xref: /openbmc/linux/drivers/scsi/sr.c (revision e481ff3f)
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 	else if (med->media_event_code == 3)
224 		return DISK_EVENT_EJECT_REQUEST;
225 	return 0;
226 }
227 
228 /*
229  * This function checks to see if the media has been changed or eject
230  * button has been pressed.  It is possible that we have already
231  * sensed a change, or the drive may have sensed one and not yet
232  * reported it.  The past events are accumulated in sdev->changed and
233  * returned together with the current state.
234  */
235 static unsigned int sr_check_events(struct cdrom_device_info *cdi,
236 				    unsigned int clearing, int slot)
237 {
238 	struct scsi_cd *cd = cdi->handle;
239 	bool last_present;
240 	struct scsi_sense_hdr sshdr;
241 	unsigned int events;
242 	int ret;
243 
244 	/* no changer support */
245 	if (CDSL_CURRENT != slot)
246 		return 0;
247 
248 	events = sr_get_events(cd->device);
249 	cd->get_event_changed |= events & DISK_EVENT_MEDIA_CHANGE;
250 
251 	/*
252 	 * If earlier GET_EVENT_STATUS_NOTIFICATION and TUR did not agree
253 	 * for several times in a row.  We rely on TUR only for this likely
254 	 * broken device, to prevent generating incorrect media changed
255 	 * events for every open().
256 	 */
257 	if (cd->ignore_get_event) {
258 		events &= ~DISK_EVENT_MEDIA_CHANGE;
259 		goto do_tur;
260 	}
261 
262 	/*
263 	 * GET_EVENT_STATUS_NOTIFICATION is enough unless MEDIA_CHANGE
264 	 * is being cleared.  Note that there are devices which hang
265 	 * if asked to execute TUR repeatedly.
266 	 */
267 	if (cd->device->changed) {
268 		events |= DISK_EVENT_MEDIA_CHANGE;
269 		cd->device->changed = 0;
270 		cd->tur_changed = true;
271 	}
272 
273 	if (!(clearing & DISK_EVENT_MEDIA_CHANGE))
274 		return events;
275 do_tur:
276 	/* let's see whether the media is there with TUR */
277 	last_present = cd->media_present;
278 	ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
279 
280 	/*
281 	 * Media is considered to be present if TUR succeeds or fails with
282 	 * sense data indicating something other than media-not-present
283 	 * (ASC 0x3a).
284 	 */
285 	cd->media_present = scsi_status_is_good(ret) ||
286 		(scsi_sense_valid(&sshdr) && sshdr.asc != 0x3a);
287 
288 	if (last_present != cd->media_present)
289 		cd->device->changed = 1;
290 
291 	if (cd->device->changed) {
292 		events |= DISK_EVENT_MEDIA_CHANGE;
293 		cd->device->changed = 0;
294 		cd->tur_changed = true;
295 	}
296 
297 	if (cd->ignore_get_event)
298 		return events;
299 
300 	/* check whether GET_EVENT is reporting spurious MEDIA_CHANGE */
301 	if (!cd->tur_changed) {
302 		if (cd->get_event_changed) {
303 			if (cd->tur_mismatch++ > 8) {
304 				sr_printk(KERN_WARNING, cd,
305 					  "GET_EVENT and TUR disagree continuously, suppress GET_EVENT events\n");
306 				cd->ignore_get_event = true;
307 			}
308 		} else {
309 			cd->tur_mismatch = 0;
310 		}
311 	}
312 	cd->tur_changed = false;
313 	cd->get_event_changed = false;
314 
315 	return events;
316 }
317 
318 /*
319  * sr_done is the interrupt routine for the device driver.
320  *
321  * It will be notified on the end of a SCSI read / write, and will take one
322  * of several actions based on success or failure.
323  */
324 static int sr_done(struct scsi_cmnd *SCpnt)
325 {
326 	int result = SCpnt->result;
327 	int this_count = scsi_bufflen(SCpnt);
328 	int good_bytes = (result == 0 ? this_count : 0);
329 	int block_sectors = 0;
330 	long error_sector;
331 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
332 
333 #ifdef DEBUG
334 	scmd_printk(KERN_INFO, SCpnt, "done: %x\n", result);
335 #endif
336 
337 	/*
338 	 * Handle MEDIUM ERRORs or VOLUME OVERFLOWs that indicate partial
339 	 * success.  Since this is a relatively rare error condition, no
340 	 * care is taken to avoid unnecessary additional work such as
341 	 * memcpy's that could be avoided.
