xref: /openbmc/linux/drivers/scsi/st.c (revision 827634ad)
1 /*
2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
3    file Documentation/scsi/st.txt for more information.
4 
5    History:
6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
7    Contribution and ideas from several people including (in alphabetical
8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
10    Michael Schaefer, J"org Weule, and Eric Youngdale.
11 
12    Copyright 1992 - 2010 Kai Makisara
13    email Kai.Makisara@kolumbus.fi
14 
15    Some small formal changes - aeb, 950809
16 
17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
18  */
19 
20 static const char *verstr = "20101219";
21 
22 #include <linux/module.h>
23 
24 #include <linux/fs.h>
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/mm.h>
28 #include <linux/init.h>
29 #include <linux/string.h>
30 #include <linux/slab.h>
31 #include <linux/errno.h>
32 #include <linux/mtio.h>
33 #include <linux/cdrom.h>
34 #include <linux/ioctl.h>
35 #include <linux/fcntl.h>
36 #include <linux/spinlock.h>
37 #include <linux/blkdev.h>
38 #include <linux/moduleparam.h>
39 #include <linux/cdev.h>
40 #include <linux/idr.h>
41 #include <linux/delay.h>
42 #include <linux/mutex.h>
43 
44 #include <asm/uaccess.h>
45 #include <asm/dma.h>
46 
47 #include <scsi/scsi.h>
48 #include <scsi/scsi_dbg.h>
49 #include <scsi/scsi_device.h>
50 #include <scsi/scsi_driver.h>
51 #include <scsi/scsi_eh.h>
52 #include <scsi/scsi_host.h>
53 #include <scsi/scsi_ioctl.h>
54 #include <scsi/sg.h>
55 
56 
57 /* The driver prints some debugging information on the console if DEBUG
58    is defined and non-zero. */
59 #define DEBUG 1
60 #define NO_DEBUG 0
61 
62 #define ST_DEB_MSG  KERN_NOTICE
63 #if DEBUG
64 /* The message level for the debug messages is currently set to KERN_NOTICE
65    so that people can easily see the messages. Later when the debugging messages
66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
67 #define DEB(a) a
68 #define DEBC(a) if (debugging) { a ; }
69 #else
70 #define DEB(a)
71 #define DEBC(a)
72 #endif
73 
74 #define ST_KILOBYTE 1024
75 
76 #include "st_options.h"
77 #include "st.h"
78 
79 static int buffer_kbs;
80 static int max_sg_segs;
81 static int try_direct_io = TRY_DIRECT_IO;
82 static int try_rdio = 1;
83 static int try_wdio = 1;
84 static int debug_flag;
85 
86 static struct class st_sysfs_class;
87 static const struct attribute_group *st_dev_groups[];
88 
89 MODULE_AUTHOR("Kai Makisara");
90 MODULE_DESCRIPTION("SCSI tape (st) driver");
91 MODULE_LICENSE("GPL");
92 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
93 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
94 
95 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
96  * of sysfs parameters (which module_param doesn't yet support).
97  * Sysfs parameters defined explicitly later.
98  */
99 module_param_named(buffer_kbs, buffer_kbs, int, 0);
100 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
101 module_param_named(max_sg_segs, max_sg_segs, int, 0);
102 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
103 module_param_named(try_direct_io, try_direct_io, int, 0);
104 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
105 module_param_named(debug_flag, debug_flag, int, 0);
106 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
107 
108 
109 /* Extra parameters for testing */
110 module_param_named(try_rdio, try_rdio, int, 0);
111 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
112 module_param_named(try_wdio, try_wdio, int, 0);
113 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
114 
115 #ifndef MODULE
116 static int write_threshold_kbs;  /* retained for compatibility */
117 static struct st_dev_parm {
118 	char *name;
119 	int *val;
120 } parms[] __initdata = {
121 	{
122 		"buffer_kbs", &buffer_kbs
123 	},
124 	{       /* Retained for compatibility with 2.4 */
125 		"write_threshold_kbs", &write_threshold_kbs
126 	},
127 	{
128 		"max_sg_segs", NULL
129 	},
130 	{
131 		"try_direct_io", &try_direct_io
132 	},
133 	{
134 		"debug_flag", &debug_flag
135 	}
136 };
137 #endif
138 
139 /* Restrict the number of modes so that names for all are assigned */
140 #if ST_NBR_MODES > 16
141 #error "Maximum number of modes is 16"
142 #endif
143 /* Bit reversed order to get same names for same minors with all
144    mode counts */
145 static const char *st_formats[] = {
146 	"",  "r", "k", "s", "l", "t", "o", "u",
147 	"m", "v", "p", "x", "a", "y", "q", "z"};
148 
149 /* The default definitions have been moved to st_options.h */
150 
151 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
152 
153 /* The buffer size should fit into the 24 bits for length in the
154    6-byte SCSI read and write commands. */
155 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
156 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
157 #endif
158 
159 static int debugging = DEBUG;
160 
161 #define MAX_RETRIES 0
162 #define MAX_WRITE_RETRIES 0
163 #define MAX_READY_RETRIES 0
164 #define NO_TAPE  NOT_READY
165 
166 #define ST_TIMEOUT (900 * HZ)
167 #define ST_LONG_TIMEOUT (14000 * HZ)
168 
169 /* Remove mode bits and auto-rewind bit (7) */
170 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
171     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
172 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
173 
174 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
175 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
176   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
177 
178 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
179    24 bits) */
180 #define SET_DENS_AND_BLK 0x10001
181 
182 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
183 static int st_max_sg_segs = ST_MAX_SG;
184 
185 static int modes_defined;
186 
187 static int enlarge_buffer(struct st_buffer *, int, int);
188 static void clear_buffer(struct st_buffer *);
189 static void normalize_buffer(struct st_buffer *);
190 static int append_to_buffer(const char __user *, struct st_buffer *, int);
191 static int from_buffer(struct st_buffer *, char __user *, int);
192 static void move_buffer_data(struct st_buffer *, int);
193 
194 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
195 			      unsigned long, size_t, int);
196 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
197 
198 static int st_probe(struct device *);
199 static int st_remove(struct device *);
200 
201 static int do_create_sysfs_files(void);
202 static void do_remove_sysfs_files(void);
203 
204 static struct scsi_driver st_template = {
205 	.gendrv = {
206 		.name		= "st",
207 		.owner		= THIS_MODULE,
208 		.probe		= st_probe,
209 		.remove		= st_remove,
210 	},
211 };
212 
213 static int st_compression(struct scsi_tape *, int);
214 
215 static int find_partition(struct scsi_tape *);
216 static int switch_partition(struct scsi_tape *);
217 
218 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
219 
220 static void scsi_tape_release(struct kref *);
221 
222 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
223 
224 static DEFINE_MUTEX(st_ref_mutex);
225 static DEFINE_SPINLOCK(st_index_lock);
226 static DEFINE_SPINLOCK(st_use_lock);
227 static DEFINE_IDR(st_index_idr);
228 
229 
230 
231 #include "osst_detect.h"
232 #ifndef SIGS_FROM_OSST
233 #define SIGS_FROM_OSST \
234 	{"OnStream", "SC-", "", "osst"}, \
235 	{"OnStream", "DI-", "", "osst"}, \
236 	{"OnStream", "DP-", "", "osst"}, \
237 	{"OnStream", "USB", "", "osst"}, \
238 	{"OnStream", "FW-", "", "osst"}
239 #endif
240 
241 static struct scsi_tape *scsi_tape_get(int dev)
242 {
243 	struct scsi_tape *STp = NULL;
244 
245 	mutex_lock(&st_ref_mutex);
246 	spin_lock(&st_index_lock);
247 
248 	STp = idr_find(&st_index_idr, dev);
249 	if (!STp) goto out;
250 
251 	kref_get(&STp->kref);
252 
253 	if (!STp->device)
254 		goto out_put;
255 
256 	if (scsi_device_get(STp->device))
257 		goto out_put;
258 
259 	goto out;
260 
261 out_put:
262 	kref_put(&STp->kref, scsi_tape_release);
263 	STp = NULL;
264 out:
265 	spin_unlock(&st_index_lock);
266 	mutex_unlock(&st_ref_mutex);
267 	return STp;
268 }
269 
270 static void scsi_tape_put(struct scsi_tape *STp)
271 {
272 	struct scsi_device *sdev = STp->device;
273 
274 	mutex_lock(&st_ref_mutex);
275 	kref_put(&STp->kref, scsi_tape_release);
276 	scsi_device_put(sdev);
277 	mutex_unlock(&st_ref_mutex);
278 }
279 
280 struct st_reject_data {
281 	char *vendor;
282 	char *model;
283 	char *rev;
284 	char *driver_hint; /* Name of the correct driver, NULL if unknown */
285 };
286 
287 static struct st_reject_data reject_list[] = {
288 	/* {"XXX", "Yy-", "", NULL},  example */
289 	SIGS_FROM_OSST,
290 	{NULL, }};
291 
292 /* If the device signature is on the list of incompatible drives, the
293    function returns a pointer to the name of the correct driver (if known) */
294 static char * st_incompatible(struct scsi_device* SDp)
295 {
296 	struct st_reject_data *rp;
297 
298 	for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
299 		if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
300 		    !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
301 		    !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
302 			if (rp->driver_hint)
303 				return rp->driver_hint;
304 			else
305 				return "unknown";
306 		}
307 	return NULL;
308 }
309 
310 
311 static inline char *tape_name(struct scsi_tape *tape)
312 {
313 	return tape->disk->disk_name;
314 }
315 
316 #define st_printk(prefix, t, fmt, a...) \
317 	sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
318 #ifdef DEBUG
319 #define DEBC_printk(t, fmt, a...) \
320 	if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
321 #else
322 #define DEBC_printk(t, fmt, a...)
323 #endif
324 
325 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
326 {
327 	const u8 *ucp;
328 	const u8 *sense = SRpnt->sense;
329 
330 	s->have_sense = scsi_normalize_sense(SRpnt->sense,
331 				SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
332 	s->flags = 0;
333 
334 	if (s->have_sense) {
335 		s->deferred = 0;
336 		s->remainder_valid =
337 			scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
338 		switch (sense[0] & 0x7f) {
339 		case 0x71:
340 			s->deferred = 1;
341 		case 0x70:
342 			s->fixed_format = 1;
343 			s->flags = sense[2] & 0xe0;
344 			break;
345 		case 0x73:
346 			s->deferred = 1;
347 		case 0x72:
348 			s->fixed_format = 0;
349 			ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
350 			s->flags = ucp ? (ucp[3] & 0xe0) : 0;
351 			break;
352 		}
353 	}
354 }
355 
356 
357 /* Convert the result to success code */
358 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
359 {
360 	int result = SRpnt->result;
361 	u8 scode;
362 	DEB(const char *stp;)
363 	char *name = tape_name(STp);
364 	struct st_cmdstatus *cmdstatp;
365 
366 	if (!result)
367 		return 0;
368 
369 	cmdstatp = &STp->buffer->cmdstat;
370 	st_analyze_sense(SRpnt, cmdstatp);
371 
372 	if (cmdstatp->have_sense)
373 		scode = STp->buffer->cmdstat.sense_hdr.sense_key;
374 	else
375 		scode = 0;
376 
377 	DEB(
378 	if (debugging) {
379 		st_printk(ST_DEB_MSG, STp,
380 			    "Error: %x, cmd: %x %x %x %x %x %x\n", result,
381 			    SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
382 			    SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
383 		if (cmdstatp->have_sense)
384 			__scsi_print_sense(STp->device, name,
385 					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
386 	} ) /* end DEB */
387 	if (!debugging) { /* Abnormal conditions for tape */
388 		if (!cmdstatp->have_sense)
389 			st_printk(KERN_WARNING, STp,
390 			       "Error %x (driver bt 0x%x, host bt 0x%x).\n",
391 			       result, driver_byte(result), host_byte(result));
392 		else if (cmdstatp->have_sense &&
393 			 scode != NO_SENSE &&
394 			 scode != RECOVERED_ERROR &&
395 			 /* scode != UNIT_ATTENTION && */
396 			 scode != BLANK_CHECK &&
397 			 scode != VOLUME_OVERFLOW &&
398 			 SRpnt->cmd[0] != MODE_SENSE &&
399 			 SRpnt->cmd[0] != TEST_UNIT_READY) {
400 
401 			__scsi_print_sense(STp->device, name,
402 					   SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
403 		}
404 	}
405 
406 	if (cmdstatp->fixed_format &&
407 	    STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
408 		if (STp->cln_sense_value)
409 			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
410 					       STp->cln_sense_mask) == STp->cln_sense_value);
411 		else
412 			STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
413 					       STp->cln_sense_mask) != 0);
414 	}
415 	if (cmdstatp->have_sense &&
416 	    cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
417 		STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
418 
419 	STp->pos_unknown |= STp->device->was_reset;
420 
421 	if (cmdstatp->have_sense &&
422 	    scode == RECOVERED_ERROR
423 #if ST_RECOVERED_WRITE_FATAL
424 	    && SRpnt->cmd[0] != WRITE_6
425 	    && SRpnt->cmd[0] != WRITE_FILEMARKS
426 #endif
427 	    ) {
428 		STp->recover_count++;
429 		STp->recover_reg++;
430 
431 		DEB(
432 		if (debugging) {
433 			if (SRpnt->cmd[0] == READ_6)
434 				stp = "read";
435 			else if (SRpnt->cmd[0] == WRITE_6)
436 				stp = "write";
437 			else
438 				stp = "ioctl";
439 			st_printk(ST_DEB_MSG, STp,
440 				  "Recovered %s error (%d).\n",
441 				  stp, STp->recover_count);
442 		} ) /* end DEB */
443 
444 		if (cmdstatp->flags == 0)
445 			return 0;
446 	}
447 	return (-EIO);
448 }
449 
450 static struct st_request *st_allocate_request(struct scsi_tape *stp)
451 {
452 	struct st_request *streq;
453 
454 	streq = kzalloc(sizeof(*streq), GFP_KERNEL);
455 	if (streq)
456 		streq->stp = stp;
457 	else {
458 		st_printk(KERN_ERR, stp,
459 			  "Can't get SCSI request.\n");
460 		if (signal_pending(current))
461 			stp->buffer->syscall_result = -EINTR;
462 		else
463 			stp->buffer->syscall_result = -EBUSY;
464 	}
465 
466 	return streq;
467 }
468 
469 static void st_release_request(struct st_request *streq)
470 {
471 	kfree(streq);
472 }
473 
474 static void st_scsi_execute_end(struct request *req, int uptodate)
475 {
476 	struct st_request *SRpnt = req->end_io_data;
477 	struct scsi_tape *STp = SRpnt->stp;
478 	struct bio *tmp;
479 
480 	STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
481 	STp->buffer->cmdstat.residual = req->resid_len;
482 
483 	tmp = SRpnt->bio;
484 	if (SRpnt->waiting)
485 		complete(SRpnt->waiting);
486 
487 	blk_rq_unmap_user(tmp);
488 	__blk_put_request(req->q, req);
489 }
490 
491 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
492 			   int data_direction, void *buffer, unsigned bufflen,
493 			   int timeout, int retries)
494 {
495 	struct request *req;
496 	struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
497 	int err = 0;
498 	int write = (data_direction == DMA_TO_DEVICE);
499 
500 	req = blk_get_request(SRpnt->stp->device->request_queue, write,
501 			      GFP_KERNEL);
502 	if (IS_ERR(req))
503 		return DRIVER_ERROR << 24;
504 
505 	blk_rq_set_block_pc(req);
506 	req->cmd_flags |= REQ_QUIET;
507 
508 	mdata->null_mapped = 1;
509 
510 	if (bufflen) {
511 		err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
512 				      GFP_KERNEL);
513 		if (err) {
514 			blk_put_request(req);
515 			return DRIVER_ERROR << 24;
516 		}
517 	}
518 
519 	SRpnt->bio = req->bio;
520 	req->cmd_len = COMMAND_SIZE(cmd[0]);
521 	memset(req->cmd, 0, BLK_MAX_CDB);
522 	memcpy(req->cmd, cmd, req->cmd_len);
523 	req->sense = SRpnt->sense;
524 	req->sense_len = 0;
525 	req->timeout = timeout;
526 	req->retries = retries;
527 	req->end_io_data = SRpnt;
528 
529 	blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
530 	return 0;
531 }
532 
533 /* Do the scsi command. Waits until command performed if do_wait is true.
