xref: /openbmc/linux/drivers/scsi/sr.c (revision f20c7d91)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  sr.c Copyright (C) 1992 David Giller
4  *           Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5  *
6  *  adapted from:
7  *      sd.c Copyright (C) 1992 Drew Eckhardt
8  *      Linux scsi disk driver by
9  *              Drew Eckhardt <drew@colorado.edu>
10  *
11  *	Modified by Eric Youngdale ericy@andante.org to
12  *	add scatter-gather, multiple outstanding request, and other
13  *	enhancements.
14  *
15  *      Modified by Eric Youngdale eric@andante.org to support loadable
16  *      low-level scsi drivers.
17  *
18  *      Modified by Thomas Quinot thomas@melchior.cuivre.fdn.fr to
19  *      provide auto-eject.
20  *
21  *      Modified by Gerd Knorr <kraxel@cs.tu-berlin.de> to support the
22  *      generic cdrom interface
23  *
24  *      Modified by Jens Axboe <axboe@suse.de> - Uniform sr_packet()
25  *      interface, capabilities probe additions, ioctl cleanups, etc.
26  *
27  *	Modified by Richard Gooch <rgooch@atnf.csiro.au> to support devfs
28  *
29  *	Modified by Jens Axboe <axboe@suse.de> - support DVD-RAM
30  *	transparently and lose the GHOST hack
31  *
32  *	Modified by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
33  *	check resource allocation in sr_init and some cleanups
34  */
35 
36 #include <linux/module.h>
37 #include <linux/fs.h>
38 #include <linux/kernel.h>
39 #include <linux/mm.h>
40 #include <linux/bio.h>
41 #include <linux/compat.h>
42 #include <linux/string.h>
43 #include <linux/errno.h>
44 #include <linux/cdrom.h>
45 #include <linux/interrupt.h>
46 #include <linux/init.h>
47 #include <linux/blkdev.h>
48 #include <linux/blk-pm.h>
49 #include <linux/mutex.h>
50 #include <linux/slab.h>
51 #include <linux/pm_runtime.h>
52 #include <linux/uaccess.h>
53 
54 #include <asm/unaligned.h>
55 
56 #include <scsi/scsi.h>
57 #include <scsi/scsi_dbg.h>
58 #include <scsi/scsi_device.h>
59 #include <scsi/scsi_driver.h>
60 #include <scsi/scsi_cmnd.h>
61 #include <scsi/scsi_eh.h>
62 #include <scsi/scsi_host.h>
63 #include <scsi/scsi_ioctl.h>	/* For the door lock/unlock commands */
64 
65 #include "scsi_logging.h"
66 #include "sr.h"
67 
68 
69 MODULE_DESCRIPTION("SCSI cdrom (sr) driver");
70 MODULE_LICENSE("GPL");
71 MODULE_ALIAS_BLOCKDEV_MAJOR(SCSI_CDROM_MAJOR);
72 MODULE_ALIAS_SCSI_DEVICE(TYPE_ROM);
73 MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
74 
75 #define SR_DISKS	256
76 
77 #define SR_CAPABILITIES \
78 	(CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|CDC_SELECT_SPEED| \
79 	 CDC_SELECT_DISC|CDC_MULTI_SESSION|CDC_MCN|CDC_MEDIA_CHANGED| \
80 	 CDC_PLAY_AUDIO|CDC_RESET|CDC_DRIVE_STATUS| \
81 	 CDC_CD_R|CDC_CD_RW|CDC_DVD|CDC_DVD_R|CDC_DVD_RAM|CDC_GENERIC_PACKET| \
82 	 CDC_MRW|CDC_MRW_W|CDC_RAM)
83 
84 static int sr_probe(struct device *);
85 static int sr_remove(struct device *);
86 static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt);
87 static int sr_done(struct scsi_cmnd *);
88 static int sr_runtime_suspend(struct device *dev);
89 
90 static const struct dev_pm_ops sr_pm_ops = {
91 	.runtime_suspend	= sr_runtime_suspend,
92 };
93 
94 static struct scsi_driver sr_template = {
95 	.gendrv = {
96 		.name   	= "sr",
97 		.owner		= THIS_MODULE,
98 		.probe		= sr_probe,
99 		.remove		= sr_remove,
100 		.pm		= &sr_pm_ops,
101 	},
102 	.init_command		= sr_init_command,
103 	.done			= sr_done,
104 };
105 
106 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
107 static DEFINE_SPINLOCK(sr_index_lock);
108 
109 /* This semaphore is used to mediate the 0->1 reference get in the
110  * face of object destruction (i.e. we can't allow a get on an
111  * object after last put) */
112 static DEFINE_MUTEX(sr_ref_mutex);
113 
114 static int sr_open(struct cdrom_device_info *, int);
115 static void sr_release(struct cdrom_device_info *);
116 
117 static void get_sectorsize(struct scsi_cd *);
118 static void get_capabilities(struct scsi_cd *);
119 
120 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
121 				    unsigned int clearing, int slot);
