aboutsummaryrefslogtreecommitdiff
path: root/drivers/target/target_core_sbc.c
blob: 4714c6f8da4be5fe39e797237fa8a35de0450883 (plain)
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
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
/*
 * SCSI Block Commands (SBC) parsing and emulation.
 *
 * (c) Copyright 2002-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ratelimit.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_tcq.h>

#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>

#include "target_core_internal.h"
#include "target_core_ua.h"


static sense_reason_t
sbc_emulate_readcapacity(struct se_cmd *cmd)
{
	struct se_device *dev = cmd->se_dev;
	unsigned char *cdb = cmd->t_task_cdb;
	unsigned long long blocks_long = dev->transport->get_blocks(dev);
	unsigned char *rbuf;
	unsigned char buf[8];
	u32 blocks;

	/*
	 * SBC-2 says:
	 *   If the PMI bit is set to zero and the LOGICAL BLOCK
	 *   ADDRESS field is not set to zero, the device server shall
	 *   terminate the command with CHECK CONDITION status with
	 *   the sense key set to ILLEGAL REQUEST and the additional
	 *   sense code set to INVALID FIELD IN CDB.
	 *
	 * In SBC-3, these fields are obsolete, but some SCSI
	 * compliance tests actually check this, so we might as well
	 * follow SBC-2.
	 */
	if (!(cdb[8] & 1) && !!(cdb[2] | cdb[3] | cdb[4] | cdb[5]))
		return TCM_INVALID_CDB_FIELD;

	if (blocks_long >= 0x00000000ffffffff)
		blocks = 0xffffffff;
	else
		blocks = (u32)blocks_long;

	buf[0] = (blocks >> 24) & 0xff;
	buf[1] = (blocks >> 16) & 0xff;
	buf[2] = (blocks >> 8) & 0xff;
	buf[3] = blocks & 0xff;
	buf[4] = (dev->dev_attrib.block_size >> 24) & 0xff;
	buf[5] = (dev->dev_attrib.block_size >> 16) & 0xff;
	buf[6] = (dev->dev_attrib.block_size >> 8) & 0xff;
	buf[7] = dev->dev_attrib.block_size & 0xff;

	rbuf = transport_kmap_data_sg(cmd);
	if (rbuf) {
		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
		transport_kunmap_data_sg(cmd);
	}

	target_complete_cmd(cmd, GOOD);
	return 0;
}

static sense_reason_t
sbc_emulate_readcapacity_16(struct se_cmd *cmd)
{
	struct se_device *dev = cmd->se_dev;
	unsigned char *rbuf;
	unsigned char buf[32];
	unsigned long long blocks = dev->transport->get_blocks(dev);

	memset(buf, 0, sizeof(buf));
	buf[0] = (blocks >> 56) & 0xff;
	buf[1] = (blocks >> 48) & 0xff;
	buf[2] = (blocks >> 40) & 0xff;
	buf[3] = (blocks >> 32) & 0xff;
	buf[4] = (blocks >> 24) & 0xff;
	buf[5] = (blocks >> 16) & 0xff;
	buf[6] = (blocks >> 8) & 0xff;
	buf[7] = blocks & 0xff;
	buf[8] = (dev->dev_attrib.block_size >> 24) & 0xff;
	buf[9] = (dev->dev_attrib.block_size >> 16) & 0xff;
	buf[10] = (dev->dev_attrib.block_size >> 8) & 0xff;
	buf[11] = dev->dev_attrib.block_size & 0xff;
	/*
	 * Set Thin Provisioning Enable bit following sbc3r22 in section
	 * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
	 */
	if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws)
		buf[14] = 0x80;

	rbuf = transport_kmap_data_sg(cmd);
	if (rbuf) {
		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
		transport_kunmap_data_sg(cmd);
	}

	target_complete_cmd(cmd, GOOD);
	return 0;
}

sector_t sbc_get_write_same_sectors(struct se_cmd *cmd)
{
	u32 num_blocks;

	if (cmd->t_task_cdb[0] == WRITE_SAME)
		num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
	else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
	else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);