534    Otherwise write_behind_check() is used to check that the command
535    has finished. */
536 static struct st_request *
537 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
538 	   int bytes, int direction, int timeout, int retries, int do_wait)
539 {
540 	struct completion *waiting;
541 	struct rq_map_data *mdata = &STp->buffer->map_data;
542 	int ret;
543 
544 	/* if async, make sure there's no command outstanding */
545 	if (!do_wait && ((STp->buffer)->last_SRpnt)) {
546 		st_printk(KERN_ERR, STp,
547 			  "Async command already active.\n");
548 		if (signal_pending(current))
549 			(STp->buffer)->syscall_result = (-EINTR);
550 		else
551 			(STp->buffer)->syscall_result = (-EBUSY);
552 		return NULL;
553 	}
554 
555 	if (!SRpnt) {
556 		SRpnt = st_allocate_request(STp);
557 		if (!SRpnt)
558 			return NULL;
559 	}
560 
561 	/* If async IO, set last_SRpnt. This ptr tells write_behind_check
562 	   which IO is outstanding. It's nulled out when the IO completes. */
563 	if (!do_wait)
564 		(STp->buffer)->last_SRpnt = SRpnt;
565 
566 	waiting = &STp->wait;
567 	init_completion(waiting);
568 	SRpnt->waiting = waiting;
569 
570 	if (STp->buffer->do_dio) {
571 		mdata->page_order = 0;
572 		mdata->nr_entries = STp->buffer->sg_segs;
573 		mdata->pages = STp->buffer->mapped_pages;
574 	} else {
575 		mdata->page_order = STp->buffer->reserved_page_order;
576 		mdata->nr_entries =
577 			DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
578 		mdata->pages = STp->buffer->reserved_pages;
579 		mdata->offset = 0;
580 	}
581 
582 	memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
583 	STp->buffer->cmdstat.have_sense = 0;
584 	STp->buffer->syscall_result = 0;
585 
586 	ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
587 			      retries);
588 	if (ret) {
589 		/* could not allocate the buffer or request was too large */
590 		(STp->buffer)->syscall_result = (-EBUSY);
591 		(STp->buffer)->last_SRpnt = NULL;
592 	} else if (do_wait) {
593 		wait_for_completion(waiting);
594 		SRpnt->waiting = NULL;
595 		(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
596 	}
597 
598 	return SRpnt;
599 }
600 
601 
602 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
603    write has been correct but EOM early warning reached, -EIO if write ended in
604    error or zero if write successful. Asynchronous writes are used only in
605    variable block mode. */
606 static int write_behind_check(struct scsi_tape * STp)
607 {
608 	int retval = 0;
609 	struct st_buffer *STbuffer;
610 	struct st_partstat *STps;
611 	struct st_cmdstatus *cmdstatp;
612 	struct st_request *SRpnt;
613 
614 	STbuffer = STp->buffer;
615 	if (!STbuffer->writing)
616 		return 0;
617 
618 	DEB(
619 	if (STp->write_pending)
620 		STp->nbr_waits++;
621 	else
622 		STp->nbr_finished++;
623 	) /* end DEB */
624 
625 	wait_for_completion(&(STp->wait));
626 	SRpnt = STbuffer->last_SRpnt;
627 	STbuffer->last_SRpnt = NULL;
628 	SRpnt->waiting = NULL;
629 
630 	(STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
631 	st_release_request(SRpnt);
632 
633 	STbuffer->buffer_bytes -= STbuffer->writing;
634 	STps = &(STp->ps[STp->partition]);
635 	if (STps->drv_block >= 0) {
636 		if (STp->block_size == 0)
637 			STps->drv_block++;
638 		else
639 			STps->drv_block += STbuffer->writing / STp->block_size;
640 	}
641 
642 	cmdstatp = &STbuffer->cmdstat;
643 	if (STbuffer->syscall_result) {
644 		retval = -EIO;
645 		if (cmdstatp->have_sense && !cmdstatp->deferred &&
646 		    (cmdstatp->flags & SENSE_EOM) &&
647 		    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
648 		     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
649 			/* EOM at write-behind, has all data been written? */
650 			if (!cmdstatp->remainder_valid ||
651 			    cmdstatp->uremainder64 == 0)
652 				retval = -ENOSPC;
653 		}
654 		if (retval == -EIO)
655 			STps->drv_block = -1;
656 	}
657 	STbuffer->writing = 0;
658 
659 	DEB(if (debugging && retval)
660 		    st_printk(ST_DEB_MSG, STp,
661 				"Async write error %x, return value %d.\n",
662 				STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
663 
664 	return retval;
665 }
666 
667 
668 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
669    it messes up the block number). */
670 static int cross_eof(struct scsi_tape * STp, int forward)
671 {
672 	struct st_request *SRpnt;
673 	unsigned char cmd[MAX_COMMAND_SIZE];
674 
675 	cmd[0] = SPACE;
676 	cmd[1] = 0x01;		/* Space FileMarks */
677 	if (forward) {
678 		cmd[2] = cmd[3] = 0;
679 		cmd[4] = 1;
680 	} else
681 		cmd[2] = cmd[3] = cmd[4] = 0xff;	/* -1 filemarks */
682 	cmd[5] = 0;
683 
684 	DEBC_printk(STp, "Stepping over filemark %s.\n",
685 		    forward ? "forward" : "backward");
686 
687 	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
688 			   STp->device->request_queue->rq_timeout,
689 			   MAX_RETRIES, 1);
690 	if (!SRpnt)
691 		return (STp->buffer)->syscall_result;
692 
693 	st_release_request(SRpnt);
694 	SRpnt = NULL;
695 
696 	if ((STp->buffer)->cmdstat.midlevel_result != 0)
697 		st_printk(KERN_ERR, STp,
698 			  "Stepping over filemark %s failed.\n",
699 			  forward ? "forward" : "backward");
700 
701 	return (STp->buffer)->syscall_result;
702 }
703 
704 
705 /* Flush the write buffer (never need to write if variable blocksize). */
706 static int st_flush_write_buffer(struct scsi_tape * STp)
707 {
708 	int transfer, blks;
709 	int result;
710 	unsigned char cmd[MAX_COMMAND_SIZE];
711 	struct st_request *SRpnt;
712 	struct st_partstat *STps;
713 
714 	result = write_behind_check(STp);
715 	if (result)
716 		return result;
717 
718 	result = 0;
719 	if (STp->dirty == 1) {
720 
721 		transfer = STp->buffer->buffer_bytes;
722 		DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
723 
724 		memset(cmd, 0, MAX_COMMAND_SIZE);
725 		cmd[0] = WRITE_6;
726 		cmd[1] = 1;
727 		blks = transfer / STp->block_size;
728 		cmd[2] = blks >> 16;
729 		cmd[3] = blks >> 8;
730 		cmd[4] = blks;
731 
732 		SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
733 				   STp->device->request_queue->rq_timeout,
734 				   MAX_WRITE_RETRIES, 1);
735 		if (!SRpnt)
736 			return (STp->buffer)->syscall_result;
737 
738 		STps = &(STp->ps[STp->partition]);
739 		if ((STp->buffer)->syscall_result != 0) {
740 			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
741 
742 			if (cmdstatp->have_sense && !cmdstatp->deferred &&
743 			    (cmdstatp->flags & SENSE_EOM) &&
744 			    (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
745 			     cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
746 			    (!cmdstatp->remainder_valid ||
747 			     cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
748 				STp->dirty = 0;
749 				(STp->buffer)->buffer_bytes = 0;
750 				if (STps->drv_block >= 0)
751 					STps->drv_block += blks;
752 				result = (-ENOSPC);
753 			} else {
754 				st_printk(KERN_ERR, STp, "Error on flush.\n");
755 				STps->drv_block = (-1);
756 				result = (-EIO);
757 			}
758 		} else {
759 			if (STps->drv_block >= 0)
760 				STps->drv_block += blks;
761 			STp->dirty = 0;
762 			(STp->buffer)->buffer_bytes = 0;
763 		}
764 		st_release_request(SRpnt);
765 		SRpnt = NULL;
766 	}
767 	return result;
768 }
769 
770 
771 /* Flush the tape buffer. The tape will be positioned correctly unless
772    seek_next is true. */
773 static int flush_buffer(struct scsi_tape *STp, int seek_next)
774 {
775 	int backspace, result;
776 	struct st_buffer *STbuffer;
777 	struct st_partstat *STps;
778 
779 	STbuffer = STp->buffer;
780 
781 	/*
782 	 * If there was a bus reset, block further access
783 	 * to this device.
784 	 */
785 	if (STp->pos_unknown)
786 		return (-EIO);
787 
788 	if (STp->ready != ST_READY)
789 		return 0;
790 	STps = &(STp->ps[STp->partition]);
791 	if (STps->rw == ST_WRITING)	/* Writing */
792 		return st_flush_write_buffer(STp);
793 
794 	if (STp->block_size == 0)
795 		return 0;
796 
797 	backspace = ((STp->buffer)->buffer_bytes +
798 		     (STp->buffer)->read_pointer) / STp->block_size -
799 	    ((STp->buffer)->read_pointer + STp->block_size - 1) /
800 	    STp->block_size;
801 	(STp->buffer)->buffer_bytes = 0;
802 	(STp->buffer)->read_pointer = 0;
803 	result = 0;
804 	if (!seek_next) {
805 		if (STps->eof == ST_FM_HIT) {
806 			result = cross_eof(STp, 0);	/* Back over the EOF hit */
807 			if (!result)
808 				STps->eof = ST_NOEOF;
809 			else {
810 				if (STps->drv_file >= 0)
811 					STps->drv_file++;
812 				STps->drv_block = 0;
813 			}
814 		}
815 		if (!result && backspace > 0)
816 			result = st_int_ioctl(STp, MTBSR, backspace);
817 	} else if (STps->eof == ST_FM_HIT) {
818 		if (STps->drv_file >= 0)
819 			STps->drv_file++;
820 		STps->drv_block = 0;
821 		STps->eof = ST_NOEOF;
822 	}
823 	return result;
824 
825 }
826 
827 /* Set the mode parameters */
828 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
829 {
830 	int set_it = 0;
831 	unsigned long arg;
832 
833 	if (!STp->density_changed &&
834 	    STm->default_density >= 0 &&
835 	    STm->default_density != STp->density) {
836 		arg = STm->default_density;
837 		set_it = 1;
838 	} else
839 		arg = STp->density;
840 	arg <<= MT_ST_DENSITY_SHIFT;
841 	if (!STp->blksize_changed &&
842 	    STm->default_blksize >= 0 &&
843 	    STm->default_blksize != STp->block_size) {
844 		arg |= STm->default_blksize;
845 		set_it = 1;
846 	} else
847 		arg |= STp->block_size;
848 	if (set_it &&
849 	    st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
850 		st_printk(KERN_WARNING, STp,
851 			  "Can't set default block size to %d bytes "
852 			  "and density %x.\n",
853 			  STm->default_blksize, STm->default_density);
854 		if (modes_defined)
855 			return (-EINVAL);
856 	}
857 	return 0;
858 }
859 
860 
861 /* Lock or unlock the drive door. Don't use when st_request allocated. */
862 static int do_door_lock(struct scsi_tape * STp, int do_lock)
863 {
864 	int retval;
865 
866 	DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
867 
868 	retval = scsi_set_medium_removal(STp->device,
869 			do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
870 	if (!retval)
871 		STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
872 	else
873 		STp->door_locked = ST_LOCK_FAILS;
874 	return retval;
875 }
876 
877 
878 /* Set the internal state after reset */
879 static void reset_state(struct scsi_tape *STp)
880 {
881 	int i;
882 	struct st_partstat *STps;
883 
884 	STp->pos_unknown = 0;
885 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
886 		STps = &(STp->ps[i]);
887 		STps->rw = ST_IDLE;
888 		STps->eof = ST_NOEOF;
889 		STps->at_sm = 0;
890 		STps->last_block_valid = 0;
891 		STps->drv_block = -1;
892 		STps->drv_file = -1;
893 	}
894 	if (STp->can_partitions) {
895 		STp->partition = find_partition(STp);
896 		if (STp->partition < 0)
897 			STp->partition = 0;
898 		STp->new_partition = STp->partition;
899 	}
900 }
901 
902 /* Test if the drive is ready. Returns either one of the codes below or a negative system
903    error code. */
904 #define CHKRES_READY       0
905 #define CHKRES_NEW_SESSION 1
906 #define CHKRES_NOT_READY   2
907 #define CHKRES_NO_TAPE     3
908 
909 #define MAX_ATTENTIONS    10
910 
911 static int test_ready(struct scsi_tape *STp, int do_wait)
912 {
913 	int attentions, waits, max_wait, scode;
914 	int retval = CHKRES_READY, new_session = 0;
915 	unsigned char cmd[MAX_COMMAND_SIZE];
916 	struct st_request *SRpnt = NULL;
917 	struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
918 
919 	max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
920 
921 	for (attentions=waits=0; ; ) {
922 		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
923 		cmd[0] = TEST_UNIT_READY;
924 		SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
925 				   STp->long_timeout, MAX_READY_RETRIES, 1);
926 
927 		if (!SRpnt) {
928 			retval = (STp->buffer)->syscall_result;
929 			break;
930 		}
931 
932 		if (cmdstatp->have_sense) {
933 
934 			scode = cmdstatp->sense_hdr.sense_key;
935 
936 			if (scode == UNIT_ATTENTION) { /* New media? */
937 				new_session = 1;
938 				if (attentions < MAX_ATTENTIONS) {
939 					attentions++;
940 					continue;
941 				}
942 				else {
943 					retval = (-EIO);
944 					break;
945 				}
946 			}
947 
948 			if (scode == NOT_READY) {
949 				if (waits < max_wait) {
950 					if (msleep_interruptible(1000)) {
951 						retval = (-EINTR);
952 						break;
953 					}
954 					waits++;
955 					continue;
956 				}
957 				else {
958 					if ((STp->device)->scsi_level >= SCSI_2 &&
959 					    cmdstatp->sense_hdr.asc == 0x3a)	/* Check ASC */
960 						retval = CHKRES_NO_TAPE;
961 					else
962 						retval = CHKRES_NOT_READY;
963 					break;
964 				}
965 			}
966 		}
967 
968 		retval = (STp->buffer)->syscall_result;
969 		if (!retval)
970 			retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
971 		break;
972 	}
973 
974 	if (SRpnt != NULL)
975 		st_release_request(SRpnt);
976 	return retval;
977 }
978 
979 
980 /* See if the drive is ready and gather information about the tape. Return values:
981    < 0   negative error code from errno.h
982    0     drive ready
983    1     drive not ready (possibly no tape)
984 */
985 static int check_tape(struct scsi_tape *STp, struct file *filp)
986 {
987 	int i, retval, new_session = 0, do_wait;
988 	unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
989 	unsigned short st_flags = filp->f_flags;
990 	struct st_request *SRpnt = NULL;
991 	struct st_modedef *STm;
992 	struct st_partstat *STps;
993 	struct inode *inode = file_inode(filp);
994 	int mode = TAPE_MODE(inode);
995 
996 	STp->ready = ST_READY;
997 
998 	if (mode != STp->current_mode) {
999 		DEBC_printk(STp, "Mode change from %d to %d.\n",
1000 			    STp->current_mode, mode);
1001 		new_session = 1;
1002 		STp->current_mode = mode;
1003 	}
1004 	STm = &(STp->modes[STp->current_mode]);
1005 
1006 	saved_cleaning = STp->cleaning_req;
1007 	STp->cleaning_req = 0;
1008 
1009 	do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1010 	retval = test_ready(STp, do_wait);
1011 
1012 	if (retval < 0)
1013 	    goto err_out;
1014 
1015 	if (retval == CHKRES_NEW_SESSION) {
1016 		STp->pos_unknown = 0;
1017 		STp->partition = STp->new_partition = 0;
1018 		if (STp->can_partitions)
1019 			STp->nbr_partitions = 1; /* This guess will be updated later
1020                                                     if necessary */
1021 		for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1022 			STps = &(STp->ps[i]);
1023 			STps->rw = ST_IDLE;
1024 			STps->eof = ST_NOEOF;
1025 			STps->at_sm = 0;
1026 			STps->last_block_valid = 0;
1027 			STps->drv_block = 0;
1028 			STps->drv_file = 0;
1029 		}
1030 		new_session = 1;
1031 	}
1032 	else {
1033 		STp->cleaning_req |= saved_cleaning;
1034 
1035 		if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1036 			if (retval == CHKRES_NO_TAPE)
1037 				STp->ready = ST_NO_TAPE;
1038 			else
1039 				STp->ready = ST_NOT_READY;
1040 
1041 			STp->density = 0;	/* Clear the erroneous "residue" */
1042 			STp->write_prot = 0;
1043 			STp->block_size = 0;
1044 			STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1045 			STp->partition = STp->new_partition = 0;
1046 			STp->door_locked = ST_UNLOCKED;
1047 			return CHKRES_NOT_READY;
1048 		}
1049 	}
1050 
1051 	if (STp->omit_blklims)
1052 		STp->min_block = STp->max_block = (-1);
1053 	else {
1054 		memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1055 		cmd[0] = READ_BLOCK_LIMITS;
1056 
1057 		SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1058 				   STp->device->request_queue->rq_timeout,
1059 				   MAX_READY_RETRIES, 1);
1060 		if (!SRpnt) {
1061 			retval = (STp->buffer)->syscall_result;
1062 			goto err_out;
1063 		}
1064 
1065 		if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1066 			STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1067 			    ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1068 			STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1069 			    (STp->buffer)->b_data[5];
1070 			if ( DEB( debugging || ) !STp->inited)
1071 				st_printk(KERN_INFO, STp,
1072 					  "Block limits %d - %d bytes.\n",
1073 					  STp->min_block, STp->max_block);
1074 		} else {
1075 			STp->min_block = STp->max_block = (-1);
1076 			DEBC_printk(STp, "Can't read block limits.\n");
1077 		}
1078 	}
1079 
1080 	memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1081 	cmd[0] = MODE_SENSE;
1082 	cmd[4] = 12;
1083 
1084 	SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1085 			   STp->device->request_queue->rq_timeout,
1086 			   MAX_READY_RETRIES, 1);
1087 	if (!SRpnt) {
1088 		retval = (STp->buffer)->syscall_result;
1089 		goto err_out;
1090 	}
1091 
1092 	if ((STp->buffer)->syscall_result != 0) {
1093 		DEBC_printk(STp, "No Mode Sense.\n");
1094 		STp->block_size = ST_DEFAULT_BLOCK;	/* Educated guess (?) */
1095 		(STp->buffer)->syscall_result = 0;	/* Prevent error propagation */
1096 		STp->drv_write_prot = 0;
1097 	} else {
1098 		DEBC_printk(STp,"Mode sense. Length %d, "
1099 			    "medium %x, WBS %x, BLL %d\n",
1100 			    (STp->buffer)->b_data[0],
1101 			    (STp->buffer)->b_data[1],
1102 			    (STp->buffer)->b_data[2],
1103 			    (STp->buffer)->b_data[3]);
1104 
1105 		if ((STp->buffer)->b_data[3] >= 8) {
1106 			STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1107 			STp->density = (STp->buffer)->b_data[4];
1108 			STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1109 			    (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1110 			DEBC_printk(STp, "Density %x, tape length: %x, "
1111 				    "drv buffer: %d\n",
1112 				    STp->density,
1113 				    (STp->buffer)->b_data[5] * 65536 +
1114 				    (STp->buffer)->b_data[6] * 256 +
1115 				    (STp->buffer)->b_data[7],
1116 				    STp->drv_buffer);
1117 		}
1118 		STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1119 		if (!STp->drv_buffer && STp->immediate_filemark) {
1120 			st_printk(KERN_WARNING, STp,
1121 				  "non-buffered tape: disabling "
1122 				  "writing immediate filemarks\n");
1123 			STp->immediate_filemark = 0;
1124 		}
1125 	}
1126 	st_release_request(SRpnt);
1127 	SRpnt = NULL;
1128 	STp->inited = 1;
1129 
1130 	if (STp->block_size > 0)
1131 		(STp->buffer)->buffer_blocks =
1132 			(STp->buffer)->buffer_size / STp->block_size;
1133 	else
1134 		(STp->buffer)->buffer_blocks = 1;
1135 	(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1136 
1137 	DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1138 		    STp->block_size, (STp->buffer)->buffer_size,
1139 		    (STp->buffer)->buffer_blocks);
1140 
1141 	if (STp->drv_write_prot) {
1142 		STp->write_prot = 1;
1143 
1144 		DEBC_printk(STp, "Write protected\n");
1145 
1146 		if (do_wait &&
1147 		    ((st_flags & O_ACCMODE) == O_WRONLY ||
1148 		     (st_flags & O_ACCMODE) == O_RDWR)) {
1149 			retval = (-EROFS);
1150 			goto err_out;
1151 		}
1152 	}
1153 
1154 	if (STp->can_partitions && STp->nbr_partitions < 1) {
1155 		/* This code is reached when the device is opened for the first time
1156 		   after the driver has been initialized with tape in the drive and the
1157 		   partition support has been enabled. */
1158 		DEBC_printk(STp, "Updating partition number in status.\n");
1159 		if ((STp->partition = find_partition(STp)) < 0) {
1160 			retval = STp->partition;
1161 			goto err_out;
1162 		}
1163 		STp->new_partition = STp->partition;
1164 		STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1165 	}
1166 
1167 	if (new_session) {	/* Change the drive parameters for the new mode */
1168 		STp->density_changed = STp->blksize_changed = 0;
1169 		STp->compression_changed = 0;
