1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * SCSI Block Commands (SBC) parsing and emulation.
4  *
5  * (c) Copyright 2002-2013 Datera, Inc.
6  *
7  * Nicholas A. Bellinger <nab@kernel.org>
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/ratelimit.h>
13 #include <linux/crc-t10dif.h>
14 #include <linux/t10-pi.h>
15 #include <asm/unaligned.h>
16 #include <scsi/scsi_proto.h>
17 #include <scsi/scsi_tcq.h>
18 
19 #include <target/target_core_base.h>
20 #include <target/target_core_backend.h>
21 #include <target/target_core_fabric.h>
22 
23 #include "target_core_internal.h"
24 #include "target_core_ua.h"
25 #include "target_core_alua.h"
26 
27 static sense_reason_t
28 sbc_check_prot(struct se_device *, struct se_cmd *, unsigned char, u32, bool);
29 static sense_reason_t sbc_execute_unmap(struct se_cmd *cmd);
30 
31 static sense_reason_t
32 sbc_emulate_readcapacity(struct se_cmd *cmd)
33 {
34 	struct se_device *dev = cmd->se_dev;
35 	unsigned char *cdb = cmd->t_task_cdb;
36 	unsigned long long blocks_long = dev->transport->get_blocks(dev);
37 	unsigned char *rbuf;
38 	unsigned char buf[8];
39 	u32 blocks;
40 
41 	/*
42 	 * SBC-2 says:
43 	 *   If the PMI bit is set to zero and the LOGICAL BLOCK
44 	 *   ADDRESS field is not set to zero, the device server shall
45 	 *   terminate the command with CHECK CONDITION status with
46 	 *   the sense key set to ILLEGAL REQUEST and the additional
47 	 *   sense code set to INVALID FIELD IN CDB.
48 	 *
49 	 * In SBC-3, these fields are obsolete, but some SCSI
50 	 * compliance tests actually check this, so we might as well
51 	 * follow SBC-2.
52 	 */
53 	if (!(cdb[8] & 1) && !!(cdb[2] | cdb[3] | cdb[4] | cdb[5]))
54 		return TCM_INVALID_CDB_FIELD;
55 
56 	if (blocks_long >= 0x00000000ffffffff)
57 		blocks = 0xffffffff;
58 	else
59 		blocks = (u32)blocks_long;
60 
61 	put_unaligned_be32(blocks, &buf[0]);
62 	put_unaligned_be32(dev->dev_attrib.block_size, &buf[4]);
63 
64 	rbuf = transport_kmap_data_sg(cmd);
65 	if (rbuf) {
66 		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
67 		transport_kunmap_data_sg(cmd);
68 	}
69 
70 	target_complete_cmd_with_length(cmd, SAM_STAT_GOOD, 8);
71 	return 0;
72 }
73 
74 static sense_reason_t
75 sbc_emulate_readcapacity_16(struct se_cmd *cmd)
76 {
77 	struct se_device *dev = cmd->se_dev;
78 	struct se_session *sess = cmd->se_sess;
79 	int pi_prot_type = dev->dev_attrib.pi_prot_type;
80 
81 	unsigned char *rbuf;
82 	unsigned char buf[32];
83 	unsigned long long blocks = dev->transport->get_blocks(dev);
84 
85 	memset(buf, 0, sizeof(buf));
86 	put_unaligned_be64(blocks, &buf[0]);
87 	put_unaligned_be32(dev->dev_attrib.block_size, &buf[8]);
88 	/*
89 	 * Set P_TYPE and PROT_EN bits for DIF support
90 	 */
91 	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
92 		/*
93 		 * Only override a device's pi_prot_type if no T10-PI is
94 		 * available, and sess_prot_type has been explicitly enabled.
