free electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
/*
 * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 *
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/cdrom.h>
#include <linux/ratelimit.h>
#include <linux/slab.h>
#include <linux/times.h>
#include <linux/uio.h>
#include <linux/uaccess.h>

#include <scsi/scsi.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_cmnd.h>

struct blk_cmd_filter {
	unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
	unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
};

static struct blk_cmd_filter blk_default_cmd_filter;

/* Command group 3 is reserved and should never be used.  */
const unsigned char scsi_command_size_tbl[8] =
{
	6, 10, 10, 12,
	16, 12, 10, 10
};
EXPORT_SYMBOL(scsi_command_size_tbl);

#include <scsi/sg.h>

static int sg_get_version(int __user *p)
{
	static const int sg_version_num = 30527;
	return put_user(sg_version_num, p);
}

static int scsi_get_idlun(struct request_queue *q, int __user *p)
{
	return put_user(0, p);
}

static int scsi_get_bus(struct request_queue *q, int __user *p)
{
	return put_user(0, p);
}

static int sg_get_timeout(struct request_queue *q)
{
	return jiffies_to_clock_t(q->sg_timeout);
}

static int sg_set_timeout(struct request_queue *q, int __user *p)
{
	int timeout, err = get_user(timeout, p);

	if (!err)
		q->sg_timeout = clock_t_to_jiffies(timeout);

	return err;
}

static int max_sectors_bytes(struct request_queue *q)
{
	unsigned int max_sectors = queue_max_sectors(q);

	max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);

	return max_sectors << 9;
}

static int sg_get_reserved_size(struct request_queue *q, int __user *p)
{
	int val = min_t(int, q->sg_reserved_size, max_sectors_bytes(q));

	return put_user(val, p);
}

static int sg_set_reserved_size(struct request_queue *q, int __user *p)
{
	int size, err = get_user(size, p);

	if (err)
		return err;

	if (size < 0)
		return -EINVAL;

	q->sg_reserved_size = min(size, max_sectors_bytes(q));
	return 0;
}

/*
 * will always return that we are ATAPI even for a real SCSI drive, I'm not
 * so sure this is worth doing anything about (why would you care??)
 */
static int sg_emulated_host(struct request_queue *q, int __user *p)
{
	return put_user(1, p);
}

static void blk_set_cmd_filter_defaults(struct blk_cmd_filter *filter)
{
	/* Basic read-only commands */
	__set_bit(TEST_UNIT_READY, filter->read_ok);
	__set_bit(REQUEST_SENSE, filter->read_ok);
	__set_bit(READ_6, filter->read_ok);
	__set_bit(READ_10, filter->read_ok);
	__set_bit(READ_12, filter->read_ok);
	__set_bit(READ_16, filter->read_ok);
	__set_bit(READ_BUFFER, filter->read_ok);
	__set_bit(READ_DEFECT_DATA, filter->read_ok);
	__set_bit(READ_CAPACITY, filter->read_ok);
	__set_bit(READ_LONG, filter->read_ok);
	__set_bit(INQUIRY, filter->read_ok);
	__set_bit(MODE_SENSE, filter->read_ok);
	__set_bit(MODE_SENSE_10, filter->read_ok);
	__set_bit(LOG_SENSE, filter->read_ok);
	__set_bit(START_STOP, filter->read_ok);
	__set_bit(GPCMD_VERIFY_10, filter->read_ok);
	__set_bit(VERIFY_16, filter->read_ok);
	__set_bit(REPORT_LUNS, filter->read_ok);
	__set_bit(SERVICE_ACTION_IN_16, filter->read_ok);
	__set_bit(RECEIVE_DIAGNOSTIC, filter->read_ok);
	__set_bit(MAINTENANCE_IN, filter->read_ok);
	__set_bit(GPCMD_READ_BUFFER_CAPACITY, filter->read_ok);

	/* Audio CD commands */
	__set_bit(GPCMD_PLAY_CD, filter->read_ok);
	__set_bit(GPCMD_PLAY_AUDIO_10, filter->read_ok);
	__set_bit(GPCMD_PLAY_AUDIO_MSF, filter->read_ok);
	__set_bit(GPCMD_PLAY_AUDIO_TI, filter->read_ok);
	__set_bit(GPCMD_PAUSE_RESUME, filter->read_ok);

