
1635 	struct st_buffer *STbp;
1636 
1637 	if (mutex_lock_interruptible(&STp->lock))
1638 		return -ERESTARTSYS;
1639 
1640 	retval = rw_checks(STp, filp, count);
1641 	if (retval || count == 0)
1642 		goto out;
1643 
1644 	/* Write must be integral number of blocks */
1645 	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1646 		st_printk(KERN_WARNING, STp,
1647 			  "Write not multiple of tape block size.\n");
1648 		retval = (-EINVAL);
1649 		goto out;
1650 	}
1651 
1652 	STm = &(STp->modes[STp->current_mode]);
1653 	STps = &(STp->ps[STp->partition]);
1654 
1655 	if (STp->write_prot) {
1656 		retval = (-EACCES);
1657 		goto out;
1658 	}
1659 
1660 
1661 	if (STps->rw == ST_READING) {
1662 		retval = flush_buffer(STp, 0);
1663 		if (retval)
1664 			goto out;
1665 		STps->rw = ST_WRITING;
1666 	} else if (STps->rw != ST_WRITING &&
1667 		   STps->drv_file == 0 && STps->drv_block == 0) {
1668 		if ((retval = set_mode_densblk(STp, STm)) < 0)
1669 			goto out;
1670 		if (STm->default_compression != ST_DONT_TOUCH &&
1671 		    !(STp->compression_changed)) {
1672 			if (st_compression(STp, (STm->default_compression == ST_YES))) {
1673 				st_printk(KERN_WARNING, STp,
1674 					  "Can't set default compression.\n");
1675 				if (modes_defined) {
1676 					retval = (-EINVAL);
1677 					goto out;
1678 				}
1679 			}
1680 		}
1681 	}
1682 
1683 	STbp = STp->buffer;
1684 	i = write_behind_check(STp);
1685 	if (i) {
1686 		if (i == -ENOSPC)
1687 			STps->eof = ST_EOM_OK;
1688 		else
1689 			STps->eof = ST_EOM_ERROR;
1690 	}
1691 
1692 	if (STps->eof == ST_EOM_OK) {
1693 		STps->eof = ST_EOD_1;  /* allow next write */
1694 		retval = (-ENOSPC);
1695 		goto out;
1696 	}
1697 	else if (STps->eof == ST_EOM_ERROR) {
1698 		retval = (-EIO);
1699 		goto out;
1700 	}
1701 
1702 	/* Check the buffer readability in cases where copy_user might catch
1703 	   the problems after some tape movement. */
1704 	if (STp->block_size != 0 &&
1705 	    !STbp->do_dio &&
1706 	    (copy_from_user(&i, buf, 1) != 0 ||
1707 	     copy_from_user(&i, buf + count - 1, 1) != 0)) {
1708 		retval = (-EFAULT);
1709 		goto out;
1710 	}
1711 
1712 	retval = setup_buffering(STp, buf, count, 0);
1713 	if (retval)
1714 		goto out;
1715 
1716 	total = count;
1717 
1718 	memset(cmd, 0, MAX_COMMAND_SIZE);
1719 	cmd[0] = WRITE_6;
1720 	cmd[1] = (STp->block_size != 0);
1721 
1722 	STps->rw = ST_WRITING;
1723 
1724 	b_point = buf;
1725 	while (count > 0 && !retry_eot) {
1726 
1727 		if (STbp->do_dio) {
1728 			do_count = count;
1729 		}
1730 		else {
1731 			if (STp->block_size == 0)
1732 				do_count = count;
1733 			else {
1734 				do_count = STbp->buffer_blocks * STp->block_size -
1735 					STbp->buffer_bytes;
1736 				if (do_count > count)
1737 					do_count = count;
1738 			}
1739 
1740 			i = append_to_buffer(b_point, STbp, do_count);
1741 			if (i) {
1742 				retval = i;
1743 				goto out;
1744 			}
1745 		}
1746 		count -= do_count;
1747 		b_point += do_count;
1748 
1749 		async_write = STp->block_size == 0 && !STbp->do_dio &&
1750 			STm->do_async_writes && STps->eof < ST_EOM_OK;
1751 
1752 		if (STp->block_size != 0 && STm->do_buffer_writes &&
1753 		    !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1754 		    STbp->buffer_bytes < STbp->buffer_size) {
1755 			STp->dirty = 1;
1756 			/* Don't write a buffer that is not full enough. */
1757 			if (!async_write && count == 0)
1758 				break;
1759 		}
1760 
1761 	retry_write:
1762 		if (STp->block_size == 0)
1763 			blks = transfer = do_count;
1764 		else {
1765 			if (!STbp->do_dio)
1766 				blks = STbp->buffer_bytes;
1767 			else
1768 				blks = do_count;
1769 			blks /= STp->block_size;
1770 			transfer = blks * STp->block_size;
1771 		}
1772 		cmd[2] = blks >> 16;
1773 		cmd[3] = blks >> 8;
1774 		cmd[4] = blks;
1775 
1776 		SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1777 				   STp->device->request_queue->rq_timeout,
1778 				   MAX_WRITE_RETRIES, !async_write);
1779 		if (!SRpnt) {
1780 			retval = STbp->syscall_result;
1781 			goto out;
1782 		}
1783 		if (async_write && !STbp->syscall_result) {
1784 			STbp->writing = transfer;
1785 			STp->dirty = !(STbp->writing ==
1786 				       STbp->buffer_bytes);
1787 			SRpnt = NULL;  /* Prevent releasing this request! */
1788 			DEB( STp->write_pending = 1; )
1789 			break;
1790 		}
1791 
1792 		if (STbp->syscall_result != 0) {
1793 			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1794 
1795 			DEBC_printk(STp, "Error on write:\n");
1796 			if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1797 				scode = cmdstatp->sense_hdr.sense_key;
1798 				if (cmdstatp->remainder_valid)
1799 					undone = (int)cmdstatp->uremainder64;
1800 				else if (STp->block_size == 0 &&
1801 					 scode == VOLUME_OVERFLOW)
1802 					undone = transfer;
1803 				else
1804 					undone = 0;
1805 				if (STp->block_size != 0)
1806 					undone *= STp->block_size;
1807 				if (undone <= do_count) {
1808 					/* Only data from this write is not written */
1809 					count += undone;
1810 					b_point -= undone;
1811 					do_count -= undone;
1812 					if (STp->block_size)
1813 						blks = (transfer - undone) / STp->block_size;
1814 					STps->eof = ST_EOM_OK;
1815 					/* Continue in fixed block mode if all written
1816 					   in this request but still something left to write
1817 					   (retval left to zero)
1818 					*/
1819 					if (STp->block_size == 0 ||
1820 					    undone > 0 || count == 0)
1821 						retval = (-ENOSPC); /* EOM within current request */
1822 					DEBC_printk(STp, "EOM with %d "
1823 						    "bytes unwritten.\n",
1824 						    (int)count);
1825 				} else {
1826 					/* EOT within data buffered earlier (possible only
1827 					   in fixed block mode without direct i/o) */
1828 					if (!retry_eot && !cmdstatp->deferred &&
1829 					    (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1830 						move_buffer_data(STp->buffer, transfer - undone);
1831 						retry_eot = 1;
1832 						if (STps->drv_block >= 0) {
1833 							STps->drv_block += (transfer - undone) /
1834 								STp->block_size;
1835 						}
1836 						STps->eof = ST_EOM_OK;
1837 						DEBC_printk(STp, "Retry "
1838 							    "write of %d "
1839 							    "bytes at EOM.\n",
1840 							    STp->buffer->buffer_bytes);
1841 						goto retry_write;
1842 					}
1843 					else {
1844 						/* Either error within data buffered by driver or
1845 						   failed retry */
1846 						count -= do_count;
1847 						blks = do_count = 0;
1848 						STps->eof = ST_EOM_ERROR;
1849 						STps->drv_block = (-1); /* Too cautious? */
1850 						retval = (-EIO);	/* EOM for old data */
1851 						DEBC_printk(STp, "EOM with "
1852 							    "lost data.\n");
1853 					}
1854 				}
1855 			} else {
1856 				count += do_count;
1857 				STps->drv_block = (-1);		/* Too cautious? */
1858 				retval = STbp->syscall_result;
1859 			}
1860 
1861 		}
1862 
1863 		if (STps->drv_block >= 0) {
1864 			if (STp->block_size == 0)
1865 				STps->drv_block += (do_count > 0);
1866 			else
1867 				STps->drv_block += blks;
1868 		}
1869 
1870 		STbp->buffer_bytes = 0;
1871 		STp->dirty = 0;
1872 
1873 		if (retval || retry_eot) {
1874 			if (count < total)
1875 				retval = total - count;
1876 			goto out;
1877 		}
1878 	}
1879 
1880 	if (STps->eof == ST_EOD_1)
1881 		STps->eof = ST_EOM_OK;
1882 	else if (STps->eof != ST_EOM_OK)
1883 		STps->eof = ST_NOEOF;
1884 	retval = total - count;
1885 
1886  out:
1887 	if (SRpnt != NULL)
1888 		st_release_request(SRpnt);
1889 	release_buffering(STp, 0);
1890 	mutex_unlock(&STp->lock);
1891 
1892 	return retval;
1893 }
1894 
1895 /* Read data from the tape. Returns zero in the normal case, one if the
1896    eof status has changed, and the negative error code in case of a
1897    fatal error. Otherwise updates the buffer and the eof state.
1898 
1899    Does release user buffer mapping if it is set.
1900 */
1901 static long read_tape(struct scsi_tape *STp, long count,
1902 		      struct st_request ** aSRpnt)
1903 {
1904 	int transfer, blks, bytes;
1905 	unsigned char cmd[MAX_COMMAND_SIZE];
1906 	struct st_request *SRpnt;
1907 	struct st_modedef *STm;
1908 	struct st_partstat *STps;
1909 	struct st_buffer *STbp;
1910 	int retval = 0;
1911 
1912 	if (count == 0)
1913 		return 0;
1914 
1915 	STm = &(STp->modes[STp->current_mode]);
1916 	STps = &(STp->ps[STp->partition]);
1917 	if (STps->eof == ST_FM_HIT)
1918 		return 1;
1919 	STbp = STp->buffer;
1920 
1921 	if (STp->block_size == 0)
1922 		blks = bytes = count;
1923 	else {
1924 		if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1925 			blks = (STp->buffer)->buffer_blocks;
1926 			bytes = blks * STp->block_size;
1927 		} else {
1928 			bytes = count;
1929 			if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1930 				bytes = (STp->buffer)->buffer_size;
1931 			blks = bytes / STp->block_size;
1932 			bytes = blks * STp->block_size;
1933 		}
1934 	}
1935 
1936 	memset(cmd, 0, MAX_COMMAND_SIZE);
1937 	cmd[0] = READ_6;
1938 	cmd[1] = (STp->block_size != 0);
1939 	if (!cmd[1] && STp->sili)
1940 		cmd[1] |= 2;
1941 	cmd[2] = blks >> 16;
1942 	cmd[3] = blks >> 8;
1943 	cmd[4] = blks;
1944 
1945 	SRpnt = *aSRpnt;
1946 	SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1947 			   STp->device->request_queue->rq_timeout,
1948 			   MAX_RETRIES, 1);
1949 	release_buffering(STp, 1);
1950 	*aSRpnt = SRpnt;
1951 	if (!SRpnt)
1952 		return STbp->syscall_result;
1953 
1954 	STbp->read_pointer = 0;
1955 	STps->at_sm = 0;
1956 
1957 	/* Something to check */
1958 	if (STbp->syscall_result) {
1959 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1960 
1961 		retval = 1;
1962 		DEBC_printk(STp,
1963 			    "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1964 			    SRpnt->sense[0], SRpnt->sense[1],
1965 			    SRpnt->sense[2], SRpnt->sense[3],
1966 			    SRpnt->sense[4], SRpnt->sense[5],
1967 			    SRpnt->sense[6], SRpnt->sense[7]);
1968 		if (cmdstatp->have_sense) {
1969 
1970 			if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1971 				cmdstatp->flags &= 0xcf;	/* No need for EOM in this case */
1972 
1973 			if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1974 				/* Compute the residual count */
1975 				if (cmdstatp->remainder_valid)
1976 					transfer = (int)cmdstatp->uremainder64;
1977 				else
1978 					transfer = 0;
1979 				if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1980 					if (STp->block_size == 0)
1981 						transfer = bytes;
1982 					/* Some drives set ILI with MEDIUM ERROR */
1983 					cmdstatp->flags &= ~SENSE_ILI;
1984 				}
1985 
1986 				if (cmdstatp->flags & SENSE_ILI) {	/* ILI */
1987 					if (STp->block_size == 0 &&
1988 					    transfer < 0) {
1989 						st_printk(KERN_NOTICE, STp,
1990 							  "Failed to read %d "
1991 							  "byte block with %d "
1992 							  "byte transfer.\n",
1993 							  bytes - transfer,
1994 							  bytes);
1995 						if (STps->drv_block >= 0)
1996 							STps->drv_block += 1;
1997 						STbp->buffer_bytes = 0;
1998 						return (-ENOMEM);
1999 					} else if (STp->block_size == 0) {
2000 						STbp->buffer_bytes = bytes - transfer;
2001 					} else {
2002 						st_release_request(SRpnt);
2003 						SRpnt = *aSRpnt = NULL;
2004 						if (transfer == blks) {	/* We did not get anything, error */
2005 							st_printk(KERN_NOTICE, STp,
2006 								  "Incorrect "
2007 								  "block size.\n");
2008 							if (STps->drv_block >= 0)
2009 								STps->drv_block += blks - transfer + 1;
2010 							st_int_ioctl(STp, MTBSR, 1);
2011 							return (-EIO);
2012 						}
2013 						/* We have some data, deliver it */
2014 						STbp->buffer_bytes = (blks - transfer) *
2015 						    STp->block_size;
2016 						DEBC_printk(STp, "ILI but "
2017 							    "enough data "
2018 							    "received %ld "
2019 							    "%d.\n", count,
2020 							    STbp->buffer_bytes);
2021 						if (STps->drv_block >= 0)
2022 							STps->drv_block += 1;
2023 						if (st_int_ioctl(STp, MTBSR, 1))
2024 							return (-EIO);
2025 					}
2026 				} else if (cmdstatp->flags & SENSE_FMK) {	/* FM overrides EOM */
2027 					if (STps->eof != ST_FM_HIT)
2028 						STps->eof = ST_FM_HIT;
2029 					else
2030 						STps->eof = ST_EOD_2;
2031 					if (STp->block_size == 0)
2032 						STbp->buffer_bytes = 0;
2033 					else
2034 						STbp->buffer_bytes =
2035 						    bytes - transfer * STp->block_size;
2036 					DEBC_printk(STp, "EOF detected (%d "
2037 						    "bytes read).\n",
2038 						    STbp->buffer_bytes);
2039 				} else if (cmdstatp->flags & SENSE_EOM) {
2040 					if (STps->eof == ST_FM)
2041 						STps->eof = ST_EOD_1;
2042 					else
2043 						STps->eof = ST_EOM_OK;
2044 					if (STp->block_size == 0)
2045 						STbp->buffer_bytes = bytes - transfer;
2046 					else
2047 						STbp->buffer_bytes =
2048 						    bytes - transfer * STp->block_size;
2049 
2050 					DEBC_printk(STp, "EOM detected (%d "
2051 						    "bytes read).\n",
2052 						    STbp->buffer_bytes);
2053 				}
2054 			}
2055 			/* end of EOF, EOM, ILI test */
2056 			else {	/* nonzero sense key */
2057 				DEBC_printk(STp, "Tape error while reading.\n");
2058 				STps->drv_block = (-1);
2059 				if (STps->eof == ST_FM &&
2060 				    cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2061 					DEBC_printk(STp, "Zero returned for "
2062 						    "first BLANK CHECK "
2063 						    "after EOF.\n");
2064 					STps->eof = ST_EOD_2;	/* First BLANK_CHECK after FM */
2065 				} else	/* Some other extended sense code */
2066 					retval = (-EIO);
2067 			}
2068 
2069 			if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2070 				STbp->buffer_bytes = 0;
2071 		}
2072 		/* End of extended sense test */
2073 		else {		/* Non-extended sense */
2074 			retval = STbp->syscall_result;
2075 		}
2076 
2077 	}
2078 	/* End of error handling */
2079 	else {			/* Read successful */
2080 		STbp->buffer_bytes = bytes;
2081 		if (STp->sili) /* In fixed block mode residual is always zero here */
2082 			STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2083 	}
2084 
2085 	if (STps->drv_block >= 0) {
2086 		if (STp->block_size == 0)
2087 			STps->drv_block++;
2088 		else
2089 			STps->drv_block += STbp->buffer_bytes / STp->block_size;
2090 	}
2091 	return retval;
2092 }
2093 
2094 
2095 /* Read command */
2096 static ssize_t
2097 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2098 {
2099 	ssize_t total;
2100 	ssize_t retval = 0;