122 static int sr_packet(struct cdrom_device_info *, struct packet_command *);
123 
124 static const struct cdrom_device_ops sr_dops = {
125 	.open			= sr_open,
126 	.release	 	= sr_release,
127 	.drive_status	 	= sr_drive_status,
128 	.check_events		= sr_check_events,
129 	.tray_move		= sr_tray_move,
130 	.lock_door		= sr_lock_door,
131 	.select_speed		= sr_select_speed,
132 	.get_last_session	= sr_get_last_session,
133 	.get_mcn		= sr_get_mcn,
134 	.reset			= sr_reset,
135 	.audio_ioctl		= sr_audio_ioctl,
136 	.capability		= SR_CAPABILITIES,
137 	.generic_packet		= sr_packet,
138 };
139 
140 static void sr_kref_release(struct kref *kref);
141 
142 static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
143 {
144 	return container_of(disk->private_data, struct scsi_cd, driver);
145 }
146 
147 static int sr_runtime_suspend(struct device *dev)
148 {
149 	struct scsi_cd *cd = dev_get_drvdata(dev);
150 
151 	if (!cd)	/* E.g.: runtime suspend following sr_remove() */
152 		return 0;
153 
154 	if (cd->media_present)
155 		return -EBUSY;
156 	else
157 		return 0;
158 }
159 
160 /*
161  * The get and put routines for the struct scsi_cd.  Note this entity
162  * has a scsi_device pointer and owns a reference to this.
163  */
164 static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk)
165 {
166 	struct scsi_cd *cd = NULL;
167 
168 	mutex_lock(&sr_ref_mutex);
169 	if (disk->private_data == NULL)
170 		goto out;
171 	cd = scsi_cd(disk);
172 	kref_get(&cd->kref);
173 	if (scsi_device_get(cd->device)) {
174 		kref_put(&cd->kref, sr_kref_release);
175 		cd = NULL;
176 	}
177  out:
178 	mutex_unlock(&sr_ref_mutex);
179 	return cd;
180 }
181 
182 static void scsi_cd_put(struct scsi_cd *cd)
183 {
184 	struct scsi_device *sdev = cd->device;
185 
186 	mutex_lock(&sr_ref_mutex);
187 	kref_put(&cd->kref, sr_kref_release);
188 	scsi_device_put(sdev);
189 	mutex_unlock(&sr_ref_mutex);
190 }
191 
192 static unsigned int sr_get_events(struct scsi_device *sdev)
193 {
194 	u8 buf[8];
195 	u8 cmd[] = { GET_EVENT_STATUS_NOTIFICATION,
196 		     1,			/* polled */
197 		     0, 0,		/* reserved */
198 		     1 << 4,		/* notification class: media */
199 		     0, 0,		/* reserved */
200 		     0, sizeof(buf),	/* allocation length */
201 		     0,			/* control */
202 	};
203 	struct event_header *eh = (void *)buf;
204 	struct media_event_desc *med = (void *)(buf + 4);
205 	struct scsi_sense_hdr sshdr;
206 	int result;
207 
208 	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buf, sizeof(buf),
209 				  &sshdr, SR_TIMEOUT, MAX_RETRIES, NULL);
210 	if (scsi_sense_valid(&sshdr) && sshdr.sense_key == UNIT_ATTENTION)
211 		return DISK_EVENT_MEDIA_CHANGE;
212 
213 	if (result || be16_to_cpu(eh->data_len) < sizeof(*med))
214 		return 0;
215 
216 	if (eh->nea || eh->notification_class != 0x4)
217 		return 0;
218 
219 	if (med->media_event_code == 1)
220 		return DISK_EVENT_EJECT_REQUEST;
221 	else if (med->media_event_code == 2)
222 		return DISK_EVENT_MEDIA_CHANGE;
223 	return 0;
224 }
225 
226 /*
227  * This function checks to see if the media has been changed or eject
228  * button has been pressed.  It is possible that we have already
229  * sensed a change, or the drive may have sensed one and not yet
230  * reported it.  The past events are accumulated in sdev->changed and
231  * returned together with the current state.
232  */
233 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
234 				    unsigned int clearing, int slot)
235 {
236 	struct scsi_cd *cd = cdi->handle;
237 	bool last_present;
238 	struct scsi_sense_hdr sshdr;
239 	unsigned int events;
240 	int ret;
241 
242 	/* no changer support */
243 	if (CDSL_CURRENT != slot)
244 		return 0;
245 
246 	events = sr_get_events(cd->device);
247 	cd->get_event_changed |= events & DISK_EVENT_MEDIA_CHANGE;
248 
249 	/*
250 	 * If earlier GET_EVENT_STATUS_NOTIFICATION and TUR did not agree
251 	 * for several times in a row.  We rely on TUR only for this likely
252 	 * broken device, to prevent generating incorrect media changed
253 	 * events for every open().