	/* CD/DVD data reading */
	__set_bit(GPCMD_READ_CD, filter->read_ok);
	__set_bit(GPCMD_READ_CD_MSF, filter->read_ok);
	__set_bit(GPCMD_READ_DISC_INFO, filter->read_ok);
	__set_bit(GPCMD_READ_CDVD_CAPACITY, filter->read_ok);
	__set_bit(GPCMD_READ_DVD_STRUCTURE, filter->read_ok);
	__set_bit(GPCMD_READ_HEADER, filter->read_ok);
	__set_bit(GPCMD_READ_TRACK_RZONE_INFO, filter->read_ok);
	__set_bit(GPCMD_READ_SUBCHANNEL, filter->read_ok);
	__set_bit(GPCMD_READ_TOC_PMA_ATIP, filter->read_ok);
	__set_bit(GPCMD_REPORT_KEY, filter->read_ok);
	__set_bit(GPCMD_SCAN, filter->read_ok);
	__set_bit(GPCMD_GET_CONFIGURATION, filter->read_ok);
	__set_bit(GPCMD_READ_FORMAT_CAPACITIES, filter->read_ok);
	__set_bit(GPCMD_GET_EVENT_STATUS_NOTIFICATION, filter->read_ok);
	__set_bit(GPCMD_GET_PERFORMANCE, filter->read_ok);
	__set_bit(GPCMD_SEEK, filter->read_ok);
	__set_bit(GPCMD_STOP_PLAY_SCAN, filter->read_ok);

	/* Basic writing commands */
	__set_bit(WRITE_6, filter->write_ok);
	__set_bit(WRITE_10, filter->write_ok);
	__set_bit(WRITE_VERIFY, filter->write_ok);
	__set_bit(WRITE_12, filter->write_ok);
	__set_bit(WRITE_VERIFY_12, filter->write_ok);
	__set_bit(WRITE_16, filter->write_ok);
	__set_bit(WRITE_LONG, filter->write_ok);
	__set_bit(WRITE_LONG_2, filter->write_ok);
	__set_bit(WRITE_SAME, filter->write_ok);
	__set_bit(WRITE_SAME_16, filter->write_ok);
	__set_bit(WRITE_SAME_32, filter->write_ok);
	__set_bit(ERASE, filter->write_ok);
	__set_bit(GPCMD_MODE_SELECT_10, filter->write_ok);
	__set_bit(MODE_SELECT, filter->write_ok);
	__set_bit(LOG_SELECT, filter->write_ok);
	__set_bit(GPCMD_BLANK, filter->write_ok);
	__set_bit(GPCMD_CLOSE_TRACK, filter->write_ok);
	__set_bit(GPCMD_FLUSH_CACHE, filter->write_ok);
	__set_bit(GPCMD_FORMAT_UNIT, filter->write_ok);
	__set_bit(GPCMD_REPAIR_RZONE_TRACK, filter->write_ok);
	__set_bit(GPCMD_RESERVE_RZONE_TRACK, filter->write_ok);
	__set_bit(GPCMD_SEND_DVD_STRUCTURE, filter->write_ok);
	__set_bit(GPCMD_SEND_EVENT, filter->write_ok);
	__set_bit(GPCMD_SEND_KEY, filter->write_ok);
	__set_bit(GPCMD_SEND_OPC, filter->write_ok);
	__set_bit(GPCMD_SEND_CUE_SHEET, filter->write_ok);
	__set_bit(GPCMD_SET_SPEED, filter->write_ok);
	__set_bit(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, filter->write_ok);
	__set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok);
	__set_bit(GPCMD_SET_STREAMING, filter->write_ok);
	__set_bit(GPCMD_SET_READ_AHEAD, filter->write_ok);
}

int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm)
{
	struct blk_cmd_filter *filter = &blk_default_cmd_filter;

	/* root can do any command. */
	if (capable(CAP_SYS_RAWIO))
		return 0;

	/* Anybody who can open the device can do a read-safe command */
	if (test_bit(cmd[0], filter->read_ok))
		return 0;