	/*
	 * Use the explicit range when non zero is supplied, otherwise calculate
	 * the remaining range based on ->get_blocks() - starting LBA.
	 */
	if (num_blocks)
		return num_blocks;

	return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
		cmd->t_task_lba + 1;
}
EXPORT_SYMBOL(sbc_get_write_same_sectors);

static sense_reason_t
sbc_emulate_noop(struct se_cmd *cmd)
{
	target_complete_cmd(cmd, GOOD);
	return 0;
}

static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
{
	return cmd->se_dev->dev_attrib.block_size * sectors;
}

static int sbc_check_valid_sectors(struct se_cmd *cmd)
{
	struct se_device *dev = cmd->se_dev;
	unsigned long long end_lba;
	u32 sectors;

	sectors = cmd->data_length / dev->dev_attrib.block_size;
	end_lba = dev->transport->get_blocks(dev) + 1;

	if (cmd->t_task_lba + sectors > end_lba) {
		pr_err("target: lba %llu, sectors %u exceeds end lba %llu\n",
			cmd->t_task_lba, sectors, end_lba);
		return -EINVAL;
	}

	return 0;
}

static inline u32 transport_get_sectors_6(unsigned char *cdb)
{
	/*
	 * Use 8-bit sector value.  SBC-3 says:
	 *
	 *   A TRANSFER LENGTH field set to zero specifies that 256
	 *   logical blocks shall be written.  Any other value
	 *   specifies the number of logical blocks that shall be
	 *   written.
	 */
	return cdb[4] ? : 256;
}

static inline u32 transport_get_sectors_10(unsigned char *cdb)
{
	return (u32)(cdb[7] << 8) + cdb[8];
}

static inline u32 transport_get_sectors_12(unsigned char *cdb)
{
	return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
}

static inline u32 transport_get_sectors_16(unsigned char *cdb)
{
	return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
		    (cdb[12] << 8) + cdb[13];
}

/*
 * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
 */
static inline u32 transport_get_sectors_32(unsigned char *cdb)
{
	return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
		    (cdb[30] << 8) + cdb[31];

}

static inline u32 transport_lba_21(unsigned char *cdb)
{
	return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
}

static inline u32 transport_lba_32(unsigned char *cdb)
{
	return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
}

static inline unsigned long long transport_lba_64(unsigned char *cdb)
{
	unsigned int __v1, __v2;

	__v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
	__v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];

	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
}

/*
 * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
 */
static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
{
	unsigned int __v1, __v2;

	__v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
	__v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];

	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
}

static sense_reason_t
sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *ops)
{
	unsigned int sectors = sbc_get_write_same_sectors(cmd);

	if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
		pr_err("WRITE_SAME PBDATA and LBDATA"
			" bits not supported for Block Discard"
			" Emulation\n");
		return TCM_UNSUPPORTED_SCSI_OPCODE;
	}
	if (sectors > cmd->se_dev->dev_attrib.max_write_same_len) {
		pr_warn("WRITE_SAME sectors: %u exceeds max_write_same_len: %u\n",
			sectors, cmd->se_dev->dev_attrib.max_write_same_len);
		return TCM_INVALID_CDB_FIELD;
	}
	/*
	 * Special case for WRITE_SAME w/ UNMAP=1 that ends up getting
	 * translated into block discard requests within backend code.
	 */
	if (flags[0] & 0x08) {
		if (!ops->execute_write_same_unmap)
			return TCM_UNSUPPORTED_SCSI_OPCODE;

		cmd->execute_cmd = ops->execute_write_same_unmap;
		return 0;
	}
	if (!ops->execute_write_same)
		return TCM_UNSUPPORTED_SCSI_OPCODE;