254 	 */
255 	if (cd->ignore_get_event) {
256 		events &= ~DISK_EVENT_MEDIA_CHANGE;
257 		goto do_tur;
258 	}
259 
260 	/*
261 	 * GET_EVENT_STATUS_NOTIFICATION is enough unless MEDIA_CHANGE
262 	 * is being cleared.  Note that there are devices which hang
263 	 * if asked to execute TUR repeatedly.
264 	 */
265 	if (cd->device->changed) {
266 		events |= DISK_EVENT_MEDIA_CHANGE;
267 		cd->device->changed = 0;
268 		cd->tur_changed = true;
269 	}
270 
271 	if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
272 		return events;
273 do_tur:
274 	/* let's see whether the media is there with TUR */
275 	last_present = cd->media_present;
276 	ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
277 
278 	/*
279 	 * Media is considered to be present if TUR succeeds or fails with
280 	 * sense data indicating something other than media-not-present
281 	 * (ASC 0x3a).
282 	 */
283 	cd->media_present = scsi_status_is_good(ret) ||
284 		(scsi_sense_valid(&sshdr) && sshdr.asc != 0x3a);
285 
286 	if (last_present != cd->media_present)
287 		cd->device->changed = 1;
288 
289 	if (cd->device->changed) {
290 		events |= DISK_EVENT_MEDIA_CHANGE;
291 		cd->device->changed = 0;
292 		cd->tur_changed = true;
293 	}
294 
295 	if (cd->ignore_get_event)
296 		return events;
297 
298 	/* check whether GET_EVENT is reporting spurious MEDIA_CHANGE */
299 	if (!cd->tur_changed) {
300 		if (cd->get_event_changed) {
301 			if (cd->tur_mismatch++ > 8) {
302 				sr_printk(KERN_WARNING, cd,
303 					  "GET_EVENT and TUR disagree continuously, suppress GET_EVENT events\n");
304 				cd->ignore_get_event = true;
305 			}
306 		} else {
307 			cd->tur_mismatch = 0;
308 		}
309 	}
310 	cd->tur_changed = false;
311 	cd->get_event_changed = false;
312 
313 	return events;
314 }
315 
316 /*
317  * sr_done is the interrupt routine for the device driver.
318  *
319  * It will be notified on the end of a SCSI read / write, and will take one
320  * of several actions based on success or failure.
321  */
322 static int sr_done(struct scsi_cmnd *SCpnt)
323 {
324 	int result = SCpnt->result;
325 	int this_count = scsi_bufflen(SCpnt);
326 	int good_bytes = (result == 0 ? this_count : 0);
327 	int block_sectors = 0;
328 	long error_sector;
329 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
330 
331 #ifdef DEBUG
332 	scmd_printk(KERN_INFO, SCpnt, "done: %x\n", result);
333 #endif
334 
335 	/*
336 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
337 	 * success.  Since this is a relatively rare error condition, no
338 	 * care is taken to avoid unnecessary additional work such as
339 	 * memcpy's that could be avoided.
340 	 */
341 	if (driver_byte(result) != 0 &&		/* An error occurred */
342 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
343 		switch (SCpnt->sense_buffer[2]) {
344 		case MEDIUM_ERROR:
345 		case VOLUME_OVERFLOW:
346 		case ILLEGAL_REQUEST:
347 			if (!(SCpnt->sense_buffer[0] & 0x90))
348 				break;
349 			error_sector =
350 				get_unaligned_be32(&SCpnt->sense_buffer[3]);
351 			if (SCpnt->request->bio != NULL)
352 				block_sectors =
353 					bio_sectors(SCpnt->request->bio);
354 			if (block_sectors < 4)
355 				block_sectors = 4;
356 			if (cd->device->sector_size == 2048)
357 				error_sector <<= 2;
358 			error_sector &= ~(block_sectors - 1);
359 			good_bytes = (error_sector -
360 				      blk_rq_pos(SCpnt->request)) << 9;
361 			if (good_bytes < 0 || good_bytes >= this_count)
362 				good_bytes = 0;
363 			/*
364 			 * The SCSI specification allows for the value
365 			 * returned by READ CAPACITY to be up to 75 2K
366 			 * sectors past the last readable block.
367 			 * Therefore, if we hit a medium error within the
368 			 * last 75 2K sectors, we decrease the saved size
369 			 * value.