	/* Write-safe commands require a writable open */
	if (test_bit(cmd[0], filter->write_ok) && has_write_perm)
		return 0;

	return -EPERM;
}
EXPORT_SYMBOL(blk_verify_command);

static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq,
			     struct sg_io_hdr *hdr, fmode_t mode)
{
	struct scsi_request *req = scsi_req(rq);

	if (copy_from_user(req->cmd, hdr->cmdp, hdr->cmd_len))
		return -EFAULT;
	if (blk_verify_command(req->cmd, mode & FMODE_WRITE))
		return -EPERM;

	/*
	 * fill in request structure
	 */
	req->cmd_len = hdr->cmd_len;

	rq->timeout = msecs_to_jiffies(hdr->timeout);
	if (!rq->timeout)
		rq->timeout = q->sg_timeout;
	if (!rq->timeout)
		rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
	if (rq->timeout < BLK_MIN_SG_TIMEOUT)
		rq->timeout = BLK_MIN_SG_TIMEOUT;

	return 0;
}

static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
				 struct bio *bio)
{
	struct scsi_request *req = scsi_req(rq);
	int r, ret = 0;

	/*
	 * fill in all the output members
	 */
	hdr->status = rq->errors & 0xff;
	hdr->masked_status = status_byte(rq->errors);
	hdr->msg_status = msg_byte(rq->errors);
	hdr->host_status = host_byte(rq->errors);
	hdr->driver_status = driver_byte(rq->errors);
	hdr->info = 0;
	if (hdr->masked_status || hdr->host_status || hdr->driver_status)
		hdr->info |= SG_INFO_CHECK;
	hdr->resid = req->resid_len;
	hdr->sb_len_wr = 0;

	if (req->sense_len && hdr->sbp) {
		int len = min((unsigned int) hdr->mx_sb_len, req->sense_len);

		if (!copy_to_user(hdr->sbp, req->sense, len))
			hdr->sb_len_wr = len;
		else
			ret = -EFAULT;
	}

	r = blk_rq_unmap_user(bio);
	if (!ret)
		ret = r;

	return ret;
}

static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
		struct sg_io_hdr *hdr, fmode_t mode)
{
	unsigned long start_time;
	ssize_t ret = 0;
	int writing = 0;
	int at_head = 0;
	struct request *rq;
	struct scsi_request *req;
	struct bio *bio;

	if (hdr->interface_id != 'S')
		return -EINVAL;

	if (hdr->dxfer_len > (queue_max_hw_sectors(q) << 9))
		return -EIO;

	if (hdr->dxfer_len)
		switch (hdr->dxfer_direction) {
		default:
			return -EINVAL;
		case SG_DXFER_TO_DEV:
			writing = 1;
			break;
		case SG_DXFER_TO_FROM_DEV:
		case SG_DXFER_FROM_DEV:
			break;
		}
	if (hdr->flags & SG_FLAG_Q_AT_HEAD)
		at_head = 1;

	ret = -ENOMEM;
	rq = blk_get_request(q, writing ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
			GFP_KERNEL);
	if (IS_ERR(rq))
		return PTR_ERR(rq);
	req = scsi_req(rq);
	scsi_req_init(rq);

	if (hdr->cmd_len > BLK_MAX_CDB) {
		req->cmd = kzalloc(hdr->cmd_len, GFP_KERNEL);
		if (!req->cmd)
			goto out_put_request;
	}

	ret = blk_fill_sghdr_rq(q, rq, hdr, mode);
	if (ret < 0)
		goto out_free_cdb;

	ret = 0;
	if (hdr->iovec_count) {
		struct iov_iter i;
		struct iovec *iov = NULL;

		ret = import_iovec(rq_data_dir(rq),
				   hdr->dxferp, hdr->iovec_count,
				   0, &iov, &i);
		if (ret < 0)
			goto out_free_cdb;

		/* SG_IO howto says that the shorter of the two wins */
		iov_iter_truncate(&i, hdr->dxfer_len);

		ret = blk_rq_map_user_iov(q, rq, NULL, &i, GFP_KERNEL);
		kfree(iov);
	} else if (hdr->dxfer_len)
		ret = blk_rq_map_user(q, rq, NULL, hdr->dxferp, hdr->dxfer_len,
				      GFP_KERNEL);

	if (ret)
		goto out_free_cdb;

	bio = rq->bio;
	rq->retries = 0;

	start_time = jiffies;