95 		 */
96 		if (!pi_prot_type)
97 			pi_prot_type = sess->sess_prot_type;
98 
99 		if (pi_prot_type)
100 			buf[12] = (pi_prot_type - 1) << 1 | 0x1;
101 	}
102 
103 	if (dev->transport->get_lbppbe)
104 		buf[13] = dev->transport->get_lbppbe(dev) & 0x0f;
105 
106 	if (dev->transport->get_alignment_offset_lbas) {
107 		u16 lalba = dev->transport->get_alignment_offset_lbas(dev);
108 
109 		put_unaligned_be16(lalba, &buf[14]);
110 	}
111 
112 	/*
113 	 * Set Thin Provisioning Enable bit following sbc3r22 in section
114 	 * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
115 	 */
116 	if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws) {
117 		buf[14] |= 0x80;
118 
119 		/*
120 		 * LBPRZ signifies that zeroes will be read back from an LBA after
121 		 * an UNMAP or WRITE SAME w/ unmap bit (sbc3r36 5.16.2)
122 		 */
123 		if (dev->dev_attrib.unmap_zeroes_data)
124 			buf[14] |= 0x40;
125 	}
126 
127 	rbuf = transport_kmap_data_sg(cmd);
128 	if (rbuf) {
129 		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
130 		transport_kunmap_data_sg(cmd);
131 	}
132 
133 	target_complete_cmd_with_length(cmd, SAM_STAT_GOOD, 32);
134 	return 0;
135 }
136 
137 static sense_reason_t
138 sbc_emulate_startstop(struct se_cmd *cmd)
139 {
140 	unsigned char *cdb = cmd->t_task_cdb;
141 
142 	/*
143 	 * See sbc3r36 section 5.25
144 	 * Immediate bit should be set since there is nothing to complete
145 	 * POWER CONDITION MODIFIER 0h
146 	 */
147 	if (!(cdb[1] & 1) || cdb[2] || cdb[3])
148 		return TCM_INVALID_CDB_FIELD;
149 
150 	/*
151 	 * See sbc3r36 section 5.25
152 	 * POWER CONDITION 0h START_VALID - process START and LOEJ
153 	 */
154 	if (cdb[4] >> 4 & 0xf)
155 		return TCM_INVALID_CDB_FIELD;
156 
157 	/*
158 	 * See sbc3r36 section 5.25
159 	 * LOEJ 0h - nothing to load or unload
160 	 * START 1h - we are ready
161 	 */
162 	if (!(cdb[4] & 1) || (cdb[4] & 2) || (cdb[4] & 4))
163 		return TCM_INVALID_CDB_FIELD;
164 
165 	target_complete_cmd(cmd, SAM_STAT_GOOD);
166 	return 0;
167 }
168 
169 sector_t sbc_get_write_same_sectors(struct se_cmd *cmd)
170 {
171 	u32 num_blocks;
172 
173 	if (cmd->t_task_cdb[0] == WRITE_SAME)
174 		num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
175 	else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
176 		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
177 	else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
178 		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
179 
180 	/*
181 	 * Use the explicit range when non zero is supplied, otherwise calculate
182 	 * the remaining range based on ->get_blocks() - starting LBA.
183 	 */
184 	if (num_blocks)
185 		return num_blocks;
186 
187 	return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
188 		cmd->t_task_lba + 1;
189 }
190 EXPORT_SYMBOL(sbc_get_write_same_sectors);
191 
192 static sense_reason_t
193 sbc_execute_write_same_unmap(struct se_cmd *cmd)
194 {
195 	struct exec_cmd_ops *ops = cmd->protocol_data;
196 	sector_t nolb = sbc_get_write_same_sectors(cmd);
197 	sense_reason_t ret;
198 
199 	if (nolb) {
200 		ret = ops->execute_unmap(cmd, cmd->t_task_lba, nolb);
201 		if (ret)
202 			return ret;
203 	}
204 
205 	target_complete_cmd(cmd, SAM_STAT_GOOD);
206 	return 0;
207 }
208 
209 static sense_reason_t
210 sbc_emulate_noop(struct se_cmd *cmd)
211 {
212 	target_complete_cmd(cmd, SAM_STAT_GOOD);
213 	return 0;
214 }
215 
216 static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
217 {
218 	return cmd->se_dev->dev_attrib.block_size * sectors;
219 }
220 
221 static inline u32 transport_get_sectors_6(unsigned char *cdb)
222 {
223 	/*
224 	 * Use 8-bit sector value.  SBC-3 says:
225 	 *
226 	 *   A TRANSFER LENGTH field set to zero specifies that 256
227 	 *   logical blocks shall be written.  Any other value
228 	 *   specifies the number of logical blocks that shall be
229 	 *   written.