370 			 */
371 			if (error_sector < get_capacity(cd->disk) &&
372 			    cd->capacity - error_sector < 4 * 75)
373 				set_capacity(cd->disk, error_sector);
374 			break;
375 
376 		case RECOVERED_ERROR:
377 			good_bytes = this_count;
378 			break;
379 
380 		default:
381 			break;
382 		}
383 	}
384 
385 	return good_bytes;
386 }
387 
388 static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
389 {
390 	int block = 0, this_count, s_size;
391 	struct scsi_cd *cd;
392 	struct request *rq = SCpnt->request;
393 	blk_status_t ret;
394 
395 	ret = scsi_init_io(SCpnt);
396 	if (ret != BLK_STS_OK)
397 		goto out;
398 	cd = scsi_cd(rq->rq_disk);
399 
400 	/* from here on until we're complete, any goto out
401 	 * is used for a killable error condition */
402 	ret = BLK_STS_IOERR;
403 
404 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
405 		"Doing sr request, block = %d\n", block));
406 
407 	if (!cd->device || !scsi_device_online(cd->device)) {
408 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
409 			"Finishing %u sectors\n", blk_rq_sectors(rq)));
410 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
411 			"Retry with 0x%p\n", SCpnt));
412 		goto out;
413 	}
414 
415 	if (cd->device->changed) {
416 		/*
417 		 * quietly refuse to do anything to a changed disc until the
418 		 * changed bit has been reset
419 		 */
420 		goto out;
421 	}
422 
423 	/*
424 	 * we do lazy blocksize switching (when reading XA sectors,
425 	 * see CDROMREADMODE2 ioctl)
426 	 */
427 	s_size = cd->device->sector_size;
428 	if (s_size > 2048) {
429 		if (!in_interrupt())
430 			sr_set_blocklength(cd, 2048);
431 		else
432 			scmd_printk(KERN_INFO, SCpnt,
433 				    "can't switch blocksize: in interrupt\n");
434 	}
435 
436 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
437 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
438 		goto out;
439 	}
440 
441 	switch (req_op(rq)) {
442 	case REQ_OP_WRITE:
443 		if (!cd->writeable)
444 			goto out;
445 		SCpnt->cmnd[0] = WRITE_10;
446 		cd->cdi.media_written = 1;
447 		break;
448 	case REQ_OP_READ:
449 		SCpnt->cmnd[0] = READ_10;
450 		break;
451 	default:
452 		blk_dump_rq_flags(rq, "Unknown sr command");
453 		goto out;
454 	}
455 
456 	{
457 		struct scatterlist *sg;
458 		int i, size = 0, sg_count = scsi_sg_count(SCpnt);
459 
460 		scsi_for_each_sg(SCpnt, sg, sg_count, i)
461 			size += sg->length;
462 
463 		if (size != scsi_bufflen(SCpnt)) {
464 			scmd_printk(KERN_ERR, SCpnt,
465 				"mismatch count %d, bytes %d\n",
466 				size, scsi_bufflen(SCpnt));
467 			if (scsi_bufflen(SCpnt) > size)
468 				SCpnt->sdb.length = size;
469 		}
470 	}
471 
472 	/*
473 	 * request doesn't start on hw block boundary, add scatter pads
474 	 */
475 	if (((unsigned int)blk_rq_pos(rq) % (s_size >> 9)) ||
476 	    (scsi_bufflen(SCpnt) % s_size)) {
477 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
478 		goto out;
479 	}
480 
481 	this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
482 
483 
484 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
485 					"%s %d/%u 512 byte blocks.\n",
486 					(rq_data_dir(rq) == WRITE) ?
487 					"writing" : "reading",
488 					this_count, blk_rq_sectors(rq)));
489 
490 	SCpnt->cmnd[1] = 0;
491 	block = (unsigned int)blk_rq_pos(rq) / (s_size >> 9);
492 
493 	if (this_count > 0xffff) {
494 		this_count = 0xffff;
495 		SCpnt->sdb.length = this_count * s_size;
496 	}
497 
498 	put_unaligned_be32(block, &SCpnt->cmnd[2]);
499 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
500 	put_unaligned_be16(this_count, &SCpnt->cmnd[7]);
501 
502 	/*
503 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
504 	 * host adapter, it's safe to assume that we can at least transfer
505 	 * this many bytes between each connect / disconnect.
506 	 */
507 	SCpnt->transfersize = cd->device->sector_size;
508 	SCpnt->underflow = this_count << 9;
509 	SCpnt->allowed = MAX_RETRIES;
510 
511 	/*
512 	 * This indicates that the command is ready from our end to be
513 	 * queued.