	/* ignore return value. All information is passed back to caller
	 * (if he doesn't check that is his problem).
	 * N.B. a non-zero SCSI status is _not_ necessarily an error.
	 */
	blk_execute_rq(q, bd_disk, rq, at_head);

	hdr->duration = jiffies_to_msecs(jiffies - start_time);

	ret = blk_complete_sghdr_rq(rq, hdr, bio);

out_free_cdb:
	scsi_req_free_cmd(req);
out_put_request:
	blk_put_request(rq);
	return ret;
}

/**
 * sg_scsi_ioctl  --  handle deprecated SCSI_IOCTL_SEND_COMMAND ioctl
 * @file:	file this ioctl operates on (optional)
 * @q:		request queue to send scsi commands down
 * @disk:	gendisk to operate on (option)
 * @sic:	userspace structure describing the command to perform
 *
 * Send down the scsi command described by @sic to the device below
 * the request queue @q.  If @file is non-NULL it's used to perform
 * fine-grained permission checks that allow users to send down
 * non-destructive SCSI commands.  If the caller has a struct gendisk
 * available it should be passed in as @disk to allow the low level
 * driver to use the information contained in it.  A non-NULL @disk
 * is only allowed if the caller knows that the low level driver doesn't
 * need it (e.g. in the scsi subsystem).
 *
 * Notes:
 *   -  This interface is deprecated - users should use the SG_IO
 *      interface instead, as this is a more flexible approach to
 *      performing SCSI commands on a device.
 *   -  The SCSI command length is determined by examining the 1st byte
 *      of the given command. There is no way to override this.
 *   -  Data transfers are limited to PAGE_SIZE
 *   -  The length (x + y) must be at least OMAX_SB_LEN bytes long to
 *      accommodate the sense buffer when an error occurs.
 *      The sense buffer is truncated to OMAX_SB_LEN (16) bytes so that
 *      old code will not be surprised.
 *   -  If a Unix error occurs (e.g. ENOMEM) then the user will receive
 *      a negative return and the Unix error code in 'errno'.
 *      If the SCSI command succeeds then 0 is returned.
 *      Positive numbers returned are the compacted SCSI error codes (4
 *      bytes in one int) where the lowest byte is the SCSI status.
 */
#define OMAX_SB_LEN 16          /* For backward compatibility */
int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode,
		struct scsi_ioctl_command __user *sic)
{
	struct request *rq;
	struct scsi_request *req;
	int err;
	unsigned int in_len, out_len, bytes, opcode, cmdlen;
	char *buffer = NULL;

	if (!sic)
		return -EINVAL;

	/*
	 * get in an out lengths, verify they don't exceed a page worth of data
	 */
	if (get_user(in_len, &sic->inlen))
		return -EFAULT;
	if (get_user(out_len, &sic->outlen))
		return -EFAULT;
	if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
		return -EINVAL;
	if (get_user(opcode, sic->data))
		return -EFAULT;

	bytes = max(in_len, out_len);
	if (bytes) {
		buffer = kzalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN);
		if (!buffer)
			return -ENOMEM;

	}

	rq = blk_get_request(q, in_len ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
			__GFP_RECLAIM);
	if (IS_ERR(rq)) {
		err = PTR_ERR(rq);
		goto error_free_buffer;
	}
	req = scsi_req(rq);
	scsi_req_init(rq);

	cmdlen = COMMAND_SIZE(opcode);

	/*
	 * get command and data to send to device, if any
	 */
	err = -EFAULT;
	req->cmd_len = cmdlen;
	if (copy_from_user(req->cmd, sic->data, cmdlen))
		goto error;

	if (in_len && copy_from_user(buffer, sic->data + cmdlen, in_len))
		goto error;

	err = blk_verify_command(req->cmd, mode & FMODE_WRITE);
	if (err)
		goto error;