2101 	ssize_t i, transfer;
2102 	int special, do_dio = 0;
2103 	struct st_request *SRpnt = NULL;
2104 	struct scsi_tape *STp = filp->private_data;
2105 	struct st_modedef *STm;
2106 	struct st_partstat *STps;
2107 	struct st_buffer *STbp = STp->buffer;
2108 
2109 	if (mutex_lock_interruptible(&STp->lock))
2110 		return -ERESTARTSYS;
2111 
2112 	retval = rw_checks(STp, filp, count);
2113 	if (retval || count == 0)
2114 		goto out;
2115 
2116 	STm = &(STp->modes[STp->current_mode]);
2117 	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2118 		if (!STm->do_read_ahead) {
2119 			retval = (-EINVAL);	/* Read must be integral number of blocks */
2120 			goto out;
2121 		}
2122 		STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2123 	}
2124 
2125 	STps = &(STp->ps[STp->partition]);
2126 	if (STps->rw == ST_WRITING) {
2127 		retval = flush_buffer(STp, 0);
2128 		if (retval)
2129 			goto out;
2130 		STps->rw = ST_READING;
2131 	}
2132 	DEB(
2133 	if (debugging && STps->eof != ST_NOEOF)
2134 		st_printk(ST_DEB_MSG, STp,
2135 			  "EOF/EOM flag up (%d). Bytes %d\n",
2136 			  STps->eof, STbp->buffer_bytes);
2137 	) /* end DEB */
2138 
2139 	retval = setup_buffering(STp, buf, count, 1);
2140 	if (retval)
2141 		goto out;
2142 	do_dio = STbp->do_dio;
2143 
2144 	if (STbp->buffer_bytes == 0 &&
2145 	    STps->eof >= ST_EOD_1) {
2146 		if (STps->eof < ST_EOD) {
2147 			STps->eof += 1;
2148 			retval = 0;
2149 			goto out;
2150 		}
2151 		retval = (-EIO);	/* EOM or Blank Check */
2152 		goto out;
2153 	}
2154 
2155 	if (do_dio) {
2156 		/* Check the buffer writability before any tape movement. Don't alter
2157 		   buffer data. */
2158 		if (copy_from_user(&i, buf, 1) != 0 ||
2159 		    copy_to_user(buf, &i, 1) != 0 ||
2160 		    copy_from_user(&i, buf + count - 1, 1) != 0 ||
2161 		    copy_to_user(buf + count - 1, &i, 1) != 0) {
2162 			retval = (-EFAULT);
2163 			goto out;
2164 		}
2165 	}
2166 
2167 	STps->rw = ST_READING;
2168 
2169 
2170 	/* Loop until enough data in buffer or a special condition found */
2171 	for (total = 0, special = 0; total < count && !special;) {
2172 
2173 		/* Get new data if the buffer is empty */
2174 		if (STbp->buffer_bytes == 0) {
2175 			special = read_tape(STp, count - total, &SRpnt);
2176 			if (special < 0) {	/* No need to continue read */
2177 				retval = special;
2178 				goto out;
2179 			}
2180 		}
2181 
2182 		/* Move the data from driver buffer to user buffer */
2183 		if (STbp->buffer_bytes > 0) {
2184 			DEB(
2185 			if (debugging && STps->eof != ST_NOEOF)
2186 				st_printk(ST_DEB_MSG, STp,
2187 					  "EOF up (%d). Left %d, needed %d.\n",
2188 					  STps->eof, STbp->buffer_bytes,
2189 					  (int)(count - total));
2190 			) /* end DEB */
2191 			transfer = STbp->buffer_bytes < count - total ?
2192 			    STbp->buffer_bytes : count - total;
2193 			if (!do_dio) {
2194 				i = from_buffer(STbp, buf, transfer);
2195 				if (i) {
2196 					retval = i;
2197 					goto out;
2198 				}
2199 			}
2200 			buf += transfer;
2201 			total += transfer;
2202 		}
2203 
2204 		if (STp->block_size == 0)
2205 			break;	/* Read only one variable length block */
2206 
2207 	}			/* for (total = 0, special = 0;
2208                                    total < count && !special; ) */
2209 
2210 	/* Change the eof state if no data from tape or buffer */
2211 	if (total == 0) {
2212 		if (STps->eof == ST_FM_HIT) {
2213 			STps->eof = ST_FM;
2214 			STps->drv_block = 0;
2215 			if (STps->drv_file >= 0)
2216 				STps->drv_file++;
2217 		} else if (STps->eof == ST_EOD_1) {
2218 			STps->eof = ST_EOD_2;
2219 			STps->drv_block = 0;
2220 			if (STps->drv_file >= 0)
2221 				STps->drv_file++;
2222 		} else if (STps->eof == ST_EOD_2)
2223 			STps->eof = ST_EOD;
2224 	} else if (STps->eof == ST_FM)
2225 		STps->eof = ST_NOEOF;
2226 	retval = total;
2227 
2228  out:
2229 	if (SRpnt != NULL) {
2230 		st_release_request(SRpnt);
2231 		SRpnt = NULL;
2232 	}
2233 	if (do_dio) {
2234 		release_buffering(STp, 1);
2235 		STbp->buffer_bytes = 0;
2236 	}
2237 	mutex_unlock(&STp->lock);
2238 
2239 	return retval;
2240 }
2241 
2242 
2243 
2244 DEB(
2245 /* Set the driver options */
2246 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2247 {
2248 	if (debugging) {
2249 		st_printk(KERN_INFO, STp,
2250 			  "Mode %d options: buffer writes: %d, "
2251 			  "async writes: %d, read ahead: %d\n",
2252 			  STp->current_mode, STm->do_buffer_writes,
2253 			  STm->do_async_writes, STm->do_read_ahead);
2254 		st_printk(KERN_INFO, STp,
2255 			  "    can bsr: %d, two FMs: %d, "
2256 			  "fast mteom: %d, auto lock: %d,\n",
2257 			  STp->can_bsr, STp->two_fm, STp->fast_mteom,
2258 			  STp->do_auto_lock);
2259 		st_printk(KERN_INFO, STp,
2260 			  "    defs for wr: %d, no block limits: %d, "
2261 			  "partitions: %d, s2 log: %d\n",
2262 			  STm->defaults_for_writes, STp->omit_blklims,
2263 			  STp->can_partitions, STp->scsi2_logical);
2264 		st_printk(KERN_INFO, STp,
2265 			  "    sysv: %d nowait: %d sili: %d "
2266 			  "nowait_filemark: %d\n",
2267 			  STm->sysv, STp->immediate, STp->sili,
2268 			  STp->immediate_filemark);
2269 		st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2270 	}
2271 }
2272 	)
2273 
2274 
2275 static int st_set_options(struct scsi_tape *STp, long options)
2276 {
2277 	int value;
2278 	long code;
2279 	struct st_modedef *STm;
2280 	struct cdev *cd0, *cd1;
2281 	struct device *d0, *d1;
2282 
2283 	STm = &(STp->modes[STp->current_mode]);
2284 	if (!STm->defined) {
2285 		cd0 = STm->cdevs[0];
2286 		cd1 = STm->cdevs[1];
2287 		d0  = STm->devs[0];
2288 		d1  = STm->devs[1];
2289 		memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2290 		STm->cdevs[0] = cd0;
2291 		STm->cdevs[1] = cd1;
2292 		STm->devs[0]  = d0;
2293 		STm->devs[1]  = d1;
2294 		modes_defined = 1;
2295 		DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2296 			    STp->current_mode);
2297 	}
2298 
2299 	code = options & MT_ST_OPTIONS;
2300 	if (code == MT_ST_BOOLEANS) {
2301 		STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2302 		STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2303 		STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2304 		STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2305 		STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2306 		STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2307 		STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2308 		STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2309 		STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2310 		if ((STp->device)->scsi_level >= SCSI_2)
2311 			STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2312 		STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2313 		STp->immediate = (options & MT_ST_NOWAIT) != 0;
2314 		STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2315 		STm->sysv = (options & MT_ST_SYSV) != 0;
2316 		STp->sili = (options & MT_ST_SILI) != 0;
2317 		DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2318 		     st_log_options(STp, STm); )
2319 	} else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2320 		value = (code == MT_ST_SETBOOLEANS);
2321 		if ((options & MT_ST_BUFFER_WRITES) != 0)
2322 			STm->do_buffer_writes = value;
2323 		if ((options & MT_ST_ASYNC_WRITES) != 0)
2324 			STm->do_async_writes = value;
2325 		if ((options & MT_ST_DEF_WRITES) != 0)
2326 			STm->defaults_for_writes = value;
2327 		if ((options & MT_ST_READ_AHEAD) != 0)
2328 			STm->do_read_ahead = value;
2329 		if ((options & MT_ST_TWO_FM) != 0)
2330 			STp->two_fm = value;
2331 		if ((options & MT_ST_FAST_MTEOM) != 0)
2332 			STp->fast_mteom = value;
2333 		if ((options & MT_ST_AUTO_LOCK) != 0)
2334 			STp->do_auto_lock = value;
2335 		if ((options & MT_ST_CAN_BSR) != 0)
2336 			STp->can_bsr = value;
2337 		if ((options & MT_ST_NO_BLKLIMS) != 0)
2338 			STp->omit_blklims = value;
2339 		if ((STp->device)->scsi_level >= SCSI_2 &&
2340 		    (options & MT_ST_CAN_PARTITIONS) != 0)
2341 			STp->can_partitions = value;
2342 		if ((options & MT_ST_SCSI2LOGICAL) != 0)
2343 			STp->scsi2_logical = value;
2344 		if ((options & MT_ST_NOWAIT) != 0)
2345 			STp->immediate = value;
2346 		if ((options & MT_ST_NOWAIT_EOF) != 0)
2347 			STp->immediate_filemark = value;
2348 		if ((options & MT_ST_SYSV) != 0)
2349 			STm->sysv = value;
2350 		if ((options & MT_ST_SILI) != 0)
2351 			STp->sili = value;
2352 		DEB(
2353 		if ((options & MT_ST_DEBUGGING) != 0)
2354 			debugging = value;
2355 			st_log_options(STp, STm); )
2356 	} else if (code == MT_ST_WRITE_THRESHOLD) {
2357 		/* Retained for compatibility */
2358 	} else if (code == MT_ST_DEF_BLKSIZE) {
2359 		value = (options & ~MT_ST_OPTIONS);
2360 		if (value == ~MT_ST_OPTIONS) {
2361 			STm->default_blksize = (-1);
2362 			DEBC_printk(STp, "Default block size disabled.\n");
2363 		} else {
2364 			STm->default_blksize = value;
2365 			DEBC_printk(STp,"Default block size set to "
2366 				    "%d bytes.\n", STm->default_blksize);
2367 			if (STp->ready == ST_READY) {
2368 				STp->blksize_changed = 0;
2369 				set_mode_densblk(STp, STm);
2370 			}
2371 		}
2372 	} else if (code == MT_ST_TIMEOUTS) {
2373 		value = (options & ~MT_ST_OPTIONS);
2374 		if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2375 			STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2376 			DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2377 				    (value & ~MT_ST_SET_LONG_TIMEOUT));
2378 		} else {
2379 			blk_queue_rq_timeout(STp->device->request_queue,
2380 					     value * HZ);
2381 			DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2382 				    value);
2383 		}
2384 	} else if (code == MT_ST_SET_CLN) {
2385 		value = (options & ~MT_ST_OPTIONS) & 0xff;
2386 		if (value != 0 &&
2387 			(value < EXTENDED_SENSE_START ||
2388 				value >= SCSI_SENSE_BUFFERSIZE))
2389 			return (-EINVAL);
2390 		STp->cln_mode = value;
2391 		STp->cln_sense_mask = (options >> 8) & 0xff;
2392 		STp->cln_sense_value = (options >> 16) & 0xff;
2393 		st_printk(KERN_INFO, STp,
2394 			  "Cleaning request mode %d, mask %02x, value %02x\n",
2395 			  value, STp->cln_sense_mask, STp->cln_sense_value);
2396 	} else if (code == MT_ST_DEF_OPTIONS) {
2397 		code = (options & ~MT_ST_CLEAR_DEFAULT);
2398 		value = (options & MT_ST_CLEAR_DEFAULT);
2399 		if (code == MT_ST_DEF_DENSITY) {
2400 			if (value == MT_ST_CLEAR_DEFAULT) {
2401 				STm->default_density = (-1);
2402 				DEBC_printk(STp,
2403 					    "Density default disabled.\n");
2404 			} else {
2405 				STm->default_density = value & 0xff;
2406 				DEBC_printk(STp, "Density default set to %x\n",
2407 					    STm->default_density);
2408 				if (STp->ready == ST_READY) {
2409 					STp->density_changed = 0;
2410 					set_mode_densblk(STp, STm);
2411 				}
2412 			}
2413 		} else if (code == MT_ST_DEF_DRVBUFFER) {
2414 			if (value == MT_ST_CLEAR_DEFAULT) {
2415 				STp->default_drvbuffer = 0xff;
2416 				DEBC_printk(STp,
2417 					    "Drive buffer default disabled.\n");
2418 			} else {
2419 				STp->default_drvbuffer = value & 7;
2420 				DEBC_printk(STp,
2421 					    "Drive buffer default set to %x\n",
2422 					    STp->default_drvbuffer);
2423 				if (STp->ready == ST_READY)
2424 					st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2425 			}
2426 		} else if (code == MT_ST_DEF_COMPRESSION) {
2427 			if (value == MT_ST_CLEAR_DEFAULT) {
2428 				STm->default_compression = ST_DONT_TOUCH;
2429 				DEBC_printk(STp,
2430 					    "Compression default disabled.\n");
2431 			} else {
2432 				if ((value & 0xff00) != 0) {
2433 					STp->c_algo = (value & 0xff00) >> 8;
2434 					DEBC_printk(STp, "Compression "
2435 						    "algorithm set to 0x%x.\n",
2436 						    STp->c_algo);
2437 				}
2438 				if ((value & 0xff) != 0xff) {
2439 					STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2440 					DEBC_printk(STp, "Compression default "
2441 						    "set to %x\n",
2442 						    (value & 1));
2443 					if (STp->ready == ST_READY) {
2444 						STp->compression_changed = 0;
2445 						st_compression(STp, (STm->default_compression == ST_YES));
2446 					}
2447 				}
2448 			}
2449 		}
2450 	} else
2451 		return (-EIO);
2452 
2453 	return 0;
2454 }
2455 
2456 #define MODE_HEADER_LENGTH  4
2457 
2458 /* Mode header and page byte offsets */
2459 #define MH_OFF_DATA_LENGTH     0
2460 #define MH_OFF_MEDIUM_TYPE     1
2461 #define MH_OFF_DEV_SPECIFIC    2
2462 #define MH_OFF_BDESCS_LENGTH   3
2463 #define MP_OFF_PAGE_NBR        0
2464 #define MP_OFF_PAGE_LENGTH     1
2465 
2466 /* Mode header and page bit masks */
2467 #define MH_BIT_WP              0x80
2468 #define MP_MSK_PAGE_NBR        0x3f
2469 
2470 /* Don't return block descriptors */
2471 #define MODE_SENSE_OMIT_BDESCS 0x08
2472 
2473 #define MODE_SELECT_PAGE_FORMAT 0x10
2474 
2475 /* Read a mode page into the tape buffer. The block descriptors are included
2476    if incl_block_descs is true. The page control is ored to the page number
2477    parameter, if necessary. */
2478 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2479 {
2480 	unsigned char cmd[MAX_COMMAND_SIZE];
2481 	struct st_request *SRpnt;
2482 
2483 	memset(cmd, 0, MAX_COMMAND_SIZE);
2484 	cmd[0] = MODE_SENSE;
2485 	if (omit_block_descs)
2486 		cmd[1] = MODE_SENSE_OMIT_BDESCS;
2487 	cmd[2] = page;
2488 	cmd[4] = 255;
2489 
2490 	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2491 			   STp->device->request_queue->rq_timeout, 0, 1);
2492 	if (SRpnt == NULL)
2493 		return (STp->buffer)->syscall_result;
2494 
2495 	st_release_request(SRpnt);
2496 
2497 	return STp->buffer->syscall_result;
2498 }
2499 
2500 
2501 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2502    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2503 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2504 {
2505 	int pgo;
2506 	unsigned char cmd[MAX_COMMAND_SIZE];
2507 	struct st_request *SRpnt;
2508 	int timeout;
2509 
2510 	memset(cmd, 0, MAX_COMMAND_SIZE);
2511 	cmd[0] = MODE_SELECT;
2512 	cmd[1] = MODE_SELECT_PAGE_FORMAT;
2513 	pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2514 	cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2515 
2516 	/* Clear reserved fields */
2517 	(STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2518 	(STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2519 	(STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2520 	(STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2521 
2522 	timeout = slow ?