514 	 */
515 	ret = BLK_STS_OK;
516  out:
517 	return ret;
518 }
519 
520 static int sr_block_open(struct block_device *bdev, fmode_t mode)
521 {
522 	struct scsi_cd *cd;
523 	struct scsi_device *sdev;
524 	int ret = -ENXIO;
525 
526 	cd = scsi_cd_get(bdev->bd_disk);
527 	if (!cd)
528 		goto out;
529 
530 	sdev = cd->device;
531 	scsi_autopm_get_device(sdev);
532 	check_disk_change(bdev);
533 
534 	mutex_lock(&cd->lock);
535 	ret = cdrom_open(&cd->cdi, bdev, mode);
536 	mutex_unlock(&cd->lock);
537 
538 	scsi_autopm_put_device(sdev);
539 	if (ret)
540 		scsi_cd_put(cd);
541 
542 out:
543 	return ret;
544 }
545 
546 static void sr_block_release(struct gendisk *disk, fmode_t mode)
547 {
548 	struct scsi_cd *cd = scsi_cd(disk);
549 
550 	mutex_lock(&cd->lock);
551 	cdrom_release(&cd->cdi, mode);
552 	mutex_unlock(&cd->lock);
553 
554 	scsi_cd_put(cd);
555 }
556 
557 static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
558 			  unsigned long arg)
559 {
560 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
561 	struct scsi_device *sdev = cd->device;
562 	void __user *argp = (void __user *)arg;
563 	int ret;
564 
565 	mutex_lock(&cd->lock);
566 
567 	ret = scsi_ioctl_block_when_processing_errors(sdev, cmd,
568 			(mode & FMODE_NDELAY) != 0);
569 	if (ret)
570 		goto out;
571 
572 	scsi_autopm_get_device(sdev);
573 
574 	/*
575 	 * Send SCSI addressing ioctls directly to mid level, send other
576 	 * ioctls to cdrom/block level.
577 	 */
578 	switch (cmd) {
579 	case SCSI_IOCTL_GET_IDLUN:
580 	case SCSI_IOCTL_GET_BUS_NUMBER:
581 		ret = scsi_ioctl(sdev, cmd, argp);
582 		goto put;
583 	}
584 
585 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, arg);
586 	if (ret != -ENOSYS)
587 		goto put;
588 
589 	ret = scsi_ioctl(sdev, cmd, argp);
590 
591 put:
592 	scsi_autopm_put_device(sdev);
593 
594 out:
595 	mutex_unlock(&cd->lock);
596 	return ret;
597 }
598 
599 #ifdef CONFIG_COMPAT
600 static int sr_block_compat_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
601 			  unsigned long arg)
602 {
603 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
604 	struct scsi_device *sdev = cd->device;
605 	void __user *argp = compat_ptr(arg);
606 	int ret;
607 
608 	mutex_lock(&cd->lock);
609 
610 	ret = scsi_ioctl_block_when_processing_errors(sdev, cmd,
611 			(mode & FMODE_NDELAY) != 0);
612 	if (ret)
613 		goto out;
614 
615 	scsi_autopm_get_device(sdev);
616 
617 	/*
618 	 * Send SCSI addressing ioctls directly to mid level, send other
619 	 * ioctls to cdrom/block level.
620 	 */
621 	switch (cmd) {
622 	case SCSI_IOCTL_GET_IDLUN:
623 	case SCSI_IOCTL_GET_BUS_NUMBER:
624 		ret = scsi_compat_ioctl(sdev, cmd, argp);
625 		goto put;
626 	}
627 
628 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, (unsigned long)argp);
629 	if (ret != -ENOSYS)
630 		goto put;
631 
632 	ret = scsi_compat_ioctl(sdev, cmd, argp);
633 
634 put:
635 	scsi_autopm_put_device(sdev);
636 
637 out:
638 	mutex_unlock(&cd->lock);
639 	return ret;
640 
641 }
642 #endif
643 
644 static unsigned int sr_block_check_events(struct gendisk *disk,
645 					  unsigned int clearing)
646 {
647 	unsigned int ret = 0;
648 	struct scsi_cd *cd;
649 
650 	cd = scsi_cd_get(disk);
651 	if (!cd)
652 		return 0;
653 
654 	if (!atomic_read(&cd->device->disk_events_disable_depth))
655 		ret = cdrom_check_events(&cd->cdi, clearing);
656 
657 	scsi_cd_put(cd);
658 	return ret;
659 }
660 
661 static int sr_block_revalidate_disk(struct gendisk *disk)
662 {
663 	struct scsi_sense_hdr sshdr;
664 	struct scsi_cd *cd;
665 
666 	cd = scsi_cd_get(disk);
667 	if (!cd)
668 		return -ENXIO;
669 
670 	/* if the unit is not ready, nothing more to do */
671 	if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
672 		goto out;
673 
674 	sr_cd_check(&cd->cdi);
675 	get_sectorsize(cd);
676 out:
677 	scsi_cd_put(cd);
678 	return 0;
679 }
680 
681 static const struct block_device_operations sr_bdops =
682 {
683 	.owner		= THIS_MODULE,
684 	.open		= sr_block_open,
685 	.release	= sr_block_release,
686 	.ioctl		= sr_block_ioctl,
687 #ifdef CONFIG_COMPAT
688 	.compat_ioctl	= sr_block_compat_ioctl,
689 #endif
690 	.check_events	= sr_block_check_events,
691 	.revalidate_disk = sr_block_revalidate_disk,
692 };
693 
694 static int sr_open(struct cdrom_device_info *cdi, int purpose)
695 {
696 	struct scsi_cd *cd = cdi->handle;
697 	struct scsi_device *sdev = cd->device;
698 	int retval;
699 
700 	/*
701 	 * If the device is in error recovery, wait until it is done.