230 	 */
231 	return cdb[4] ? : 256;
232 }
233 
234 static inline u32 transport_get_sectors_10(unsigned char *cdb)
235 {
236 	return get_unaligned_be16(&cdb[7]);
237 }
238 
239 static inline u32 transport_get_sectors_12(unsigned char *cdb)
240 {
241 	return get_unaligned_be32(&cdb[6]);
242 }
243 
244 static inline u32 transport_get_sectors_16(unsigned char *cdb)
245 {
246 	return get_unaligned_be32(&cdb[10]);
247 }
248 
249 /*
250  * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
251  */
252 static inline u32 transport_get_sectors_32(unsigned char *cdb)
253 {
254 	return get_unaligned_be32(&cdb[28]);
255 
256 }
257 
258 static inline u32 transport_lba_21(unsigned char *cdb)
259 {
260 	return get_unaligned_be24(&cdb[1]) & 0x1fffff;
261 }
262 
263 static inline u32 transport_lba_32(unsigned char *cdb)
264 {
265 	return get_unaligned_be32(&cdb[2]);
266 }
267 
268 static inline unsigned long long transport_lba_64(unsigned char *cdb)
269 {
270 	return get_unaligned_be64(&cdb[2]);
271 }
272 
273 static sense_reason_t
274 sbc_setup_write_same(struct se_cmd *cmd, unsigned char flags,
275 		     struct exec_cmd_ops *ops)
276 {
277 	struct se_device *dev = cmd->se_dev;
278 	sector_t end_lba = dev->transport->get_blocks(dev) + 1;
279 	unsigned int sectors = sbc_get_write_same_sectors(cmd);
280 	sense_reason_t ret;
281 
282 	if ((flags & 0x04) || (flags & 0x02)) {
283 		pr_err("WRITE_SAME PBDATA and LBDATA"
284 			" bits not supported for Block Discard"
285 			" Emulation\n");
286 		return TCM_UNSUPPORTED_SCSI_OPCODE;
287 	}
288 	if (sectors > cmd->se_dev->dev_attrib.max_write_same_len) {
289 		pr_warn("WRITE_SAME sectors: %u exceeds max_write_same_len: %u\n",
290 			sectors, cmd->se_dev->dev_attrib.max_write_same_len);
291 		return TCM_INVALID_CDB_FIELD;
292 	}
293 	/*
294 	 * Sanity check for LBA wrap and request past end of device.
295 	 */
296 	if (((cmd->t_task_lba + sectors) < cmd->t_task_lba) ||
297 	    ((cmd->t_task_lba + sectors) > end_lba)) {
298 		pr_err("WRITE_SAME exceeds last lba %llu (lba %llu, sectors %u)\n",
299 		       (unsigned long long)end_lba, cmd->t_task_lba, sectors);
300 		return TCM_ADDRESS_OUT_OF_RANGE;
301 	}
302 
303 	/* We always have ANC_SUP == 0 so setting ANCHOR is always an error */
304 	if (flags & 0x10) {
305 		pr_warn("WRITE SAME with ANCHOR not supported\n");
306 		return TCM_INVALID_CDB_FIELD;
307 	}
308 
309 	if (flags & 0x01) {
310 		pr_warn("WRITE SAME with NDOB not supported\n");
311 		return TCM_INVALID_CDB_FIELD;
312 	}
313 
314 	/*
315 	 * Special case for WRITE_SAME w/ UNMAP=1 that ends up getting
316 	 * translated into block discard requests within backend code.