1170 		if (!(STm->defaults_for_writes) &&
1171 		    (retval = set_mode_densblk(STp, STm)) < 0)
1172 		    goto err_out;
1173 
1174 		if (STp->default_drvbuffer != 0xff) {
1175 			if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1176 				st_printk(KERN_WARNING, STp,
1177 					  "Can't set default drive "
1178 					  "buffering to %d.\n",
1179 					  STp->default_drvbuffer);
1180 		}
1181 	}
1182 
1183 	return CHKRES_READY;
1184 
1185  err_out:
1186 	return retval;
1187 }
1188 
1189 
1190 /* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1191    module count. */
1192 static int st_open(struct inode *inode, struct file *filp)
1193 {
1194 	int i, retval = (-EIO);
1195 	int resumed = 0;
1196 	struct scsi_tape *STp;
1197 	struct st_partstat *STps;
1198 	int dev = TAPE_NR(inode);
1199 
1200 	/*
1201 	 * We really want to do nonseekable_open(inode, filp); here, but some
1202 	 * versions of tar incorrectly call lseek on tapes and bail out if that
1203 	 * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1204 	 */
1205 	filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1206 
1207 	if (!(STp = scsi_tape_get(dev))) {
1208 		return -ENXIO;
1209 	}
1210 
1211 	filp->private_data = STp;
1212 
1213 	spin_lock(&st_use_lock);
1214 	if (STp->in_use) {
1215 		spin_unlock(&st_use_lock);
1216 		scsi_tape_put(STp);
1217 		DEBC_printk(STp, "Device already in use.\n");
1218 		return (-EBUSY);
1219 	}
1220 
1221 	STp->in_use = 1;
1222 	spin_unlock(&st_use_lock);
1223 	STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1224 
1225 	if (scsi_autopm_get_device(STp->device) < 0) {
1226 		retval = -EIO;
1227 		goto err_out;
1228 	}
1229 	resumed = 1;
1230 	if (!scsi_block_when_processing_errors(STp->device)) {
1231 		retval = (-ENXIO);
1232 		goto err_out;
1233 	}
1234 
1235 	/* See that we have at least a one page buffer available */
1236 	if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1237 		st_printk(KERN_WARNING, STp,
1238 			  "Can't allocate one page tape buffer.\n");
1239 		retval = (-EOVERFLOW);
1240 		goto err_out;
1241 	}
1242 
1243 	(STp->buffer)->cleared = 0;
1244 	(STp->buffer)->writing = 0;
1245 	(STp->buffer)->syscall_result = 0;
1246 
1247 	STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1248 
1249 	STp->dirty = 0;
1250 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1251 		STps = &(STp->ps[i]);
1252 		STps->rw = ST_IDLE;
1253 	}
1254 	STp->try_dio_now = STp->try_dio;
1255 	STp->recover_count = 0;
1256 	DEB( STp->nbr_waits = STp->nbr_finished = 0;
1257 	     STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1258 
1259 	retval = check_tape(STp, filp);
1260 	if (retval < 0)
1261 		goto err_out;
1262 	if ((filp->f_flags & O_NONBLOCK) == 0 &&
1263 	    retval != CHKRES_READY) {
1264 		if (STp->ready == NO_TAPE)
1265 			retval = (-ENOMEDIUM);
1266 		else
1267 			retval = (-EIO);
1268 		goto err_out;
1269 	}
1270 	return 0;
1271 
1272  err_out:
1273 	normalize_buffer(STp->buffer);
1274 	spin_lock(&st_use_lock);
1275 	STp->in_use = 0;
1276 	spin_unlock(&st_use_lock);
1277 	scsi_tape_put(STp);
1278 	if (resumed)
1279 		scsi_autopm_put_device(STp->device);
1280 	return retval;
1281 
1282 }
1283 
1284 
1285 /* Flush the tape buffer before close */
1286 static int st_flush(struct file *filp, fl_owner_t id)
1287 {
1288 	int result = 0, result2;
1289 	unsigned char cmd[MAX_COMMAND_SIZE];
1290 	struct st_request *SRpnt;
1291 	struct scsi_tape *STp = filp->private_data;
1292 	struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1293 	struct st_partstat *STps = &(STp->ps[STp->partition]);
1294 
1295 	if (file_count(filp) > 1)
1296 		return 0;
1297 
1298 	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1299 		result = st_flush_write_buffer(STp);
1300 		if (result != 0 && result != (-ENOSPC))
1301 			goto out;
1302 	}
1303 
1304 	if (STp->can_partitions &&
1305 	    (result2 = switch_partition(STp)) < 0) {
1306 		DEBC_printk(STp, "switch_partition at close failed.\n");
1307 		if (result == 0)
1308 			result = result2;
1309 		goto out;
1310 	}
1311 
1312 	DEBC( if (STp->nbr_requests)
1313 		st_printk(KERN_DEBUG, STp,
1314 			  "Number of r/w requests %d, dio used in %d, "
1315 			  "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1316 			  STp->nbr_pages));
1317 
1318 	if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1319 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1320 
1321 #if DEBUG
1322 		DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1323 			    STp->nbr_waits, STp->nbr_finished);
1324 #endif
1325 		memset(cmd, 0, MAX_COMMAND_SIZE);
1326 		cmd[0] = WRITE_FILEMARKS;
1327 		if (STp->immediate_filemark)
1328 			cmd[1] = 1;
1329 		cmd[4] = 1 + STp->two_fm;
1330 
1331 		SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1332 				   STp->device->request_queue->rq_timeout,
1333 				   MAX_WRITE_RETRIES, 1);
1334 		if (!SRpnt) {
1335 			result = (STp->buffer)->syscall_result;
1336 			goto out;
1337 		}
1338 
1339 		if (STp->buffer->syscall_result == 0 ||
1340 		    (cmdstatp->have_sense && !cmdstatp->deferred &&
1341 		     (cmdstatp->flags & SENSE_EOM) &&
1342 		     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1343 		      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1344 		     (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1345 			/* Write successful at EOM */
1346 			st_release_request(SRpnt);
1347 			SRpnt = NULL;
1348 			if (STps->drv_file >= 0)
1349 				STps->drv_file++;
1350 			STps->drv_block = 0;
1351 			if (STp->two_fm)
1352 				cross_eof(STp, 0);
1353 			STps->eof = ST_FM;
1354 		}
1355 		else { /* Write error */
1356 			st_release_request(SRpnt);
1357 			SRpnt = NULL;
1358 			st_printk(KERN_ERR, STp,
1359 				  "Error on write filemark.\n");
1360 			if (result == 0)
1361 				result = (-EIO);
1362 		}
1363 
1364 		DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1365 	} else if (!STp->rew_at_close) {
1366 		STps = &(STp->ps[STp->partition]);
1367 		if (!STm->sysv || STps->rw != ST_READING) {
1368 			if (STp->can_bsr)
1369 				result = flush_buffer(STp, 0);
1370 			else if (STps->eof == ST_FM_HIT) {
1371 				result = cross_eof(STp, 0);
1372 				if (result) {
1373 					if (STps->drv_file >= 0)
1374 						STps->drv_file++;
1375 					STps->drv_block = 0;
1376 					STps->eof = ST_FM;
1377 				} else
1378 					STps->eof = ST_NOEOF;
1379 			}
1380 		} else if ((STps->eof == ST_NOEOF &&
1381 			    !(result = cross_eof(STp, 1))) ||
1382 			   STps->eof == ST_FM_HIT) {
1383 			if (STps->drv_file >= 0)
1384 				STps->drv_file++;
1385 			STps->drv_block = 0;
1386 			STps->eof = ST_FM;
1387 		}
1388 	}
1389 
1390       out:
1391 	if (STp->rew_at_close) {
1392 		result2 = st_int_ioctl(STp, MTREW, 1);
1393 		if (result == 0)
1394 			result = result2;
1395 	}
1396 	return result;
1397 }
1398 
1399 
1400 /* Close the device and release it. BKL is not needed: this is the only thread
1401    accessing this tape. */
1402 static int st_release(struct inode *inode, struct file *filp)
1403 {
1404 	int result = 0;
1405 	struct scsi_tape *STp = filp->private_data;
1406 
1407 	if (STp->door_locked == ST_LOCKED_AUTO)
1408 		do_door_lock(STp, 0);
1409 
1410 	normalize_buffer(STp->buffer);
1411 	spin_lock(&st_use_lock);
1412 	STp->in_use = 0;
1413 	spin_unlock(&st_use_lock);
1414 	scsi_autopm_put_device(STp->device);
1415 	scsi_tape_put(STp);
1416 
1417 	return result;
1418 }
1419 
1420 /* The checks common to both reading and writing */
1421 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1422 {
1423 	ssize_t retval = 0;
1424 
1425 	/*
1426 	 * If we are in the middle of error recovery, don't let anyone
1427 	 * else try and use this device.  Also, if error recovery fails, it
1428 	 * may try and take the device offline, in which case all further
1429 	 * access to the device is prohibited.
1430 	 */
1431 	if (!scsi_block_when_processing_errors(STp->device)) {
1432 		retval = (-ENXIO);
1433 		goto out;
1434 	}
1435 
1436 	if (STp->ready != ST_READY) {
1437 		if (STp->ready == ST_NO_TAPE)
1438 			retval = (-ENOMEDIUM);
1439 		else
1440 			retval = (-EIO);
1441 		goto out;
1442 	}
1443 
1444 	if (! STp->modes[STp->current_mode].defined) {
1445 		retval = (-ENXIO);
1446 		goto out;
1447 	}
1448 
1449 
1450 	/*
1451 	 * If there was a bus reset, block further access
1452 	 * to this device.
1453 	 */
1454 	if (STp->pos_unknown) {
1455 		retval = (-EIO);
1456 		goto out;
1457 	}
1458 
1459 	if (count == 0)
1460 		goto out;
1461 
1462 	DEB(
1463 	if (!STp->in_use) {
1464 		st_printk(ST_DEB_MSG, STp,
1465 			  "Incorrect device.\n");
1466 		retval = (-EIO);
1467 		goto out;
1468 	} ) /* end DEB */
1469 
1470 	if (STp->can_partitions &&
1471 	    (retval = switch_partition(STp)) < 0)
1472 		goto out;
1473 
1474 	if (STp->block_size == 0 && STp->max_block > 0 &&
1475 	    (count < STp->min_block || count > STp->max_block)) {
1476 		retval = (-EINVAL);
1477 		goto out;
1478 	}
1479 
1480 	if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1481 	    !do_door_lock(STp, 1))
1482 		STp->door_locked = ST_LOCKED_AUTO;
1483 
1484  out:
1485 	return retval;
1486 }
1487 
1488 
1489 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1490 			   size_t count, int is_read)
1491 {
1492 	int i, bufsize, retval = 0;
1493 	struct st_buffer *STbp = STp->buffer;
1494 
1495 	if (is_read)
1496 		i = STp->try_dio_now && try_rdio;
1497 	else
1498 		i = STp->try_dio_now && try_wdio;
1499 
1500 	if (i && ((unsigned long)buf & queue_dma_alignment(
1501 					STp->device->request_queue)) == 0) {
1502 		i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1503 				       count, (is_read ? READ : WRITE));
1504 		if (i > 0) {
1505 			STbp->do_dio = i;
1506 			STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1507 		}
1508 		else
1509 			STbp->do_dio = 0;  /* fall back to buffering with any error */
1510 		STbp->sg_segs = STbp->do_dio;
1511 		DEB(
1512 		     if (STbp->do_dio) {
1513 			STp->nbr_dio++;
1514 			STp->nbr_pages += STbp->do_dio;
1515 		     }
1516 		)
1517 	} else
1518 		STbp->do_dio = 0;
1519 	DEB( STp->nbr_requests++; )
1520 
1521 	if (!STbp->do_dio) {
1522 		if (STp->block_size)
1523 			bufsize = STp->block_size > st_fixed_buffer_size ?
1524 				STp->block_size : st_fixed_buffer_size;
1525 		else {
1526 			bufsize = count;
1527 			/* Make sure that data from previous user is not leaked even if
1528 			   HBA does not return correct residual */
1529 			if (is_read && STp->sili && !STbp->cleared)
1530 				clear_buffer(STbp);
1531 		}
1532 
1533 		if (bufsize > STbp->buffer_size &&
1534 		    !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1535 			st_printk(KERN_WARNING, STp,
1536 				  "Can't allocate %d byte tape buffer.\n",
1537 				  bufsize);
1538 			retval = (-EOVERFLOW);
1539 			goto out;
1540 		}
1541 		if (STp->block_size)
1542 			STbp->buffer_blocks = bufsize / STp->block_size;
1543 	}
1544 
1545  out:
1546 	return retval;
1547 }
1548 
1549 
1550 /* Can be called more than once after each setup_buffer() */
1551 static void release_buffering(struct scsi_tape *STp, int is_read)
1552 {
1553 	struct st_buffer *STbp;
1554 
1555 	STbp = STp->buffer;
1556 	if (STbp->do_dio) {
1557 		sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1558 		STbp->do_dio = 0;
1559 		STbp->sg_segs = 0;
1560 	}
1561 }
1562 
1563 
1564 /* Write command */
1565 static ssize_t
1566 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1567 {
1568 	ssize_t total;
1569 	ssize_t i, do_count, blks, transfer;
1570 	ssize_t retval;
1571 	int undone, retry_eot = 0, scode;
1572 	int async_write;
1573 	unsigned char cmd[MAX_COMMAND_SIZE];
1574 	const char __user *b_point;
1575 	struct st_request *SRpnt = NULL;
1576 	struct scsi_tape *STp = filp->private_data;
1577 	struct st_modedef *STm;
1578 	struct st_partstat *STps;
1579 	struct st_buffer *STbp;
1580 
1581 	if (mutex_lock_interruptible(&STp->lock))
1582 		return -ERESTARTSYS;
1583 
1584 	retval = rw_checks(STp, filp, count);
1585 	if (retval || count == 0)
1586 		goto out;
1587 
1588 	/* Write must be integral number of blocks */
1589 	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1590 		st_printk(KERN_WARNING, STp,
1591 			  "Write not multiple of tape block size.\n");
1592 		retval = (-EINVAL);
1593 		goto out;
1594 	}
1595 
1596 	STm = &(STp->modes[STp->current_mode]);
1597 	STps = &(STp->ps[STp->partition]);
1598 
1599 	if (STp->write_prot) {
1600 		retval = (-EACCES);
1601 		goto out;
1602 	}
1603 
1604 
1605 	if (STps->rw == ST_READING) {
1606 		retval = flush_buffer(STp, 0);
1607 		if (retval)
1608 			goto out;
1609 		STps->rw = ST_WRITING;
1610 	} else if (STps->rw != ST_WRITING &&
1611 		   STps->drv_file == 0 && STps->drv_block == 0) {
1612 		if ((retval = set_mode_densblk(STp, STm)) < 0)
1613 			goto out;
1614 		if (STm->default_compression != ST_DONT_TOUCH &&
1615 		    !(STp->compression_changed)) {
1616 			if (st_compression(STp, (STm->default_compression == ST_YES))) {
1617 				st_printk(KERN_WARNING, STp,
1618 					  "Can't set default compression.\n");
1619 				if (modes_defined) {
1620 					retval = (-EINVAL);
1621 					goto out;
1622 				}
1623 			}
1624 		}
1625 	}
1626 
1627 	STbp = STp->buffer;
1628 	i = write_behind_check(STp);
1629 	if (i) {
1630 		if (i == -ENOSPC)
1631 			STps->eof = ST_EOM_OK;
1632 		else
1633 			STps->eof = ST_EOM_ERROR;
1634 	}
1635 
1636 	if (STps->eof == ST_EOM_OK) {
1637 		STps->eof = ST_EOD_1;  /* allow next write */
1638 		retval = (-ENOSPC);
1639 		goto out;
1640 	}
1641 	else if (STps->eof == ST_EOM_ERROR) {
1642 		retval = (-EIO);
1643 		goto out;
1644 	}
1645 
1646 	/* Check the buffer readability in cases where copy_user might catch
1647 	   the problems after some tape movement. */
1648 	if (STp->block_size != 0 &&
1649 	    !STbp->do_dio &&
1650 	    (copy_from_user(&i, buf, 1) != 0 ||
1651 	     copy_from_user(&i, buf + count - 1, 1) != 0)) {
1652 		retval = (-EFAULT);
1653 		goto out;
1654 	}
1655 
1656 	retval = setup_buffering(STp, buf, count, 0);
1657 	if (retval)
1658 		goto out;
1659 
1660 	total = count;
1661 
1662 	memset(cmd, 0, MAX_COMMAND_SIZE);
1663 	cmd[0] = WRITE_6;
1664 	cmd[1] = (STp->block_size != 0);
1665 
1666 	STps->rw = ST_WRITING;
1667 
1668 	b_point = buf;
1669 	while (count > 0 && !retry_eot) {
1670 
1671 		if (STbp->do_dio) {
1672 			do_count = count;
1673 		}
1674 		else {
1675 			if (STp->block_size == 0)
1676 				do_count = count;
1677 			else {
1678 				do_count = STbp->buffer_blocks * STp->block_size -
1679 					STbp->buffer_bytes;
1680 				if (do_count > count)
1681 					do_count = count;
1682 			}
1683 
1684 			i = append_to_buffer(b_point, STbp, do_count);
1685 			if (i) {
1686 				retval = i;
1687 				goto out;
1688 			}
1689 		}
1690 		count -= do_count;
1691 		b_point += do_count;
1692 
1693 		async_write = STp->block_size == 0 && !STbp->do_dio &&
1694 			STm->do_async_writes && STps->eof < ST_EOM_OK;
1695 
1696 		if (STp->block_size != 0 && STm->do_buffer_writes &&
1697 		    !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1698 		    STbp->buffer_bytes < STbp->buffer_size) {
1699 			STp->dirty = 1;
1700 			/* Don't write a buffer that is not full enough. */
1701 			if (!async_write && count == 0)
1702 				break;
1703 		}
1704 
1705 	retry_write:
1706 		if (STp->block_size == 0)
1707 			blks = transfer = do_count;
1708 		else {
1709 			if (!STbp->do_dio)
1710 				blks = STbp->buffer_bytes;
1711 			else
1712 				blks = do_count;
1713 			blks /= STp->block_size;
1714 			transfer = blks * STp->block_size;
1715 		}
1716 		cmd[2] = blks >> 16;
1717 		cmd[3] = blks >> 8;
1718 		cmd[4] = blks;
1719 
1720 		SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1721 				   STp->device->request_queue->rq_timeout,
1722 				   MAX_WRITE_RETRIES, !async_write);
1723 		if (!SRpnt) {
1724 			retval = STbp->syscall_result;
1725 			goto out;
1726 		}
1727 		if (async_write && !STbp->syscall_result) {
1728 			STbp->writing = transfer;
1729 			STp->dirty = !(STbp->writing ==
1730 				       STbp->buffer_bytes);
1731 			SRpnt = NULL;  /* Prevent releasing this request! */
1732 			DEB( STp->write_pending = 1; )
1733 			break;
1734 		}
1735 
1736 		if (STbp->syscall_result != 0) {
1737 			struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1738 
1739 			DEBC_printk(STp, "Error on write:\n");
1740 			if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1741 				scode = cmdstatp->sense_hdr.sense_key;
1742 				if (cmdstatp->remainder_valid)
1743 					undone = (int)cmdstatp->uremainder64;
1744 				else if (STp->block_size == 0 &&
1745 					 scode == VOLUME_OVERFLOW)
1746 					undone = transfer;
1747 				else
1748 					undone = 0;
1749 				if (STp->block_size != 0)
1750 					undone *= STp->block_size;
1751 				if (undone <= do_count) {
1752 					/* Only data from this write is not written */
1753 					count += undone;
1754 					b_point -= undone;
1755 					do_count -= undone;
1756 					if (STp->block_size)
1757 						blks = (transfer - undone) / STp->block_size;
1758 					STps->eof = ST_EOM_OK;
1759 					/* Continue in fixed block mode if all written
1760 					   in this request but still something left to write
1761 					   (retval left to zero)
1762 					*/
1763 					if (STp->block_size == 0 ||
1764 					    undone > 0 || count == 0)
1765 						retval = (-ENOSPC); /* EOM within current request */
1766 					DEBC_printk(STp, "EOM with %d "
1767 						    "bytes unwritten.\n",
1768 						    (int)count);
1769 				} else {
1770 					/* EOT within data buffered earlier (possible only
1771 					   in fixed block mode without direct i/o) */
1772 					if (!retry_eot && !cmdstatp->deferred &&
1773 					    (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1774 						move_buffer_data(STp->buffer, transfer - undone);
1775 						retry_eot = 1;
1776 						if (STps->drv_block >= 0) {
1777 							STps->drv_block += (transfer - undone) /
1778 								STp->block_size;
1779 						}
1780 						STps->eof = ST_EOM_OK;
1781 						DEBC_printk(STp, "Retry "
1782 							    "write of %d "
1783 							    "bytes at EOM.\n",
1784 							    STp->buffer->buffer_bytes);
1785 						goto retry_write;
1786 					}
1787 					else {
1788 						/* Either error within data buffered by driver or
1789 						   failed retry */
1790 						count -= do_count;
1791 						blks = do_count = 0;
1792 						STps->eof = ST_EOM_ERROR;
1793 						STps->drv_block = (-1); /* Too cautious? */
1794 						retval = (-EIO);	/* EOM for old data */
1795 						DEBC_printk(STp, "EOM with "
1796 							    "lost data.\n");
1797 					}
1798 				}
1799 			} else {
1800 				count += do_count;
1801 				STps->drv_block = (-1);		/* Too cautious? */
1802 				retval = STbp->syscall_result;
1803 			}
1804 
1805 		}
1806 
1807 		if (STps->drv_block >= 0) {
1808 			if (STp->block_size == 0)
1809 				STps->drv_block += (do_count > 0);
1810 			else
1811 				STps->drv_block += blks;
1812 		}
1813 
1814 		STbp->buffer_bytes = 0;
1815 		STp->dirty = 0;
1816 
1817 		if (retval || retry_eot) {
1818 			if (count < total)
1819 				retval = total - count;
1820 			goto out;
1821 		}
1822 	}
1823 
1824 	if (STps->eof == ST_EOD_1)
1825 		STps->eof = ST_EOM_OK;
1826 	else if (STps->eof != ST_EOM_OK)
1827 		STps->eof = ST_NOEOF;
1828 	retval = total - count;
1829 
1830  out:
1831 	if (SRpnt != NULL)
1832 		st_release_request(SRpnt);
1833 	release_buffering(STp, 0);
1834 	mutex_unlock(&STp->lock);
1835 
1836 	return retval;
1837 }
1838 
1839 /* Read data from the tape. Returns zero in the normal case, one if the
1840    eof status has changed, and the negative error code in case of a
1841    fatal error. Otherwise updates the buffer and the eof state.