702 	 * If the device is offline, then disallow any access to it.
703 	 */
704 	retval = -ENXIO;
705 	if (!scsi_block_when_processing_errors(sdev))
706 		goto error_out;
707 
708 	return 0;
709 
710 error_out:
711 	return retval;
712 }
713 
714 static void sr_release(struct cdrom_device_info *cdi)
715 {
716 	struct scsi_cd *cd = cdi->handle;
717 
718 	if (cd->device->sector_size > 2048)
719 		sr_set_blocklength(cd, 2048);
720 
721 }
722 
723 static int sr_probe(struct device *dev)
724 {
725 	struct scsi_device *sdev = to_scsi_device(dev);
726 	struct gendisk *disk;
727 	struct scsi_cd *cd;
728 	int minor, error;
729 
730 	scsi_autopm_get_device(sdev);
731 	error = -ENODEV;
732 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
733 		goto fail;
734 
735 	error = -ENOMEM;
736 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
737 	if (!cd)
738 		goto fail;
739 
740 	kref_init(&cd->kref);
741 
742 	disk = alloc_disk(1);
743 	if (!disk)
744 		goto fail_free;
745 	mutex_init(&cd->lock);
746 
747 	spin_lock(&sr_index_lock);
748 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
749 	if (minor == SR_DISKS) {
750 		spin_unlock(&sr_index_lock);
751 		error = -EBUSY;
752 		goto fail_put;
753 	}
754 	__set_bit(minor, sr_index_bits);
755 	spin_unlock(&sr_index_lock);
756 
757 	disk->major = SCSI_CDROM_MAJOR;
758 	disk->first_minor = minor;
759 	sprintf(disk->disk_name, "sr%d", minor);
760 	disk->fops = &sr_bdops;
761 	disk->flags = GENHD_FL_CD | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
762 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
763 	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT;
764 
765 	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
766 
767 	cd->device = sdev;
768 	cd->disk = disk;
769 	cd->driver = &sr_template;
770 	cd->disk = disk;
771 	cd->capacity = 0x1fffff;
772 	cd->device->changed = 1;	/* force recheck CD type */
773 	cd->media_present = 1;
774 	cd->use = 1;
775 	cd->readcd_known = 0;
776 	cd->readcd_cdda = 0;
777 
778 	cd->cdi.ops = &sr_dops;
779 	cd->cdi.handle = cd;
780 	cd->cdi.mask = 0;
781 	cd->cdi.capacity = 1;
782 	sprintf(cd->cdi.name, "sr%d", minor);
783 
784 	sdev->sector_size = 2048;	/* A guess, just in case */
785 
786 	/* FIXME: need to handle a get_capabilities failure properly ?? */
787 	get_capabilities(cd);
788 	sr_vendor_init(cd);
789 
790 	set_capacity(disk, cd->capacity);
791 	disk->private_data = &cd->driver;
792 	disk->queue = sdev->request_queue;
793 
794 	if (register_cdrom(disk, &cd->cdi))
795 		goto fail_minor;
796 
797 	/*
798 	 * Initialize block layer runtime PM stuffs before the
799 	 * periodic event checking request gets started in add_disk.