	/* default.  possible overriden later */
	rq->retries = 5;

	switch (opcode) {
	case SEND_DIAGNOSTIC:
	case FORMAT_UNIT:
		rq->timeout = FORMAT_UNIT_TIMEOUT;
		rq->retries = 1;
		break;
	case START_STOP:
		rq->timeout = START_STOP_TIMEOUT;
		break;
	case MOVE_MEDIUM:
		rq->timeout = MOVE_MEDIUM_TIMEOUT;
		break;
	case READ_ELEMENT_STATUS:
		rq->timeout = READ_ELEMENT_STATUS_TIMEOUT;
		break;
	case READ_DEFECT_DATA:
		rq->timeout = READ_DEFECT_DATA_TIMEOUT;
		rq->retries = 1;
		break;
	default:
		rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
		break;
	}

	if (bytes && blk_rq_map_kern(q, rq, buffer, bytes, __GFP_RECLAIM)) {
		err = DRIVER_ERROR << 24;
		goto error;
	}

	blk_execute_rq(q, disk, rq, 0);

	err = rq->errors & 0xff;	/* only 8 bit SCSI status */
	if (err) {
		if (req->sense_len && req->sense) {
			bytes = (OMAX_SB_LEN > req->sense_len) ?
				req->sense_len : OMAX_SB_LEN;
			if (copy_to_user(sic->data, req->sense, bytes))
				err = -EFAULT;
		}
	} else {
		if (copy_to_user(sic->data, buffer, out_len))
			err = -EFAULT;
	}
	
error:
	blk_put_request(rq);

error_free_buffer:
	kfree(buffer);

	return err;
}
EXPORT_SYMBOL_GPL(sg_scsi_ioctl);

/* Send basic block requests */
static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
			      int cmd, int data)
{
	struct request *rq;
	int err;

	rq = blk_get_request(q, REQ_OP_SCSI_OUT, __GFP_RECLAIM);
	if (IS_ERR(rq))
		return PTR_ERR(rq);
	scsi_req_init(rq);
	rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
	scsi_req(rq)->cmd[0] = cmd;
	scsi_req(rq)->cmd[4] = data;
	scsi_req(rq)->cmd_len = 6;
	err = blk_execute_rq(q, bd_disk, rq, 0);
	blk_put_request(rq);

	return err;
}

static inline int blk_send_start_stop(struct request_queue *q,
				      struct gendisk *bd_disk, int data)
{
	return __blk_send_generic(q, bd_disk, GPCMD_START_STOP_UNIT, data);
}

int scsi_cmd_ioctl(struct request_queue *q, struct gendisk *bd_disk, fmode_t mode,
		   unsigned int cmd, void __user *arg)
{
	int err;

	if (!q)
		return -ENXIO;

	switch (cmd) {
		/*
		 * new sgv3 interface
		 */
		case SG_GET_VERSION_NUM:
			err = sg_get_version(arg);
			break;
		case SCSI_IOCTL_GET_IDLUN:
			err = scsi_get_idlun(q, arg);
			break;
		case SCSI_IOCTL_GET_BUS_NUMBER:
			err = scsi_get_bus(q, arg);
			break;
		case SG_SET_TIMEOUT:
			err = sg_set_timeout(q, arg);
			break;
		case SG_GET_TIMEOUT:
			err = sg_get_timeout(q);
			break;
		case SG_GET_RESERVED_SIZE:
			err = sg_get_reserved_size(q, arg);
			break;
		case SG_SET_RESERVED_SIZE:
			err = sg_set_reserved_size(q, arg);
			break;
		case SG_EMULATED_HOST:
			err = sg_emulated_host(q, arg);
			break;
		case SG_IO: {
			struct sg_io_hdr hdr;

			err = -EFAULT;
			if (copy_from_user(&hdr, arg, sizeof(hdr)))
				break;
			err = sg_io(q, bd_disk, &hdr, mode);
			if (err == -EFAULT)
				break;

			if (copy_to_user(arg, &hdr, sizeof(hdr)))
				err = -EFAULT;
			break;
		}
		case CDROM_SEND_PACKET: {
			struct cdrom_generic_command cgc;
			struct sg_io_hdr hdr;

			err = -EFAULT;
			if (copy_from_user(&cgc, arg, sizeof(cgc)))
				break;
			cgc.timeout = clock_t_to_jiffies(cgc.timeout);
			memset(&hdr, 0, sizeof(hdr));
			hdr.interface_id = 'S';
			hdr.cmd_len = sizeof(cgc.cmd);
			hdr.dxfer_len = cgc.buflen;
			err = 0;
			switch (cgc.data_direction) {
				case CGC_DATA_UNKNOWN:
					hdr.dxfer_direction = SG_DXFER_UNKNOWN;
					break;
				case CGC_DATA_WRITE:
					hdr.dxfer_direction = SG_DXFER_TO_DEV;
					break;
				case CGC_DATA_READ:
					hdr.dxfer_direction = SG_DXFER_FROM_DEV;
					break;
				case CGC_DATA_NONE:
					hdr.dxfer_direction = SG_DXFER_NONE;
					break;
				default:
					err = -EINVAL;
			}
			if (err)
				break;