1842 
1843    Does release user buffer mapping if it is set.
1844 */
1845 static long read_tape(struct scsi_tape *STp, long count,
1846 		      struct st_request ** aSRpnt)
1847 {
1848 	int transfer, blks, bytes;
1849 	unsigned char cmd[MAX_COMMAND_SIZE];
1850 	struct st_request *SRpnt;
1851 	struct st_modedef *STm;
1852 	struct st_partstat *STps;
1853 	struct st_buffer *STbp;
1854 	int retval = 0;
1855 
1856 	if (count == 0)
1857 		return 0;
1858 
1859 	STm = &(STp->modes[STp->current_mode]);
1860 	STps = &(STp->ps[STp->partition]);
1861 	if (STps->eof == ST_FM_HIT)
1862 		return 1;
1863 	STbp = STp->buffer;
1864 
1865 	if (STp->block_size == 0)
1866 		blks = bytes = count;
1867 	else {
1868 		if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1869 			blks = (STp->buffer)->buffer_blocks;
1870 			bytes = blks * STp->block_size;
1871 		} else {
1872 			bytes = count;
1873 			if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1874 				bytes = (STp->buffer)->buffer_size;
1875 			blks = bytes / STp->block_size;
1876 			bytes = blks * STp->block_size;
1877 		}
1878 	}
1879 
1880 	memset(cmd, 0, MAX_COMMAND_SIZE);
1881 	cmd[0] = READ_6;
1882 	cmd[1] = (STp->block_size != 0);
1883 	if (!cmd[1] && STp->sili)
1884 		cmd[1] |= 2;
1885 	cmd[2] = blks >> 16;
1886 	cmd[3] = blks >> 8;
1887 	cmd[4] = blks;
1888 
1889 	SRpnt = *aSRpnt;
1890 	SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1891 			   STp->device->request_queue->rq_timeout,
1892 			   MAX_RETRIES, 1);
1893 	release_buffering(STp, 1);
1894 	*aSRpnt = SRpnt;
1895 	if (!SRpnt)
1896 		return STbp->syscall_result;
1897 
1898 	STbp->read_pointer = 0;
1899 	STps->at_sm = 0;
1900 
1901 	/* Something to check */
1902 	if (STbp->syscall_result) {
1903 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1904 
1905 		retval = 1;
1906 		DEBC_printk(STp,
1907 			    "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1908 			    SRpnt->sense[0], SRpnt->sense[1],
1909 			    SRpnt->sense[2], SRpnt->sense[3],
1910 			    SRpnt->sense[4], SRpnt->sense[5],
1911 			    SRpnt->sense[6], SRpnt->sense[7]);
1912 		if (cmdstatp->have_sense) {
1913 
1914 			if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1915 				cmdstatp->flags &= 0xcf;	/* No need for EOM in this case */
1916 
1917 			if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1918 				/* Compute the residual count */
1919 				if (cmdstatp->remainder_valid)
1920 					transfer = (int)cmdstatp->uremainder64;
1921 				else
1922 					transfer = 0;
1923 				if (STp->block_size == 0 &&
1924 				    cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR)
1925 					transfer = bytes;
1926 
1927 				if (cmdstatp->flags & SENSE_ILI) {	/* ILI */
1928 					if (STp->block_size == 0 &&
1929 					    transfer < 0) {
1930 						st_printk(KERN_NOTICE, STp,
1931 							  "Failed to read %d "
1932 							  "byte block with %d "
1933 							  "byte transfer.\n",
1934 							  bytes - transfer,
1935 							  bytes);
1936 						if (STps->drv_block >= 0)
1937 							STps->drv_block += 1;
1938 						STbp->buffer_bytes = 0;
1939 						return (-ENOMEM);
1940 					} else if (STp->block_size == 0) {
1941 						STbp->buffer_bytes = bytes - transfer;
1942 					} else {
1943 						st_release_request(SRpnt);
1944 						SRpnt = *aSRpnt = NULL;
1945 						if (transfer == blks) {	/* We did not get anything, error */
1946 							st_printk(KERN_NOTICE, STp,
1947 								  "Incorrect "
1948 								  "block size.\n");
1949 							if (STps->drv_block >= 0)
1950 								STps->drv_block += blks - transfer + 1;
1951 							st_int_ioctl(STp, MTBSR, 1);
1952 							return (-EIO);
1953 						}
1954 						/* We have some data, deliver it */
1955 						STbp->buffer_bytes = (blks - transfer) *
1956 						    STp->block_size;
1957 						DEBC_printk(STp, "ILI but "
1958 							    "enough data "
1959 							    "received %ld "
1960 							    "%d.\n", count,
1961 							    STbp->buffer_bytes);
1962 						if (STps->drv_block >= 0)
1963 							STps->drv_block += 1;
1964 						if (st_int_ioctl(STp, MTBSR, 1))
1965 							return (-EIO);
1966 					}
1967 				} else if (cmdstatp->flags & SENSE_FMK) {	/* FM overrides EOM */
1968 					if (STps->eof != ST_FM_HIT)
1969 						STps->eof = ST_FM_HIT;
1970 					else
1971 						STps->eof = ST_EOD_2;
1972 					if (STp->block_size == 0)
1973 						STbp->buffer_bytes = 0;
1974 					else
1975 						STbp->buffer_bytes =
1976 						    bytes - transfer * STp->block_size;
1977 					DEBC_printk(STp, "EOF detected (%d "
1978 						    "bytes read).\n",
1979 						    STbp->buffer_bytes);
1980 				} else if (cmdstatp->flags & SENSE_EOM) {
1981 					if (STps->eof == ST_FM)
1982 						STps->eof = ST_EOD_1;
1983 					else
1984 						STps->eof = ST_EOM_OK;
1985 					if (STp->block_size == 0)
1986 						STbp->buffer_bytes = bytes - transfer;
1987 					else
1988 						STbp->buffer_bytes =
1989 						    bytes - transfer * STp->block_size;
1990 
1991 					DEBC_printk(STp, "EOM detected (%d "
1992 						    "bytes read).\n",
1993 						    STbp->buffer_bytes);
1994 				}
1995 			}
1996 			/* end of EOF, EOM, ILI test */
1997 			else {	/* nonzero sense key */
1998 				DEBC_printk(STp, "Tape error while reading.\n");
1999 				STps->drv_block = (-1);
2000 				if (STps->eof == ST_FM &&
2001 				    cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2002 					DEBC_printk(STp, "Zero returned for "
2003 						    "first BLANK CHECK "
2004 						    "after EOF.\n");
2005 					STps->eof = ST_EOD_2;	/* First BLANK_CHECK after FM */
2006 				} else	/* Some other extended sense code */
2007 					retval = (-EIO);
2008 			}
2009 
2010 			if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2011 				STbp->buffer_bytes = 0;
2012 		}
2013 		/* End of extended sense test */
2014 		else {		/* Non-extended sense */
2015 			retval = STbp->syscall_result;
2016 		}
2017 
2018 	}
2019 	/* End of error handling */
2020 	else {			/* Read successful */
2021 		STbp->buffer_bytes = bytes;
2022 		if (STp->sili) /* In fixed block mode residual is always zero here */
2023 			STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2024 	}
2025 
2026 	if (STps->drv_block >= 0) {
2027 		if (STp->block_size == 0)
2028 			STps->drv_block++;
2029 		else
2030 			STps->drv_block += STbp->buffer_bytes / STp->block_size;
2031 	}
2032 	return retval;
2033 }
2034 
2035 
2036 /* Read command */
2037 static ssize_t
2038 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2039 {
2040 	ssize_t total;
2041 	ssize_t retval = 0;
2042 	ssize_t i, transfer;
2043 	int special, do_dio = 0;
2044 	struct st_request *SRpnt = NULL;
2045 	struct scsi_tape *STp = filp->private_data;
2046 	struct st_modedef *STm;
2047 	struct st_partstat *STps;
2048 	struct st_buffer *STbp = STp->buffer;
2049 
2050 	if (mutex_lock_interruptible(&STp->lock))
2051 		return -ERESTARTSYS;
2052 
2053 	retval = rw_checks(STp, filp, count);
2054 	if (retval || count == 0)
2055 		goto out;
2056 
2057 	STm = &(STp->modes[STp->current_mode]);
2058 	if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2059 		if (!STm->do_read_ahead) {
2060 			retval = (-EINVAL);	/* Read must be integral number of blocks */
2061 			goto out;
2062 		}
2063 		STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2064 	}
2065 
2066 	STps = &(STp->ps[STp->partition]);
2067 	if (STps->rw == ST_WRITING) {
2068 		retval = flush_buffer(STp, 0);
2069 		if (retval)
2070 			goto out;
2071 		STps->rw = ST_READING;
2072 	}
2073 	DEB(
2074 	if (debugging && STps->eof != ST_NOEOF)
2075 		st_printk(ST_DEB_MSG, STp,
2076 			  "EOF/EOM flag up (%d). Bytes %d\n",
2077 			  STps->eof, STbp->buffer_bytes);
2078 	) /* end DEB */
2079 
2080 	retval = setup_buffering(STp, buf, count, 1);
2081 	if (retval)
2082 		goto out;
2083 	do_dio = STbp->do_dio;
2084 
2085 	if (STbp->buffer_bytes == 0 &&
2086 	    STps->eof >= ST_EOD_1) {
2087 		if (STps->eof < ST_EOD) {
2088 			STps->eof += 1;
2089 			retval = 0;
2090 			goto out;
2091 		}
2092 		retval = (-EIO);	/* EOM or Blank Check */
2093 		goto out;
2094 	}
2095 
2096 	if (do_dio) {
2097 		/* Check the buffer writability before any tape movement. Don't alter
2098 		   buffer data. */
2099 		if (copy_from_user(&i, buf, 1) != 0 ||
2100 		    copy_to_user(buf, &i, 1) != 0 ||
2101 		    copy_from_user(&i, buf + count - 1, 1) != 0 ||
2102 		    copy_to_user(buf + count - 1, &i, 1) != 0) {
2103 			retval = (-EFAULT);
2104 			goto out;
2105 		}
2106 	}
2107 
2108 	STps->rw = ST_READING;
2109 
2110 
2111 	/* Loop until enough data in buffer or a special condition found */
2112 	for (total = 0, special = 0; total < count && !special;) {
2113 
2114 		/* Get new data if the buffer is empty */
2115 		if (STbp->buffer_bytes == 0) {
2116 			special = read_tape(STp, count - total, &SRpnt);
2117 			if (special < 0) {	/* No need to continue read */
2118 				retval = special;
2119 				goto out;
2120 			}
2121 		}
2122 
2123 		/* Move the data from driver buffer to user buffer */
2124 		if (STbp->buffer_bytes > 0) {
2125 			DEB(
2126 			if (debugging && STps->eof != ST_NOEOF)
2127 				st_printk(ST_DEB_MSG, STp,
2128 					  "EOF up (%d). Left %d, needed %d.\n",
2129 					  STps->eof, STbp->buffer_bytes,
2130 					  (int)(count - total));
2131 			) /* end DEB */
2132 			transfer = STbp->buffer_bytes < count - total ?
2133 			    STbp->buffer_bytes : count - total;
2134 			if (!do_dio) {
2135 				i = from_buffer(STbp, buf, transfer);
2136 				if (i) {
2137 					retval = i;
2138 					goto out;
2139 				}
2140 			}
2141 			buf += transfer;
2142 			total += transfer;
2143 		}
2144 
2145 		if (STp->block_size == 0)
2146 			break;	/* Read only one variable length block */
2147 
2148 	}			/* for (total = 0, special = 0;
2149                                    total < count && !special; ) */
2150 
2151 	/* Change the eof state if no data from tape or buffer */
2152 	if (total == 0) {
2153 		if (STps->eof == ST_FM_HIT) {
2154 			STps->eof = ST_FM;
2155 			STps->drv_block = 0;
2156 			if (STps->drv_file >= 0)
2157 				STps->drv_file++;
2158 		} else if (STps->eof == ST_EOD_1) {
2159 			STps->eof = ST_EOD_2;
2160 			STps->drv_block = 0;
2161 			if (STps->drv_file >= 0)
2162 				STps->drv_file++;
2163 		} else if (STps->eof == ST_EOD_2)
2164 			STps->eof = ST_EOD;
2165 	} else if (STps->eof == ST_FM)
2166 		STps->eof = ST_NOEOF;
2167 	retval = total;
2168 
2169  out:
2170 	if (SRpnt != NULL) {
2171 		st_release_request(SRpnt);
2172 		SRpnt = NULL;
2173 	}
2174 	if (do_dio) {
2175 		release_buffering(STp, 1);
2176 		STbp->buffer_bytes = 0;
2177 	}
2178 	mutex_unlock(&STp->lock);
2179 
2180 	return retval;
2181 }
2182 
2183 
2184 
2185 DEB(
2186 /* Set the driver options */
2187 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2188 {
2189 	if (debugging) {
2190 		st_printk(KERN_INFO, STp,
2191 			  "Mode %d options: buffer writes: %d, "
2192 			  "async writes: %d, read ahead: %d\n",
2193 			  STp->current_mode, STm->do_buffer_writes,
2194 			  STm->do_async_writes, STm->do_read_ahead);
2195 		st_printk(KERN_INFO, STp,
2196 			  "    can bsr: %d, two FMs: %d, "
2197 			  "fast mteom: %d, auto lock: %d,\n",
2198 			  STp->can_bsr, STp->two_fm, STp->fast_mteom,
2199 			  STp->do_auto_lock);
2200 		st_printk(KERN_INFO, STp,
2201 			  "    defs for wr: %d, no block limits: %d, "
2202 			  "partitions: %d, s2 log: %d\n",
2203 			  STm->defaults_for_writes, STp->omit_blklims,
2204 			  STp->can_partitions, STp->scsi2_logical);
2205 		st_printk(KERN_INFO, STp,
2206 			  "    sysv: %d nowait: %d sili: %d "
2207 			  "nowait_filemark: %d\n",
2208 			  STm->sysv, STp->immediate, STp->sili,
2209 			  STp->immediate_filemark);
2210 		st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2211 	}
2212 }
2213 	)
2214 
2215 
2216 static int st_set_options(struct scsi_tape *STp, long options)
2217 {
2218 	int value;
2219 	long code;
2220 	struct st_modedef *STm;
2221 	struct cdev *cd0, *cd1;
2222 	struct device *d0, *d1;
2223 
2224 	STm = &(STp->modes[STp->current_mode]);
2225 	if (!STm->defined) {
2226 		cd0 = STm->cdevs[0];
2227 		cd1 = STm->cdevs[1];
2228 		d0  = STm->devs[0];
2229 		d1  = STm->devs[1];
2230 		memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2231 		STm->cdevs[0] = cd0;
2232 		STm->cdevs[1] = cd1;
2233 		STm->devs[0]  = d0;
2234 		STm->devs[1]  = d1;
2235 		modes_defined = 1;
2236 		DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2237 			    STp->current_mode);
2238 	}
2239 
2240 	code = options & MT_ST_OPTIONS;
2241 	if (code == MT_ST_BOOLEANS) {
2242 		STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2243 		STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2244 		STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2245 		STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2246 		STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2247 		STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2248 		STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2249 		STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2250 		STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2251 		if ((STp->device)->scsi_level >= SCSI_2)
2252 			STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2253 		STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2254 		STp->immediate = (options & MT_ST_NOWAIT) != 0;
2255 		STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2256 		STm->sysv = (options & MT_ST_SYSV) != 0;
2257 		STp->sili = (options & MT_ST_SILI) != 0;
2258 		DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2259 		     st_log_options(STp, STm); )
2260 	} else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2261 		value = (code == MT_ST_SETBOOLEANS);
2262 		if ((options & MT_ST_BUFFER_WRITES) != 0)
2263 			STm->do_buffer_writes = value;
2264 		if ((options & MT_ST_ASYNC_WRITES) != 0)
2265 			STm->do_async_writes = value;
2266 		if ((options & MT_ST_DEF_WRITES) != 0)
2267 			STm->defaults_for_writes = value;
2268 		if ((options & MT_ST_READ_AHEAD) != 0)
2269 			STm->do_read_ahead = value;
2270 		if ((options & MT_ST_TWO_FM) != 0)
2271 			STp->two_fm = value;
2272 		if ((options & MT_ST_FAST_MTEOM) != 0)
2273 			STp->fast_mteom = value;
2274 		if ((options & MT_ST_AUTO_LOCK) != 0)
2275 			STp->do_auto_lock = value;
2276 		if ((options & MT_ST_CAN_BSR) != 0)
2277 			STp->can_bsr = value;
2278 		if ((options & MT_ST_NO_BLKLIMS) != 0)
2279 			STp->omit_blklims = value;
2280 		if ((STp->device)->scsi_level >= SCSI_2 &&
2281 		    (options & MT_ST_CAN_PARTITIONS) != 0)
2282 			STp->can_partitions = value;
2283 		if ((options & MT_ST_SCSI2LOGICAL) != 0)
2284 			STp->scsi2_logical = value;
2285 		if ((options & MT_ST_NOWAIT) != 0)
2286 			STp->immediate = value;
2287 		if ((options & MT_ST_NOWAIT_EOF) != 0)
2288 			STp->immediate_filemark = value;
2289 		if ((options & MT_ST_SYSV) != 0)
2290 			STm->sysv = value;
2291 		if ((options & MT_ST_SILI) != 0)
2292 			STp->sili = value;
2293 		DEB(
2294 		if ((options & MT_ST_DEBUGGING) != 0)
2295 			debugging = value;
2296 			st_log_options(STp, STm); )
2297 	} else if (code == MT_ST_WRITE_THRESHOLD) {
2298 		/* Retained for compatibility */
2299 	} else if (code == MT_ST_DEF_BLKSIZE) {
2300 		value = (options & ~MT_ST_OPTIONS);
2301 		if (value == ~MT_ST_OPTIONS) {
2302 			STm->default_blksize = (-1);
2303 			DEBC_printk(STp, "Default block size disabled.\n");
2304 		} else {
2305 			STm->default_blksize = value;
2306 			DEBC_printk(STp,"Default block size set to "
2307 				    "%d bytes.\n", STm->default_blksize);
2308 			if (STp->ready == ST_READY) {
2309 				STp->blksize_changed = 0;
2310 				set_mode_densblk(STp, STm);
2311 			}
2312 		}
2313 	} else if (code == MT_ST_TIMEOUTS) {
2314 		value = (options & ~MT_ST_OPTIONS);
2315 		if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2316 			STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2317 			DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2318 				    (value & ~MT_ST_SET_LONG_TIMEOUT));
2319 		} else {
2320 			blk_queue_rq_timeout(STp->device->request_queue,
2321 					     value * HZ);
2322 			DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2323 				    value);
2324 		}
2325 	} else if (code == MT_ST_SET_CLN) {
2326 		value = (options & ~MT_ST_OPTIONS) & 0xff;
2327 		if (value != 0 &&
2328 			(value < EXTENDED_SENSE_START ||
2329 				value >= SCSI_SENSE_BUFFERSIZE))
2330 			return (-EINVAL);
2331 		STp->cln_mode = value;
2332 		STp->cln_sense_mask = (options >> 8) & 0xff;
2333 		STp->cln_sense_value = (options >> 16) & 0xff;
2334 		st_printk(KERN_INFO, STp,
2335 			  "Cleaning request mode %d, mask %02x, value %02x\n",
2336 			  value, STp->cln_sense_mask, STp->cln_sense_value);
2337 	} else if (code == MT_ST_DEF_OPTIONS) {
2338 		code = (options & ~MT_ST_CLEAR_DEFAULT);
2339 		value = (options & MT_ST_CLEAR_DEFAULT);
2340 		if (code == MT_ST_DEF_DENSITY) {
2341 			if (value == MT_ST_CLEAR_DEFAULT) {
2342 				STm->default_density = (-1);
2343 				DEBC_printk(STp,
2344 					    "Density default disabled.\n");
2345 			} else {
2346 				STm->default_density = value & 0xff;
2347 				DEBC_printk(STp, "Density default set to %x\n",
2348 					    STm->default_density);
2349 				if (STp->ready == ST_READY) {
2350 					STp->density_changed = 0;
2351 					set_mode_densblk(STp, STm);
2352 				}
2353 			}
2354 		} else if (code == MT_ST_DEF_DRVBUFFER) {
2355 			if (value == MT_ST_CLEAR_DEFAULT) {
2356 				STp->default_drvbuffer = 0xff;
2357 				DEBC_printk(STp,
2358 					    "Drive buffer default disabled.\n");
2359 			} else {
2360 				STp->default_drvbuffer = value & 7;
2361 				DEBC_printk(STp,
2362 					    "Drive buffer default set to %x\n",
2363 					    STp->default_drvbuffer);
2364 				if (STp->ready == ST_READY)
2365 					st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2366 			}
2367 		} else if (code == MT_ST_DEF_COMPRESSION) {
2368 			if (value == MT_ST_CLEAR_DEFAULT) {
2369 				STm->default_compression = ST_DONT_TOUCH;
2370 				DEBC_printk(STp,
2371 					    "Compression default disabled.\n");
2372 			} else {
2373 				if ((value & 0xff00) != 0) {
2374 					STp->c_algo = (value & 0xff00) >> 8;
2375 					DEBC_printk(STp, "Compression "
2376 						    "algorithm set to 0x%x.\n",
2377 						    STp->c_algo);
2378 				}
2379 				if ((value & 0xff) != 0xff) {
2380 					STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2381 					DEBC_printk(STp, "Compression default "
2382 						    "set to %x\n",
2383 						    (value & 1));
2384 					if (STp->ready == ST_READY) {
2385 						STp->compression_changed = 0;
2386 						st_compression(STp, (STm->default_compression == ST_YES));
2387 					}
2388 				}
2389 			}
2390 		}
2391 	} else
2392 		return (-EIO);
2393 
2394 	return 0;
2395 }
2396 
2397 #define MODE_HEADER_LENGTH  4
2398 
2399 /* Mode header and page byte offsets */
2400 #define MH_OFF_DATA_LENGTH     0
2401 #define MH_OFF_MEDIUM_TYPE     1
2402 #define MH_OFF_DEV_SPECIFIC    2
2403 #define MH_OFF_BDESCS_LENGTH   3
2404 #define MP_OFF_PAGE_NBR        0
2405 #define MP_OFF_PAGE_LENGTH     1
2406 
2407 /* Mode header and page bit masks */
2408 #define MH_BIT_WP              0x80
2409 #define MP_MSK_PAGE_NBR        0x3f
2410 
2411 /* Don't return block descriptors */
2412 #define MODE_SENSE_OMIT_BDESCS 0x08
2413 
2414 #define MODE_SELECT_PAGE_FORMAT 0x10
2415 
2416 /* Read a mode page into the tape buffer. The block descriptors are included
2417    if incl_block_descs is true. The page control is ored to the page number
2418    parameter, if necessary. */
2419 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2420 {
2421 	unsigned char cmd[MAX_COMMAND_SIZE];
2422 	struct st_request *SRpnt;
2423 
2424 	memset(cmd, 0, MAX_COMMAND_SIZE);
2425 	cmd[0] = MODE_SENSE;
2426 	if (omit_block_descs)
2427 		cmd[1] = MODE_SENSE_OMIT_BDESCS;
2428 	cmd[2] = page;
2429 	cmd[4] = 255;
2430 
2431 	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2432 			   STp->device->request_queue->rq_timeout, 0, 1);
2433 	if (SRpnt == NULL)
2434 		return (STp->buffer)->syscall_result;
2435 
2436 	st_release_request(SRpnt);
2437 
2438 	return STp->buffer->syscall_result;
2439 }
2440 
2441 
2442 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2443    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2444 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2445 {
2446 	int pgo;
2447 	unsigned char cmd[MAX_COMMAND_SIZE];
2448 	struct st_request *SRpnt;
2449 	int timeout;
2450 
2451 	memset(cmd, 0, MAX_COMMAND_SIZE);
2452 	cmd[0] = MODE_SELECT;
2453 	cmd[1] = MODE_SELECT_PAGE_FORMAT;
2454 	pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2455 	cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2456 
2457 	/* Clear reserved fields */
2458 	(STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2459 	(STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2460 	(STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2461 	(STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2462 
2463 	timeout = slow ?