317 	 */
318 	if (flags & 0x08) {
319 		if (!ops->execute_unmap)
320 			return TCM_UNSUPPORTED_SCSI_OPCODE;
321 
322 		if (!dev->dev_attrib.emulate_tpws) {
323 			pr_err("Got WRITE_SAME w/ UNMAP=1, but backend device"
324 			       " has emulate_tpws disabled\n");
325 			return TCM_UNSUPPORTED_SCSI_OPCODE;
326 		}
327 		cmd->execute_cmd = sbc_execute_write_same_unmap;
328 		return 0;
329 	}
330 	if (!ops->execute_write_same)
331 		return TCM_UNSUPPORTED_SCSI_OPCODE;
332 
333 	ret = sbc_check_prot(dev, cmd, flags >> 5, sectors, true);
334 	if (ret)
335 		return ret;
336 
337 	cmd->execute_cmd = ops->execute_write_same;
338 	return 0;
339 }
340 
341 static sense_reason_t
342 sbc_execute_rw(struct se_cmd *cmd)
343 {
344 	struct exec_cmd_ops *ops = cmd->protocol_data;
345 
346 	return ops->execute_rw(cmd, cmd->t_data_sg, cmd->t_data_nents,
347 			       cmd->data_direction);
348 }
349 
350 static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success,
351 					     int *post_ret)
352 {
353 	struct se_device *dev = cmd->se_dev;
354 	sense_reason_t ret = TCM_NO_SENSE;
355 
356 	spin_lock_irq(&cmd->t_state_lock);
357 	if (success) {
358 		*post_ret = 1;
359 
360 		if (cmd->scsi_status == SAM_STAT_CHECK_CONDITION)
361 			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
362 	}
363 	spin_unlock_irq(&cmd->t_state_lock);
364 
365 	/*
366 	 * Unlock ->caw_sem originally obtained during sbc_compare_and_write()
367 	 * before the original READ I/O submission.
368 	 */
369 	up(&dev->caw_sem);
370 
371 	return ret;
372 }
373 
374 /*
375  * compare @cmp_len bytes of @read_sgl with @cmp_sgl. On miscompare, fill
376  * @miscmp_off and return TCM_MISCOMPARE_VERIFY.
377  */
378 static sense_reason_t
379 compare_and_write_do_cmp(struct scatterlist *read_sgl, unsigned int read_nents,
380 			 struct scatterlist *cmp_sgl, unsigned int cmp_nents,
381 			 unsigned int cmp_len, unsigned int *miscmp_off)
382 {
383 	unsigned char *buf = NULL;
384 	struct scatterlist *sg;
385 	sense_reason_t ret;
386 	unsigned int offset;
387 	size_t rc;
388 	int sg_cnt;
389 
390 	buf = kzalloc(cmp_len, GFP_KERNEL);
391 	if (!buf) {
392 		ret = TCM_OUT_OF_RESOURCES;
393 		goto out;
394 	}
395 
396 	rc = sg_copy_to_buffer(cmp_sgl, cmp_nents, buf, cmp_len);
397 	if (!rc) {
398 		pr_err("sg_copy_to_buffer() failed for compare_and_write\n");
399 		ret = TCM_OUT_OF_RESOURCES;
400 		goto out;
401 	}
402 	/*
403 	 * Compare SCSI READ payload against verify payload
404 	 */
405 	offset = 0;
406 	ret = TCM_NO_SENSE;
407 	for_each_sg(read_sgl, sg, read_nents, sg_cnt) {
408 		unsigned int len = min(sg->length, cmp_len);
409 		unsigned char *addr = kmap_atomic(sg_page(sg));
410 
411 		if (memcmp(addr, buf + offset, len)) {
412 			unsigned int i;
413 
414 			for (i = 0; i < len && addr[i] == buf[offset + i]; i++)
415 				;
416 			*miscmp_off = offset + i;
417 			pr_warn("Detected MISCOMPARE at offset %u\n",
418 				*miscmp_off);
419 			ret = TCM_MISCOMPARE_VERIFY;
420 		}
421 		kunmap_atomic(addr);
422 		if (ret != TCM_NO_SENSE)
423 			goto out;
424 
425 		offset += len;
426 		cmp_len -= len;
427 		if (!cmp_len)
428 			break;
429 	}
430 	pr_debug("COMPARE AND WRITE read data matches compare data\n");
431 out:
432 	kfree(buf);
433 	return ret;
434 }
435 
436 static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool success,
437 						 int *post_ret)
438 {
439 	struct se_device *dev = cmd->se_dev;
440 	struct sg_table write_tbl = { };
441 	struct scatterlist *write_sg;
442 	struct sg_mapping_iter m;
443 	unsigned int len;
444 	unsigned int block_size = dev->dev_attrib.block_size;
445 	unsigned int compare_len = (cmd->t_task_nolb * block_size);
446 	unsigned int miscmp_off = 0;
447 	sense_reason_t ret = TCM_NO_SENSE;
448 	int i;
449 
450 	if (!success) {
451 		/*
452 		 * Handle early failure in transport_generic_request_failure(),
453 		 * which will not have taken ->caw_sem yet..