2523 		STp->long_timeout : STp->device->request_queue->rq_timeout;
2524 	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2525 			   timeout, 0, 1);
2526 	if (SRpnt == NULL)
2527 		return (STp->buffer)->syscall_result;
2528 
2529 	st_release_request(SRpnt);
2530 
2531 	return STp->buffer->syscall_result;
2532 }
2533 
2534 
2535 #define COMPRESSION_PAGE        0x0f
2536 #define COMPRESSION_PAGE_LENGTH 16
2537 
2538 #define CP_OFF_DCE_DCC          2
2539 #define CP_OFF_C_ALGO           7
2540 
2541 #define DCE_MASK  0x80
2542 #define DCC_MASK  0x40
2543 #define RED_MASK  0x60
2544 
2545 
2546 /* Control the compression with mode page 15. Algorithm not changed if zero.
2547 
2548    The block descriptors are read and written because Sony SDT-7000 does not
2549    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2550    Including block descriptors should not cause any harm to other drives. */
2551 
2552 static int st_compression(struct scsi_tape * STp, int state)
2553 {
2554 	int retval;
2555 	int mpoffs;  /* Offset to mode page start */
2556 	unsigned char *b_data = (STp->buffer)->b_data;
2557 
2558 	if (STp->ready != ST_READY)
2559 		return (-EIO);
2560 
2561 	/* Read the current page contents */
2562 	retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2563 	if (retval) {
2564 		DEBC_printk(STp, "Compression mode page not supported.\n");
2565 		return (-EIO);
2566 	}
2567 
2568 	mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2569 	DEBC_printk(STp, "Compression state is %d.\n",
2570 		    (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2571 
2572 	/* Check if compression can be changed */
2573 	if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2574 		DEBC_printk(STp, "Compression not supported.\n");
2575 		return (-EIO);
2576 	}
2577 
2578 	/* Do the change */
2579 	if (state) {
2580 		b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2581 		if (STp->c_algo != 0)
2582 			b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2583 	}
2584 	else {
2585 		b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2586 		if (STp->c_algo != 0)
2587 			b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2588 	}
2589 
2590 	retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2591 	if (retval) {
2592 		DEBC_printk(STp, "Compression change failed.\n");
2593 		return (-EIO);
2594 	}
2595 	DEBC_printk(STp, "Compression state changed to %d.\n", state);
2596 
2597 	STp->compression_changed = 1;
2598 	return 0;
2599 }
2600 
2601 
2602 /* Process the load and unload commands (does unload if the load code is zero) */
2603 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2604 {
2605 	int retval = (-EIO), timeout;
2606 	unsigned char cmd[MAX_COMMAND_SIZE];
2607 	struct st_partstat *STps;
2608 	struct st_request *SRpnt;
2609 
2610 	if (STp->ready != ST_READY && !load_code) {
2611 		if (STp->ready == ST_NO_TAPE)
2612 			return (-ENOMEDIUM);
2613 		else
2614 			return (-EIO);
2615 	}
2616 
2617 	memset(cmd, 0, MAX_COMMAND_SIZE);
2618 	cmd[0] = START_STOP;
2619 	if (load_code)
2620 		cmd[4] |= 1;
2621 	/*
2622 	 * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2623 	 */
2624 	if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2625 	    && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2626 		DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2627 			    (cmd[4]) ? "" : "un",
2628 			    load_code - MT_ST_HPLOADER_OFFSET);
2629 		cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2630 	}
2631 	if (STp->immediate) {
2632 		cmd[1] = 1;	/* Don't wait for completion */
2633 		timeout = STp->device->request_queue->rq_timeout;
2634 	}
2635 	else
2636 		timeout = STp->long_timeout;
2637 
2638 	DEBC(
2639 		if (!load_code)
2640 			st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2641 		else
2642 			st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2643 		);
2644 
2645 	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2646 			   timeout, MAX_RETRIES, 1);
2647 	if (!SRpnt)
2648 		return (STp->buffer)->syscall_result;
2649 
2650 	retval = (STp->buffer)->syscall_result;
2651 	st_release_request(SRpnt);
2652 
2653 	if (!retval) {	/* SCSI command successful */
2654 
2655 		if (!load_code) {
2656 			STp->rew_at_close = 0;
2657 			STp->ready = ST_NO_TAPE;
2658 		}
2659 		else {
2660 			STp->rew_at_close = STp->autorew_dev;
2661 			retval = check_tape(STp, filp);
2662 			if (retval > 0)
2663 				retval = 0;
2664 		}
2665 	}
2666 	else {
2667 		STps = &(STp->ps[STp->partition]);
2668 		STps->drv_file = STps->drv_block = (-1);
2669 	}
2670 
2671 	return retval;
2672 }
2673 
2674 #if DEBUG
2675 #define ST_DEB_FORWARD  0
2676 #define ST_DEB_BACKWARD 1
2677 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2678 {
2679 	s32 sc;
2680 
2681 	if (!debugging)
2682 		return;
2683 
2684 	sc = sign_extend32(get_unaligned_be24(&cmd[2]), 23);
2685 	if (direction)
2686 		sc = -sc;
2687 	st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2688 		  direction ? "backward" : "forward", sc, units);
2689 }
2690 #else
2691 #define ST_DEB_FORWARD  0
2692 #define ST_DEB_BACKWARD 1
2693 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2694 #endif
2695 
2696 
2697 /* Internal ioctl function */
2698 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2699 {
2700 	int timeout;
2701 	long ltmp;
2702 	int ioctl_result;
2703 	int chg_eof = 1;
2704 	unsigned char cmd[MAX_COMMAND_SIZE];
2705 	struct st_request *SRpnt;
2706 	struct st_partstat *STps;
2707 	int fileno, blkno, at_sm, undone;
2708 	int datalen = 0, direction = DMA_NONE;
2709 
2710 	WARN_ON(STp->buffer->do_dio != 0);
2711 	if (STp->ready != ST_READY) {
2712 		if (STp->ready == ST_NO_TAPE)
2713 			return (-ENOMEDIUM);
2714 		else
2715 			return (-EIO);
2716 	}
2717 	timeout = STp->long_timeout;
2718 	STps = &(STp->ps[STp->partition]);
2719 	fileno = STps->drv_file;
2720 	blkno = STps->drv_block;
2721 	at_sm = STps->at_sm;
2722 
2723 	memset(cmd, 0, MAX_COMMAND_SIZE);
2724 	switch (cmd_in) {
2725 	case MTFSFM:
2726 		chg_eof = 0;	/* Changed from the FSF after this */
2727 		/* fall through */
2728 	case MTFSF:
2729 		cmd[0] = SPACE;
2730 		cmd[1] = 0x01;	/* Space FileMarks */
2731 		cmd[2] = (arg >> 16);
2732 		cmd[3] = (arg >> 8);
2733 		cmd[4] = arg;
2734 		deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2735 		if (fileno >= 0)
2736 			fileno += arg;
2737 		blkno = 0;
2738 		at_sm &= (arg == 0);
2739 		break;
2740 	case MTBSFM:
2741 		chg_eof = 0;	/* Changed from the FSF after this */
2742 		/* fall through */
2743 	case MTBSF:
2744 		cmd[0] = SPACE;
2745 		cmd[1] = 0x01;	/* Space FileMarks */
2746 		ltmp = (-arg);
2747 		cmd[2] = (ltmp >> 16);
2748 		cmd[3] = (ltmp >> 8);
2749 		cmd[4] = ltmp;
2750 		deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2751 		if (fileno >= 0)
2752 			fileno -= arg;
2753 		blkno = (-1);	/* We can't know the block number */
2754 		at_sm &= (arg == 0);
2755 		break;
2756 	case MTFSR:
2757 		cmd[0] = SPACE;
2758 		cmd[1] = 0x00;	/* Space Blocks */
2759 		cmd[2] = (arg >> 16);
2760 		cmd[3] = (arg >> 8);
2761 		cmd[4] = arg;
2762 		deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2763 		if (blkno >= 0)
2764 			blkno += arg;
2765 		at_sm &= (arg == 0);
2766 		break;
2767 	case MTBSR:
2768 		cmd[0] = SPACE;
2769 		cmd[1] = 0x00;	/* Space Blocks */
2770 		ltmp = (-arg);
2771 		cmd[2] = (ltmp >> 16);
2772 		cmd[3] = (ltmp >> 8);
2773 		cmd[4] = ltmp;
2774 		deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2775 		if (blkno >= 0)
2776 			blkno -= arg;
2777 		at_sm &= (arg == 0);
2778 		break;
2779 	case MTFSS:
2780 		cmd[0] = SPACE;
2781 		cmd[1] = 0x04;	/* Space Setmarks */
2782 		cmd[2] = (arg >> 16);
2783 		cmd[3] = (arg >> 8);
2784 		cmd[4] = arg;
2785 		deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2786 		if (arg != 0) {
2787 			blkno = fileno = (-1);
2788 			at_sm = 1;
2789 		}
2790 		break;
2791 	case MTBSS:
2792 		cmd[0] = SPACE;
2793 		cmd[1] = 0x04;	/* Space Setmarks */
2794 		ltmp = (-arg);
2795 		cmd[2] = (ltmp >> 16);
2796 		cmd[3] = (ltmp >> 8);
2797 		cmd[4] = ltmp;
2798 		deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2799 		if (arg != 0) {
2800 			blkno = fileno = (-1);
2801 			at_sm = 1;
2802 		}
2803 		break;
2804 	case MTWEOF:
2805 	case MTWEOFI:
2806 	case MTWSM:
2807 		if (STp->write_prot)
2808 			return (-EACCES);
2809 		cmd[0] = WRITE_FILEMARKS;
2810 		if (cmd_in == MTWSM)
2811 			cmd[1] = 2;
2812 		if (cmd_in == MTWEOFI ||
2813 		    (cmd_in == MTWEOF && STp->immediate_filemark))
2814 			cmd[1] |= 1;
2815 		cmd[2] = (arg >> 16);
2816 		cmd[3] = (arg >> 8);
2817 		cmd[4] = arg;
2818 		timeout = STp->device->request_queue->rq_timeout;
2819 		DEBC(
2820 			if (cmd_in != MTWSM)
2821 				st_printk(ST_DEB_MSG, STp,
2822 					  "Writing %d filemarks.\n",
2823 					  cmd[2] * 65536 +
2824 					  cmd[3] * 256 +
2825 					  cmd[4]);
2826 			else
2827 				st_printk(ST_DEB_MSG, STp,
2828 					  "Writing %d setmarks.\n",
2829 					  cmd[2] * 65536 +
2830 					  cmd[3] * 256 +
2831 					  cmd[4]);
2832 		)
2833 		if (fileno >= 0)
2834 			fileno += arg;
2835 		blkno = 0;
2836 		at_sm = (cmd_in == MTWSM);
2837 		break;
2838 	case MTREW:
2839 		cmd[0] = REZERO_UNIT;
2840 		if (STp->immediate) {
2841 			cmd[1] = 1;	/* Don't wait for completion */
2842 			timeout = STp->device->request_queue->rq_timeout;
2843 		}
2844 		DEBC_printk(STp, "Rewinding tape.\n");
2845 		fileno = blkno = at_sm = 0;
2846 		break;
2847 	case MTNOP:
2848 		DEBC_printk(STp, "No op on tape.\n");
2849 		return 0;	/* Should do something ? */
2850 		break;
2851 	case MTRETEN:
2852 		cmd[0] = START_STOP;
2853 		if (STp->immediate) {
2854 			cmd[1] = 1;	/* Don't wait for completion */
2855 			timeout = STp->device->request_queue->rq_timeout;
2856 		}
2857 		cmd[4] = 3;
2858 		DEBC_printk(STp, "Retensioning tape.\n");
2859 		fileno = blkno = at_sm = 0;
2860 		break;
2861 	case MTEOM:
2862 		if (!STp->fast_mteom) {
2863 			/* space to the end of tape */
2864 			ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2865 			fileno = STps->drv_file;
2866 			if (STps->eof >= ST_EOD_1)
2867 				return 0;
2868 			/* The next lines would hide the number of spaced FileMarks
2869 			   That's why I inserted the previous lines. I had no luck
2870 			   with detecting EOM with FSF, so we go now to EOM.