342 	 */
343 	if (scsi_status_is_check_condition(result) &&
344 	    (SCpnt->sense_buffer[0] & 0x7f) == 0x70) { /* Sense current */
345 		switch (SCpnt->sense_buffer[2]) {
346 		case MEDIUM_ERROR:
347 		case VOLUME_OVERFLOW:
348 		case ILLEGAL_REQUEST:
349 			if (!(SCpnt->sense_buffer[0] & 0x90))
350 				break;
351 			error_sector =
352 				get_unaligned_be32(&SCpnt->sense_buffer[3]);
353 			if (SCpnt->request->bio != NULL)
354 				block_sectors =
355 					bio_sectors(SCpnt->request->bio);
356 			if (block_sectors < 4)
357 				block_sectors = 4;
358 			if (cd->device->sector_size == 2048)
359 				error_sector <<= 2;
360 			error_sector &= ~(block_sectors - 1);
361 			good_bytes = (error_sector -
362 				      blk_rq_pos(SCpnt->request)) << 9;
363 			if (good_bytes < 0 || good_bytes >= this_count)
364 				good_bytes = 0;
365 			/*
366 			 * The SCSI specification allows for the value
367 			 * returned by READ CAPACITY to be up to 75 2K
368 			 * sectors past the last readable block.
369 			 * Therefore, if we hit a medium error within the
370 			 * last 75 2K sectors, we decrease the saved size
371 			 * value.
372 			 */
373 			if (error_sector < get_capacity(cd->disk) &&
374 			    cd->capacity - error_sector < 4 * 75)
375 				set_capacity(cd->disk, error_sector);
376 			break;
377 
378 		case RECOVERED_ERROR:
379 			good_bytes = this_count;
380 			break;
381 
382 		default:
383 			break;
384 		}
385 	}
386 
387 	return good_bytes;
388 }
389 
390 static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
391 {
392 	int block = 0, this_count, s_size;
393 	struct scsi_cd *cd;
394 	struct request *rq = SCpnt->request;
395 	blk_status_t ret;
396 
397 	ret = scsi_alloc_sgtables(SCpnt);
398 	if (ret != BLK_STS_OK)
399 		return ret;
400 	cd = scsi_cd(rq->rq_disk);
401 
402 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
403 		"Doing sr request, block = %d\n", block));
404 
405 	if (!cd->device || !scsi_device_online(cd->device)) {
406 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
407 			"Finishing %u sectors\n", blk_rq_sectors(rq)));
408 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
409 			"Retry with 0x%p\n", SCpnt));
410 		goto out;
411 	}
412 
413 	if (cd->device->changed) {
414 		/*
415 		 * quietly refuse to do anything to a changed disc until the
416 		 * changed bit has been reset
417 		 */
418 		goto out;
419 	}
420 
421 	s_size = cd->device->sector_size;
422 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
423 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
424 		goto out;
425 	}
426 
427 	switch (req_op(rq)) {
428 	case REQ_OP_WRITE:
429 		if (!cd->writeable)
430 			goto out;
431 		SCpnt->cmnd[0] = WRITE_10;
432 		cd->cdi.media_written = 1;
433 		break;
434 	case REQ_OP_READ:
435 		SCpnt->cmnd[0] = READ_10;
436 		break;
437 	default:
438 		blk_dump_rq_flags(rq, "Unknown sr command");
439 		goto out;
440 	}
441 
442 	{
443 		struct scatterlist *sg;
444 		int i, size = 0, sg_count = scsi_sg_count(SCpnt);
445 
446 		scsi_for_each_sg(SCpnt, sg, sg_count, i)
447 			size += sg->length;
448 
449 		if (size != scsi_bufflen(SCpnt)) {
450 			scmd_printk(KERN_ERR, SCpnt,
451 				"mismatch count %d, bytes %d\n",
452 				size, scsi_bufflen(SCpnt));
453 			if (scsi_bufflen(SCpnt) > size)
454 				SCpnt->sdb.length = size;
455 		}
456 	}
457 
458 	/*
459 	 * request doesn't start on hw block boundary, add scatter pads
460 	 */
461 	if (((unsigned int)blk_rq_pos(rq) % (s_size >> 9)) ||
462 	    (scsi_bufflen(SCpnt) % s_size)) {
463 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
464 		goto out;
465 	}
466 
467 	this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
468 
469 
470 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
471 					"%s %d/%u 512 byte blocks.\n",
472 					(rq_data_dir(rq) == WRITE) ?