2464 		STp->long_timeout : STp->device->request_queue->rq_timeout;
2465 	SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2466 			   timeout, 0, 1);
2467 	if (SRpnt == NULL)
2468 		return (STp->buffer)->syscall_result;
2469 
2470 	st_release_request(SRpnt);
2471 
2472 	return STp->buffer->syscall_result;
2473 }
2474 
2475 
2476 #define COMPRESSION_PAGE        0x0f
2477 #define COMPRESSION_PAGE_LENGTH 16
2478 
2479 #define CP_OFF_DCE_DCC          2
2480 #define CP_OFF_C_ALGO           7
2481 
2482 #define DCE_MASK  0x80
2483 #define DCC_MASK  0x40
2484 #define RED_MASK  0x60
2485 
2486 
2487 /* Control the compression with mode page 15. Algorithm not changed if zero.
2488 
2489    The block descriptors are read and written because Sony SDT-7000 does not
2490    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2491    Including block descriptors should not cause any harm to other drives. */
2492 
2493 static int st_compression(struct scsi_tape * STp, int state)
2494 {
2495 	int retval;
2496 	int mpoffs;  /* Offset to mode page start */
2497 	unsigned char *b_data = (STp->buffer)->b_data;
2498 
2499 	if (STp->ready != ST_READY)
2500 		return (-EIO);
2501 
2502 	/* Read the current page contents */
2503 	retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2504 	if (retval) {
2505 		DEBC_printk(STp, "Compression mode page not supported.\n");
2506 		return (-EIO);
2507 	}
2508 
2509 	mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2510 	DEBC_printk(STp, "Compression state is %d.\n",
2511 		    (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2512 
2513 	/* Check if compression can be changed */
2514 	if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2515 		DEBC_printk(STp, "Compression not supported.\n");
2516 		return (-EIO);
2517 	}
2518 
2519 	/* Do the change */
2520 	if (state) {
2521 		b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2522 		if (STp->c_algo != 0)
2523 			b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2524 	}
2525 	else {
2526 		b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2527 		if (STp->c_algo != 0)
2528 			b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2529 	}
2530 
2531 	retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2532 	if (retval) {
2533 		DEBC_printk(STp, "Compression change failed.\n");
2534 		return (-EIO);
2535 	}
2536 	DEBC_printk(STp, "Compression state changed to %d.\n", state);
2537 
2538 	STp->compression_changed = 1;
2539 	return 0;
2540 }
2541 
2542 
2543 /* Process the load and unload commands (does unload if the load code is zero) */
2544 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2545 {
2546 	int retval = (-EIO), timeout;
2547 	unsigned char cmd[MAX_COMMAND_SIZE];
2548 	struct st_partstat *STps;
2549 	struct st_request *SRpnt;
2550 
2551 	if (STp->ready != ST_READY && !load_code) {
2552 		if (STp->ready == ST_NO_TAPE)
2553 			return (-ENOMEDIUM);
2554 		else
2555 			return (-EIO);
2556 	}
2557 
2558 	memset(cmd, 0, MAX_COMMAND_SIZE);
2559 	cmd[0] = START_STOP;
2560 	if (load_code)
2561 		cmd[4] |= 1;
2562 	/*
2563 	 * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2564 	 */
2565 	if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2566 	    && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2567 		DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2568 			    (cmd[4]) ? "" : "un",
2569 			    load_code - MT_ST_HPLOADER_OFFSET);
2570 		cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2571 	}
2572 	if (STp->immediate) {
2573 		cmd[1] = 1;	/* Don't wait for completion */
2574 		timeout = STp->device->request_queue->rq_timeout;
2575 	}
2576 	else
2577 		timeout = STp->long_timeout;
2578 
2579 	DEBC(
2580 		if (!load_code)
2581 			st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2582 		else
2583 			st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2584 		);
2585 
2586 	SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2587 			   timeout, MAX_RETRIES, 1);
2588 	if (!SRpnt)
2589 		return (STp->buffer)->syscall_result;
2590 
2591 	retval = (STp->buffer)->syscall_result;
2592 	st_release_request(SRpnt);
2593 
2594 	if (!retval) {	/* SCSI command successful */
2595 
2596 		if (!load_code) {
2597 			STp->rew_at_close = 0;
2598 			STp->ready = ST_NO_TAPE;
2599 		}
2600 		else {
2601 			STp->rew_at_close = STp->autorew_dev;
2602 			retval = check_tape(STp, filp);
2603 			if (retval > 0)
2604 				retval = 0;
2605 		}
2606 	}
2607 	else {
2608 		STps = &(STp->ps[STp->partition]);
2609 		STps->drv_file = STps->drv_block = (-1);
2610 	}
2611 
2612 	return retval;
2613 }
2614 
2615 #if DEBUG
2616 #define ST_DEB_FORWARD  0
2617 #define ST_DEB_BACKWARD 1
2618 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2619 {
2620 	s32 sc;
2621 
2622 	if (!debugging)
2623 		return;
2624 
2625 	sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2626 	sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2627 	if (direction)
2628 		sc = -sc;
2629 	st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2630 		  direction ? "backward" : "forward", sc, units);
2631 }
2632 #else
2633 #define ST_DEB_FORWARD  0
2634 #define ST_DEB_BACKWARD 1
2635 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2636 #endif
2637 
2638 
2639 /* Internal ioctl function */
2640 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2641 {
2642 	int timeout;
2643 	long ltmp;
2644 	int ioctl_result;
2645 	int chg_eof = 1;
2646 	unsigned char cmd[MAX_COMMAND_SIZE];
2647 	struct st_request *SRpnt;
2648 	struct st_partstat *STps;
2649 	int fileno, blkno, at_sm, undone;
2650 	int datalen = 0, direction = DMA_NONE;
2651 
2652 	WARN_ON(STp->buffer->do_dio != 0);
2653 	if (STp->ready != ST_READY) {
2654 		if (STp->ready == ST_NO_TAPE)
2655 			return (-ENOMEDIUM);
2656 		else
2657 			return (-EIO);
2658 	}
2659 	timeout = STp->long_timeout;
2660 	STps = &(STp->ps[STp->partition]);
2661 	fileno = STps->drv_file;
2662 	blkno = STps->drv_block;
2663 	at_sm = STps->at_sm;
2664 
2665 	memset(cmd, 0, MAX_COMMAND_SIZE);
2666 	switch (cmd_in) {
2667 	case MTFSFM:
2668 		chg_eof = 0;	/* Changed from the FSF after this */
2669 	case MTFSF:
2670 		cmd[0] = SPACE;
2671 		cmd[1] = 0x01;	/* Space FileMarks */
2672 		cmd[2] = (arg >> 16);
2673 		cmd[3] = (arg >> 8);
2674 		cmd[4] = arg;
2675 		deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2676 		if (fileno >= 0)
2677 			fileno += arg;
2678 		blkno = 0;
2679 		at_sm &= (arg == 0);
2680 		break;
2681 	case MTBSFM:
2682 		chg_eof = 0;	/* Changed from the FSF after this */
2683 	case MTBSF:
2684 		cmd[0] = SPACE;
2685 		cmd[1] = 0x01;	/* Space FileMarks */
2686 		ltmp = (-arg);
2687 		cmd[2] = (ltmp >> 16);
2688 		cmd[3] = (ltmp >> 8);
2689 		cmd[4] = ltmp;
2690 		deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2691 		if (fileno >= 0)
2692 			fileno -= arg;
2693 		blkno = (-1);	/* We can't know the block number */
2694 		at_sm &= (arg == 0);
2695 		break;
2696 	case MTFSR:
2697 		cmd[0] = SPACE;
2698 		cmd[1] = 0x00;	/* Space Blocks */
2699 		cmd[2] = (arg >> 16);
2700 		cmd[3] = (arg >> 8);
2701 		cmd[4] = arg;
2702 		deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2703 		if (blkno >= 0)
2704 			blkno += arg;
2705 		at_sm &= (arg == 0);
2706 		break;
2707 	case MTBSR:
2708 		cmd[0] = SPACE;
2709 		cmd[1] = 0x00;	/* Space Blocks */
2710 		ltmp = (-arg);
2711 		cmd[2] = (ltmp >> 16);
2712 		cmd[3] = (ltmp >> 8);
2713 		cmd[4] = ltmp;
2714 		deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2715 		if (blkno >= 0)
2716 			blkno -= arg;
2717 		at_sm &= (arg == 0);
2718 		break;
2719 	case MTFSS:
2720 		cmd[0] = SPACE;
2721 		cmd[1] = 0x04;	/* Space Setmarks */
2722 		cmd[2] = (arg >> 16);
2723 		cmd[3] = (arg >> 8);
2724 		cmd[4] = arg;
2725 		deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2726 		if (arg != 0) {
2727 			blkno = fileno = (-1);
2728 			at_sm = 1;
2729 		}
2730 		break;
2731 	case MTBSS:
2732 		cmd[0] = SPACE;
2733 		cmd[1] = 0x04;	/* Space Setmarks */
2734 		ltmp = (-arg);
2735 		cmd[2] = (ltmp >> 16);
2736 		cmd[3] = (ltmp >> 8);
2737 		cmd[4] = ltmp;
2738 		deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2739 		if (arg != 0) {
2740 			blkno = fileno = (-1);
2741 			at_sm = 1;
2742 		}
2743 		break;
2744 	case MTWEOF:
2745 	case MTWEOFI:
2746 	case MTWSM:
2747 		if (STp->write_prot)
2748 			return (-EACCES);
2749 		cmd[0] = WRITE_FILEMARKS;
2750 		if (cmd_in == MTWSM)
2751 			cmd[1] = 2;
2752 		if (cmd_in == MTWEOFI ||
2753 		    (cmd_in == MTWEOF && STp->immediate_filemark))
2754 			cmd[1] |= 1;
2755 		cmd[2] = (arg >> 16);
2756 		cmd[3] = (arg >> 8);
2757 		cmd[4] = arg;
2758 		timeout = STp->device->request_queue->rq_timeout;
2759 		DEBC(
2760 			if (cmd_in != MTWSM)
2761 				st_printk(ST_DEB_MSG, STp,
2762 					  "Writing %d filemarks.\n",
2763 					  cmd[2] * 65536 +
2764 					  cmd[3] * 256 +
2765 					  cmd[4]);
2766 			else
2767 				st_printk(ST_DEB_MSG, STp,
2768 					  "Writing %d setmarks.\n",
2769 					  cmd[2] * 65536 +
2770 					  cmd[3] * 256 +
2771 					  cmd[4]);
2772 		)
2773 		if (fileno >= 0)
2774 			fileno += arg;
2775 		blkno = 0;
2776 		at_sm = (cmd_in == MTWSM);
2777 		break;
2778 	case MTREW:
2779 		cmd[0] = REZERO_UNIT;
2780 		if (STp->immediate) {
2781 			cmd[1] = 1;	/* Don't wait for completion */
2782 			timeout = STp->device->request_queue->rq_timeout;
2783 		}
2784 		DEBC_printk(STp, "Rewinding tape.\n");
2785 		fileno = blkno = at_sm = 0;
2786 		break;
2787 	case MTNOP:
2788 		DEBC_printk(STp, "No op on tape.\n");
2789 		return 0;	/* Should do something ? */
2790 		break;
2791 	case MTRETEN:
2792 		cmd[0] = START_STOP;
2793 		if (STp->immediate) {
2794 			cmd[1] = 1;	/* Don't wait for completion */
2795 			timeout = STp->device->request_queue->rq_timeout;
2796 		}
2797 		cmd[4] = 3;
2798 		DEBC_printk(STp, "Retensioning tape.\n");
2799 		fileno = blkno = at_sm = 0;
2800 		break;
2801 	case MTEOM:
2802 		if (!STp->fast_mteom) {
2803 			/* space to the end of tape */
2804 			ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2805 			fileno = STps->drv_file;
2806 			if (STps->eof >= ST_EOD_1)
2807 				return 0;
2808 			/* The next lines would hide the number of spaced FileMarks
2809 			   That's why I inserted the previous lines. I had no luck
2810 			   with detecting EOM with FSF, so we go now to EOM.