2871 			   Joerg Weule */
2872 		} else
2873 			fileno = (-1);
2874 		cmd[0] = SPACE;
2875 		cmd[1] = 3;
2876 		DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2877 		blkno = -1;
2878 		at_sm = 0;
2879 		break;
2880 	case MTERASE:
2881 		if (STp->write_prot)
2882 			return (-EACCES);
2883 		cmd[0] = ERASE;
2884 		cmd[1] = (arg ? 1 : 0);	/* Long erase with non-zero argument */
2885 		if (STp->immediate) {
2886 			cmd[1] |= 2;	/* Don't wait for completion */
2887 			timeout = STp->device->request_queue->rq_timeout;
2888 		}
2889 		else
2890 			timeout = STp->long_timeout * 8;
2891 
2892 		DEBC_printk(STp, "Erasing tape.\n");
2893 		fileno = blkno = at_sm = 0;
2894 		break;
2895 	case MTSETBLK:		/* Set block length */
2896 	case MTSETDENSITY:	/* Set tape density */
2897 	case MTSETDRVBUFFER:	/* Set drive buffering */
2898 	case SET_DENS_AND_BLK:	/* Set density and block size */
2899 		chg_eof = 0;
2900 		if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2901 			return (-EIO);	/* Not allowed if data in buffer */
2902 		if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2903 		    (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2904 		    STp->max_block > 0 &&
2905 		    ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2906 		     (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2907 			st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2908 			return (-EINVAL);
2909 		}
2910 		cmd[0] = MODE_SELECT;
2911 		if ((STp->use_pf & USE_PF))
2912 			cmd[1] = MODE_SELECT_PAGE_FORMAT;
2913 		cmd[4] = datalen = 12;
2914 		direction = DMA_TO_DEVICE;
2915 
2916 		memset((STp->buffer)->b_data, 0, 12);
2917 		if (cmd_in == MTSETDRVBUFFER)
2918 			(STp->buffer)->b_data[2] = (arg & 7) << 4;
2919 		else
2920 			(STp->buffer)->b_data[2] =
2921 			    STp->drv_buffer << 4;
2922 		(STp->buffer)->b_data[3] = 8;	/* block descriptor length */
2923 		if (cmd_in == MTSETDENSITY) {
2924 			(STp->buffer)->b_data[4] = arg;
2925 			STp->density_changed = 1;	/* At least we tried ;-) */
2926 		} else if (cmd_in == SET_DENS_AND_BLK)
2927 			(STp->buffer)->b_data[4] = arg >> 24;
2928 		else
2929 			(STp->buffer)->b_data[4] = STp->density;
2930 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2931 			ltmp = arg & MT_ST_BLKSIZE_MASK;
2932 			if (cmd_in == MTSETBLK)
2933 				STp->blksize_changed = 1; /* At least we tried ;-) */
2934 		} else
2935 			ltmp = STp->block_size;
2936 		(STp->buffer)->b_data[9] = (ltmp >> 16);
2937 		(STp->buffer)->b_data[10] = (ltmp >> 8);
2938 		(STp->buffer)->b_data[11] = ltmp;
2939 		timeout = STp->device->request_queue->rq_timeout;
2940 		DEBC(
2941 			if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2942 				st_printk(ST_DEB_MSG, STp,
2943 					  "Setting block size to %d bytes.\n",
2944 					  (STp->buffer)->b_data[9] * 65536 +
2945 					  (STp->buffer)->b_data[10] * 256 +
2946 					  (STp->buffer)->b_data[11]);
2947 			if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2948 				st_printk(ST_DEB_MSG, STp,
2949 					  "Setting density code to %x.\n",
2950 					  (STp->buffer)->b_data[4]);
2951 			if (cmd_in == MTSETDRVBUFFER)
2952 				st_printk(ST_DEB_MSG, STp,
2953 					  "Setting drive buffer code to %d.\n",
2954 					  ((STp->buffer)->b_data[2] >> 4) & 7);
2955 		)
2956 		break;
2957 	default:
2958 		return (-ENOSYS);
2959 	}
2960 
2961 	SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2962 			   timeout, MAX_RETRIES, 1);
2963 	if (!SRpnt)
2964 		return (STp->buffer)->syscall_result;
2965 
2966 	ioctl_result = (STp->buffer)->syscall_result;
2967 
2968 	if (!ioctl_result) {	/* SCSI command successful */
2969 		st_release_request(SRpnt);
2970 		SRpnt = NULL;
2971 		STps->drv_block = blkno;
2972 		STps->drv_file = fileno;
2973 		STps->at_sm = at_sm;
2974 
2975 		if (cmd_in == MTBSFM)
2976 			ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2977 		else if (cmd_in == MTFSFM)
2978 			ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2979 
2980 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2981 			STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2982 			if (STp->block_size != 0) {
2983 				(STp->buffer)->buffer_blocks =
2984 				    (STp->buffer)->buffer_size / STp->block_size;
2985 			}
2986 			(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2987 			if (cmd_in == SET_DENS_AND_BLK)
2988 				STp->density = arg >> MT_ST_DENSITY_SHIFT;
2989 		} else if (cmd_in == MTSETDRVBUFFER)
2990 			STp->drv_buffer = (arg & 7);
2991 		else if (cmd_in == MTSETDENSITY)
2992 			STp->density = arg;
2993 
2994 		if (cmd_in == MTEOM)
2995 			STps->eof = ST_EOD;
2996 		else if (cmd_in == MTFSF)
2997 			STps->eof = ST_FM;
2998 		else if (chg_eof)
2999 			STps->eof = ST_NOEOF;
3000 
3001 		if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3002 			STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3003 	} else { /* SCSI command was not completely successful. Don't return
3004                     from this block without releasing the SCSI command block! */
3005 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3006 
3007 		if (cmdstatp->flags & SENSE_EOM) {
3008 			if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3009 			    cmd_in != MTBSR && cmd_in != MTBSS)
3010 				STps->eof = ST_EOM_OK;
3011 			STps->drv_block = 0;
3012 		}
3013 
3014 		if (cmdstatp->remainder_valid)
3015 			undone = (int)cmdstatp->uremainder64;
3016 		else
3017 			undone = 0;
3018 
3019 		if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3020 		    cmdstatp->have_sense &&
3021 		    (cmdstatp->flags & SENSE_EOM)) {
3022 			if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3023 			    cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3024 				ioctl_result = 0;	/* EOF(s) written successfully at EOM */
3025 				STps->eof = ST_NOEOF;
3026 			} else {  /* Writing EOF(s) failed */
3027 				if (fileno >= 0)
3028 					fileno -= undone;
3029 				if (undone < arg)
3030 					STps->eof = ST_NOEOF;
3031 			}
3032 			STps->drv_file = fileno;
3033 		} else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3034 			if (fileno >= 0)
3035 				STps->drv_file = fileno - undone;
3036 			else
3037 				STps->drv_file = fileno;
3038 			STps->drv_block = -1;
3039 			STps->eof = ST_NOEOF;
3040 		} else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3041 			if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3042 				undone = (-undone);
3043 			if (STps->drv_file >= 0)
3044 				STps->drv_file = fileno + undone;
3045 			STps->drv_block = 0;
3046 			STps->eof = ST_NOEOF;
3047 		} else if (cmd_in == MTFSR) {
3048 			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3049 				if (STps->drv_file >= 0)
3050 					STps->drv_file++;
3051 				STps->drv_block = 0;
3052 				STps->eof = ST_FM;
3053 			} else {
3054 				if (blkno >= undone)
3055 					STps->drv_block = blkno - undone;
3056 				else
3057 					STps->drv_block = (-1);
3058 				STps->eof = ST_NOEOF;
3059 			}
3060 		} else if (cmd_in == MTBSR) {
3061 			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3062 				STps->drv_file--;
3063 				STps->drv_block = (-1);
3064 			} else {
3065 				if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3066 					undone = (-undone);
3067 				if (STps->drv_block >= 0)
3068 					STps->drv_block = blkno + undone;
3069 			}
3070 			STps->eof = ST_NOEOF;
3071 		} else if (cmd_in == MTEOM) {
3072 			STps->drv_file = (-1);
3073 			STps->drv_block = (-1);
3074 			STps->eof = ST_EOD;
3075 		} else if (cmd_in == MTSETBLK ||
3076 			   cmd_in == MTSETDENSITY ||
3077 			   cmd_in == MTSETDRVBUFFER ||
3078 			   cmd_in == SET_DENS_AND_BLK) {
3079 			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3080 			    !(STp->use_pf & PF_TESTED)) {
3081 				/* Try the other possible state of Page Format if not
3082 				   already tried */
3083 				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3084 				st_release_request(SRpnt);
3085 				SRpnt = NULL;
3086 				return st_int_ioctl(STp, cmd_in, arg);
3087 			}
3088 		} else if (chg_eof)
3089 			STps->eof = ST_NOEOF;
3090 
3091 		if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3092 			STps->eof = ST_EOD;
3093 
3094 		st_release_request(SRpnt);
3095 		SRpnt = NULL;
3096 	}
3097 
3098 	return ioctl_result;
3099 }
3100 
3101 
3102 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3103    structure. */
3104 
3105 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3106 			int logical)
3107 {
3108 	int result;
3109 	unsigned char scmd[MAX_COMMAND_SIZE];
3110 	struct st_request *SRpnt;
3111 
3112 	if (STp->ready != ST_READY)
3113 		return (-EIO);
3114 
3115 	memset(scmd, 0, MAX_COMMAND_SIZE);
3116 	if ((STp->device)->scsi_level < SCSI_2) {
3117 		scmd[0] = QFA_REQUEST_BLOCK;
3118 		scmd[4] = 3;
3119 	} else {
3120 		scmd[0] = READ_POSITION;
3121 		if (!logical && !STp->scsi2_logical)
3122 			scmd[1] = 1;
3123 	}
3124 	SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3125 			   STp->device->request_queue->rq_timeout,
3126 			   MAX_READY_RETRIES, 1);
3127 	if (!SRpnt)
3128 		return (STp->buffer)->syscall_result;
3129 
3130 	if ((STp->buffer)->syscall_result != 0 ||
3131 	    (STp->device->scsi_level >= SCSI_2 &&
3132 	     ((STp->buffer)->b_data[0] & 4) != 0)) {
3133 		*block = *partition = 0;
3134 		DEBC_printk(STp, " Can't read tape position.\n");
3135 		result = (-EIO);
3136 	} else {
3137 		result = 0;
3138 		if ((STp->device)->scsi_level < SCSI_2) {
3139 			*block = ((STp->buffer)->b_data[0] << 16)
3140 			    + ((STp->buffer)->b_data[1] << 8)
3141 			    + (STp->buffer)->b_data[2];
3142 			*partition = 0;
3143 		} else {
3144 			*block = ((STp->buffer)->b_data[4] << 24)
3145 			    + ((STp->buffer)->b_data[5] << 16)
3146 			    + ((STp->buffer)->b_data[6] << 8)
3147 			    + (STp->buffer)->b_data[7];
3148 			*partition = (STp->buffer)->b_data[1];
3149 			if (((STp->buffer)->b_data[0] & 0x80) &&
3150 			    (STp->buffer)->b_data[1] == 0)	/* BOP of partition 0 */
3151 				STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3152 		}
3153 		DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3154 			    *block, *partition);
3155 	}
3156 	st_release_request(SRpnt);
3157 	SRpnt = NULL;
3158 
3159 	return result;
3160 }
3161 
3162 
3163 /* Set the tape block and partition. Negative partition means that only the
3164    block should be set in vendor specific way. */
3165 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3166 			int logical)
3167 {
3168 	struct st_partstat *STps;
3169 	int result, p;
3170 	unsigned int blk;
3171 	int timeout;
3172 	unsigned char scmd[MAX_COMMAND_SIZE];
3173 	struct st_request *SRpnt;
3174 
3175 	if (STp->ready != ST_READY)
3176 		return (-EIO);
3177 	timeout = STp->long_timeout;
3178 	STps = &(STp->ps[STp->partition]);
3179 
3180 	DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3181 		    block, partition);
3182 	DEB(if (partition < 0)
3183 		return (-EIO); )
3184 
3185 	/* Update the location at the partition we are leaving */
3186 	if ((!STp->can_partitions && partition != 0) ||
3187 	    partition >= ST_NBR_PARTITIONS)
3188 		return (-EINVAL);
3189 	if (partition != STp->partition) {
3190 		if (get_location(STp, &blk, &p, 1))
3191 			STps->last_block_valid = 0;
3192 		else {
3193 			STps->last_block_valid = 1;
3194 			STps->last_block_visited = blk;
3195 			DEBC_printk(STp, "Visited block %d for "
3196 				    "partition %d saved.\n",
3197 				    blk, STp->partition);
3198 		}
3199 	}
3200 
3201 	memset(scmd, 0, MAX_COMMAND_SIZE);
3202 	if ((STp->device)->scsi_level < SCSI_2) {
3203 		scmd[0] = QFA_SEEK_BLOCK;
3204 		scmd[2] = (block >> 16);
3205 		scmd[3] = (block >> 8);
3206 		scmd[4] = block;
3207 		scmd[5] = 0;
3208 	} else {
3209 		scmd[0] = SEEK_10;
3210 		scmd[3] = (block >> 24);
3211 		scmd[4] = (block >> 16);
3212 		scmd[5] = (block >> 8);
3213 		scmd[6] = block;
3214 		if (!logical && !STp->scsi2_logical)
3215 			scmd[1] = 4;
3216 		if (STp->partition != partition) {
3217 			scmd[1] |= 2;
3218 			scmd[8] = partition;
3219 			DEBC_printk(STp, "Trying to change partition "
3220 				    "from %d to %d\n", STp->partition,
3221 				    partition);
3222 		}
3223 	}
3224 	if (STp->immediate) {
3225 		scmd[1] |= 1;		/* Don't wait for completion */
3226 		timeout = STp->device->request_queue->rq_timeout;
3227 	}
3228 
3229 	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3230 			   timeout, MAX_READY_RETRIES, 1);
3231 	if (!SRpnt)
3232 		return (STp->buffer)->syscall_result;
3233 
3234 	STps->drv_block = STps->drv_file = (-1);
3235 	STps->eof = ST_NOEOF;
3236 	if ((STp->buffer)->syscall_result != 0) {
3237 		result = (-EIO);
3238 		if (STp->can_partitions &&
3239 		    (STp->device)->scsi_level >= SCSI_2 &&
3240 		    (p = find_partition(STp)) >= 0)