800 	 */
801 	blk_pm_runtime_init(sdev->request_queue, dev);
802 
803 	dev_set_drvdata(dev, cd);
804 	disk->flags |= GENHD_FL_REMOVABLE;
805 	device_add_disk(&sdev->sdev_gendev, disk, NULL);
806 
807 	sdev_printk(KERN_DEBUG, sdev,
808 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
809 	scsi_autopm_put_device(cd->device);
810 
811 	return 0;
812 
813 fail_minor:
814 	spin_lock(&sr_index_lock);
815 	clear_bit(minor, sr_index_bits);
816 	spin_unlock(&sr_index_lock);
817 fail_put:
818 	put_disk(disk);
819 	mutex_destroy(&cd->lock);
820 fail_free:
821 	kfree(cd);
822 fail:
823 	scsi_autopm_put_device(sdev);
824 	return error;
825 }
826 
827 
828 static void get_sectorsize(struct scsi_cd *cd)
829 {
830 	unsigned char cmd[10];
831 	unsigned char buffer[8];
832 	int the_result, retries = 3;
833 	int sector_size;
834 	struct request_queue *queue;
835 
836 	do {
837 		cmd[0] = READ_CAPACITY;
838 		memset((void *) &cmd[1], 0, 9);
839 		memset(buffer, 0, sizeof(buffer));
840 
841 		/* Do the command and wait.. */
842 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
843 					      buffer, sizeof(buffer), NULL,
844 					      SR_TIMEOUT, MAX_RETRIES, NULL);
845 
846 		retries--;
847 
848 	} while (the_result && retries);
849 
850 
851 	if (the_result) {
852 		cd->capacity = 0x1fffff;
853 		sector_size = 2048;	/* A guess, just in case */
854 	} else {
855 		long last_written;
856 
857 		cd->capacity = 1 + get_unaligned_be32(&buffer[0]);
858 		/*
859 		 * READ_CAPACITY doesn't return the correct size on
860 		 * certain UDF media.  If last_written is larger, use
861 		 * it instead.
862 		 *
863 		 * http://bugzilla.kernel.org/show_bug.cgi?id=9668
864 		 */
865 		if (!cdrom_get_last_written(&cd->cdi, &last_written))
866 			cd->capacity = max_t(long, cd->capacity, last_written);
867 
868 		sector_size = get_unaligned_be32(&buffer[4]);
869 		switch (sector_size) {
870 			/*
871 			 * HP 4020i CD-Recorder reports 2340 byte sectors
872 			 * Philips CD-Writers report 2352 byte sectors
873 			 *
874 			 * Use 2k sectors for them..
875 			 */
876 		case 0:
877 		case 2340:
878 		case 2352:
879 			sector_size = 2048;
880 			/* fall through */
881 		case 2048:
882 			cd->capacity *= 4;
883 			/* fall through */
884 		case 512:
885 			break;
886 		default:
887 			sr_printk(KERN_INFO, cd,
888 				  "unsupported sector size %d.", sector_size);
889 			cd->capacity = 0;
890 		}
891 
892 		cd->device->sector_size = sector_size;
893 
894 		/*
895 		 * Add this so that we have the ability to correctly gauge
896 		 * what the device is capable of.
897 		 */
898 		set_capacity(cd->disk, cd->capacity);
899 	}
900 
901 	queue = cd->device->request_queue;
902 	blk_queue_logical_block_size(queue, sector_size);
903 
904 	return;
905 }
906 
907 static void get_capabilities(struct scsi_cd *cd)
908 {
909 	unsigned char *buffer;
910 	struct scsi_mode_data data;
911 	struct scsi_sense_hdr sshdr;
912 	unsigned int ms_len = 128;
913 	int rc, n;
914 
915 	static const char *loadmech[] =
916 	{
917 		"caddy",
918 		"tray",
919 		"pop-up",
920 		"",
921 		"changer",
922 		"cartridge changer",
923 		"",
924 		""
925 	};
926 
927 
928 	/* allocate transfer buffer */
929 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
930 	if (!buffer) {
931 		sr_printk(KERN_ERR, cd, "out of memory.\n");
932 		return;
933 	}
934 
935 	/* eat unit attentions */
936 	scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
937 
938 	/* ask for mode page 0x2a */
939 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, ms_len,
940 			     SR_TIMEOUT, 3, &data, NULL);
941 
942 	if (!scsi_status_is_good(rc) || data.length > ms_len ||
943 	    data.header_length + data.block_descriptor_length > data.length) {
944 		/* failed, drive doesn't have capabilities mode page */
945 		cd->cdi.speed = 1;
946 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
947 				 CDC_DVD | CDC_DVD_RAM |
948 				 CDC_SELECT_DISC | CDC_SELECT_SPEED |
949 				 CDC_MRW | CDC_MRW_W | CDC_RAM);
950 		kfree(buffer);
951 		sr_printk(KERN_INFO, cd, "scsi-1 drive");
952 		return;
953 	}
954 
955 	n = data.header_length + data.block_descriptor_length;
956 	cd->cdi.speed = get_unaligned_be16(&buffer[n + 8]) / 176;
957 	cd->readcd_known = 1;
958 	cd->readcd_cdda = buffer[n + 5] & 0x01;
959 	/* print some capability bits */