473 					"writing" : "reading",
474 					this_count, blk_rq_sectors(rq)));
475 
476 	SCpnt->cmnd[1] = 0;
477 	block = (unsigned int)blk_rq_pos(rq) / (s_size >> 9);
478 
479 	if (this_count > 0xffff) {
480 		this_count = 0xffff;
481 		SCpnt->sdb.length = this_count * s_size;
482 	}
483 
484 	put_unaligned_be32(block, &SCpnt->cmnd[2]);
485 	SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
486 	put_unaligned_be16(this_count, &SCpnt->cmnd[7]);
487 
488 	/*
489 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
490 	 * host adapter, it's safe to assume that we can at least transfer
491 	 * this many bytes between each connect / disconnect.
492 	 */
493 	SCpnt->transfersize = cd->device->sector_size;
494 	SCpnt->underflow = this_count << 9;
495 	SCpnt->allowed = MAX_RETRIES;
496 	SCpnt->cmd_len = 10;
497 
498 	/*
499 	 * This indicates that the command is ready from our end to be queued.
500 	 */
501 	return BLK_STS_OK;
502  out:
503 	scsi_free_sgtables(SCpnt);
504 	return BLK_STS_IOERR;
505 }
506 
507 static void sr_revalidate_disk(struct scsi_cd *cd)
508 {
509 	struct scsi_sense_hdr sshdr;
510 
511 	/* if the unit is not ready, nothing more to do */
512 	if (scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr))
513 		return;
514 	sr_cd_check(&cd->cdi);
515 	get_sectorsize(cd);
516 }
517 
518 static int sr_block_open(struct block_device *bdev, fmode_t mode)
519 {
520 	struct scsi_cd *cd;
521 	struct scsi_device *sdev;
522 	int ret = -ENXIO;
523 
524 	cd = scsi_cd_get(bdev->bd_disk);
525 	if (!cd)
526 		goto out;
527 
528 	sdev = cd->device;
529 	scsi_autopm_get_device(sdev);
530 	if (bdev_check_media_change(bdev))
531 		sr_revalidate_disk(cd);
532 
533 	mutex_lock(&cd->lock);
534 	ret = cdrom_open(&cd->cdi, bdev, mode);
535 	mutex_unlock(&cd->lock);
536 
537 	scsi_autopm_put_device(sdev);
538 	if (ret)
539 		scsi_cd_put(cd);
540 
541 out:
542 	return ret;
543 }
544 
545 static void sr_block_release(struct gendisk *disk, fmode_t mode)
546 {
547 	struct scsi_cd *cd = scsi_cd(disk);
548 
549 	mutex_lock(&cd->lock);
550 	cdrom_release(&cd->cdi, mode);
551 	mutex_unlock(&cd->lock);
552 
553 	scsi_cd_put(cd);
554 }
555 
556 static int sr_block_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
557 			  unsigned long arg)
558 {
559 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
560 	struct scsi_device *sdev = cd->device;
561 	void __user *argp = (void __user *)arg;
562 	int ret;
563 
564 	mutex_lock(&cd->lock);
565 
566 	ret = scsi_ioctl_block_when_processing_errors(sdev, cmd,
567 			(mode & FMODE_NDELAY) != 0);
568 	if (ret)
569 		goto out;
570 
571 	scsi_autopm_get_device(sdev);
572 
573 	/*
574 	 * Send SCSI addressing ioctls directly to mid level, send other
575 	 * ioctls to cdrom/block level.
576 	 */
577 	switch (cmd) {
578 	case SCSI_IOCTL_GET_IDLUN:
579 	case SCSI_IOCTL_GET_BUS_NUMBER:
580 		ret = scsi_ioctl(sdev, cmd, argp);
581 		goto put;
582 	}
583 
584 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, arg);
585 	if (ret != -ENOSYS)
586 		goto put;
587 
588 	ret = scsi_ioctl(sdev, cmd, argp);
589 
590 put:
591 	scsi_autopm_put_device(sdev);
592 
593 out:
594 	mutex_unlock(&cd->lock);
595 	return ret;
596 }
597 
598 #ifdef CONFIG_COMPAT
599 static int sr_block_compat_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
600 			  unsigned long arg)
601 {
602 	struct scsi_cd *cd = scsi_cd(bdev->bd_disk);
603 	struct scsi_device *sdev = cd->device;
604 	void __user *argp = compat_ptr(arg);
605 	int ret;
606 
607 	mutex_lock(&cd->lock);
608 
609 	ret = scsi_ioctl_block_when_processing_errors(sdev, cmd,
610 			(mode & FMODE_NDELAY) != 0);
611 	if (ret)
612 		goto out;
613 
614 	scsi_autopm_get_device(sdev);
615 
616 	/*
617 	 * Send SCSI addressing ioctls directly to mid level, send other
618 	 * ioctls to cdrom/block level.