2811 			   Joerg Weule */
2812 		} else
2813 			fileno = (-1);
2814 		cmd[0] = SPACE;
2815 		cmd[1] = 3;
2816 		DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2817 		blkno = -1;
2818 		at_sm = 0;
2819 		break;
2820 	case MTERASE:
2821 		if (STp->write_prot)
2822 			return (-EACCES);
2823 		cmd[0] = ERASE;
2824 		cmd[1] = (arg ? 1 : 0);	/* Long erase with non-zero argument */
2825 		if (STp->immediate) {
2826 			cmd[1] |= 2;	/* Don't wait for completion */
2827 			timeout = STp->device->request_queue->rq_timeout;
2828 		}
2829 		else
2830 			timeout = STp->long_timeout * 8;
2831 
2832 		DEBC_printk(STp, "Erasing tape.\n");
2833 		fileno = blkno = at_sm = 0;
2834 		break;
2835 	case MTSETBLK:		/* Set block length */
2836 	case MTSETDENSITY:	/* Set tape density */
2837 	case MTSETDRVBUFFER:	/* Set drive buffering */
2838 	case SET_DENS_AND_BLK:	/* Set density and block size */
2839 		chg_eof = 0;
2840 		if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2841 			return (-EIO);	/* Not allowed if data in buffer */
2842 		if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2843 		    (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2844 		    STp->max_block > 0 &&
2845 		    ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2846 		     (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2847 			st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2848 			return (-EINVAL);
2849 		}
2850 		cmd[0] = MODE_SELECT;
2851 		if ((STp->use_pf & USE_PF))
2852 			cmd[1] = MODE_SELECT_PAGE_FORMAT;
2853 		cmd[4] = datalen = 12;
2854 		direction = DMA_TO_DEVICE;
2855 
2856 		memset((STp->buffer)->b_data, 0, 12);
2857 		if (cmd_in == MTSETDRVBUFFER)
2858 			(STp->buffer)->b_data[2] = (arg & 7) << 4;
2859 		else
2860 			(STp->buffer)->b_data[2] =
2861 			    STp->drv_buffer << 4;
2862 		(STp->buffer)->b_data[3] = 8;	/* block descriptor length */
2863 		if (cmd_in == MTSETDENSITY) {
2864 			(STp->buffer)->b_data[4] = arg;
2865 			STp->density_changed = 1;	/* At least we tried ;-) */
2866 		} else if (cmd_in == SET_DENS_AND_BLK)
2867 			(STp->buffer)->b_data[4] = arg >> 24;
2868 		else
2869 			(STp->buffer)->b_data[4] = STp->density;
2870 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2871 			ltmp = arg & MT_ST_BLKSIZE_MASK;
2872 			if (cmd_in == MTSETBLK)
2873 				STp->blksize_changed = 1; /* At least we tried ;-) */
2874 		} else
2875 			ltmp = STp->block_size;
2876 		(STp->buffer)->b_data[9] = (ltmp >> 16);
2877 		(STp->buffer)->b_data[10] = (ltmp >> 8);
2878 		(STp->buffer)->b_data[11] = ltmp;
2879 		timeout = STp->device->request_queue->rq_timeout;
2880 		DEBC(
2881 			if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2882 				st_printk(ST_DEB_MSG, STp,
2883 					  "Setting block size to %d bytes.\n",
2884 					  (STp->buffer)->b_data[9] * 65536 +
2885 					  (STp->buffer)->b_data[10] * 256 +
2886 					  (STp->buffer)->b_data[11]);
2887 			if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2888 				st_printk(ST_DEB_MSG, STp,
2889 					  "Setting density code to %x.\n",
2890 					  (STp->buffer)->b_data[4]);
2891 			if (cmd_in == MTSETDRVBUFFER)
2892 				st_printk(ST_DEB_MSG, STp,
2893 					  "Setting drive buffer code to %d.\n",
2894 					  ((STp->buffer)->b_data[2] >> 4) & 7);
2895 		)
2896 		break;
2897 	default:
2898 		return (-ENOSYS);
2899 	}
2900 
2901 	SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2902 			   timeout, MAX_RETRIES, 1);
2903 	if (!SRpnt)
2904 		return (STp->buffer)->syscall_result;
2905 
2906 	ioctl_result = (STp->buffer)->syscall_result;
2907 
2908 	if (!ioctl_result) {	/* SCSI command successful */
2909 		st_release_request(SRpnt);
2910 		SRpnt = NULL;
2911 		STps->drv_block = blkno;
2912 		STps->drv_file = fileno;
2913 		STps->at_sm = at_sm;
2914 
2915 		if (cmd_in == MTBSFM)
2916 			ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2917 		else if (cmd_in == MTFSFM)
2918 			ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2919 
2920 		if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2921 			STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2922 			if (STp->block_size != 0) {
2923 				(STp->buffer)->buffer_blocks =
2924 				    (STp->buffer)->buffer_size / STp->block_size;
2925 			}
2926 			(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2927 			if (cmd_in == SET_DENS_AND_BLK)
2928 				STp->density = arg >> MT_ST_DENSITY_SHIFT;
2929 		} else if (cmd_in == MTSETDRVBUFFER)
2930 			STp->drv_buffer = (arg & 7);
2931 		else if (cmd_in == MTSETDENSITY)
2932 			STp->density = arg;
2933 
2934 		if (cmd_in == MTEOM)
2935 			STps->eof = ST_EOD;
2936 		else if (cmd_in == MTFSF)
2937 			STps->eof = ST_FM;
2938 		else if (chg_eof)
2939 			STps->eof = ST_NOEOF;
2940 
2941 		if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
2942 			STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
2943 	} else { /* SCSI command was not completely successful. Don't return
2944                     from this block without releasing the SCSI command block! */
2945 		struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
2946 
2947 		if (cmdstatp->flags & SENSE_EOM) {
2948 			if (cmd_in != MTBSF && cmd_in != MTBSFM &&
2949 			    cmd_in != MTBSR && cmd_in != MTBSS)
2950 				STps->eof = ST_EOM_OK;
2951 			STps->drv_block = 0;
2952 		}
2953 
2954 		if (cmdstatp->remainder_valid)
2955 			undone = (int)cmdstatp->uremainder64;
2956 		else
2957 			undone = 0;
2958 
2959 		if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
2960 		    cmdstatp->have_sense &&
2961 		    (cmdstatp->flags & SENSE_EOM)) {
2962 			if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
2963 			    cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
2964 				ioctl_result = 0;	/* EOF(s) written successfully at EOM */
2965 				STps->eof = ST_NOEOF;
2966 			} else {  /* Writing EOF(s) failed */
2967 				if (fileno >= 0)
2968 					fileno -= undone;
2969 				if (undone < arg)
2970 					STps->eof = ST_NOEOF;
2971 			}
2972 			STps->drv_file = fileno;
2973 		} else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
2974 			if (fileno >= 0)
2975 				STps->drv_file = fileno - undone;
2976 			else
2977 				STps->drv_file = fileno;
2978 			STps->drv_block = -1;
2979 			STps->eof = ST_NOEOF;
2980 		} else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
2981 			if (arg > 0 && undone < 0)  /* Some drives get this wrong */
2982 				undone = (-undone);
2983 			if (STps->drv_file >= 0)
2984 				STps->drv_file = fileno + undone;
2985 			STps->drv_block = 0;
2986 			STps->eof = ST_NOEOF;
2987 		} else if (cmd_in == MTFSR) {
2988 			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
2989 				if (STps->drv_file >= 0)
2990 					STps->drv_file++;
2991 				STps->drv_block = 0;
2992 				STps->eof = ST_FM;
2993 			} else {
2994 				if (blkno >= undone)
2995 					STps->drv_block = blkno - undone;
2996 				else
2997 					STps->drv_block = (-1);
2998 				STps->eof = ST_NOEOF;
2999 			}
3000 		} else if (cmd_in == MTBSR) {
3001 			if (cmdstatp->flags & SENSE_FMK) {	/* Hit filemark */
3002 				STps->drv_file--;
3003 				STps->drv_block = (-1);
3004 			} else {
3005 				if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3006 					undone = (-undone);
3007 				if (STps->drv_block >= 0)
3008 					STps->drv_block = blkno + undone;
3009 			}
3010 			STps->eof = ST_NOEOF;
3011 		} else if (cmd_in == MTEOM) {
3012 			STps->drv_file = (-1);
3013 			STps->drv_block = (-1);
3014 			STps->eof = ST_EOD;
3015 		} else if (cmd_in == MTSETBLK ||
3016 			   cmd_in == MTSETDENSITY ||
3017 			   cmd_in == MTSETDRVBUFFER ||
3018 			   cmd_in == SET_DENS_AND_BLK) {
3019 			if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3020 			    !(STp->use_pf & PF_TESTED)) {
3021 				/* Try the other possible state of Page Format if not
3022 				   already tried */
3023 				STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3024 				st_release_request(SRpnt);
3025 				SRpnt = NULL;
3026 				return st_int_ioctl(STp, cmd_in, arg);
3027 			}
3028 		} else if (chg_eof)
3029 			STps->eof = ST_NOEOF;
3030 
3031 		if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3032 			STps->eof = ST_EOD;
3033 
3034 		st_release_request(SRpnt);
3035 		SRpnt = NULL;
3036 	}
3037 
3038 	return ioctl_result;
3039 }
3040 
3041 
3042 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3043    structure. */
3044 
3045 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3046 			int logical)
3047 {
3048 	int result;
3049 	unsigned char scmd[MAX_COMMAND_SIZE];
3050 	struct st_request *SRpnt;
3051 
3052 	if (STp->ready != ST_READY)
3053 		return (-EIO);
3054 
3055 	memset(scmd, 0, MAX_COMMAND_SIZE);
3056 	if ((STp->device)->scsi_level < SCSI_2) {
3057 		scmd[0] = QFA_REQUEST_BLOCK;
3058 		scmd[4] = 3;
3059 	} else {
3060 		scmd[0] = READ_POSITION;
3061 		if (!logical && !STp->scsi2_logical)
3062 			scmd[1] = 1;
3063 	}
3064 	SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3065 			   STp->device->request_queue->rq_timeout,
3066 			   MAX_READY_RETRIES, 1);
3067 	if (!SRpnt)
3068 		return (STp->buffer)->syscall_result;
3069 
3070 	if ((STp->buffer)->syscall_result != 0 ||
3071 	    (STp->device->scsi_level >= SCSI_2 &&
3072 	     ((STp->buffer)->b_data[0] & 4) != 0)) {
3073 		*block = *partition = 0;
3074 		DEBC_printk(STp, " Can't read tape position.\n");
3075 		result = (-EIO);
3076 	} else {
3077 		result = 0;
3078 		if ((STp->device)->scsi_level < SCSI_2) {
3079 			*block = ((STp->buffer)->b_data[0] << 16)
3080 			    + ((STp->buffer)->b_data[1] << 8)
3081 			    + (STp->buffer)->b_data[2];
3082 			*partition = 0;
3083 		} else {
3084 			*block = ((STp->buffer)->b_data[4] << 24)
3085 			    + ((STp->buffer)->b_data[5] << 16)
3086 			    + ((STp->buffer)->b_data[6] << 8)
3087 			    + (STp->buffer)->b_data[7];
3088 			*partition = (STp->buffer)->b_data[1];
3089 			if (((STp->buffer)->b_data[0] & 0x80) &&
3090 			    (STp->buffer)->b_data[1] == 0)	/* BOP of partition 0 */
3091 				STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3092 		}
3093 		DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3094 			    *block, *partition);
3095 	}
3096 	st_release_request(SRpnt);
3097 	SRpnt = NULL;
3098 
3099 	return result;
3100 }
3101 
3102 
3103 /* Set the tape block and partition. Negative partition means that only the
3104    block should be set in vendor specific way. */
3105 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3106 			int logical)
3107 {
3108 	struct st_partstat *STps;
3109 	int result, p;
3110 	unsigned int blk;
3111 	int timeout;
3112 	unsigned char scmd[MAX_COMMAND_SIZE];
3113 	struct st_request *SRpnt;
3114 
3115 	if (STp->ready != ST_READY)
3116 		return (-EIO);
3117 	timeout = STp->long_timeout;
3118 	STps = &(STp->ps[STp->partition]);
3119 
3120 	DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3121 		    block, partition);
3122 	DEB(if (partition < 0)
3123 		return (-EIO); )
3124 
3125 	/* Update the location at the partition we are leaving */
3126 	if ((!STp->can_partitions && partition != 0) ||
3127 	    partition >= ST_NBR_PARTITIONS)
3128 		return (-EINVAL);
3129 	if (partition != STp->partition) {
3130 		if (get_location(STp, &blk, &p, 1))
3131 			STps->last_block_valid = 0;
3132 		else {
3133 			STps->last_block_valid = 1;
3134 			STps->last_block_visited = blk;
3135 			DEBC_printk(STp, "Visited block %d for "
3136 				    "partition %d saved.\n",
3137 				    blk, STp->partition);
3138 		}
3139 	}
3140 
3141 	memset(scmd, 0, MAX_COMMAND_SIZE);
3142 	if ((STp->device)->scsi_level < SCSI_2) {
3143 		scmd[0] = QFA_SEEK_BLOCK;
3144 		scmd[2] = (block >> 16);
3145 		scmd[3] = (block >> 8);
3146 		scmd[4] = block;
3147 		scmd[5] = 0;
3148 	} else {
3149 		scmd[0] = SEEK_10;
3150 		scmd[3] = (block >> 24);
3151 		scmd[4] = (block >> 16);
3152 		scmd[5] = (block >> 8);
3153 		scmd[6] = block;
3154 		if (!logical && !STp->scsi2_logical)
3155 			scmd[1] = 4;
3156 		if (STp->partition != partition) {
3157 			scmd[1] |= 2;
3158 			scmd[8] = partition;
3159 			DEBC_printk(STp, "Trying to change partition "
3160 				    "from %d to %d\n", STp->partition,
3161 				    partition);
3162 		}
3163 	}
3164 	if (STp->immediate) {
3165 		scmd[1] |= 1;		/* Don't wait for completion */
3166 		timeout = STp->device->request_queue->rq_timeout;
3167 	}
3168 
3169 	SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3170 			   timeout, MAX_READY_RETRIES, 1);
3171 	if (!SRpnt)
3172 		return (STp->buffer)->syscall_result;
3173 
3174 	STps->drv_block = STps->drv_file = (-1);
3175 	STps->eof = ST_NOEOF;
3176 	if ((STp->buffer)->syscall_result != 0) {
3177 		result = (-EIO);
3178 		if (STp->can_partitions &&
3179 		    (STp->device)->scsi_level >= SCSI_2 &&
3180 		    (p = find_partition(STp)) >= 0)
3181 			STp->partition = p;
3182 	} else {
3183 		if (STp->can_partitions) {
3184 			STp->partition = partition;
3185 			STps = &(STp->ps[partition]);
3186 			if (!STps->last_block_valid ||
3187 			    STps->last_block_visited != block) {
3188 				STps->at_sm = 0;
3189 				STps->rw = ST_IDLE;
3190 			}
3191 		} else
3192 			STps->at_sm = 0;
3193 		if (block == 0)
3194 			STps->drv_block = STps->drv_file = 0;
3195 		result = 0;
3196 	}
3197 
3198 	st_release_request(SRpnt);
3199 	SRpnt = NULL;
3200 
3201 	return result;
3202 }
3203 
3204 
3205 /* Find the current partition number for the drive status. Called from open and
3206    returns either partition number of negative error code. */
3207 static int find_partition(struct scsi_tape *STp)
3208 {
3209 	int i, partition;
3210 	unsigned int block;
3211 
3212 	if ((i = get_location(STp, &block, &partition, 1)) < 0)
3213 		return i;
3214 	if (partition >= ST_NBR_PARTITIONS)
3215 		return (-EIO);
3216 	return partition;
3217 }
3218 
3219 
3220 /* Change the partition if necessary */
3221 static int switch_partition(struct scsi_tape *STp)
3222 {
3223 	struct st_partstat *STps;
3224 
3225 	if (STp->partition == STp->new_partition)
3226 		return 0;
3227 	STps = &(STp->ps[STp->new_partition]);
3228 	if (!STps->last_block_valid)
3229 		STps->last_block_visited = 0;
3230 	return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3231 }
3232 
3233 /* Functions for reading and writing the medium partition mode page. */
3234 
3235 #define PART_PAGE   0x11
3236 #define PART_PAGE_FIXED_LENGTH 8
3237 
3238 #define PP_OFF_MAX_ADD_PARTS   2
3239 #define PP_OFF_NBR_ADD_PARTS   3
3240 #define PP_OFF_FLAGS           4
3241 #define PP_OFF_PART_UNITS      6
3242 #define PP_OFF_RESERVED        7
3243 
3244 #define PP_BIT_IDP             0x20
3245 #define PP_MSK_PSUM_MB         0x10
3246 
3247 /* Get the number of partitions on the tape. As a side effect reads the
3248    mode page into the tape buffer. */
3249 static int nbr_partitions(struct scsi_tape *STp)
3250 {
3251 	int result;
3252 
3253 	if (STp->ready != ST_READY)
3254 		return (-EIO);
3255 
3256 	result = read_mode_page(STp, PART_PAGE, 1);
3257 
3258 	if (result) {
3259 		DEBC_printk(STp, "Can't read medium partition page.\n");
3260 		result = (-EIO);
3261 	} else {
3262 		result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3263 					      PP_OFF_NBR_ADD_PARTS] + 1;
3264 		DEBC_printk(STp, "Number of partitions %d.\n", result);
3265 	}
3266 
3267 	return result;
3268 }
3269 
3270 
3271 /* Partition the tape into two partitions if size > 0 or one partition if
3272    size == 0.
3273 
3274    The block descriptors are read and written because Sony SDT-7000 does not
3275    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3276 
3277    My HP C1533A drive returns only one partition size field. This is used to
3278    set the size of partition 1. There is no size field for the default partition.
3279    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3280    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3281    The following algorithm is used to accommodate both drives: if the number of
3282    partition size fields is greater than the maximum number of additional partitions
3283    in the mode page, the second field is used. Otherwise the first field is used.
3284 
3285    For Seagate DDS drives the page length must be 8 when no partitions is defined
3286    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3287    is acceptable also to some other old drives and enforced if the first partition
3288    size field is used for the first additional partition size.
3289  */
3290 static int partition_tape(struct scsi_tape *STp, int size)
3291 {
3292 	int result;
3293 	int pgo, psd_cnt, psdo;
3294 	unsigned char *bp;
3295 
3296 	result = read_mode_page(STp, PART_PAGE, 0);
3297 	if (result) {
3298 		DEBC_printk(STp, "Can't read partition mode page.\n");
3299 		return result;
3300 	}
3301 	/* The mode page is in the buffer. Let's modify it and write it. */
3302 	bp = (STp->buffer)->b_data;
3303 	pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3304 	DEBC_printk(STp, "Partition page length is %d bytes.\n",
3305 		    bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3306 
3307 	psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3308 	psdo = pgo + PART_PAGE_FIXED_LENGTH;
3309 	if (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS]) {
3310 		bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest of the tape */
3311 		psdo += 2;
3312 	}
3313 	memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3314 
3315 	DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3316 		    psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3317 		    bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3318 
3319 	if (size <= 0) {
3320 		bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3321 		if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3322 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3323 		DEBC_printk(STp, "Formatting tape with one partition.\n");
3324 	} else {
3325 		bp[psdo] = (size >> 8) & 0xff;
3326 		bp[psdo + 1] = size & 0xff;
3327 		bp[pgo + 3] = 1;
3328 		if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3329 		    bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3330 		DEBC_printk(STp, "Formatting tape with two partitions "
3331 			    "(1 = %d MB).\n", size);
3332 	}
3333 	bp[pgo + PP_OFF_PART_UNITS] = 0;
3334 	bp[pgo + PP_OFF_RESERVED] = 0;
3335 	bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | PP_MSK_PSUM_MB;
3336 
3337 	result = write_mode_page(STp, PART_PAGE, 1);
3338 	if (result) {
3339 		st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3340 		result = (-EIO);
3341 	}
3342 
3343 	return result;
3344 }
3345 
3346 
3347 
3348 /* The ioctl command */
3349 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3350 {
3351 	int i, cmd_nr, cmd_type, bt;
3352 	int retval = 0;
3353 	unsigned int blk;
3354 	struct scsi_tape *STp = file->private_data;
3355 	struct st_modedef *STm;
3356 	struct st_partstat *STps;
3357 	void __user *p = (void __user *)arg;
3358 
3359 	if (mutex_lock_interruptible(&STp->lock))
3360 		return -ERESTARTSYS;
3361 
3362 	DEB(
3363 	if (debugging && !STp->in_use) {
3364 		st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3365 		retval = (-EIO);
3366 		goto out;
3367 	} ) /* end DEB */
3368 
3369 	STm = &(STp->modes[STp->current_mode]);
3370 	STps = &(STp->ps[STp->partition]);
3371 
3372 	/*
3373 	 * If we are in the middle of error recovery, don't let anyone
3374 	 * else try and use this device.  Also, if error recovery fails, it
3375 	 * may try and take the device offline, in which case all further
3376 	 * access to the device is prohibited.