	cmd->execute_cmd = ops->execute_write_same;
	return 0;
}

static sense_reason_t xdreadwrite_callback(struct se_cmd *cmd)
{
	unsigned char *buf, *addr;
	struct scatterlist *sg;
	unsigned int offset;
	sense_reason_t ret = TCM_NO_SENSE;
	int i, count;
	/*
	 * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
	 *
	 * 1) read the specified logical block(s);
	 * 2) transfer logical blocks from the data-out buffer;
	 * 3) XOR the logical blocks transferred from the data-out buffer with
	 *    the logical blocks read, storing the resulting XOR data in a buffer;
	 * 4) if the DISABLE WRITE bit is set to zero, then write the logical
	 *    blocks transferred from the data-out buffer; and
	 * 5) transfer the resulting XOR data to the data-in buffer.
	 */
	buf = kmalloc(cmd->data_length, GFP_KERNEL);
	if (!buf) {
		pr_err("Unable to allocate xor_callback buf\n");
		return TCM_OUT_OF_RESOURCES;
	}
	/*
	 * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
	 * into the locally allocated *buf
	 */
	sg_copy_to_buffer(cmd->t_data_sg,
			  cmd->t_data_nents,
			  buf,
			  cmd->data_length);

	/*
	 * Now perform the XOR against the BIDI read memory located at
	 * cmd->t_mem_bidi_list
	 */

	offset = 0;
	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
		addr = kmap_atomic(sg_page(sg));
		if (!addr) {
			ret = TCM_OUT_OF_RESOURCES;
			goto out;
		}

		for (i = 0; i < sg->length; i++)
			*(addr + sg->offset + i) ^= *(buf + offset + i);

		offset += sg->length;
		kunmap_atomic(addr);
	}

out:
	kfree(buf);
	return ret;
}

static sense_reason_t
sbc_execute_rw(struct se_cmd *cmd)
{
	return cmd->execute_rw(cmd, cmd->t_data_sg, cmd->t_data_nents,
			       cmd->data_direction);
}

static sense_reason_t compare_and_write_post(struct se_cmd *cmd)
{
	struct se_device *dev = cmd->se_dev;

	/*
	 * Only set SCF_COMPARE_AND_WRITE_POST to force a response fall-through
	 * within target_complete_ok_work() if the command was successfully
	 * sent to the backend driver.
	 */
	spin_lock_irq(&cmd->t_state_lock);
	if ((cmd->transport_state & CMD_T_SENT) && !cmd->scsi_status)
		cmd->se_cmd_flags |= SCF_COMPARE_AND_WRITE_POST;
	spin_unlock_irq(&cmd->t_state_lock);

	/*
	 * Unlock ->caw_sem originally obtained during sbc_compare_and_write()
	 * before the original READ I/O submission.
	 */
	up(&dev->caw_sem);

	return TCM_NO_SENSE;
}

static sense_reason_t compare_and_write_callback(struct se_cmd *cmd)
{
	struct se_device *dev = cmd->se_dev;
	struct scatterlist *write_sg = NULL, *sg;
	unsigned char *buf = NULL, *addr;
	struct sg_mapping_iter m;
	unsigned int offset = 0, len;
	unsigned int nlbas = cmd->t_task_nolb;
	unsigned int block_size = dev->dev_attrib.block_size;
	unsigned int compare_len = (nlbas * block_size);
	sense_reason_t ret = TCM_NO_SENSE;
	int rc, i;

	/*
	 * Handle early failure in transport_generic_request_failure(),
	 * which will not have taken ->caw_mutex yet..
	 */
	if (!cmd->t_data_sg || !cmd->t_bidi_data_sg)
		return TCM_NO_SENSE;
	/*
	 * Immediately exit + release dev->caw_sem if command has already
	 * been failed with a non-zero SCSI status.
	 */
	if (cmd->scsi_status) {
		pr_err("compare_and_write_callback: non zero scsi_status:"
			" 0x%02x\n", cmd->scsi_status);
		goto out;
	}

	buf = kzalloc(cmd->data_length, GFP_KERNEL);
	if (!buf) {
		pr_err("Unable to allocate compare_and_write buf\n");
		ret = TCM_OUT_OF_RESOURCES;
		goto out;
	}