960 	sr_printk(KERN_INFO, cd,
961 		  "scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n",
962 		  get_unaligned_be16(&buffer[n + 14]) / 176,
963 		  cd->cdi.speed,
964 		  buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
965 		  buffer[n + 3] & 0x20 ? "dvd-ram " : "",
966 		  buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
967 		  buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
968 		  buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
969 		  loadmech[buffer[n + 6] >> 5]);
970 	if ((buffer[n + 6] >> 5) == 0)
971 		/* caddy drives can't close tray... */
972 		cd->cdi.mask |= CDC_CLOSE_TRAY;
973 	if ((buffer[n + 2] & 0x8) == 0)
974 		/* not a DVD drive */
975 		cd->cdi.mask |= CDC_DVD;
976 	if ((buffer[n + 3] & 0x20) == 0)
977 		/* can't write DVD-RAM media */
978 		cd->cdi.mask |= CDC_DVD_RAM;
979 	if ((buffer[n + 3] & 0x10) == 0)
980 		/* can't write DVD-R media */
981 		cd->cdi.mask |= CDC_DVD_R;
982 	if ((buffer[n + 3] & 0x2) == 0)
983 		/* can't write CD-RW media */
984 		cd->cdi.mask |= CDC_CD_RW;
985 	if ((buffer[n + 3] & 0x1) == 0)
986 		/* can't write CD-R media */
987 		cd->cdi.mask |= CDC_CD_R;
988 	if ((buffer[n + 6] & 0x8) == 0)
989 		/* can't eject */
990 		cd->cdi.mask |= CDC_OPEN_TRAY;
991 
992 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
993 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
994 		cd->cdi.capacity =
995 		    cdrom_number_of_slots(&cd->cdi);
996 	if (cd->cdi.capacity <= 1)
997 		/* not a changer */
998 		cd->cdi.mask |= CDC_SELECT_DISC;
999 	/*else    I don't think it can close its tray
1000 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
1001 
1002 	/*
1003 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
1004 	 */
1005 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
1006 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
1007 		cd->writeable = 1;
1008 	}
1009 
1010 	kfree(buffer);
1011 }
1012 
1013 /*
1014  * sr_packet() is the entry point for the generic commands generated
1015  * by the Uniform CD-ROM layer.
1016  */
1017 static int sr_packet(struct cdrom_device_info *cdi,
1018 		struct packet_command *cgc)
1019 {
1020 	struct scsi_cd *cd = cdi->handle;
1021 	struct scsi_device *sdev = cd->device;
1022 
1023 	if (cgc->cmd[0] == GPCMD_READ_DISC_INFO && sdev->no_read_disc_info)
1024 		return -EDRIVE_CANT_DO_THIS;
1025 
1026 	if (cgc->timeout <= 0)
1027 		cgc->timeout = IOCTL_TIMEOUT;
1028 
1029 	sr_do_ioctl(cd, cgc);
1030 
1031 	return cgc->stat;
1032 }
1033 
1034 /**
1035  *	sr_kref_release - Called to free the scsi_cd structure
1036  *	@kref: pointer to embedded kref
1037  *
1038  *	sr_ref_mutex must be held entering this routine.  Because it is
1039  *	called on last put, you should always use the scsi_cd_get()
1040  *	scsi_cd_put() helpers which manipulate the semaphore directly
1041  *	and never do a direct kref_put().
1042  **/
1043 static void sr_kref_release(struct kref *kref)
1044 {
1045 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
1046 	struct gendisk *disk = cd->disk;
1047 
1048 	spin_lock(&sr_index_lock);
1049 	clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
1050 	spin_unlock(&sr_index_lock);
1051 
1052 	unregister_cdrom(&cd->cdi);
1053 
1054 	disk->private_data = NULL;
1055 
1056 	put_disk(disk);
1057 
1058 	mutex_destroy(&cd->lock);
1059 
1060 	kfree(cd);
1061 }
1062 
1063 static int sr_remove(struct device *dev)
1064 {
1065 	struct scsi_cd *cd = dev_get_drvdata(dev);
1066 
1067 	scsi_autopm_get_device(cd->device);
1068 
1069 	del_gendisk(cd->disk);
1070 	dev_set_drvdata(dev, NULL);
1071 
1072 	mutex_lock(&sr_ref_mutex);
1073 	kref_put(&cd->kref, sr_kref_release);
1074 	mutex_unlock(&sr_ref_mutex);
1075 
1076 	return 0;
1077 }
1078 
1079 static int __init init_sr(void)
1080 {
1081 	int rc;
1082 
1083 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
1084 	if (rc)
1085 		return rc;
1086 	rc = scsi_register_driver(&sr_template.gendrv);
1087 	if (rc)
1088 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
1089 
1090 	return rc;
1091 }
1092 
1093 static void __exit exit_sr(void)
1094 {
1095 	scsi_unregister_driver(&sr_template.gendrv);
1096 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
1097 }
1098 
1099 module_init(init_sr);
1100 module_exit(exit_sr);
1101 MODULE_LICENSE("GPL");
1102