3377 	 */
3378 	retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3379 			file->f_flags & O_NDELAY);
3380 	if (retval)
3381 		goto out;
3382 
3383 	cmd_type = _IOC_TYPE(cmd_in);
3384 	cmd_nr = _IOC_NR(cmd_in);
3385 
3386 	if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3387 		struct mtop mtc;
3388 
3389 		if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3390 			retval = (-EINVAL);
3391 			goto out;
3392 		}
3393 
3394 		i = copy_from_user(&mtc, p, sizeof(struct mtop));
3395 		if (i) {
3396 			retval = (-EFAULT);
3397 			goto out;
3398 		}
3399 
3400 		if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3401 			st_printk(KERN_WARNING, STp,
3402 				  "MTSETDRVBUFFER only allowed for root.\n");
3403 			retval = (-EPERM);
3404 			goto out;
3405 		}
3406 		if (!STm->defined &&
3407 		    (mtc.mt_op != MTSETDRVBUFFER &&
3408 		     (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3409 			retval = (-ENXIO);
3410 			goto out;
3411 		}
3412 
3413 		if (!STp->pos_unknown) {
3414 
3415 			if (STps->eof == ST_FM_HIT) {
3416 				if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3417                                     mtc.mt_op == MTEOM) {
3418 					mtc.mt_count -= 1;
3419 					if (STps->drv_file >= 0)
3420 						STps->drv_file += 1;
3421 				} else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3422 					mtc.mt_count += 1;
3423 					if (STps->drv_file >= 0)
3424 						STps->drv_file += 1;
3425 				}
3426 			}
3427 
3428 			if (mtc.mt_op == MTSEEK) {
3429 				/* Old position must be restored if partition will be
3430                                    changed */
3431 				i = !STp->can_partitions ||
3432 				    (STp->new_partition != STp->partition);
3433 			} else {
3434 				i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3435 				    mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3436 				    mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3437 				    mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3438 				    mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3439 				    mtc.mt_op == MTCOMPRESSION;
3440 			}
3441 			i = flush_buffer(STp, i);
3442 			if (i < 0) {
3443 				retval = i;
3444 				goto out;
3445 			}
3446 			if (STps->rw == ST_WRITING &&
3447 			    (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3448 			     mtc.mt_op == MTSEEK ||
3449 			     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3450 				i = st_int_ioctl(STp, MTWEOF, 1);
3451 				if (i < 0) {
3452 					retval = i;
3453 					goto out;
3454 				}
3455 				if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3456 					mtc.mt_count++;
3457 				STps->rw = ST_IDLE;
3458 			     }
3459 
3460 		} else {
3461 			/*
3462 			 * If there was a bus reset, block further access
3463 			 * to this device.  If the user wants to rewind the tape,
3464 			 * then reset the flag and allow access again.
3465 			 */
3466 			if (mtc.mt_op != MTREW &&
3467 			    mtc.mt_op != MTOFFL &&
3468 			    mtc.mt_op != MTRETEN &&
3469 			    mtc.mt_op != MTERASE &&
3470 			    mtc.mt_op != MTSEEK &&
3471 			    mtc.mt_op != MTEOM) {
3472 				retval = (-EIO);
3473 				goto out;
3474 			}
3475 			reset_state(STp);
3476 			/* remove this when the midlevel properly clears was_reset */
3477 			STp->device->was_reset = 0;
3478 		}
3479 
3480 		if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3481 		    mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3482 		    mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3483 			STps->rw = ST_IDLE;	/* Prevent automatic WEOF and fsf */
3484 
3485 		if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3486 			do_door_lock(STp, 0);	/* Ignore result! */
3487 
3488 		if (mtc.mt_op == MTSETDRVBUFFER &&
3489 		    (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3490 			retval = st_set_options(STp, mtc.mt_count);
3491 			goto out;
3492 		}
3493 
3494 		if (mtc.mt_op == MTSETPART) {
3495 			if (!STp->can_partitions ||
3496 			    mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3497 				retval = (-EINVAL);
3498 				goto out;
3499 			}
3500 			if (mtc.mt_count >= STp->nbr_partitions &&
3501 			    (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3502 				retval = (-EIO);
3503 				goto out;
3504 			}
3505 			if (mtc.mt_count >= STp->nbr_partitions) {
3506 				retval = (-EINVAL);
3507 				goto out;
3508 			}
3509 			STp->new_partition = mtc.mt_count;
3510 			retval = 0;
3511 			goto out;
3512 		}
3513 
3514 		if (mtc.mt_op == MTMKPART) {
3515 			if (!STp->can_partitions) {
3516 				retval = (-EINVAL);
3517 				goto out;
3518 			}
3519 			if ((i = st_int_ioctl(STp, MTREW, 0)) < 0 ||
3520 			    (i = partition_tape(STp, mtc.mt_count)) < 0) {
3521 				retval = i;
3522 				goto out;
3523 			}
3524 			for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3525 				STp->ps[i].rw = ST_IDLE;
3526 				STp->ps[i].at_sm = 0;
3527 				STp->ps[i].last_block_valid = 0;
3528 			}
3529 			STp->partition = STp->new_partition = 0;
3530 			STp->nbr_partitions = 1;	/* Bad guess ?-) */
3531 			STps->drv_block = STps->drv_file = 0;
3532 			retval = 0;
3533 			goto out;
3534 		}
3535 
3536 		if (mtc.mt_op == MTSEEK) {
3537 			i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3538 			if (!STp->can_partitions)
3539 				STp->ps[0].rw = ST_IDLE;
3540 			retval = i;
3541 			goto out;
3542 		}
3543 
3544 		if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3545 			retval = do_load_unload(STp, file, 0);
3546 			goto out;
3547 		}
3548 
3549 		if (mtc.mt_op == MTLOAD) {
3550 			retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3551 			goto out;
3552 		}
3553 
3554 		if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3555 			retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3556 			goto out;
3557 		}
3558 
3559 		if (STp->can_partitions && STp->ready == ST_READY &&
3560 		    (i = switch_partition(STp)) < 0) {
3561 			retval = i;
3562 			goto out;
3563 		}
3564 
3565 		if (mtc.mt_op == MTCOMPRESSION)
3566 			retval = st_compression(STp, (mtc.mt_count & 1));
3567 		else
3568 			retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3569 		goto out;
3570 	}
3571 	if (!STm->defined) {
3572 		retval = (-ENXIO);
3573 		goto out;
3574 	}
3575 
3576 	if ((i = flush_buffer(STp, 0)) < 0) {
3577 		retval = i;
3578 		goto out;
3579 	}
3580 	if (STp->can_partitions &&
3581 	    (i = switch_partition(STp)) < 0) {
3582 		retval = i;
3583 		goto out;
3584 	}
3585 
3586 	if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3587 		struct mtget mt_status;
3588 
3589 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3590 			 retval = (-EINVAL);
3591 			 goto out;
3592 		}
3593 
3594 		mt_status.mt_type = STp->tape_type;
3595 		mt_status.mt_dsreg =
3596 		    ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3597 		    ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3598 		mt_status.mt_blkno = STps->drv_block;
3599 		mt_status.mt_fileno = STps->drv_file;
3600 		if (STp->block_size != 0) {
3601 			if (STps->rw == ST_WRITING)
3602 				mt_status.mt_blkno +=
3603 				    (STp->buffer)->buffer_bytes / STp->block_size;
3604 			else if (STps->rw == ST_READING)
3605 				mt_status.mt_blkno -=
3606                                         ((STp->buffer)->buffer_bytes +
3607                                          STp->block_size - 1) / STp->block_size;
3608 		}
3609 
3610 		mt_status.mt_gstat = 0;
3611 		if (STp->drv_write_prot)
3612 			mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3613 		if (mt_status.mt_blkno == 0) {
3614 			if (mt_status.mt_fileno == 0)
3615 				mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3616 			else
3617 				mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3618 		}
3619 		mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3620 		mt_status.mt_resid = STp->partition;
3621 		if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3622 			mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3623 		else if (STps->eof >= ST_EOM_OK)
3624 			mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3625 		if (STp->density == 1)
3626 			mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3627 		else if (STp->density == 2)
3628 			mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3629 		else if (STp->density == 3)
3630 			mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3631 		if (STp->ready == ST_READY)
3632 			mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3633 		if (STp->ready == ST_NO_TAPE)
3634 			mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3635 		if (STps->at_sm)
3636 			mt_status.mt_gstat |= GMT_SM(0xffffffff);
3637 		if (STm->do_async_writes ||
3638                     (STm->do_buffer_writes && STp->block_size != 0) ||
3639 		    STp->drv_buffer != 0)
3640 			mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3641 		if (STp->cleaning_req)
3642 			mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3643 
3644 		i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3645 		if (i) {
3646 			retval = (-EFAULT);
3647 			goto out;
3648 		}
3649 
3650 		STp->recover_reg = 0;		/* Clear after read */
3651 		retval = 0;
3652 		goto out;
3653 	}			/* End of MTIOCGET */
3654 	if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3655 		struct mtpos mt_pos;
3656 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3657 			 retval = (-EINVAL);
3658 			 goto out;
3659 		}
3660 		if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3661 			retval = i;
3662 			goto out;
3663 		}
3664 		mt_pos.mt_blkno = blk;
3665 		i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3666 		if (i)
3667 			retval = (-EFAULT);
3668 		goto out;
3669 	}
3670 	mutex_unlock(&STp->lock);
3671 	switch (cmd_in) {
3672 		case SCSI_IOCTL_GET_IDLUN:
3673 		case SCSI_IOCTL_GET_BUS_NUMBER:
3674 			break;
3675 		default:
3676 			if ((cmd_in == SG_IO ||
3677 			     cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3678 			     cmd_in == CDROM_SEND_PACKET) &&
3679 			    !capable(CAP_SYS_RAWIO))
3680 				i = -EPERM;
3681 			else
3682 				i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3683 						   file->f_mode, cmd_in, p);
3684 			if (i != -ENOTTY)
3685 				return i;
3686 			break;
3687 	}
3688 	retval = scsi_ioctl(STp->device, cmd_in, p);
3689 	if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3690 		STp->rew_at_close = 0;
3691 		STp->ready = ST_NO_TAPE;
3692 	}
3693 	return retval;
3694 
3695  out:
3696 	mutex_unlock(&STp->lock);
3697 	return retval;
3698 }
3699 
3700 #ifdef CONFIG_COMPAT
3701 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3702 {
3703 	struct scsi_tape *STp = file->private_data;
3704 	struct scsi_device *sdev = STp->device;
3705 	int ret = -ENOIOCTLCMD;
3706 	if (sdev->host->hostt->compat_ioctl) {
3707 
3708 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3709 
3710 	}
3711 	return ret;
3712 }
3713 #endif
3714 
3715 
3716 
3717 /* Try to allocate a new tape buffer. Calling function must not hold
3718    dev_arr_lock. */
3719 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3720 {
3721 	struct st_buffer *tb;
3722 
3723 	tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3724 	if (!tb) {
3725 		printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3726 		return NULL;
3727 	}
3728 	tb->frp_segs = 0;
3729 	tb->use_sg = max_sg;
3730 	tb->dma = need_dma;
3731 	tb->buffer_size = 0;
3732 
3733 	tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3734 				     GFP_ATOMIC);
3735 	if (!tb->reserved_pages) {
3736 		kfree(tb);
3737 		return NULL;
3738 	}
3739 
3740 	return tb;
3741 }
3742 
3743 
3744 /* Try to allocate enough space in the tape buffer */
3745 #define ST_MAX_ORDER 6
3746 
3747 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3748 {
3749 	int segs, max_segs, b_size, order, got;
3750 	gfp_t priority;
3751 
3752 	if (new_size <= STbuffer->buffer_size)
3753 		return 1;
3754 
3755 	if (STbuffer->buffer_size <= PAGE_SIZE)
3756 		normalize_buffer(STbuffer);  /* Avoid extra segment */
3757 
3758 	max_segs = STbuffer->use_sg;
3759 
3760 	priority = GFP_KERNEL | __GFP_NOWARN;
3761 	if (need_dma)
3762 		priority |= GFP_DMA;
3763 
3764 	if (STbuffer->cleared)
3765 		priority |= __GFP_ZERO;
3766 
3767 	if (STbuffer->frp_segs) {
3768 		order = STbuffer->reserved_page_order;
3769 		b_size = PAGE_SIZE << order;
3770 	} else {
3771 		for (b_size = PAGE_SIZE, order = 0;
3772 		     order < ST_MAX_ORDER &&
3773 			     max_segs * (PAGE_SIZE << order) < new_size;
3774 		     order++, b_size *= 2)
3775 			;  /* empty */
3776 		STbuffer->reserved_page_order = order;
3777 	}
3778 	if (max_segs * (PAGE_SIZE << order) < new_size) {
3779 		if (order == ST_MAX_ORDER)
3780 			return 0;
3781 		normalize_buffer(STbuffer);
3782 		return enlarge_buffer(STbuffer, new_size, need_dma);
3783 	}
3784 
3785 	for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3786 	     segs < max_segs && got < new_size;) {
3787 		struct page *page;
3788 
3789 		page = alloc_pages(priority, order);
3790 		if (!page) {
3791 			DEB(STbuffer->buffer_size = got);
3792 			normalize_buffer(STbuffer);
3793 			return 0;
3794 		}
3795 
3796 		STbuffer->frp_segs += 1;
3797 		got += b_size;
3798 		STbuffer->buffer_size = got;
3799 		STbuffer->reserved_pages[segs] = page;
3800 		segs++;
3801 	}
3802 	STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3803 
3804 	return 1;
3805 }
3806 
3807 
3808 /* Make sure that no data from previous user is in the internal buffer */
3809 static void clear_buffer(struct st_buffer * st_bp)
3810 {
3811 	int i;
3812 
3813 	for (i=0; i < st_bp->frp_segs; i++)
3814 		memset(page_address(st_bp->reserved_pages[i]), 0,
3815 		       PAGE_SIZE << st_bp->reserved_page_order);
3816 	st_bp->cleared = 1;
3817 }
3818 
3819 
3820 /* Release the extra buffer */
3821 static void normalize_buffer(struct st_buffer * STbuffer)
3822 {
3823 	int i, order = STbuffer->reserved_page_order;
3824 
3825 	for (i = 0; i < STbuffer->frp_segs; i++) {
3826 		__free_pages(STbuffer->reserved_pages[i], order);
3827 		STbuffer->buffer_size -= (PAGE_SIZE << order);
3828 	}
3829 	STbuffer->frp_segs = 0;
3830 	STbuffer->sg_segs = 0;
3831 	STbuffer->reserved_page_order = 0;
3832 	STbuffer->map_data.offset = 0;
3833 }
3834 
3835 
3836 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3837    negative error code. */
3838 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3839 {
3840 	int i, cnt, res, offset;
3841 	int length = PAGE_SIZE << st_bp->reserved_page_order;
3842 
3843 	for (i = 0, offset = st_bp->buffer_bytes;
3844 	     i < st_bp->frp_segs && offset >= length; i++)
3845 		offset -= length;
3846 	if (i == st_bp->frp_segs) {	/* Should never happen */
3847 		printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
3848 		return (-EIO);
3849 	}
3850 	for (; i < st_bp->frp_segs && do_count > 0; i++) {
3851 		struct page *page = st_bp->reserved_pages[i];
3852 		cnt = length - offset < do_count ? length - offset : do_count;
3853 		res = copy_from_user(page_address(page) + offset, ubp, cnt);
3854 		if (res)
3855 			return (-EFAULT);
3856 		do_count -= cnt;
3857 		st_bp->buffer_bytes += cnt;
3858 		ubp += cnt;
3859 		offset = 0;
3860 	}
3861 	if (do_count) /* Should never happen */
3862 		return (-EIO);
3863 
3864 	return 0;
3865 }
3866 
3867 
3868 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
3869    negative error code. */
3870 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
3871 {
3872 	int i, cnt, res, offset;
3873 	int length = PAGE_SIZE << st_bp->reserved_page_order;
3874 
3875 	for (i = 0, offset = st_bp->read_pointer;
3876 	     i < st_bp->frp_segs && offset >= length; i++)
3877 		offset -= length;
3878 	if (i == st_bp->frp_segs) {	/* Should never happen */
3879 		printk(KERN_WARNING "st: from_buffer offset overflow.\n");
3880 		return (-EIO);
3881 	}
3882 	for (; i < st_bp->frp_segs && do_count > 0; i++) {
3883 		struct page *page = st_bp->reserved_pages[i];
3884 		cnt = length - offset < do_count ? length - offset : do_count;
3885 		res = copy_to_user(ubp, page_address(page) + offset, cnt);
3886 		if (res)
3887 			return (-EFAULT);
3888 		do_count -= cnt;
3889 		st_bp->buffer_bytes -= cnt;
3890 		st_bp->read_pointer += cnt;
3891 		ubp += cnt;
3892 		offset = 0;
3893 	}
3894 	if (do_count) /* Should never happen */
3895 		return (-EIO);
3896 
3897 	return 0;
3898 }
3899 
3900 
3901 /* Move data towards start of buffer */
3902 static void move_buffer_data(struct st_buffer * st_bp, int offset)
3903 {
3904 	int src_seg, dst_seg, src_offset = 0, dst_offset;
3905 	int count, total;
3906 	int length = PAGE_SIZE << st_bp->reserved_page_order;
3907 
3908 	if (offset == 0)
3909 		return;
3910 
3911 	total=st_bp->buffer_bytes - offset;
3912 	for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
3913 		src_offset = offset;
3914 		if (src_offset < length)
3915 			break;
3916 		offset -= length;
3917 	}
3918 
3919 	st_bp->buffer_bytes = st_bp->read_pointer = total;
3920 	for (dst_seg=dst_offset=0; total > 0; ) {
3921 		struct page *dpage = st_bp->reserved_pages[dst_seg];
3922 		struct page *spage = st_bp->reserved_pages[src_seg];
3923 
3924 		count = min(length - dst_offset, length - src_offset);
3925 		memmove(page_address(dpage) + dst_offset,
3926 			page_address(spage) + src_offset, count);
3927 		src_offset += count;
3928 		if (src_offset >= length) {
3929 			src_seg++;
3930 			src_offset = 0;
3931 		}
3932 		dst_offset += count;
3933 		if (dst_offset >= length) {
3934 			dst_seg++;
3935 			dst_offset = 0;
3936 		}
3937 		total -= count;
3938 	}
3939 }
3940 
3941 /* Validate the options from command line or module parameters */
3942 static void validate_options(void)
3943 {
3944 	if (buffer_kbs > 0)
3945 		st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
3946 	if (max_sg_segs >= ST_FIRST_SG)
3947 		st_max_sg_segs = max_sg_segs;
3948 }
3949 
3950 #ifndef MODULE
3951 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
3952  */
3953 static int __init st_setup(char *str)
3954 {
3955 	int i, len, ints[5];
3956 	char *stp;
3957 
3958 	stp = get_options(str, ARRAY_SIZE(ints), ints);
3959 
3960 	if (ints[0] > 0) {
3961 		for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
3962 			if (parms[i].val)
3963 				*parms[i].val = ints[i + 1];
3964 	} else {
3965 		while (stp != NULL) {
3966 			for (i = 0; i < ARRAY_SIZE(parms); i++) {
3967 				len = strlen(parms[i].name);
3968 				if (!strncmp(stp, parms[i].name, len) &&
3969 				    (*(stp + len) == ':' || *(stp + len) == '=')) {
3970 					if (parms[i].val)
3971 						*parms[i].val =
3972 							simple_strtoul(stp + len + 1, NULL, 0);
3973 					else
3974 						printk(KERN_WARNING "st: Obsolete parameter %s\n",
3975 						       parms[i].name);
3976 					break;
3977 				}
3978 			}
3979 			if (i >= ARRAY_SIZE(parms))
3980 				 printk(KERN_WARNING "st: invalid parameter in '%s'\n",
3981 					stp);
3982 			stp = strchr(stp, ',');
3983 			if (stp)
3984 				stp++;