	write_sg = kzalloc(sizeof(struct scatterlist) * cmd->t_data_nents,
			   GFP_KERNEL);
	if (!write_sg) {
		pr_err("Unable to allocate compare_and_write sg\n");
		ret = TCM_OUT_OF_RESOURCES;
		goto out;
	}
	/*
	 * Setup verify and write data payloads from total NumberLBAs.
	 */
	rc = sg_copy_to_buffer(cmd->t_data_sg, cmd->t_data_nents, buf,
			       cmd->data_length);
	if (!rc) {
		pr_err("sg_copy_to_buffer() failed for compare_and_write\n");
		ret = TCM_OUT_OF_RESOURCES;
		goto out;
	}
	/*
	 * Compare against SCSI READ payload against verify payload
	 */
	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, i) {
		addr = (unsigned char *)kmap_atomic(sg_page(sg));
		if (!addr) {
			ret = TCM_OUT_OF_RESOURCES;
			goto out;
		}

		len = min(sg->length, compare_len);

		if (memcmp(addr, buf + offset, len)) {
			pr_warn("Detected MISCOMPARE for addr: %p buf: %p\n",
				addr, buf + offset);
			kunmap_atomic(addr);
			goto miscompare;
		}
		kunmap_atomic(addr);

		offset += len;
		compare_len -= len;
		if (!compare_len)
			break;
	}

	i = 0;
	len = cmd->t_task_nolb * block_size;
	sg_miter_start(&m, cmd->t_data_sg, cmd->t_data_nents, SG_MITER_TO_SG);
	/*
	 * Currently assumes NoLB=1 and SGLs are PAGE_SIZE..
	 */
	while (len) {
		sg_miter_next(&m);

		if (block_size < PAGE_SIZE) {
			sg_set_page(&write_sg[i], m.page, block_size,
				    block_size);
		} else {
			sg_miter_next(&m);
			sg_set_page(&write_sg[i], m.page, block_size,
				    0);
		}
		len -= block_size;
		i++;
	}
	sg_miter_stop(&m);
	/*
	 * Save the original SGL + nents values before updating to new
	 * assignments, to be released in transport_free_pages() ->
	 * transport_reset_sgl_orig()
	 */
	cmd->t_data_sg_orig = cmd->t_data_sg;
	cmd->t_data_sg = write_sg;
	cmd->t_data_nents_orig = cmd->t_data_nents;
	cmd->t_data_nents = 1;

	cmd->sam_task_attr = MSG_HEAD_TAG;
	cmd->transport_complete_callback = compare_and_write_post;
	/*
	 * Now reset ->execute_cmd() to the normal sbc_execute_rw() handler
	 * for submitting the adjusted SGL to write instance user-data.
	 */
	cmd->execute_cmd = sbc_execute_rw;

	spin_lock_irq(&cmd->t_state_lock);
	cmd->t_state = TRANSPORT_PROCESSING;
	cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
	spin_unlock_irq(&cmd->t_state_lock);

	__target_execute_cmd(cmd);

	kfree(buf);
	return ret;

miscompare:
	pr_warn("Target/%s: Send MISCOMPARE check condition and sense\n",
		dev->transport->name);
	ret = TCM_MISCOMPARE_VERIFY;
out:
	/*
	 * In the MISCOMPARE or failure case, unlock ->caw_sem obtained in
	 * sbc_compare_and_write() before the original READ I/O submission.
	 */
	up(&dev->caw_sem);
	kfree(write_sg);
	kfree(buf);
	return ret;
}

static sense_reason_t
sbc_compare_and_write(struct se_cmd *cmd)
{
	struct se_device *dev = cmd->se_dev;
	sense_reason_t ret;
	int rc;
	/*
	 * Submit the READ first for COMPARE_AND_WRITE to perform the
	 * comparision using SGLs at cmd->t_bidi_data_sg..
	 */
	rc = down_interruptible(&dev->caw_sem);
	if ((rc != 0) || signal_pending(current)) {
		cmd->transport_complete_callback = NULL;
		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
	}
	/*
	 * Reset cmd->data_length to individual block_size in order to not
	 * confuse backend drivers that depend on this value matching the
	 * size of the I/O being submitted.
	 */
	cmd->data_length = cmd->t_task_nolb * dev->dev_attrib.block_size;