3241 			STp->partition = p;
3242 	} else {
3243 		if (STp->can_partitions) {
3244 			STp->partition = partition;
3245 			STps = &(STp->ps[partition]);
3246 			if (!STps->last_block_valid ||
3247 			    STps->last_block_visited != block) {
3248 				STps->at_sm = 0;
3249 				STps->rw = ST_IDLE;
3250 			}
3251 		} else
3252 			STps->at_sm = 0;
3253 		if (block == 0)
3254 			STps->drv_block = STps->drv_file = 0;
3255 		result = 0;
3256 	}
3257 
3258 	st_release_request(SRpnt);
3259 	SRpnt = NULL;
3260 
3261 	return result;
3262 }
3263 
3264 
3265 /* Find the current partition number for the drive status. Called from open and
3266    returns either partition number of negative error code. */
3267 static int find_partition(struct scsi_tape *STp)
3268 {
3269 	int i, partition;
3270 	unsigned int block;
3271 
3272 	if ((i = get_location(STp, &block, &partition, 1)) < 0)
3273 		return i;
3274 	if (partition >= ST_NBR_PARTITIONS)
3275 		return (-EIO);
3276 	return partition;
3277 }
3278 
3279 
3280 /* Change the partition if necessary */
3281 static int switch_partition(struct scsi_tape *STp)
3282 {
3283 	struct st_partstat *STps;
3284 
3285 	if (STp->partition == STp->new_partition)
3286 		return 0;
3287 	STps = &(STp->ps[STp->new_partition]);
3288 	if (!STps->last_block_valid)
3289 		STps->last_block_visited = 0;
3290 	return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3291 }
3292 
3293 /* Functions for reading and writing the medium partition mode page. */
3294 
3295 #define PART_PAGE   0x11
3296 #define PART_PAGE_FIXED_LENGTH 8
3297 
3298 #define PP_OFF_MAX_ADD_PARTS   2
3299 #define PP_OFF_NBR_ADD_PARTS   3
3300 #define PP_OFF_FLAGS           4
3301 #define PP_OFF_PART_UNITS      6
3302 #define PP_OFF_RESERVED        7
3303 
3304 #define PP_BIT_IDP             0x20
3305 #define PP_BIT_FDP             0x80
3306 #define PP_MSK_PSUM_MB         0x10
3307 #define PP_MSK_PSUM_UNITS      0x18
3308 #define PP_MSK_POFM            0x04
3309 
3310 /* Get the number of partitions on the tape. As a side effect reads the
3311    mode page into the tape buffer. */
3312 static int nbr_partitions(struct scsi_tape *STp)
3313 {
3314 	int result;
3315 
3316 	if (STp->ready != ST_READY)
3317 		return (-EIO);
3318 
3319 	result = read_mode_page(STp, PART_PAGE, 1);
3320 
3321 	if (result) {
3322 		DEBC_printk(STp, "Can't read medium partition page.\n");
3323 		result = (-EIO);
3324 	} else {
3325 		result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3326 					      PP_OFF_NBR_ADD_PARTS] + 1;
3327 		DEBC_printk(STp, "Number of partitions %d.\n", result);
3328 	}
3329 
3330 	return result;
3331 }
3332 
3333 
3334 static int format_medium(struct scsi_tape *STp, int format)
3335 {
3336 	int result = 0;
3337 	int timeout = STp->long_timeout;
3338 	unsigned char scmd[MAX_COMMAND_SIZE];
3339 	struct st_request *SRpnt;
3340 
3341 	memset(scmd, 0, MAX_COMMAND_SIZE);
3342 	scmd[0] = FORMAT_UNIT;
3343 	scmd[2] = format;
3344 	if (STp->immediate) {
3345 		scmd[1] |= 1;		/* Don't wait for completion */
3346 		timeout = STp->device->request_queue->rq_timeout;
3347 	}
3348 	DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3349 	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3350 			   timeout, MAX_RETRIES, 1);
3351 	if (!SRpnt)
3352 		result = STp->buffer->syscall_result;
3353 	return result;
3354 }
3355 
3356 
3357 /* Partition the tape into two partitions if size > 0 or one partition if
3358    size == 0.
3359 
3360    The block descriptors are read and written because Sony SDT-7000 does not
3361    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3362 
3363    My HP C1533A drive returns only one partition size field. This is used to
3364    set the size of partition 1. There is no size field for the default partition.
3365    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3366    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3367    The following algorithm is used to accommodate both drives: if the number of
3368    partition size fields is greater than the maximum number of additional partitions
3369    in the mode page, the second field is used. Otherwise the first field is used.
3370 
3371    For Seagate DDS drives the page length must be 8 when no partitions is defined
3372    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3373    is acceptable also to some other old drives and enforced if the first partition
3374    size field is used for the first additional partition size.
3375 
3376    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3377  */
3378 static int partition_tape(struct scsi_tape *STp, int size)
3379 {
3380 	int result;
3381 	int target_partition;
3382 	bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3383 	int pgo, psd_cnt, psdo;
3384 	int psum = PP_MSK_PSUM_MB, units = 0;
3385 	unsigned char *bp;
3386 
3387 	result = read_mode_page(STp, PART_PAGE, 0);
3388 	if (result) {
3389 		DEBC_printk(STp, "Can't read partition mode page.\n");
3390 		return result;
3391 	}
3392 	target_partition = 1;
3393 	if (size < 0) {
3394 		target_partition = 0;
3395 		size = -size;
3396 	}
3397 
3398 	/* The mode page is in the buffer. Let's modify it and write it. */
3399 	bp = (STp->buffer)->b_data;
3400 	pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3401 	DEBC_printk(STp, "Partition page length is %d bytes.\n",
3402 		    bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3403 
3404 	psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3405 
3406 	if (scsi3) {
3407 		needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3408 		if (needs_format && size == 0) {
3409 			/* No need to write the mode page when clearing
3410 			 *  partitioning
3411 			 */
3412 			DEBC_printk(STp, "Formatting tape with one partition.\n");
3413 			result = format_medium(STp, 0);
3414 			goto out;
3415 		}
3416 		if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3417 			psd_cnt = 2;
3418 		if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3419 			/* Use units scaling for large partitions if the device
3420 			 * suggests it and no precision lost. Required for IBM
3421 			 * TS1140/50 drives that don't support MB units.
3422 			 */
3423 			if (size >= 1000 && (size % 1000) == 0) {
3424 				size /= 1000;
3425 				psum = PP_MSK_PSUM_UNITS;
3426 				units = 9; /* GB */
3427 			}
3428 		}
3429 		/* Try it anyway if too large to specify in MB */
3430 		if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3431 			size /= 1000;
3432 			psum = PP_MSK_PSUM_UNITS;
3433 			units = 9;  /* GB */
3434 		}
3435 	}
3436 
3437 	if (size >= 65535 ||  /* Does not fit into two bytes */
3438 	    (target_partition == 0 && psd_cnt < 2)) {
3439 		result = -EINVAL;
3440 		goto out;
3441 	}
3442 
3443 	psdo = pgo + PART_PAGE_FIXED_LENGTH;
3444 	/* The second condition is for HP DDS which use only one partition size
3445 	 * descriptor
3446 	 */
3447 	if (target_partition > 0 &&
3448 	    (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3449 	     bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3450 		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3451 		psdo += 2;
3452 	}
3453 	memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3454 
3455 	DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3456 		    psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3457 		    bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3458 
3459 	if (size == 0) {
3460 		bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3461 		if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3462 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3463 		DEBC_printk(STp, "Formatting tape with one partition.\n");
3464 	} else {
3465 		bp[psdo] = (size >> 8) & 0xff;
3466 		bp[psdo + 1] = size & 0xff;
3467 		if (target_partition == 0)
3468 			bp[psdo + 2] = bp[psdo + 3] = 0xff;
3469 		bp[pgo + 3] = 1;
3470 		if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3471 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3472 		DEBC_printk(STp,
3473 			    "Formatting tape with two partitions (%i = %d MB).\n",
3474 			    target_partition, units > 0 ? size * 1000 : size);
3475 	}
3476 	bp[pgo + PP_OFF_PART_UNITS] = 0;
3477 	bp[pgo + PP_OFF_RESERVED] = 0;
3478 	if (size != 1 || units != 0) {
3479 		bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3480 			(bp[pgo + PP_OFF_FLAGS] & 0x07);
3481 		bp[pgo + PP_OFF_PART_UNITS] = units;
3482 	} else
3483 		bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3484 			(bp[pgo + PP_OFF_FLAGS] & 0x1f);
3485 	bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3486 
3487 	result = write_mode_page(STp, PART_PAGE, 1);
3488 
3489 	if (!result && needs_format)
3490 		result = format_medium(STp, 1);
3491 
3492 	if (result) {
3493 		st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3494 		result = (-EIO);
3495 	}
3496 
3497 out:
3498 	return result;
3499 }
3500 
3501 
3502 
3503 /* The ioctl command */
3504 static long st_ioctl_common(struct file *file, unsigned int cmd_in, void __user *p)
3505 {
3506 	int i, cmd_nr, cmd_type, bt;
3507 	int retval = 0;
3508 	unsigned int blk;
3509 	struct scsi_tape *STp = file->private_data;
3510 	struct st_modedef *STm;
3511 	struct st_partstat *STps;
3512 
3513 	if (mutex_lock_interruptible(&STp->lock))
3514 		return -ERESTARTSYS;
3515 
3516 	DEB(
3517 	if (debugging && !STp->in_use) {
3518 		st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3519 		retval = (-EIO);
3520 		goto out;
3521 	} ) /* end DEB */
3522 
3523 	STm = &(STp->modes[STp->current_mode]);
3524 	STps = &(STp->ps[STp->partition]);
3525 
3526 	/*
3527 	 * If we are in the middle of error recovery, don't let anyone
3528 	 * else try and use this device.  Also, if error recovery fails, it
3529 	 * may try and take the device offline, in which case all further
3530 	 * access to the device is prohibited.
3531 	 */
3532 	retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3533 			file->f_flags & O_NDELAY);
3534 	if (retval)
3535 		goto out;
3536 
3537 	cmd_type = _IOC_TYPE(cmd_in);
3538 	cmd_nr = _IOC_NR(cmd_in);
3539 
3540 	if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3541 		struct mtop mtc;
3542 
3543 		if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3544 			retval = (-EINVAL);
3545 			goto out;
3546 		}
3547 
3548 		i = copy_from_user(&mtc, p, sizeof(struct mtop));
3549 		if (i) {
3550 			retval = (-EFAULT);
3551 			goto out;
3552 		}
3553 
3554 		if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3555 			st_printk(KERN_WARNING, STp,
3556 				  "MTSETDRVBUFFER only allowed for root.\n");
3557 			retval = (-EPERM);
3558 			goto out;
3559 		}
3560 		if (!STm->defined &&
3561 		    (mtc.mt_op != MTSETDRVBUFFER &&
3562 		     (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3563 			retval = (-ENXIO);
3564 			goto out;
3565 		}
3566 
3567 		if (!STp->pos_unknown) {
3568 
3569 			if (STps->eof == ST_FM_HIT) {
3570 				if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3571                                     mtc.mt_op == MTEOM) {
3572 					mtc.mt_count -= 1;
3573 					if (STps->drv_file >= 0)
3574 						STps->drv_file += 1;
3575 				} else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3576 					mtc.mt_count += 1;
3577 					if (STps->drv_file >= 0)
3578 						STps->drv_file += 1;
3579 				}
3580 			}
3581 
3582 			if (mtc.mt_op == MTSEEK) {
3583 				/* Old position must be restored if partition will be
3584                                    changed */
3585 				i = !STp->can_partitions ||
3586 				    (STp->new_partition != STp->partition);
3587 			} else {
3588 				i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3589 				    mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3590 				    mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3591 				    mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3592 				    mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3593 				    mtc.mt_op == MTCOMPRESSION;
3594 			}
3595 			i = flush_buffer(STp, i);
3596 			if (i < 0) {
3597 				retval = i;
3598 				goto out;
3599 			}
3600 			if (STps->rw == ST_WRITING &&
3601 			    (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3602 			     mtc.mt_op == MTSEEK ||
3603 			     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3604 				i = st_int_ioctl(STp, MTWEOF, 1);
3605 				if (i < 0) {
3606 					retval = i;
3607 					goto out;
3608 				}
3609 				if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3610 					mtc.mt_count++;
3611 				STps->rw = ST_IDLE;
3612 			     }
3613 
3614 		} else {
3615 			/*
3616 			 * If there was a bus reset, block further access
3617 			 * to this device.  If the user wants to rewind the tape,
3618 			 * then reset the flag and allow access again.