619 	 */
620 	switch (cmd) {
621 	case SCSI_IOCTL_GET_IDLUN:
622 	case SCSI_IOCTL_GET_BUS_NUMBER:
623 		ret = scsi_compat_ioctl(sdev, cmd, argp);
624 		goto put;
625 	}
626 
627 	ret = cdrom_ioctl(&cd->cdi, bdev, mode, cmd, (unsigned long)argp);
628 	if (ret != -ENOSYS)
629 		goto put;
630 
631 	ret = scsi_compat_ioctl(sdev, cmd, argp);
632 
633 put:
634 	scsi_autopm_put_device(sdev);
635 
636 out:
637 	mutex_unlock(&cd->lock);
638 	return ret;
639 
640 }
641 #endif
642 
643 static unsigned int sr_block_check_events(struct gendisk *disk,
644 					  unsigned int clearing)
645 {
646 	unsigned int ret = 0;
647 	struct scsi_cd *cd;
648 
649 	cd = scsi_cd_get(disk);
650 	if (!cd)
651 		return 0;
652 
653 	if (!atomic_read(&cd->device->disk_events_disable_depth))
654 		ret = cdrom_check_events(&cd->cdi, clearing);
655 
656 	scsi_cd_put(cd);
657 	return ret;
658 }
659 
660 static const struct block_device_operations sr_bdops =
661 {
662 	.owner		= THIS_MODULE,
663 	.open		= sr_block_open,
664 	.release	= sr_block_release,
665 	.ioctl		= sr_block_ioctl,
666 #ifdef CONFIG_COMPAT
667 	.compat_ioctl	= sr_block_compat_ioctl,
668 #endif
669 	.check_events	= sr_block_check_events,
670 };
671 
672 static int sr_open(struct cdrom_device_info *cdi, int purpose)
673 {
674 	struct scsi_cd *cd = cdi->handle;
675 	struct scsi_device *sdev = cd->device;
676 	int retval;
677 
678 	/*
679 	 * If the device is in error recovery, wait until it is done.
680 	 * If the device is offline, then disallow any access to it.
681 	 */
682 	retval = -ENXIO;
683 	if (!scsi_block_when_processing_errors(sdev))
684 		goto error_out;
685 
686 	return 0;
687 
688 error_out:
689 	return retval;
690 }
691 
692 static void sr_release(struct cdrom_device_info *cdi)
693 {
694 }
695 
696 static int sr_probe(struct device *dev)
697 {
698 	struct scsi_device *sdev = to_scsi_device(dev);
699 	struct gendisk *disk;
700 	struct scsi_cd *cd;
701 	int minor, error;
702 
703 	scsi_autopm_get_device(sdev);
704 	error = -ENODEV;
705 	if (sdev->type != TYPE_ROM && sdev->type != TYPE_WORM)
706 		goto fail;
707 
708 	error = -ENOMEM;
709 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
710 	if (!cd)
711 		goto fail;
712 
713 	kref_init(&cd->kref);
714 
715 	disk = alloc_disk(1);
716 	if (!disk)
717 		goto fail_free;
718 	mutex_init(&cd->lock);
719 
720 	spin_lock(&sr_index_lock);
721 	minor = find_first_zero_bit(sr_index_bits, SR_DISKS);
722 	if (minor == SR_DISKS) {
723 		spin_unlock(&sr_index_lock);
724 		error = -EBUSY;
725 		goto fail_put;
726 	}
727 	__set_bit(minor, sr_index_bits);
728 	spin_unlock(&sr_index_lock);
729 
730 	disk->major = SCSI_CDROM_MAJOR;
731 	disk->first_minor = minor;
732 	sprintf(disk->disk_name, "sr%d", minor);
733 	disk->fops = &sr_bdops;
734 	disk->flags = GENHD_FL_CD | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
735 	disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
736 	disk->event_flags = DISK_EVENT_FLAG_POLL | DISK_EVENT_FLAG_UEVENT;
737 
738 	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
739 