	ret = cmd->execute_rw(cmd, cmd->t_bidi_data_sg, cmd->t_bidi_data_nents,
			      DMA_FROM_DEVICE);
	if (ret) {
		cmd->transport_complete_callback = NULL;
		up(&dev->caw_sem);
		return ret;
	}
	/*
	 * Unlock of dev->caw_sem to occur in compare_and_write_callback()
	 * upon MISCOMPARE, or in compare_and_write_done() upon completion
	 * of WRITE instance user-data.
	 */
	return TCM_NO_SENSE;
}

sense_reason_t
sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
{
	struct se_device *dev = cmd->se_dev;
	unsigned char *cdb = cmd->t_task_cdb;
	unsigned int size;
	u32 sectors = 0;
	sense_reason_t ret;

	switch (cdb[0]) {
	case READ_6:
		sectors = transport_get_sectors_6(cdb);
		cmd->t_task_lba = transport_lba_21(cdb);
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case READ_10:
		sectors = transport_get_sectors_10(cdb);
		cmd->t_task_lba = transport_lba_32(cdb);
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case READ_12:
		sectors = transport_get_sectors_12(cdb);
		cmd->t_task_lba = transport_lba_32(cdb);
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case READ_16:
		sectors = transport_get_sectors_16(cdb);
		cmd->t_task_lba = transport_lba_64(cdb);
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case WRITE_6:
		sectors = transport_get_sectors_6(cdb);
		cmd->t_task_lba = transport_lba_21(cdb);
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case WRITE_10:
	case WRITE_VERIFY:
		sectors = transport_get_sectors_10(cdb);
		cmd->t_task_lba = transport_lba_32(cdb);
		if (cdb[1] & 0x8)
			cmd->se_cmd_flags |= SCF_FUA;
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case WRITE_12:
		sectors = transport_get_sectors_12(cdb);
		cmd->t_task_lba = transport_lba_32(cdb);
		if (cdb[1] & 0x8)
			cmd->se_cmd_flags |= SCF_FUA;
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case WRITE_16:
		sectors = transport_get_sectors_16(cdb);
		cmd->t_task_lba = transport_lba_64(cdb);
		if (cdb[1] & 0x8)
			cmd->se_cmd_flags |= SCF_FUA;
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		break;
	case XDWRITEREAD_10:
		if (cmd->data_direction != DMA_TO_DEVICE ||
		    !(cmd->se_cmd_flags & SCF_BIDI))
			return TCM_INVALID_CDB_FIELD;
		sectors = transport_get_sectors_10(cdb);

		cmd->t_task_lba = transport_lba_32(cdb);
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;

		/*
		 * Setup BIDI XOR callback to be run after I/O completion.
		 */
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_execute_rw;
		cmd->transport_complete_callback = &xdreadwrite_callback;
		if (cdb[1] & 0x8)
			cmd->se_cmd_flags |= SCF_FUA;
		break;
	case VARIABLE_LENGTH_CMD:
	{
		u16 service_action = get_unaligned_be16(&cdb[8]);
		switch (service_action) {
		case XDWRITEREAD_32:
			sectors = transport_get_sectors_32(cdb);

			/*
			 * Use WRITE_32 and READ_32 opcodes for the emulated
			 * XDWRITE_READ_32 logic.
			 */
			cmd->t_task_lba = transport_lba_64_ext(cdb);
			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;

			/*
			 * Setup BIDI XOR callback to be run during after I/O
			 * completion.
			 */
			cmd->execute_rw = ops->execute_rw;
			cmd->execute_cmd = sbc_execute_rw;
			cmd->transport_complete_callback = &xdreadwrite_callback;
			if (cdb[1] & 0x8)
				cmd->se_cmd_flags |= SCF_FUA;
			break;
		case WRITE_SAME_32:
			sectors = transport_get_sectors_32(cdb);
			if (!sectors) {
				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
				       " supported\n");
				return TCM_INVALID_CDB_FIELD;
			}

			size = sbc_get_size(cmd, 1);
			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);