3619 			 */
3620 			if (mtc.mt_op != MTREW &&
3621 			    mtc.mt_op != MTOFFL &&
3622 			    mtc.mt_op != MTRETEN &&
3623 			    mtc.mt_op != MTERASE &&
3624 			    mtc.mt_op != MTSEEK &&
3625 			    mtc.mt_op != MTEOM) {
3626 				retval = (-EIO);
3627 				goto out;
3628 			}
3629 			reset_state(STp);
3630 			/* remove this when the midlevel properly clears was_reset */
3631 			STp->device->was_reset = 0;
3632 		}
3633 
3634 		if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3635 		    mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3636 		    mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3637 			STps->rw = ST_IDLE;	/* Prevent automatic WEOF and fsf */
3638 
3639 		if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3640 			do_door_lock(STp, 0);	/* Ignore result! */
3641 
3642 		if (mtc.mt_op == MTSETDRVBUFFER &&
3643 		    (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3644 			retval = st_set_options(STp, mtc.mt_count);
3645 			goto out;
3646 		}
3647 
3648 		if (mtc.mt_op == MTSETPART) {
3649 			if (!STp->can_partitions ||
3650 			    mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3651 				retval = (-EINVAL);
3652 				goto out;
3653 			}
3654 			if (mtc.mt_count >= STp->nbr_partitions &&
3655 			    (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3656 				retval = (-EIO);
3657 				goto out;
3658 			}
3659 			if (mtc.mt_count >= STp->nbr_partitions) {
3660 				retval = (-EINVAL);
3661 				goto out;
3662 			}
3663 			STp->new_partition = mtc.mt_count;
3664 			retval = 0;
3665 			goto out;
3666 		}
3667 
3668 		if (mtc.mt_op == MTMKPART) {
3669 			if (!STp->can_partitions) {
3670 				retval = (-EINVAL);
3671 				goto out;
3672 			}
3673 			i = do_load_unload(STp, file, 1);
3674 			if (i < 0) {
3675 				retval = i;
3676 				goto out;
3677 			}
3678 			i = partition_tape(STp, mtc.mt_count);
3679 			if (i < 0) {
3680 				retval = i;
3681 				goto out;
3682 			}
3683 			for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3684 				STp->ps[i].rw = ST_IDLE;
3685 				STp->ps[i].at_sm = 0;
3686 				STp->ps[i].last_block_valid = 0;
3687 			}
3688 			STp->partition = STp->new_partition = 0;
3689 			STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3690 			STps->drv_block = STps->drv_file = 0;
3691 			retval = 0;
3692 			goto out;
3693 		}
3694 
3695 		if (mtc.mt_op == MTSEEK) {
3696 			i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3697 			if (!STp->can_partitions)
3698 				STp->ps[0].rw = ST_IDLE;
3699 			retval = i;
3700 			goto out;
3701 		}
3702 
3703 		if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3704 			retval = do_load_unload(STp, file, 0);
3705 			goto out;
3706 		}
3707 
3708 		if (mtc.mt_op == MTLOAD) {
3709 			retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3710 			goto out;
3711 		}
3712 
3713 		if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3714 			retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3715 			goto out;
3716 		}
3717 
3718 		if (STp->can_partitions && STp->ready == ST_READY &&
3719 		    (i = switch_partition(STp)) < 0) {
3720 			retval = i;
3721 			goto out;
3722 		}
3723 
3724 		if (mtc.mt_op == MTCOMPRESSION)
3725 			retval = st_compression(STp, (mtc.mt_count & 1));
3726 		else
3727 			retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3728 		goto out;
3729 	}
3730 	if (!STm->defined) {
3731 		retval = (-ENXIO);
3732 		goto out;
3733 	}
3734 
3735 	if ((i = flush_buffer(STp, 0)) < 0) {
3736 		retval = i;
3737 		goto out;
3738 	}
3739 	if (STp->can_partitions &&
3740 	    (i = switch_partition(STp)) < 0) {
3741 		retval = i;
3742 		goto out;
3743 	}
3744 
3745 	if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3746 		struct mtget mt_status;
3747 
3748 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3749 			 retval = (-EINVAL);
3750 			 goto out;
3751 		}
3752 
3753 		mt_status.mt_type = STp->tape_type;
3754 		mt_status.mt_dsreg =
3755 		    ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3756 		    ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3757 		mt_status.mt_blkno = STps->drv_block;
3758 		mt_status.mt_fileno = STps->drv_file;
3759 		if (STp->block_size != 0) {
3760 			if (STps->rw == ST_WRITING)
3761 				mt_status.mt_blkno +=
3762 				    (STp->buffer)->buffer_bytes / STp->block_size;
3763 			else if (STps->rw == ST_READING)
3764 				mt_status.mt_blkno -=
3765                                         ((STp->buffer)->buffer_bytes +
3766                                          STp->block_size - 1) / STp->block_size;
3767 		}
3768 
3769 		mt_status.mt_gstat = 0;
3770 		if (STp->drv_write_prot)
3771 			mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3772 		if (mt_status.mt_blkno == 0) {
3773 			if (mt_status.mt_fileno == 0)
3774 				mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3775 			else
3776 				mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3777 		}
3778 		mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3779 		mt_status.mt_resid = STp->partition;
3780 		if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3781 			mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3782 		else if (STps->eof >= ST_EOM_OK)
3783 			mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3784 		if (STp->density == 1)
3785 			mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3786 		else if (STp->density == 2)
3787 			mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3788 		else if (STp->density == 3)
3789 			mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3790 		if (STp->ready == ST_READY)
3791 			mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3792 		if (STp->ready == ST_NO_TAPE)
3793 			mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3794 		if (STps->at_sm)
3795 			mt_status.mt_gstat |= GMT_SM(0xffffffff);
3796 		if (STm->do_async_writes ||
3797                     (STm->do_buffer_writes && STp->block_size != 0) ||
3798 		    STp->drv_buffer != 0)
3799 			mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3800 		if (STp->cleaning_req)
3801 			mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3802 
3803 		retval = put_user_mtget(p, &mt_status);
3804 		if (retval)
3805 			goto out;
3806 
3807 		STp->recover_reg = 0;		/* Clear after read */
3808 		goto out;
3809 	}			/* End of MTIOCGET */
3810 	if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3811 		struct mtpos mt_pos;
3812 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3813 			 retval = (-EINVAL);
3814 			 goto out;
3815 		}
3816 		if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3817 			retval = i;
3818 			goto out;
3819 		}
3820 		mt_pos.mt_blkno = blk;
3821 		retval = put_user_mtpos(p, &mt_pos);
3822 		goto out;
3823 	}
3824 	mutex_unlock(&STp->lock);
3825 	switch (cmd_in) {
3826 		case SCSI_IOCTL_STOP_UNIT:
3827 			/* unload */
3828 			retval = scsi_ioctl(STp->device, cmd_in, p);
3829 			if (!retval) {
3830 				STp->rew_at_close = 0;
3831 				STp->ready = ST_NO_TAPE;
3832 			}
3833 			return retval;
3834 
3835 		case SCSI_IOCTL_GET_IDLUN:
3836 		case SCSI_IOCTL_GET_BUS_NUMBER:
3837 			break;
3838 
3839 		default:
3840 			if ((cmd_in == SG_IO ||
3841 			     cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3842 			     cmd_in == CDROM_SEND_PACKET) &&
3843 			    !capable(CAP_SYS_RAWIO))
3844 				i = -EPERM;
3845 			else
3846 				i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3847 						   file->f_mode, cmd_in, p);
3848 			if (i != -ENOTTY)
3849 				return i;
3850 			break;
3851 	}
3852 	return -ENOTTY;
3853 
3854  out:
3855 	mutex_unlock(&STp->lock);
3856 	return retval;
3857 }
3858 
3859 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3860 {
3861 	void __user *p = (void __user *)arg;
3862 	struct scsi_tape *STp = file->private_data;
3863 	int ret;
3864 
3865 	ret = st_ioctl_common(file, cmd_in, p);
3866 	if (ret != -ENOTTY)
3867 		return ret;
3868 
3869 	return scsi_ioctl(STp->device, cmd_in, p);
3870 }
3871 
3872 #ifdef CONFIG_COMPAT
3873 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3874 {
3875 	void __user *p = compat_ptr(arg);
3876 	struct scsi_tape *STp = file->private_data;
3877 	int ret;
3878 
3879 	/* argument conversion is handled using put_user_mtpos/put_user_mtget */
3880 	switch (cmd_in) {
3881 	case MTIOCPOS32:
3882 		return st_ioctl_common(file, MTIOCPOS, p);
3883 	case MTIOCGET32:
3884 		return st_ioctl_common(file, MTIOCGET, p);
3885 	}
3886 
3887 	ret = st_ioctl_common(file, cmd_in, p);
3888 	if (ret != -ENOTTY)
3889 		return ret;
3890 
3891 	return scsi_compat_ioctl(STp->device, cmd_in, p);
3892 }
3893 #endif
3894 
3895 
3896 
3897 /* Try to allocate a new tape buffer. Calling function must not hold
3898    dev_arr_lock. */
3899 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3900 {
3901 	struct st_buffer *tb;
3902 
3903 	tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3904 	if (!tb) {
3905 		printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3906 		return NULL;
3907 	}
3908 	tb->frp_segs = 0;
3909 	tb->use_sg = max_sg;
3910 	tb->dma = need_dma;
3911 	tb->buffer_size = 0;
3912 
3913 	tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3914 				     GFP_KERNEL);
3915 	if (!tb->reserved_pages) {
3916 		kfree(tb);
3917 		return NULL;
3918 	}
3919 
3920 	return tb;
3921 }
3922 
3923 
3924 /* Try to allocate enough space in the tape buffer */
3925 #define ST_MAX_ORDER 6
3926 
3927 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3928 {
3929 	int segs, max_segs, b_size, order, got;
3930 	gfp_t priority;
3931 
3932 	if (new_size <= STbuffer->buffer_size)
3933 		return 1;
3934 
3935 	if (STbuffer->buffer_size <= PAGE_SIZE)
3936 		normalize_buffer(STbuffer);  /* Avoid extra segment */
3937 
3938 	max_segs = STbuffer->use_sg;
3939 
3940 	priority = GFP_KERNEL | __GFP_NOWARN;
3941 	if (need_dma)
3942 		priority |= GFP_DMA;
3943 
3944 	if (STbuffer->cleared)
3945 		priority |= __GFP_ZERO;
3946 
3947 	if (STbuffer->frp_segs) {
3948 		order = STbuffer->reserved_page_order;
3949 		b_size = PAGE_SIZE << order;
3950 	} else {
3951 		for (b_size = PAGE_SIZE, order = 0;
3952 		     order < ST_MAX_ORDER &&
3953 			     max_segs * (PAGE_SIZE << order) < new_size;
3954 		     order++, b_size *= 2)
3955 			;  /* empty */
3956 		STbuffer->reserved_page_order = order;
3957 	}
3958 	if (max_segs * (PAGE_SIZE << order) < new_size) {
3959 		if (order == ST_MAX_ORDER)
3960 			return 0;
3961 		normalize_buffer(STbuffer);
3962 		return enlarge_buffer(STbuffer, new_size, need_dma);
3963 	}
3964 
3965 	for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3966 	     segs < max_segs && got < new_size;) {
3967 		struct page *page;
3968 
3969 		page = alloc_pages(priority, order);
3970 		if (!page) {
3971 			DEB(STbuffer->buffer_size = got);
3972 			normalize_buffer(STbuffer);
3973 			return 0;
3974 		}
3975 
3976 		STbuffer->frp_segs += 1;
3977 		got += b_size;
3978 		STbuffer->buffer_size = got;
3979 		STbuffer->reserved_pages[segs] = page;
3980 		segs++;
3981 	}
3982 	STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3983 
3984 	return 1;
3985 }
3986 
3987 
3988 /* Make sure that no data from previous user is in the internal buffer */
3989 static void clear_buffer(struct st_buffer * st_bp)
3990 {
3991 	int i;
3992 
3993 	for (i=0; i < st_bp->frp_segs; i++)
3994 		memset(page_address(st_bp->reserved_pages[i]), 0,
3995 		       PAGE_SIZE << st_bp->reserved_page_order);
3996 	st_bp->cleared = 1;
3997 }
3998 
3999 
4000 /* Release the extra buffer */
4001 static void normalize_buffer(struct st_buffer * STbuffer)
4002 {
4003 	int i, order = STbuffer->reserved_page_order;
4004 
4005 	for (i = 0; i < STbuffer->frp_segs; i++) {
4006 		__free_pages(STbuffer->reserved_pages[i], order);
4007 		STbuffer->buffer_size -= (PAGE_SIZE << order);
4008 	}
4009 	STbuffer->frp_segs = 0;
4010 	STbuffer->sg_segs = 0;
4011 	STbuffer->reserved_page_order = 0;
4012 	STbuffer->map_data.offset = 0;
4013 }
4014 
4015 
4016 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
4017    negative error code. */
4018 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
4019 {
4020 	int i, cnt, res, offset;
4021 	int length = PAGE_SIZE << st_bp->reserved_page_order;
4022 
4023 	for (i = 0, offset = st_bp->buffer_bytes;
4024 	     i < st_bp->frp_segs && offset >= length; i++)
4025 		offset -= length;
4026 	if (i == st_bp->frp_segs) {	/* Should never happen */
4027 		printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4028 		return (-EIO);
4029 	}
4030 	for (; i < st_bp->frp_segs && do_count > 0; i++) {
4031 		struct page *page = st_bp->reserved_pages[i];
4032 		cnt = length - offset < do_count ? length - offset : do_count;
4033 		res = copy_from_user(page_address(page) + offset, ubp, cnt);
4034 		if (res)
4035 			return (-EFAULT);
4036 		do_count -= cnt;
4037 		st_bp->buffer_bytes += cnt;
4038 		ubp += cnt;
4039 		offset = 0;
4040 	}
4041 	if (do_count) /* Should never happen */
4042 		return (-EIO);
4043 
4044 	return 0;
4045 }
4046 
4047 
4048 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4049    negative error code. */
4050 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4051 {
4052 	int i, cnt, res, offset;
4053 	int length = PAGE_SIZE << st_bp->reserved_page_order;
4054 
4055 	for (i = 0, offset = st_bp->read_pointer;
4056 	     i < st_bp->frp_segs && offset >= length; i++)
4057 		offset -= length;
4058 	if (i == st_bp->frp_segs) {	/* Should never happen */
4059 		printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4060 		return (-EIO);
4061 	}
4062 	for (; i < st_bp->frp_segs && do_count > 0; i++) {
4063 		struct page *page = st_bp->reserved_pages[i];
4064 		cnt = length - offset < do_count ? length - offset : do_count;
4065 		res = copy_to_user(ubp, page_address(page) + offset, cnt);
4066 		if (res)
4067 			return (-EFAULT);
4068 		do_count -= cnt;
4069 		st_bp->buffer_bytes -= cnt;
4070 		st_bp->read_pointer += cnt;
4071 		ubp += cnt;
4072 		offset = 0;
4073 	}
4074 	if (do_count) /* Should never happen */
4075 		return (-EIO);
4076 
4077 	return 0;
4078 }
4079 
4080 
4081 /* Move data towards start of buffer */
4082 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4083 {
4084 	int src_seg, dst_seg, src_offset = 0, dst_offset;
4085 	int count, total;
4086 	int length = PAGE_SIZE << st_bp->reserved_page_order;
4087 
4088 	if (offset == 0)
4089 		return;
4090 
4091 	total=st_bp->buffer_bytes - offset;
4092 	for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4093 		src_offset = offset;
4094 		if (src_offset < length)
4095 			break;