			hdr.dxferp = cgc.buffer;
			hdr.sbp = cgc.sense;
			if (hdr.sbp)
				hdr.mx_sb_len = sizeof(struct request_sense);
			hdr.timeout = jiffies_to_msecs(cgc.timeout);
			hdr.cmdp = ((struct cdrom_generic_command __user*) arg)->cmd;
			hdr.cmd_len = sizeof(cgc.cmd);

			err = sg_io(q, bd_disk, &hdr, mode);
			if (err == -EFAULT)
				break;

			if (hdr.status)
				err = -EIO;

			cgc.stat = err;
			cgc.buflen = hdr.resid;
			if (copy_to_user(arg, &cgc, sizeof(cgc)))
				err = -EFAULT;

			break;
		}

		/*
		 * old junk scsi send command ioctl
		 */
		case SCSI_IOCTL_SEND_COMMAND:
			printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm);
			err = -EINVAL;
			if (!arg)
				break;

			err = sg_scsi_ioctl(q, bd_disk, mode, arg);
			break;
		case CDROMCLOSETRAY:
			err = blk_send_start_stop(q, bd_disk, 0x03);
			break;
		case CDROMEJECT:
			err = blk_send_start_stop(q, bd_disk, 0x02);
			break;
		default:
			err = -ENOTTY;
	}

	return err;
}
EXPORT_SYMBOL(scsi_cmd_ioctl);

int scsi_verify_blk_ioctl(struct block_device *bd, unsigned int cmd)
{
	if (bd && bd == bd->bd_contains)
		return 0;

	/* Actually none of these is particularly useful on a partition,
	 * but they are safe.
	 */
	switch (cmd) {
	case SCSI_IOCTL_GET_IDLUN:
	case SCSI_IOCTL_GET_BUS_NUMBER:
	case SCSI_IOCTL_GET_PCI:
	case SCSI_IOCTL_PROBE_HOST:
	case SG_GET_VERSION_NUM:
	case SG_SET_TIMEOUT:
	case SG_GET_TIMEOUT:
	case SG_GET_RESERVED_SIZE:
	case SG_SET_RESERVED_SIZE:
	case SG_EMULATED_HOST:
		return 0;
	case CDROM_GET_CAPABILITY:
		/* Keep this until we remove the printk below.  udev sends it
		 * and we do not want to spam dmesg about it.   CD-ROMs do
		 * not have partitions, so we get here only for disks.
		 */
		return -ENOIOCTLCMD;
	default:
		break;
	}

	if (capable(CAP_SYS_RAWIO))
		return 0;

	/* In particular, rule out all resets and host-specific ioctls.  */
	printk_ratelimited(KERN_WARNING
			   "%s: sending ioctl %x to a partition!\n", current->comm, cmd);

	return -ENOIOCTLCMD;
}
EXPORT_SYMBOL(scsi_verify_blk_ioctl);

int scsi_cmd_blk_ioctl(struct block_device *bd, fmode_t mode,
		       unsigned int cmd, void __user *arg)
{
	int ret;

	ret = scsi_verify_blk_ioctl(bd, cmd);
	if (ret < 0)
		return ret;

	return scsi_cmd_ioctl(bd->bd_disk->queue, bd->bd_disk, mode, cmd, arg);
}
EXPORT_SYMBOL(scsi_cmd_blk_ioctl);

void scsi_req_init(struct request *rq)
{
	struct scsi_request *req = scsi_req(rq);

	memset(req->__cmd, 0, sizeof(req->__cmd));
	req->cmd = req->__cmd;
	req->cmd_len = BLK_MAX_CDB;
	req->sense_len = 0;
}
EXPORT_SYMBOL(scsi_req_init);

static int __init blk_scsi_ioctl_init(void)
{
	blk_set_cmd_filter_defaults(&blk_default_cmd_filter);
	return 0;
}
fs_initcall(blk_scsi_ioctl_init);