			ret = sbc_setup_write_same(cmd, &cdb[10], ops);
			if (ret)
				return ret;
			break;
		default:
			pr_err("VARIABLE_LENGTH_CMD service action"
				" 0x%04x not supported\n", service_action);
			return TCM_UNSUPPORTED_SCSI_OPCODE;
		}
		break;
	}
	case COMPARE_AND_WRITE:
		sectors = cdb[13];
		/*
		 * Currently enforce COMPARE_AND_WRITE for a single sector
		 */
		if (sectors > 1) {
			pr_err("COMPARE_AND_WRITE contains NoLB: %u greater"
			       " than 1\n", sectors);
			return TCM_INVALID_CDB_FIELD;
		}
		/*
		 * Double size because we have two buffers, note that
		 * zero is not an error..
		 */
		size = 2 * sbc_get_size(cmd, sectors);
		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
		cmd->t_task_nolb = sectors;
		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB | SCF_COMPARE_AND_WRITE;
		cmd->execute_rw = ops->execute_rw;
		cmd->execute_cmd = sbc_compare_and_write;
		cmd->transport_complete_callback = compare_and_write_callback;
		break;
	case READ_CAPACITY:
		size = READ_CAP_LEN;
		cmd->execute_cmd = sbc_emulate_readcapacity;
		break;
	case SERVICE_ACTION_IN:
		switch (cmd->t_task_cdb[1] & 0x1f) {
		case SAI_READ_CAPACITY_16:
			cmd->execute_cmd = sbc_emulate_readcapacity_16;
			break;
		default:
			pr_err("Unsupported SA: 0x%02x\n",
				cmd->t_task_cdb[1] & 0x1f);
			return TCM_INVALID_CDB_FIELD;
		}
		size = (cdb[10] << 24) | (cdb[11] << 16) |
		       (cdb[12] << 8) | cdb[13];
		break;
	case SYNCHRONIZE_CACHE:
	case SYNCHRONIZE_CACHE_16:
		if (!ops->execute_sync_cache) {
			size = 0;
			cmd->execute_cmd = sbc_emulate_noop;
			break;
		}

		/*
		 * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
		 */
		if (cdb[0] == SYNCHRONIZE_CACHE) {
			sectors = transport_get_sectors_10(cdb);
			cmd->t_task_lba = transport_lba_32(cdb);
		} else {
			sectors = transport_get_sectors_16(cdb);
			cmd->t_task_lba = transport_lba_64(cdb);
		}

		size = sbc_get_size(cmd, sectors);

		/*
		 * Check to ensure that LBA + Range does not exceed past end of
		 * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
		 */
		if (cmd->t_task_lba || sectors) {
			if (sbc_check_valid_sectors(cmd) < 0)
				return TCM_ADDRESS_OUT_OF_RANGE;
		}
		cmd->execute_cmd = ops->execute_sync_cache;
		break;
	case UNMAP:
		if (!ops->execute_unmap)
			return TCM_UNSUPPORTED_SCSI_OPCODE;

		size = get_unaligned_be16(&cdb[7]);
		cmd->execute_cmd = ops->execute_unmap;
		break;
	case WRITE_SAME_16:
		sectors = transport_get_sectors_16(cdb);
		if (!sectors) {
			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
			return TCM_INVALID_CDB_FIELD;
		}

		size = sbc_get_size(cmd, 1);
		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);

		ret = sbc_setup_write_same(cmd, &cdb[1], ops);
		if (ret)
			return ret;
		break;
	case WRITE_SAME:
		sectors = transport_get_sectors_10(cdb);
		if (!sectors) {
			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
			return TCM_INVALID_CDB_FIELD;
		}

		size = sbc_get_size(cmd, 1);
		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);

		/*
		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
		 * of byte 1 bit 3 UNMAP instead of original reserved field
		 */
		ret = sbc_setup_write_same(cmd, &cdb[1], ops);
		if (ret)
			return ret;
		break;
	case VERIFY:
		size = 0;
		cmd->execute_cmd = sbc_emulate_noop;
		break;
	case REZERO_UNIT:
	case SEEK_6:
	case SEEK_10:
		/*
		 * There are still clients out there which use these old SCSI-2
		 * commands. This mainly happens when running VMs with legacy
		 * guest systems, connected via SCSI command pass-through to
		 * iSCSI targets. Make them happy and return status GOOD.
		 */
		size = 0;
		cmd->execute_cmd = sbc_emulate_noop;
		break;
	default:
		ret = spc_parse_cdb(cmd, &size);
		if (ret)
			return ret;
	}