740 	cd->device = sdev;
741 	cd->disk = disk;
742 	cd->driver = &sr_template;
743 	cd->disk = disk;
744 	cd->capacity = 0x1fffff;
745 	cd->device->changed = 1;	/* force recheck CD type */
746 	cd->media_present = 1;
747 	cd->use = 1;
748 	cd->readcd_known = 0;
749 	cd->readcd_cdda = 0;
750 
751 	cd->cdi.ops = &sr_dops;
752 	cd->cdi.handle = cd;
753 	cd->cdi.mask = 0;
754 	cd->cdi.capacity = 1;
755 	sprintf(cd->cdi.name, "sr%d", minor);
756 
757 	sdev->sector_size = 2048;	/* A guess, just in case */
758 
759 	/* FIXME: need to handle a get_capabilities failure properly ?? */
760 	get_capabilities(cd);
761 	sr_vendor_init(cd);
762 
763 	set_capacity(disk, cd->capacity);
764 	disk->private_data = &cd->driver;
765 	disk->queue = sdev->request_queue;
766 
767 	if (register_cdrom(disk, &cd->cdi))
768 		goto fail_minor;
769 
770 	/*
771 	 * Initialize block layer runtime PM stuffs before the
772 	 * periodic event checking request gets started in add_disk.
773 	 */
774 	blk_pm_runtime_init(sdev->request_queue, dev);
775 
776 	dev_set_drvdata(dev, cd);
777 	disk->flags |= GENHD_FL_REMOVABLE;
778 	sr_revalidate_disk(cd);
779 	device_add_disk(&sdev->sdev_gendev, disk, NULL);
780 
781 	sdev_printk(KERN_DEBUG, sdev,
782 		    "Attached scsi CD-ROM %s\n", cd->cdi.name);
783 	scsi_autopm_put_device(cd->device);
784 
785 	return 0;
786 
787 fail_minor:
788 	spin_lock(&sr_index_lock);
789 	clear_bit(minor, sr_index_bits);
790 	spin_unlock(&sr_index_lock);
791 fail_put:
792 	put_disk(disk);
793 	mutex_destroy(&cd->lock);
794 fail_free:
795 	kfree(cd);
796 fail:
797 	scsi_autopm_put_device(sdev);
798 	return error;
799 }
800 
801 
802 static void get_sectorsize(struct scsi_cd *cd)
803 {
804 	unsigned char cmd[10];
805 	unsigned char buffer[8];
806 	int the_result, retries = 3;
807 	int sector_size;
808 	struct request_queue *queue;
809 
810 	do {
811 		cmd[0] = READ_CAPACITY;
812 		memset((void *) &cmd[1], 0, 9);
813 		memset(buffer, 0, sizeof(buffer));
814 
815 		/* Do the command and wait.. */
816 		the_result = scsi_execute_req(cd->device, cmd, DMA_FROM_DEVICE,
817 					      buffer, sizeof(buffer), NULL,
818 					      SR_TIMEOUT, MAX_RETRIES, NULL);
819 
820 		retries--;
821 
822 	} while (the_result && retries);
823 
824 
825 	if (the_result) {
826 		cd->capacity = 0x1fffff;
827 		sector_size = 2048;	/* A guess, just in case */
828 	} else {
829 		long last_written;
830 
831 		cd->capacity = 1 + get_unaligned_be32(&buffer[0]);
832 		/*
833 		 * READ_CAPACITY doesn't return the correct size on
834 		 * certain UDF media.  If last_written is larger, use
835 		 * it instead.
836 		 *
837 		 * http://bugzilla.kernel.org/show_bug.cgi?id=9668
838 		 */
839 		if (!cdrom_get_last_written(&cd->cdi, &last_written))
840 			cd->capacity = max_t(long, cd->capacity, last_written);
841 
842 		sector_size = get_unaligned_be32(&buffer[4]);
843 		switch (sector_size) {
844 			/*
845 			 * HP 4020i CD-Recorder reports 2340 byte sectors
846 			 * Philips CD-Writers report 2352 byte sectors
847 			 *
848 			 * Use 2k sectors for them..