4096 		offset -= length;
4097 	}
4098 
4099 	st_bp->buffer_bytes = st_bp->read_pointer = total;
4100 	for (dst_seg=dst_offset=0; total > 0; ) {
4101 		struct page *dpage = st_bp->reserved_pages[dst_seg];
4102 		struct page *spage = st_bp->reserved_pages[src_seg];
4103 
4104 		count = min(length - dst_offset, length - src_offset);
4105 		memmove(page_address(dpage) + dst_offset,
4106 			page_address(spage) + src_offset, count);
4107 		src_offset += count;
4108 		if (src_offset >= length) {
4109 			src_seg++;
4110 			src_offset = 0;
4111 		}
4112 		dst_offset += count;
4113 		if (dst_offset >= length) {
4114 			dst_seg++;
4115 			dst_offset = 0;
4116 		}
4117 		total -= count;
4118 	}
4119 }
4120 
4121 /* Validate the options from command line or module parameters */
4122 static void validate_options(void)
4123 {
4124 	if (buffer_kbs > 0)
4125 		st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4126 	if (max_sg_segs >= ST_FIRST_SG)
4127 		st_max_sg_segs = max_sg_segs;
4128 }
4129 
4130 #ifndef MODULE
4131 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4132  */
4133 static int __init st_setup(char *str)
4134 {
4135 	int i, len, ints[5];
4136 	char *stp;
4137 
4138 	stp = get_options(str, ARRAY_SIZE(ints), ints);
4139 
4140 	if (ints[0] > 0) {
4141 		for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4142 			if (parms[i].val)
4143 				*parms[i].val = ints[i + 1];
4144 	} else {
4145 		while (stp != NULL) {
4146 			for (i = 0; i < ARRAY_SIZE(parms); i++) {
4147 				len = strlen(parms[i].name);
4148 				if (!strncmp(stp, parms[i].name, len) &&
4149 				    (*(stp + len) == ':' || *(stp + len) == '=')) {
4150 					if (parms[i].val)
4151 						*parms[i].val =
4152 							simple_strtoul(stp + len + 1, NULL, 0);
4153 					else
4154 						printk(KERN_WARNING "st: Obsolete parameter %s\n",
4155 						       parms[i].name);
4156 					break;
4157 				}
4158 			}
4159 			if (i >= ARRAY_SIZE(parms))
4160 				 printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4161 					stp);
4162 			stp = strchr(stp, ',');
4163 			if (stp)
4164 				stp++;
4165 		}
4166 	}
4167 
4168 	validate_options();
4169 
4170 	return 1;
4171 }
4172 
4173 __setup("st=", st_setup);
4174 
4175 #endif
4176 
4177 static const struct file_operations st_fops =
4178 {
4179 	.owner =	THIS_MODULE,
4180 	.read =		st_read,
4181 	.write =	st_write,
4182 	.unlocked_ioctl = st_ioctl,
4183 #ifdef CONFIG_COMPAT
4184 	.compat_ioctl = st_compat_ioctl,
4185 #endif
4186 	.open =		st_open,
4187 	.flush =	st_flush,
4188 	.release =	st_release,
4189 	.llseek =	noop_llseek,
4190 };
4191 
4192 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4193 {
4194 	int i, error;
4195 	dev_t cdev_devno;
4196 	struct cdev *cdev;
4197 	struct device *dev;
4198 	struct st_modedef *STm = &(tape->modes[mode]);
4199 	char name[10];
4200 	int dev_num = tape->index;
4201 
4202 	cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4203 
4204 	cdev = cdev_alloc();
4205 	if (!cdev) {
4206 		pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4207 		error = -ENOMEM;
4208 		goto out;
4209 	}
4210 	cdev->owner = THIS_MODULE;
4211 	cdev->ops = &st_fops;
4212 	STm->cdevs[rew] = cdev;
4213 
4214 	error = cdev_add(cdev, cdev_devno, 1);
4215 	if (error) {
4216 		pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4217 		       rew ? "non" : "auto", mode);
4218 		pr_err("st%d: Device not attached.\n", dev_num);
4219 		goto out_free;
4220 	}
4221 
4222 	i = mode << (4 - ST_NBR_MODE_BITS);
4223 	snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4224 		 tape->disk->disk_name, st_formats[i]);
4225 
4226 	dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4227 			    cdev_devno, &tape->modes[mode], "%s", name);
4228 	if (IS_ERR(dev)) {
4229 		pr_err("st%d: device_create failed\n", dev_num);
4230 		error = PTR_ERR(dev);
4231 		goto out_free;
4232 	}
4233 
4234 	STm->devs[rew] = dev;
4235 
4236 	return 0;
4237 out_free:
4238 	cdev_del(STm->cdevs[rew]);
4239 out:
4240 	STm->cdevs[rew] = NULL;
4241 	STm->devs[rew] = NULL;
4242 	return error;
4243 }
4244 
4245 static int create_cdevs(struct scsi_tape *tape)
4246 {
4247 	int mode, error;
4248 	for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4249 		error = create_one_cdev(tape, mode, 0);
4250 		if (error)
4251 			return error;
4252 		error = create_one_cdev(tape, mode, 1);
4253 		if (error)
4254 			return error;
4255 	}
4256 
4257 	return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4258 				 &tape->modes[0].devs[0]->kobj, "tape");
4259 }
4260 
4261 static void remove_cdevs(struct scsi_tape *tape)
4262 {
4263 	int mode, rew;
4264 	sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4265 	for (mode = 0; mode < ST_NBR_MODES; mode++) {
4266 		struct st_modedef *STm = &(tape->modes[mode]);
4267 		for (rew = 0; rew < 2; rew++) {
4268 			if (STm->cdevs[rew])
4269 				cdev_del(STm->cdevs[rew]);
4270 			if (STm->devs[rew])
4271 				device_unregister(STm->devs[rew]);
4272 		}
4273 	}
4274 }
4275 
4276 static int st_probe(struct device *dev)
4277 {
4278 	struct scsi_device *SDp = to_scsi_device(dev);
4279 	struct gendisk *disk = NULL;
4280 	struct scsi_tape *tpnt = NULL;
4281 	struct st_modedef *STm;
4282 	struct st_partstat *STps;
4283 	struct st_buffer *buffer;
4284 	int i, error;
4285 	char *stp;
4286 
4287 	if (SDp->type != TYPE_TAPE)
4288 		return -ENODEV;
4289 	if ((stp = st_incompatible(SDp))) {
4290 		sdev_printk(KERN_INFO, SDp,
4291 			    "OnStream tapes are no longer supported;\n");
4292 		sdev_printk(KERN_INFO, SDp,
4293 			    "please mail to linux-scsi@vger.kernel.org.\n");
4294 		return -ENODEV;
4295 	}
4296 
4297 	scsi_autopm_get_device(SDp);
4298 	i = queue_max_segments(SDp->request_queue);
4299 	if (st_max_sg_segs < i)
4300 		i = st_max_sg_segs;
4301 	buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4302 	if (buffer == NULL) {
4303 		sdev_printk(KERN_ERR, SDp,
4304 			    "st: Can't allocate new tape buffer. "
4305 			    "Device not attached.\n");
4306 		goto out;
4307 	}
4308 
4309 	disk = alloc_disk(1);
4310 	if (!disk) {
4311 		sdev_printk(KERN_ERR, SDp,
4312 			    "st: out of memory. Device not attached.\n");
4313 		goto out_buffer_free;
4314 	}
4315 
4316 	tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4317 	if (tpnt == NULL) {
4318 		sdev_printk(KERN_ERR, SDp,
4319 			    "st: Can't allocate device descriptor.\n");
4320 		goto out_put_disk;
4321 	}
4322 	kref_init(&tpnt->kref);
4323 	tpnt->disk = disk;
4324 	disk->private_data = &tpnt->driver;
4325 	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
4326 	 * take queue reference that release_disk() expects. */
4327 	if (!blk_get_queue(SDp->request_queue))
4328 		goto out_put_disk;
4329 	disk->queue = SDp->request_queue;
4330 	tpnt->driver = &st_template;
4331 
4332 	tpnt->device = SDp;
4333 	if (SDp->scsi_level <= 2)
4334 		tpnt->tape_type = MT_ISSCSI1;
4335 	else
4336 		tpnt->tape_type = MT_ISSCSI2;
4337 
4338 	tpnt->buffer = buffer;
4339 	tpnt->buffer->last_SRpnt = NULL;
4340 
4341 	tpnt->inited = 0;
4342 	tpnt->dirty = 0;
4343 	tpnt->in_use = 0;
4344 	tpnt->drv_buffer = 1;	/* Try buffering if no mode sense */
4345 	tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4346 	tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4347 	tpnt->density = 0;
4348 	tpnt->do_auto_lock = ST_AUTO_LOCK;
4349 	tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4350 	tpnt->can_partitions = 0;
4351 	tpnt->two_fm = ST_TWO_FM;
4352 	tpnt->fast_mteom = ST_FAST_MTEOM;
4353 	tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4354 	tpnt->sili = ST_SILI;
4355 	tpnt->immediate = ST_NOWAIT;
4356 	tpnt->immediate_filemark = 0;
4357 	tpnt->default_drvbuffer = 0xff;		/* No forced buffering */
4358 	tpnt->partition = 0;
4359 	tpnt->new_partition = 0;
4360 	tpnt->nbr_partitions = 0;
4361 	blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4362 	tpnt->long_timeout = ST_LONG_TIMEOUT;
4363 	tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4364 
4365 	for (i = 0; i < ST_NBR_MODES; i++) {
4366 		STm = &(tpnt->modes[i]);
4367 		STm->defined = 0;
4368 		STm->sysv = ST_SYSV;
4369 		STm->defaults_for_writes = 0;
4370 		STm->do_async_writes = ST_ASYNC_WRITES;
4371 		STm->do_buffer_writes = ST_BUFFER_WRITES;
4372 		STm->do_read_ahead = ST_READ_AHEAD;
4373 		STm->default_compression = ST_DONT_TOUCH;
4374 		STm->default_blksize = (-1);	/* No forced size */
4375 		STm->default_density = (-1);	/* No forced density */
4376 		STm->tape = tpnt;
4377 	}
4378 
4379 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4380 		STps = &(tpnt->ps[i]);
4381 		STps->rw = ST_IDLE;
4382 		STps->eof = ST_NOEOF;
4383 		STps->at_sm = 0;
4384 		STps->last_block_valid = 0;
4385 		STps->drv_block = (-1);
4386 		STps->drv_file = (-1);
4387 	}
4388 
4389 	tpnt->current_mode = 0;
4390 	tpnt->modes[0].defined = 1;
4391 
4392 	tpnt->density_changed = tpnt->compression_changed =
4393 	    tpnt->blksize_changed = 0;
4394 	mutex_init(&tpnt->lock);
4395 
4396 	idr_preload(GFP_KERNEL);
4397 	spin_lock(&st_index_lock);
4398 	error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4399 	spin_unlock(&st_index_lock);
4400 	idr_preload_end();
4401 	if (error < 0) {
4402 		pr_warn("st: idr allocation failed: %d\n", error);
4403 		goto out_put_queue;
4404 	}
4405 	tpnt->index = error;
4406 	sprintf(disk->disk_name, "st%d", tpnt->index);
4407 	tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4408 	if (tpnt->stats == NULL) {
4409 		sdev_printk(KERN_ERR, SDp,
4410 			    "st: Can't allocate statistics.\n");
4411 		goto out_idr_remove;
4412 	}
4413 
4414 	dev_set_drvdata(dev, tpnt);
4415 
4416 
4417 	error = create_cdevs(tpnt);
4418 	if (error)
4419 		goto out_remove_devs;
4420 	scsi_autopm_put_device(SDp);
4421 
4422 	sdev_printk(KERN_NOTICE, SDp,
4423 		    "Attached scsi tape %s\n", tape_name(tpnt));
4424 	sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4425 		    tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4426 		    queue_dma_alignment(SDp->request_queue) + 1);
4427 
4428 	return 0;
4429 
4430 out_remove_devs:
4431 	remove_cdevs(tpnt);
4432 	kfree(tpnt->stats);
4433 out_idr_remove:
4434 	spin_lock(&st_index_lock);
4435 	idr_remove(&st_index_idr, tpnt->index);
4436 	spin_unlock(&st_index_lock);
4437 out_put_queue:
4438 	blk_put_queue(disk->queue);
4439 out_put_disk:
4440 	put_disk(disk);
4441 	kfree(tpnt);
4442 out_buffer_free:
4443 	kfree(buffer);
4444 out:
4445 	scsi_autopm_put_device(SDp);
4446 	return -ENODEV;
4447 };
4448 
4449 
4450 static int st_remove(struct device *dev)
4451 {
4452 	struct scsi_tape *tpnt = dev_get_drvdata(dev);
4453 	int index = tpnt->index;
4454 
4455 	scsi_autopm_get_device(to_scsi_device(dev));
4456 	remove_cdevs(tpnt);
4457 
4458 	mutex_lock(&st_ref_mutex);
4459 	kref_put(&tpnt->kref, scsi_tape_release);
4460 	mutex_unlock(&st_ref_mutex);
4461 	spin_lock(&st_index_lock);
4462 	idr_remove(&st_index_idr, index);
4463 	spin_unlock(&st_index_lock);
4464 	return 0;
4465 }
4466 
4467 /**
4468  *      scsi_tape_release - Called to free the Scsi_Tape structure
4469  *      @kref: pointer to embedded kref
4470  *
4471  *      st_ref_mutex must be held entering this routine.  Because it is
4472  *      called on last put, you should always use the scsi_tape_get()
4473  *      scsi_tape_put() helpers which manipulate the semaphore directly
4474  *      and never do a direct kref_put().
4475  **/
4476 static void scsi_tape_release(struct kref *kref)
4477 {
4478 	struct scsi_tape *tpnt = to_scsi_tape(kref);
4479 	struct gendisk *disk = tpnt->disk;
4480 
4481 	tpnt->device = NULL;
4482 
4483 	if (tpnt->buffer) {
4484 		normalize_buffer(tpnt->buffer);
4485 		kfree(tpnt->buffer->reserved_pages);
4486 		kfree(tpnt->buffer);
4487 	}
4488 
4489 	disk->private_data = NULL;
4490 	put_disk(disk);
4491 	kfree(tpnt->stats);
4492 	kfree(tpnt);
4493 	return;
4494 }
4495 
4496 static struct class st_sysfs_class = {
4497 	.name = "scsi_tape",
4498 	.dev_groups = st_dev_groups,
4499 };
4500 
4501 static int __init init_st(void)
4502 {
4503 	int err;
4504 
4505 	validate_options();
4506 
4507 	printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4508 		verstr, st_fixed_buffer_size, st_max_sg_segs);
4509 
4510 	debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4511 	if (debugging) {
4512 		printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4513 			debugging);
4514 	}
4515 
4516 	err = class_register(&st_sysfs_class);
4517 	if (err) {
4518 		pr_err("Unable register sysfs class for SCSI tapes\n");
4519 		return err;
4520 	}
4521 
4522 	err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4523 				     ST_MAX_TAPE_ENTRIES, "st");
4524 	if (err) {
4525 		printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4526 		       SCSI_TAPE_MAJOR);
4527 		goto err_class;
4528 	}
4529 
4530 	err = scsi_register_driver(&st_template.gendrv);
4531 	if (err)
4532 		goto err_chrdev;
4533 
4534 	return 0;
4535 
4536 err_chrdev:
4537 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4538 				 ST_MAX_TAPE_ENTRIES);
4539 err_class:
4540 	class_unregister(&st_sysfs_class);
4541 	return err;
4542 }
4543 
4544 static void __exit exit_st(void)
4545 {
4546 	scsi_unregister_driver(&st_template.gendrv);
4547 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4548 				 ST_MAX_TAPE_ENTRIES);
4549 	class_unregister(&st_sysfs_class);
4550 	idr_destroy(&st_index_idr);
4551 	printk(KERN_INFO "st: Unloaded.\n");
4552 }
4553 
4554 module_init(init_st);
4555 module_exit(exit_st);
4556 
4557 
4558 /* The sysfs driver interface. Read-only at the moment */
4559 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4560 {
4561 	return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4562 }
4563 static DRIVER_ATTR_RO(try_direct_io);
4564 
4565 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4566 {
4567 	return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4568 }
4569 static DRIVER_ATTR_RO(fixed_buffer_size);
4570 
4571 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4572 {
4573 	return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4574 }
4575 static DRIVER_ATTR_RO(max_sg_segs);
4576 
4577 static ssize_t version_show(struct device_driver *ddd, char *buf)
4578 {
4579 	return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4580 }
4581 static DRIVER_ATTR_RO(version);
4582 
4583 #if DEBUG
4584 static ssize_t debug_flag_store(struct device_driver *ddp,
4585 	const char *buf, size_t count)
4586 {
4587 /* We only care what the first byte of the data is the rest is unused.