	/* reject any command that we don't have a handler for */
	if (!(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) && !cmd->execute_cmd)
		return TCM_UNSUPPORTED_SCSI_OPCODE;

	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
		unsigned long long end_lba;

		if (sectors > dev->dev_attrib.fabric_max_sectors) {
			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
				" big sectors %u exceeds fabric_max_sectors:"
				" %u\n", cdb[0], sectors,
				dev->dev_attrib.fabric_max_sectors);
			return TCM_INVALID_CDB_FIELD;
		}
		if (sectors > dev->dev_attrib.hw_max_sectors) {
			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
				" big sectors %u exceeds backend hw_max_sectors:"
				" %u\n", cdb[0], sectors,
				dev->dev_attrib.hw_max_sectors);
			return TCM_INVALID_CDB_FIELD;
		}

		end_lba = dev->transport->get_blocks(dev) + 1;
		if (cmd->t_task_lba + sectors > end_lba) {
			pr_err("cmd exceeds last lba %llu "
				"(lba %llu, sectors %u)\n",
				end_lba, cmd->t_task_lba, sectors);
			return TCM_ADDRESS_OUT_OF_RANGE;
		}

		if (!(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE))
			size = sbc_get_size(cmd, sectors);
	}

	return target_cmd_size_check(cmd, size);
}
EXPORT_SYMBOL(sbc_parse_cdb);

u32 sbc_get_device_type(struct se_device *dev)
{
	return TYPE_DISK;
}
EXPORT_SYMBOL(sbc_get_device_type);

sense_reason_t
sbc_execute_unmap(struct se_cmd *cmd,
	sense_reason_t (*do_unmap_fn)(struct se_cmd *, void *,
				      sector_t, sector_t),
	void *priv)
{
	struct se_device *dev = cmd->se_dev;
	unsigned char *buf, *ptr = NULL;
	sector_t lba;
	int size;
	u32 range;
	sense_reason_t ret = 0;
	int dl, bd_dl;

	/* We never set ANC_SUP */
	if (cmd->t_task_cdb[1])
		return TCM_INVALID_CDB_FIELD;

	if (cmd->data_length == 0) {
		target_complete_cmd(cmd, SAM_STAT_GOOD);
		return 0;
	}

	if (cmd->data_length < 8) {
		pr_warn("UNMAP parameter list length %u too small\n",
			cmd->data_length);
		return TCM_PARAMETER_LIST_LENGTH_ERROR;
	}

	buf = transport_kmap_data_sg(cmd);
	if (!buf)
		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	dl = get_unaligned_be16(&buf[0]);
	bd_dl = get_unaligned_be16(&buf[2]);

	size = cmd->data_length - 8;
	if (bd_dl > size)
		pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
			cmd->data_length, bd_dl);
	else
		size = bd_dl;

	if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
		ret = TCM_INVALID_PARAMETER_LIST;
		goto err;
	}

	/* First UNMAP block descriptor starts at 8 byte offset */
	ptr = &buf[8];
	pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
		" ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);

	while (size >= 16) {
		lba = get_unaligned_be64(&ptr[0]);
		range = get_unaligned_be32(&ptr[8]);
		pr_debug("UNMAP: Using lba: %llu and range: %u\n",
				 (unsigned long long)lba, range);

		if (range > dev->dev_attrib.max_unmap_lba_count) {
			ret = TCM_INVALID_PARAMETER_LIST;
			goto err;
		}

		if (lba + range > dev->transport->get_blocks(dev) + 1) {
			ret = TCM_ADDRESS_OUT_OF_RANGE;
			goto err;
		}

		ret = do_unmap_fn(cmd, priv, lba, range);
		if (ret)
			goto err;

		ptr += 16;
		size -= 16;
	}

err:
	transport_kunmap_data_sg(cmd);
	if (!ret)
		target_complete_cmd(cmd, GOOD);
	return ret;
}
EXPORT_SYMBOL(sbc_execute_unmap);