849 			 */
850 		case 0:
851 		case 2340:
852 		case 2352:
853 			sector_size = 2048;
854 			fallthrough;
855 		case 2048:
856 			cd->capacity *= 4;
857 			fallthrough;
858 		case 512:
859 			break;
860 		default:
861 			sr_printk(KERN_INFO, cd,
862 				  "unsupported sector size %d.", sector_size);
863 			cd->capacity = 0;
864 		}
865 
866 		cd->device->sector_size = sector_size;
867 
868 		/*
869 		 * Add this so that we have the ability to correctly gauge
870 		 * what the device is capable of.
871 		 */
872 		set_capacity(cd->disk, cd->capacity);
873 	}
874 
875 	queue = cd->device->request_queue;
876 	blk_queue_logical_block_size(queue, sector_size);
877 
878 	return;
879 }
880 
881 static void get_capabilities(struct scsi_cd *cd)
882 {
883 	unsigned char *buffer;
884 	struct scsi_mode_data data;
885 	struct scsi_sense_hdr sshdr;
886 	unsigned int ms_len = 128;
887 	int rc, n;
888 
889 	static const char *loadmech[] =
890 	{
891 		"caddy",
892 		"tray",
893 		"pop-up",
894 		"",
895 		"changer",
896 		"cartridge changer",
897 		"",
898 		""
899 	};
900 
901 
902 	/* allocate transfer buffer */
903 	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
904 	if (!buffer) {
905 		sr_printk(KERN_ERR, cd, "out of memory.\n");
906 		return;
907 	}
908 
909 	/* eat unit attentions */
910 	scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
911 
912 	/* ask for mode page 0x2a */
913 	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, ms_len,
914 			     SR_TIMEOUT, 3, &data, NULL);
915 
916 	if (rc < 0 || data.length > ms_len ||
917 	    data.header_length + data.block_descriptor_length > data.length) {
918 		/* failed, drive doesn't have capabilities mode page */
919 		cd->cdi.speed = 1;
920 		cd->cdi.mask |= (CDC_CD_R | CDC_CD_RW | CDC_DVD_R |
921 				 CDC_DVD | CDC_DVD_RAM |
922 				 CDC_SELECT_DISC | CDC_SELECT_SPEED |
923 				 CDC_MRW | CDC_MRW_W | CDC_RAM);
924 		kfree(buffer);
925 		sr_printk(KERN_INFO, cd, "scsi-1 drive");
926 		return;
927 	}
928 
929 	n = data.header_length + data.block_descriptor_length;
930 	cd->cdi.speed = get_unaligned_be16(&buffer[n + 8]) / 176;
931 	cd->readcd_known = 1;
932 	cd->readcd_cdda = buffer[n + 5] & 0x01;
933 	/* print some capability bits */
934 	sr_printk(KERN_INFO, cd,
935 		  "scsi3-mmc drive: %dx/%dx %s%s%s%s%s%s\n",
936 		  get_unaligned_be16(&buffer[n + 14]) / 176,
937 		  cd->cdi.speed,
938 		  buffer[n + 3] & 0x01 ? "writer " : "", /* CD Writer */
939 		  buffer[n + 3] & 0x20 ? "dvd-ram " : "",
940 		  buffer[n + 2] & 0x02 ? "cd/rw " : "", /* can read rewriteable */
941 		  buffer[n + 4] & 0x20 ? "xa/form2 " : "",	/* can read xa/from2 */
942 		  buffer[n + 5] & 0x01 ? "cdda " : "", /* can read audio data */
943 		  loadmech[buffer[n + 6] >> 5]);
944 	if ((buffer[n + 6] >> 5) == 0)
945 		/* caddy drives can't close tray... */
946 		cd->cdi.mask |= CDC_CLOSE_TRAY;
947 	if ((buffer[n + 2] & 0x8) == 0)
948 		/* not a DVD drive */
949 		cd->cdi.mask |= CDC_DVD;
950 	if ((buffer[n + 3] & 0x20) == 0)
951 		/* can't write DVD-RAM media */
952 		cd->cdi.mask |= CDC_DVD_RAM;
953 	if ((buffer[n + 3] & 0x10) == 0)
954 		/* can't write DVD-R media */
955 		cd->cdi.mask |= CDC_DVD_R;
956 	if ((buffer[n + 3] & 0x2) == 0)
957 		/* can't write CD-RW media */