4588  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4589  * other values have -EINVAL returned if they are passed in.
4590  */
4591 	if (count > 0) {
4592 		if (buf[0] == '0') {
4593 			debugging = NO_DEBUG;
4594 			return count;
4595 		} else if (buf[0] == '1') {
4596 			debugging = 1;
4597 			return count;
4598 		}
4599 	}
4600 	return -EINVAL;
4601 }
4602 
4603 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4604 {
4605 	return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4606 }
4607 static DRIVER_ATTR_RW(debug_flag);
4608 #endif
4609 
4610 static struct attribute *st_drv_attrs[] = {
4611 	&driver_attr_try_direct_io.attr,
4612 	&driver_attr_fixed_buffer_size.attr,
4613 	&driver_attr_max_sg_segs.attr,
4614 	&driver_attr_version.attr,
4615 #if DEBUG
4616 	&driver_attr_debug_flag.attr,
4617 #endif
4618 	NULL,
4619 };
4620 ATTRIBUTE_GROUPS(st_drv);
4621 
4622 /* The sysfs simple class interface */
4623 static ssize_t
4624 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4625 {
4626 	struct st_modedef *STm = dev_get_drvdata(dev);
4627 	ssize_t l = 0;
4628 
4629 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4630 	return l;
4631 }
4632 static DEVICE_ATTR_RO(defined);
4633 
4634 static ssize_t
4635 default_blksize_show(struct device *dev, struct device_attribute *attr,
4636 		     char *buf)
4637 {
4638 	struct st_modedef *STm = dev_get_drvdata(dev);
4639 	ssize_t l = 0;
4640 
4641 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4642 	return l;
4643 }
4644 static DEVICE_ATTR_RO(default_blksize);
4645 
4646 static ssize_t
4647 default_density_show(struct device *dev, struct device_attribute *attr,
4648 		     char *buf)
4649 {
4650 	struct st_modedef *STm = dev_get_drvdata(dev);
4651 	ssize_t l = 0;
4652 	char *fmt;
4653 
4654 	fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4655 	l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4656 	return l;
4657 }
4658 static DEVICE_ATTR_RO(default_density);
4659 
4660 static ssize_t
4661 default_compression_show(struct device *dev, struct device_attribute *attr,
4662 			 char *buf)
4663 {
4664 	struct st_modedef *STm = dev_get_drvdata(dev);
4665 	ssize_t l = 0;
4666 
4667 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4668 	return l;
4669 }
4670 static DEVICE_ATTR_RO(default_compression);
4671 
4672 static ssize_t
4673 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4674 {
4675 	struct st_modedef *STm = dev_get_drvdata(dev);
4676 	struct scsi_tape *STp = STm->tape;
4677 	int options;
4678 	ssize_t l = 0;
4679 
4680 	options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4681 	options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4682 	options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4683 	DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4684 	options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4685 	options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4686 	options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4687 	options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4688 	options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4689 	options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4690 	options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4691 	options |= STm->sysv ? MT_ST_SYSV : 0;
4692 	options |= STp->immediate ? MT_ST_NOWAIT : 0;
4693 	options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4694 	options |= STp->sili ? MT_ST_SILI : 0;
4695 
4696 	l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4697 	return l;
4698 }
4699 static DEVICE_ATTR_RO(options);
4700 
4701 /* Support for tape stats */
4702 
4703 /**
4704  * read_cnt_show - return read count - count of reads made from tape drive
4705  * @dev: struct device
4706  * @attr: attribute structure
4707  * @buf: buffer to return formatted data in
4708  */
4709 static ssize_t read_cnt_show(struct device *dev,
4710 	struct device_attribute *attr, char *buf)
4711 {
4712 	struct st_modedef *STm = dev_get_drvdata(dev);
4713 
4714 	return sprintf(buf, "%lld",
4715 		       (long long)atomic64_read(&STm->tape->stats->read_cnt));
4716 }
4717 static DEVICE_ATTR_RO(read_cnt);
4718 
4719 /**
4720  * read_byte_cnt_show - return read byte count - tape drives
4721  * may use blocks less than 512 bytes this gives the raw byte count of
4722  * of data read from the tape drive.
4723  * @dev: struct device
4724  * @attr: attribute structure
4725  * @buf: buffer to return formatted data in
4726  */
4727 static ssize_t read_byte_cnt_show(struct device *dev,
4728 	struct device_attribute *attr, char *buf)
4729 {
4730 	struct st_modedef *STm = dev_get_drvdata(dev);
4731 
4732 	return sprintf(buf, "%lld",
4733 		       (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4734 }
4735 static DEVICE_ATTR_RO(read_byte_cnt);
4736 
4737 /**
4738  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4739  * @dev: struct device
4740  * @attr: attribute structure
4741  * @buf: buffer to return formatted data in
4742  */
4743 static ssize_t read_ns_show(struct device *dev,
4744 	struct device_attribute *attr, char *buf)
4745 {
4746 	struct st_modedef *STm = dev_get_drvdata(dev);
4747 
4748 	return sprintf(buf, "%lld",
4749 		       (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4750 }
4751 static DEVICE_ATTR_RO(read_ns);
4752 
4753 /**
4754  * write_cnt_show - write count - number of user calls
4755  * to write(2) that have written data to tape.
4756  * @dev: struct device
4757  * @attr: attribute structure
4758  * @buf: buffer to return formatted data in
4759  */
4760 static ssize_t write_cnt_show(struct device *dev,
4761 	struct device_attribute *attr, char *buf)
4762 {
4763 	struct st_modedef *STm = dev_get_drvdata(dev);
4764 
4765 	return sprintf(buf, "%lld",
4766 		       (long long)atomic64_read(&STm->tape->stats->write_cnt));
4767 }
4768 static DEVICE_ATTR_RO(write_cnt);
4769 
4770 /**
4771  * write_byte_cnt_show - write byte count - raw count of
4772  * bytes written to tape.
4773  * @dev: struct device
4774  * @attr: attribute structure
4775  * @buf: buffer to return formatted data in
4776  */
4777 static ssize_t write_byte_cnt_show(struct device *dev,
4778 	struct device_attribute *attr, char *buf)
4779 {
4780 	struct st_modedef *STm = dev_get_drvdata(dev);
4781 
4782 	return sprintf(buf, "%lld",
4783 		       (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4784 }
4785 static DEVICE_ATTR_RO(write_byte_cnt);
4786 
4787 /**
4788  * write_ns_show - write ns - number of nanoseconds waiting on write
4789  * requests to complete.
4790  * @dev: struct device
4791  * @attr: attribute structure
4792  * @buf: buffer to return formatted data in
4793  */
4794 static ssize_t write_ns_show(struct device *dev,
4795 	struct device_attribute *attr, char *buf)
4796 {
4797 	struct st_modedef *STm = dev_get_drvdata(dev);
4798 
4799 	return sprintf(buf, "%lld",
4800 		       (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4801 }
4802 static DEVICE_ATTR_RO(write_ns);
4803 
4804 /**
4805  * in_flight_show - number of I/Os currently in flight -
4806  * in most cases this will be either 0 or 1. It may be higher if someone
4807  * has also issued other SCSI commands such as via an ioctl.
4808  * @dev: struct device
4809  * @attr: attribute structure
4810  * @buf: buffer to return formatted data in
4811  */
4812 static ssize_t in_flight_show(struct device *dev,
4813 	struct device_attribute *attr, char *buf)
4814 {
4815 	struct st_modedef *STm = dev_get_drvdata(dev);
4816 
4817 	return sprintf(buf, "%lld",
4818 		       (long long)atomic64_read(&STm->tape->stats->in_flight));
4819 }
4820 static DEVICE_ATTR_RO(in_flight);
4821 
4822 /**
4823  * io_ns_show - io wait ns - this is the number of ns spent
4824  * waiting on all I/O to complete. This includes tape movement commands
4825  * such as rewinding, seeking to end of file or tape, it also includes
4826  * read and write. To determine the time spent on tape movement
4827  * subtract the read and write ns from this value.
4828  * @dev: struct device
4829  * @attr: attribute structure
4830  * @buf: buffer to return formatted data in
4831  */
4832 static ssize_t io_ns_show(struct device *dev,
4833 	struct device_attribute *attr, char *buf)
4834 {
4835 	struct st_modedef *STm = dev_get_drvdata(dev);
4836 
4837 	return sprintf(buf, "%lld",
4838 		       (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4839 }
4840 static DEVICE_ATTR_RO(io_ns);
4841 
4842 /**
4843  * other_cnt_show - other io count - this is the number of
4844  * I/O requests other than read and write requests.
4845  * Typically these are tape movement requests but will include driver
4846  * tape movement. This includes only requests issued by the st driver.
4847  * @dev: struct device
4848  * @attr: attribute structure
4849  * @buf: buffer to return formatted data in
4850  */
4851 static ssize_t other_cnt_show(struct device *dev,
4852 	struct device_attribute *attr, char *buf)
4853 {
4854 	struct st_modedef *STm = dev_get_drvdata(dev);
4855 
4856 	return sprintf(buf, "%lld",
4857 		       (long long)atomic64_read(&STm->tape->stats->other_cnt));
4858 }
4859 static DEVICE_ATTR_RO(other_cnt);
4860 
4861 /**
4862  * resid_cnt_show - A count of the number of times we get a residual
4863  * count - this should indicate someone issuing reads larger than the
4864  * block size on tape.
4865  * @dev: struct device
4866  * @attr: attribute structure
4867  * @buf: buffer to return formatted data in
4868  */
4869 static ssize_t resid_cnt_show(struct device *dev,
4870 	struct device_attribute *attr, char *buf)
4871 {
4872 	struct st_modedef *STm = dev_get_drvdata(dev);
4873 
4874 	return sprintf(buf, "%lld",
4875 		       (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4876 }
4877 static DEVICE_ATTR_RO(resid_cnt);
4878 
4879 static struct attribute *st_dev_attrs[] = {
4880 	&dev_attr_defined.attr,
4881 	&dev_attr_default_blksize.attr,
4882 	&dev_attr_default_density.attr,
4883 	&dev_attr_default_compression.attr,
4884 	&dev_attr_options.attr,
4885 	NULL,
4886 };
4887 
4888 static struct attribute *st_stats_attrs[] = {
4889 	&dev_attr_read_cnt.attr,
4890 	&dev_attr_read_byte_cnt.attr,
4891 	&dev_attr_read_ns.attr,
4892 	&dev_attr_write_cnt.attr,
4893 	&dev_attr_write_byte_cnt.attr,
4894 	&dev_attr_write_ns.attr,
4895 	&dev_attr_in_flight.attr,
4896 	&dev_attr_io_ns.attr,
4897 	&dev_attr_other_cnt.attr,
4898 	&dev_attr_resid_cnt.attr,
4899 	NULL,
4900 };
4901 
4902 static struct attribute_group stats_group = {
4903 	.name = "stats",
4904 	.attrs = st_stats_attrs,
4905 };
4906 
4907 static struct attribute_group st_group = {
4908 	.attrs = st_dev_attrs,
4909 };
4910 
4911 static const struct attribute_group *st_dev_groups[] = {
4912 	&st_group,
4913 	&stats_group,
4914 	NULL,
4915 };
4916 
4917 /* The following functions may be useful for a larger audience. */
4918 static int sgl_map_user_pages(struct st_buffer *STbp,
4919 			      const unsigned int max_pages, unsigned long uaddr,
4920 			      size_t count, int rw)
4921 {
4922 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4923 	unsigned long start = uaddr >> PAGE_SHIFT;
4924 	const int nr_pages = end - start;
4925 	int res, i, j;
4926 	struct page **pages;
4927 	struct rq_map_data *mdata = &STbp->map_data;
4928 
4929 	/* User attempted Overflow! */
4930 	if ((uaddr + count) < uaddr)
4931 		return -EINVAL;
4932 
4933 	/* Too big */
4934         if (nr_pages > max_pages)
4935 		return -ENOMEM;
4936 
4937 	/* Hmm? */
4938 	if (count == 0)
4939 		return 0;
4940 
4941 	pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4942 	if (pages == NULL)
4943 		return -ENOMEM;
4944 
4945         /* Try to fault in all of the necessary pages */
4946         /* rw==READ means read from drive, write into memory area */
4947 	res = get_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4948 				  pages);
4949 
4950 	/* Errors and no page mapped should return here */
4951 	if (res < nr_pages)
4952 		goto out_unmap;
4953 
4954         for (i=0; i < nr_pages; i++) {
4955                 /* FIXME: flush superflous for rw==READ,
4956                  * probably wrong function for rw==WRITE
4957                  */
4958 		flush_dcache_page(pages[i]);
4959         }
4960 
4961 	mdata->offset = uaddr & ~PAGE_MASK;
4962 	STbp->mapped_pages = pages;
4963 
4964 	return nr_pages;
4965  out_unmap:
4966 	if (res > 0) {
4967 		for (j=0; j < res; j++)
4968 			put_page(pages[j]);
4969 		res = 0;
4970 	}
4971 	kfree(pages);
4972 	return res;
4973 }
4974 
4975 
4976 /* And unmap them... */
4977 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4978 				const unsigned int nr_pages, int dirtied)
4979 {
4980 	int i;
4981 
4982 	for (i=0; i < nr_pages; i++) {
4983 		struct page *page = STbp->mapped_pages[i];
4984 
4985 		if (dirtied)
4986 			SetPageDirty(page);
4987 		/* FIXME: cache flush missing for rw==READ
4988 		 * FIXME: call the correct reference counting function
4989 		 */
4990 		put_page(page);
4991 	}
4992 	kfree(STbp->mapped_pages);
4993 	STbp->mapped_pages = NULL;
4994 
4995 	return 0;
4996 }
4997