3985 		}
3986 	}
3987 
3988 	validate_options();
3989 
3990 	return 1;
3991 }
3992 
3993 __setup("st=", st_setup);
3994 
3995 #endif
3996 
3997 static const struct file_operations st_fops =
3998 {
3999 	.owner =	THIS_MODULE,
4000 	.read =		st_read,
4001 	.write =	st_write,
4002 	.unlocked_ioctl = st_ioctl,
4003 #ifdef CONFIG_COMPAT
4004 	.compat_ioctl = st_compat_ioctl,
4005 #endif
4006 	.open =		st_open,
4007 	.flush =	st_flush,
4008 	.release =	st_release,
4009 	.llseek =	noop_llseek,
4010 };
4011 
4012 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4013 {
4014 	int i, error;
4015 	dev_t cdev_devno;
4016 	struct cdev *cdev;
4017 	struct device *dev;
4018 	struct st_modedef *STm = &(tape->modes[mode]);
4019 	char name[10];
4020 	int dev_num = tape->index;
4021 
4022 	cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4023 
4024 	cdev = cdev_alloc();
4025 	if (!cdev) {
4026 		pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4027 		error = -ENOMEM;
4028 		goto out;
4029 	}
4030 	cdev->owner = THIS_MODULE;
4031 	cdev->ops = &st_fops;
4032 
4033 	error = cdev_add(cdev, cdev_devno, 1);
4034 	if (error) {
4035 		pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4036 		       rew ? "non" : "auto", mode);
4037 		pr_err("st%d: Device not attached.\n", dev_num);
4038 		goto out_free;
4039 	}
4040 	STm->cdevs[rew] = cdev;
4041 
4042 	i = mode << (4 - ST_NBR_MODE_BITS);
4043 	snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4044 		 tape->disk->disk_name, st_formats[i]);
4045 
4046 	dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4047 			    cdev_devno, &tape->modes[mode], "%s", name);
4048 	if (IS_ERR(dev)) {
4049 		pr_err("st%d: device_create failed\n", dev_num);
4050 		error = PTR_ERR(dev);
4051 		goto out_free;
4052 	}
4053 
4054 	STm->devs[rew] = dev;
4055 
4056 	return 0;
4057 out_free:
4058 	cdev_del(STm->cdevs[rew]);
4059 	STm->cdevs[rew] = NULL;
4060 out:
4061 	return error;
4062 }
4063 
4064 static int create_cdevs(struct scsi_tape *tape)
4065 {
4066 	int mode, error;
4067 	for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4068 		error = create_one_cdev(tape, mode, 0);
4069 		if (error)
4070 			return error;
4071 		error = create_one_cdev(tape, mode, 1);
4072 		if (error)
4073 			return error;
4074 	}
4075 
4076 	return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4077 				 &tape->modes[0].devs[0]->kobj, "tape");
4078 }
4079 
4080 static void remove_cdevs(struct scsi_tape *tape)
4081 {
4082 	int mode, rew;
4083 	sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4084 	for (mode = 0; mode < ST_NBR_MODES; mode++) {
4085 		struct st_modedef *STm = &(tape->modes[mode]);
4086 		for (rew = 0; rew < 2; rew++) {
4087 			if (STm->cdevs[rew])
4088 				cdev_del(STm->cdevs[rew]);
4089 			if (STm->devs[rew])
4090 				device_unregister(STm->devs[rew]);
4091 		}
4092 	}
4093 }
4094 
4095 static int st_probe(struct device *dev)
4096 {
4097 	struct scsi_device *SDp = to_scsi_device(dev);
4098 	struct gendisk *disk = NULL;
4099 	struct scsi_tape *tpnt = NULL;
4100 	struct st_modedef *STm;
4101 	struct st_partstat *STps;
4102 	struct st_buffer *buffer;
4103 	int i, error;
4104 	char *stp;
4105 
4106 	if (SDp->type != TYPE_TAPE)
4107 		return -ENODEV;
4108 	if ((stp = st_incompatible(SDp))) {
4109 		sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4110 		sdev_printk(KERN_INFO, SDp,
4111 			    "st: The suggested driver is %s.\n", stp);
4112 		return -ENODEV;
4113 	}
4114 
4115 	scsi_autopm_get_device(SDp);
4116 	i = queue_max_segments(SDp->request_queue);
4117 	if (st_max_sg_segs < i)
4118 		i = st_max_sg_segs;
4119 	buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4120 	if (buffer == NULL) {
4121 		sdev_printk(KERN_ERR, SDp,
4122 			    "st: Can't allocate new tape buffer. "
4123 			    "Device not attached.\n");
4124 		goto out;
4125 	}
4126 
4127 	disk = alloc_disk(1);
4128 	if (!disk) {
4129 		sdev_printk(KERN_ERR, SDp,
4130 			    "st: out of memory. Device not attached.\n");
4131 		goto out_buffer_free;
4132 	}
4133 
4134 	tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4135 	if (tpnt == NULL) {
4136 		sdev_printk(KERN_ERR, SDp,
4137 			    "st: Can't allocate device descriptor.\n");
4138 		goto out_put_disk;
4139 	}
4140 	kref_init(&tpnt->kref);
4141 	tpnt->disk = disk;
4142 	disk->private_data = &tpnt->driver;
4143 	disk->queue = SDp->request_queue;
4144 	/* SCSI tape doesn't register this gendisk via add_disk().  Manually
4145 	 * take queue reference that release_disk() expects. */
4146 	if (!blk_get_queue(disk->queue))
4147 		goto out_put_disk;
4148 	tpnt->driver = &st_template;
4149 
4150 	tpnt->device = SDp;
4151 	if (SDp->scsi_level <= 2)
4152 		tpnt->tape_type = MT_ISSCSI1;
4153 	else
4154 		tpnt->tape_type = MT_ISSCSI2;
4155 
4156 	tpnt->buffer = buffer;
4157 	tpnt->buffer->last_SRpnt = NULL;
4158 
4159 	tpnt->inited = 0;
4160 	tpnt->dirty = 0;
4161 	tpnt->in_use = 0;
4162 	tpnt->drv_buffer = 1;	/* Try buffering if no mode sense */
4163 	tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4164 	tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4165 	tpnt->density = 0;
4166 	tpnt->do_auto_lock = ST_AUTO_LOCK;
4167 	tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4168 	tpnt->can_partitions = 0;
4169 	tpnt->two_fm = ST_TWO_FM;
4170 	tpnt->fast_mteom = ST_FAST_MTEOM;
4171 	tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4172 	tpnt->sili = ST_SILI;
4173 	tpnt->immediate = ST_NOWAIT;
4174 	tpnt->immediate_filemark = 0;
4175 	tpnt->default_drvbuffer = 0xff;		/* No forced buffering */
4176 	tpnt->partition = 0;
4177 	tpnt->new_partition = 0;
4178 	tpnt->nbr_partitions = 0;
4179 	blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4180 	tpnt->long_timeout = ST_LONG_TIMEOUT;
4181 	tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4182 
4183 	for (i = 0; i < ST_NBR_MODES; i++) {
4184 		STm = &(tpnt->modes[i]);
4185 		STm->defined = 0;
4186 		STm->sysv = ST_SYSV;
4187 		STm->defaults_for_writes = 0;
4188 		STm->do_async_writes = ST_ASYNC_WRITES;
4189 		STm->do_buffer_writes = ST_BUFFER_WRITES;
4190 		STm->do_read_ahead = ST_READ_AHEAD;
4191 		STm->default_compression = ST_DONT_TOUCH;
4192 		STm->default_blksize = (-1);	/* No forced size */
4193 		STm->default_density = (-1);	/* No forced density */
4194 		STm->tape = tpnt;
4195 	}
4196 
4197 	for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4198 		STps = &(tpnt->ps[i]);
4199 		STps->rw = ST_IDLE;
4200 		STps->eof = ST_NOEOF;
4201 		STps->at_sm = 0;
4202 		STps->last_block_valid = 0;
4203 		STps->drv_block = (-1);
4204 		STps->drv_file = (-1);
4205 	}
4206 
4207 	tpnt->current_mode = 0;
4208 	tpnt->modes[0].defined = 1;
4209 
4210 	tpnt->density_changed = tpnt->compression_changed =
4211 	    tpnt->blksize_changed = 0;
4212 	mutex_init(&tpnt->lock);
4213 
4214 	idr_preload(GFP_KERNEL);
4215 	spin_lock(&st_index_lock);
4216 	error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4217 	spin_unlock(&st_index_lock);
4218 	idr_preload_end();
4219 	if (error < 0) {
4220 		pr_warn("st: idr allocation failed: %d\n", error);
4221 		goto out_put_queue;
4222 	}
4223 	tpnt->index = error;
4224 	sprintf(disk->disk_name, "st%d", tpnt->index);
4225 
4226 	dev_set_drvdata(dev, tpnt);
4227 
4228 
4229 	error = create_cdevs(tpnt);
4230 	if (error)
4231 		goto out_remove_devs;
4232 	scsi_autopm_put_device(SDp);
4233 
4234 	sdev_printk(KERN_NOTICE, SDp,
4235 		    "Attached scsi tape %s\n", tape_name(tpnt));
4236 	sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4237 		    tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4238 		    queue_dma_alignment(SDp->request_queue) + 1);
4239 
4240 	return 0;
4241 
4242 out_remove_devs:
4243 	remove_cdevs(tpnt);
4244 	spin_lock(&st_index_lock);
4245 	idr_remove(&st_index_idr, tpnt->index);
4246 	spin_unlock(&st_index_lock);
4247 out_put_queue:
4248 	blk_put_queue(disk->queue);
4249 out_put_disk:
4250 	put_disk(disk);
4251 	kfree(tpnt);
4252 out_buffer_free:
4253 	kfree(buffer);
4254 out:
4255 	scsi_autopm_put_device(SDp);
4256 	return -ENODEV;
4257 };
4258 
4259 
4260 static int st_remove(struct device *dev)
4261 {
4262 	struct scsi_tape *tpnt = dev_get_drvdata(dev);
4263 	int index = tpnt->index;
4264 
4265 	scsi_autopm_get_device(to_scsi_device(dev));
4266 	remove_cdevs(tpnt);
4267 
4268 	mutex_lock(&st_ref_mutex);
4269 	kref_put(&tpnt->kref, scsi_tape_release);
4270 	mutex_unlock(&st_ref_mutex);
4271 	spin_lock(&st_index_lock);
4272 	idr_remove(&st_index_idr, index);
4273 	spin_unlock(&st_index_lock);
4274 	return 0;
4275 }
4276 
4277 /**
4278  *      scsi_tape_release - Called to free the Scsi_Tape structure
4279  *      @kref: pointer to embedded kref
4280  *
4281  *      st_ref_mutex must be held entering this routine.  Because it is
4282  *      called on last put, you should always use the scsi_tape_get()
4283  *      scsi_tape_put() helpers which manipulate the semaphore directly
4284  *      and never do a direct kref_put().
4285  **/
4286 static void scsi_tape_release(struct kref *kref)
4287 {
4288 	struct scsi_tape *tpnt = to_scsi_tape(kref);
4289 	struct gendisk *disk = tpnt->disk;
4290 
4291 	tpnt->device = NULL;
4292 
4293 	if (tpnt->buffer) {
4294 		normalize_buffer(tpnt->buffer);
4295 		kfree(tpnt->buffer->reserved_pages);
4296 		kfree(tpnt->buffer);
4297 	}
4298 
4299 	disk->private_data = NULL;
4300 	put_disk(disk);
4301 	kfree(tpnt);
4302 	return;
4303 }
4304 
4305 static struct class st_sysfs_class = {
4306 	.name = "scsi_tape",
4307 	.dev_groups = st_dev_groups,
4308 };
4309 
4310 static int __init init_st(void)
4311 {
4312 	int err;
4313 
4314 	validate_options();
4315 
4316 	printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4317 		verstr, st_fixed_buffer_size, st_max_sg_segs);
4318 
4319 	debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4320 	if (debugging) {
4321 		printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4322 			debugging);
4323 	}
4324 
4325 	err = class_register(&st_sysfs_class);
4326 	if (err) {
4327 		pr_err("Unable register sysfs class for SCSI tapes\n");
4328 		return err;
4329 	}
4330 
4331 	err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4332 				     ST_MAX_TAPE_ENTRIES, "st");
4333 	if (err) {
4334 		printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4335 		       SCSI_TAPE_MAJOR);
4336 		goto err_class;
4337 	}
4338 
4339 	err = scsi_register_driver(&st_template.gendrv);
4340 	if (err)
4341 		goto err_chrdev;
4342 
4343 	err = do_create_sysfs_files();
4344 	if (err)
4345 		goto err_scsidrv;
4346 
4347 	return 0;
4348 
4349 err_scsidrv:
4350 	scsi_unregister_driver(&st_template.gendrv);
4351 err_chrdev:
4352 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4353 				 ST_MAX_TAPE_ENTRIES);
4354 err_class:
4355 	class_unregister(&st_sysfs_class);
4356 	return err;
4357 }
4358 
4359 static void __exit exit_st(void)
4360 {
4361 	do_remove_sysfs_files();
4362 	scsi_unregister_driver(&st_template.gendrv);
4363 	unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4364 				 ST_MAX_TAPE_ENTRIES);
4365 	class_unregister(&st_sysfs_class);
4366 	printk(KERN_INFO "st: Unloaded.\n");
4367 }
4368 
4369 module_init(init_st);
4370 module_exit(exit_st);
4371 
4372 
4373 /* The sysfs driver interface. Read-only at the moment */
4374 static ssize_t st_try_direct_io_show(struct device_driver *ddp, char *buf)
4375 {
4376 	return snprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4377 }
4378 static DRIVER_ATTR(try_direct_io, S_IRUGO, st_try_direct_io_show, NULL);
4379 
4380 static ssize_t st_fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4381 {
4382 	return snprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4383 }
4384 static DRIVER_ATTR(fixed_buffer_size, S_IRUGO, st_fixed_buffer_size_show, NULL);
4385 
4386 static ssize_t st_max_sg_segs_show(struct device_driver *ddp, char *buf)
4387 {
4388 	return snprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4389 }
4390 static DRIVER_ATTR(max_sg_segs, S_IRUGO, st_max_sg_segs_show, NULL);
4391 
4392 static ssize_t st_version_show(struct device_driver *ddd, char *buf)
4393 {
4394 	return snprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4395 }
4396 static DRIVER_ATTR(version, S_IRUGO, st_version_show, NULL);
4397 
4398 static int do_create_sysfs_files(void)
4399 {
4400 	struct device_driver *sysfs = &st_template.gendrv;
4401 	int err;
4402 
4403 	err = driver_create_file(sysfs, &driver_attr_try_direct_io);
4404 	if (err)
4405 		return err;
4406 	err = driver_create_file(sysfs, &driver_attr_fixed_buffer_size);
4407 	if (err)
4408 		goto err_try_direct_io;
4409 	err = driver_create_file(sysfs, &driver_attr_max_sg_segs);
4410 	if (err)
4411 		goto err_attr_fixed_buf;
4412 	err = driver_create_file(sysfs, &driver_attr_version);
4413 	if (err)
4414 		goto err_attr_max_sg;
4415 
4416 	return 0;
4417 
4418 err_attr_max_sg:
4419 	driver_remove_file(sysfs, &driver_attr_max_sg_segs);
4420 err_attr_fixed_buf:
4421 	driver_remove_file(sysfs, &driver_attr_fixed_buffer_size);
4422 err_try_direct_io:
4423 	driver_remove_file(sysfs, &driver_attr_try_direct_io);
4424 	return err;
4425 }
4426 
4427 static void do_remove_sysfs_files(void)
4428 {
4429 	struct device_driver *sysfs = &st_template.gendrv;
4430 
4431 	driver_remove_file(sysfs, &driver_attr_version);
4432 	driver_remove_file(sysfs, &driver_attr_max_sg_segs);
4433 	driver_remove_file(sysfs, &driver_attr_fixed_buffer_size);
4434 	driver_remove_file(sysfs, &driver_attr_try_direct_io);
4435 }
4436 
4437 /* The sysfs simple class interface */
4438 static ssize_t
4439 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4440 {
4441 	struct st_modedef *STm = dev_get_drvdata(dev);
4442 	ssize_t l = 0;
4443 
4444 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4445 	return l;
4446 }
4447 static DEVICE_ATTR_RO(defined);
4448 
4449 static ssize_t
4450 default_blksize_show(struct device *dev, struct device_attribute *attr,
4451 		     char *buf)
4452 {
4453 	struct st_modedef *STm = dev_get_drvdata(dev);
4454 	ssize_t l = 0;
4455 
4456 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4457 	return l;
4458 }
4459 static DEVICE_ATTR_RO(default_blksize);
4460 
4461 static ssize_t
4462 default_density_show(struct device *dev, struct device_attribute *attr,
4463 		     char *buf)
4464 {
4465 	struct st_modedef *STm = dev_get_drvdata(dev);
4466 	ssize_t l = 0;
4467 	char *fmt;
4468 
4469 	fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4470 	l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4471 	return l;
4472 }
4473 static DEVICE_ATTR_RO(default_density);
4474 
4475 static ssize_t
4476 default_compression_show(struct device *dev, struct device_attribute *attr,
4477 			 char *buf)
4478 {
4479 	struct st_modedef *STm = dev_get_drvdata(dev);
4480 	ssize_t l = 0;
4481 
4482 	l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4483 	return l;
4484 }
4485 static DEVICE_ATTR_RO(default_compression);
4486 
4487 static ssize_t
4488 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4489 {
4490 	struct st_modedef *STm = dev_get_drvdata(dev);
4491 	struct scsi_tape *STp = STm->tape;
4492 	int options;
4493 	ssize_t l = 0;
4494 
4495 	options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4496 	options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4497 	options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4498 	DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4499 	options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4500 	options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4501 	options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4502 	options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4503 	options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4504 	options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4505 	options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4506 	options |= STm->sysv ? MT_ST_SYSV : 0;
4507 	options |= STp->immediate ? MT_ST_NOWAIT : 0;
4508 	options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4509 	options |= STp->sili ? MT_ST_SILI : 0;
4510 
4511 	l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4512 	return l;
4513 }
4514 static DEVICE_ATTR_RO(options);
4515 
4516 static struct attribute *st_dev_attrs[] = {
4517 	&dev_attr_defined.attr,
4518 	&dev_attr_default_blksize.attr,
4519 	&dev_attr_default_density.attr,
4520 	&dev_attr_default_compression.attr,
4521 	&dev_attr_options.attr,
4522 	NULL,
4523 };
4524 ATTRIBUTE_GROUPS(st_dev);
4525 
4526 /* The following functions may be useful for a larger audience. */
4527 static int sgl_map_user_pages(struct st_buffer *STbp,
4528 			      const unsigned int max_pages, unsigned long uaddr,
4529 			      size_t count, int rw)
4530 {
4531 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4532 	unsigned long start = uaddr >> PAGE_SHIFT;
4533 	const int nr_pages = end - start;
4534 	int res, i, j;
4535 	struct page **pages;
4536 	struct rq_map_data *mdata = &STbp->map_data;
4537 
4538 	/* User attempted Overflow! */
4539 	if ((uaddr + count) < uaddr)
4540 		return -EINVAL;
4541 
4542 	/* Too big */
4543         if (nr_pages > max_pages)
4544 		return -ENOMEM;
4545 
4546 	/* Hmm? */
4547 	if (count == 0)
4548 		return 0;
4549 
4550 	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4551 		return -ENOMEM;
4552 
4553         /* Try to fault in all of the necessary pages */
4554         /* rw==READ means read from drive, write into memory area */
4555 	res = get_user_pages_unlocked(
4556 		current,
4557 		current->mm,
4558 		uaddr,
4559 		nr_pages,
4560 		rw == READ,
4561 		0, /* don't force */
4562 		pages);
4563 
4564 	/* Errors and no page mapped should return here */
4565 	if (res < nr_pages)
4566 		goto out_unmap;
4567 
4568         for (i=0; i < nr_pages; i++) {
4569                 /* FIXME: flush superflous for rw==READ,
4570                  * probably wrong function for rw==WRITE
4571                  */
4572 		flush_dcache_page(pages[i]);
4573         }
4574 
4575 	mdata->offset = uaddr & ~PAGE_MASK;
4576 	STbp->mapped_pages = pages;
4577 
4578 	return nr_pages;
4579  out_unmap:
4580 	if (res > 0) {
4581 		for (j=0; j < res; j++)
4582 			page_cache_release(pages[j]);
4583 		res = 0;
4584 	}
4585 	kfree(pages);
4586 	return res;
4587 }
4588 
4589 
4590 /* And unmap them... */
4591 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4592 				const unsigned int nr_pages, int dirtied)
4593 {
4594 	int i;
4595 
4596 	for (i=0; i < nr_pages; i++) {
4597 		struct page *page = STbp->mapped_pages[i];
4598 
4599 		if (dirtied)
4600 			SetPageDirty(page);
4601 		/* FIXME: cache flush missing for rw==READ
4602 		 * FIXME: call the correct reference counting function
4603 		 */
4604 		page_cache_release(page);
4605 	}
4606 	kfree(STbp->mapped_pages);
4607 	STbp->mapped_pages = NULL;
4608 
4609 	return 0;
4610 }
4611