958 		cd->cdi.mask |= CDC_CD_RW;
959 	if ((buffer[n + 3] & 0x1) == 0)
960 		/* can't write CD-R media */
961 		cd->cdi.mask |= CDC_CD_R;
962 	if ((buffer[n + 6] & 0x8) == 0)
963 		/* can't eject */
964 		cd->cdi.mask |= CDC_OPEN_TRAY;
965 
966 	if ((buffer[n + 6] >> 5) == mechtype_individual_changer ||
967 	    (buffer[n + 6] >> 5) == mechtype_cartridge_changer)
968 		cd->cdi.capacity =
969 		    cdrom_number_of_slots(&cd->cdi);
970 	if (cd->cdi.capacity <= 1)
971 		/* not a changer */
972 		cd->cdi.mask |= CDC_SELECT_DISC;
973 	/*else    I don't think it can close its tray
974 		cd->cdi.mask |= CDC_CLOSE_TRAY; */
975 
976 	/*
977 	 * if DVD-RAM, MRW-W or CD-RW, we are randomly writable
978 	 */
979 	if ((cd->cdi.mask & (CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) !=
980 			(CDC_DVD_RAM | CDC_MRW_W | CDC_RAM | CDC_CD_RW)) {
981 		cd->writeable = 1;
982 	}
983 
984 	kfree(buffer);
985 }
986 
987 /*
988  * sr_packet() is the entry point for the generic commands generated
989  * by the Uniform CD-ROM layer.
990  */
991 static int sr_packet(struct cdrom_device_info *cdi,
992 		struct packet_command *cgc)
993 {
994 	struct scsi_cd *cd = cdi->handle;
995 	struct scsi_device *sdev = cd->device;
996 
997 	if (cgc->cmd[0] == GPCMD_READ_DISC_INFO && sdev->no_read_disc_info)
998 		return -EDRIVE_CANT_DO_THIS;
999 
1000 	if (cgc->timeout <= 0)
1001 		cgc->timeout = IOCTL_TIMEOUT;
1002 
1003 	sr_do_ioctl(cd, cgc);
1004 
1005 	return cgc->stat;
1006 }
1007 
1008 /**
1009  *	sr_kref_release - Called to free the scsi_cd structure
1010  *	@kref: pointer to embedded kref
1011  *
1012  *	sr_ref_mutex must be held entering this routine.  Because it is
1013  *	called on last put, you should always use the scsi_cd_get()
1014  *	scsi_cd_put() helpers which manipulate the semaphore directly
1015  *	and never do a direct kref_put().
1016  **/
1017 static void sr_kref_release(struct kref *kref)
1018 {
1019 	struct scsi_cd *cd = container_of(kref, struct scsi_cd, kref);
1020 	struct gendisk *disk = cd->disk;
1021 
1022 	spin_lock(&sr_index_lock);
1023 	clear_bit(MINOR(disk_devt(disk)), sr_index_bits);
1024 	spin_unlock(&sr_index_lock);
1025 
1026 	unregister_cdrom(&cd->cdi);
1027 
1028 	disk->private_data = NULL;
1029 
1030 	put_disk(disk);
1031 
1032 	mutex_destroy(&cd->lock);
1033 
1034 	kfree(cd);
1035 }
1036 
1037 static int sr_remove(struct device *dev)
1038 {
1039 	struct scsi_cd *cd = dev_get_drvdata(dev);
1040 
1041 	scsi_autopm_get_device(cd->device);
1042 
1043 	del_gendisk(cd->disk);
1044 	dev_set_drvdata(dev, NULL);
1045 
1046 	mutex_lock(&sr_ref_mutex);
1047 	kref_put(&cd->kref, sr_kref_release);
1048 	mutex_unlock(&sr_ref_mutex);
1049 
1050 	return 0;
1051 }
1052 
1053 static int __init init_sr(void)
1054 {
1055 	int rc;
1056 
1057 	rc = register_blkdev(SCSI_CDROM_MAJOR, "sr");
1058 	if (rc)
1059 		return rc;
1060 	rc = scsi_register_driver(&sr_template.gendrv);
1061 	if (rc)
1062 		unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
1063 
1064 	return rc;
1065 }
1066 
1067 static void __exit exit_sr(void)
1068 {
1069 	scsi_unregister_driver(&sr_template.gendrv);
1070 	unregister_blkdev(SCSI_CDROM_MAJOR, "sr");
1071 }
1072 
1073 module_init(init_sr);
1074 module_exit(exit_sr);
1075 MODULE_LICENSE("GPL");
1076