454 		 */
455 		if (!cmd->t_data_sg || !cmd->t_bidi_data_sg)
456 			return TCM_NO_SENSE;
457 
458 		/*
459 		 * The command has been stopped or aborted so
460 		 * we don't have to perform the write operation.
461 		 */
462 		WARN_ON(!(cmd->transport_state &
463 			(CMD_T_ABORTED | CMD_T_STOP)));
464 		goto out;
465 	}
466 	/*
467 	 * Handle special case for zero-length COMPARE_AND_WRITE
468 	 */
469 	if (!cmd->data_length)
470 		goto out;
471 	/*
472 	 * Immediately exit + release dev->caw_sem if command has already
473 	 * been failed with a non-zero SCSI status.
474 	 */
475 	if (cmd->scsi_status) {
476 		pr_debug("compare_and_write_callback: non zero scsi_status:"
477 			" 0x%02x\n", cmd->scsi_status);
478 		*post_ret = 1;
479 		if (cmd->scsi_status == SAM_STAT_CHECK_CONDITION)
480 			ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
481 		goto out;
482 	}
483 
484 	ret = compare_and_write_do_cmp(cmd->t_bidi_data_sg,
485 				       cmd->t_bidi_data_nents,
486 				       cmd->t_data_sg,
487 				       cmd->t_data_nents,
488 				       compare_len,
489 				       &miscmp_off);
490 	if (ret == TCM_MISCOMPARE_VERIFY) {
491 		/*
492 		 * SBC-4 r15: 5.3 COMPARE AND WRITE command
493 		 * In the sense data (see 4.18 and SPC-5) the offset from the
494 		 * start of the Data-Out Buffer to the first byte of data that
495 		 * was not equal shall be reported in the INFORMATION field.
496 		 */
497 		cmd->sense_info = miscmp_off;
498 		goto out;
499 	} else if (ret)
500 		goto out;
501 
502 	if (sg_alloc_table(&write_tbl, cmd->t_data_nents, GFP_KERNEL) < 0) {
503 		pr_err("Unable to allocate compare_and_write sg\n");
504 		ret = TCM_OUT_OF_RESOURCES;
505 		goto out;
506 	}
507 	write_sg = write_tbl.sgl;
508 
509 	i = 0;
510 	len = compare_len;
511 	sg_miter_start(&m, cmd->t_data_sg, cmd->t_data_nents, SG_MITER_TO_SG);
512 	/*
513 	 * Currently assumes NoLB=1 and SGLs are PAGE_SIZE..
514 	 */
515 	while (len) {
516 		sg_miter_next(&m);
517 
518 		if (block_size < PAGE_SIZE) {
519 			sg_set_page(&write_sg[i], m.page, block_size,
520 				    m.piter.sg->offset + block_size);
521 		} else {
522 			sg_miter_next(&m);
523 			sg_set_page(&write_sg[i], m.page, block_size,
524 				    m.piter.sg->offset);
525 		}
526 		len -= block_size;
527 		i++;
528 	}
529 	sg_miter_stop(&m);
530 	/*
531 	 * Save the original SGL + nents values before updating to new
532 	 * assignments, to be released in transport_free_pages() ->
533 	 * transport_reset_sgl_orig()
534 	 */
535 	cmd->t_data_sg_orig = cmd->t_data_sg;
536 	cmd->t_data_sg = write_sg;
537 	cmd->t_data_nents_orig = cmd->t_data_nents;
538 	cmd->t_data_nents = 1;
539 
540 	cmd->sam_task_attr = TCM_HEAD_TAG;
541 	cmd->transport_complete_callback = compare_and_write_post;
542 	/*
543 	 * Now reset ->execute_cmd() to the normal sbc_execute_rw() handler
544 	 * for submitting the adjusted SGL to write instance user-data.
545 	 */
546 	cmd->execute_cmd = sbc_execute_rw;
547 
548 	spin_lock_irq(&cmd->t_state_lock);
549 	cmd->t_state = TRANSPORT_PROCESSING;
550 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
551 	spin_unlock_irq(&cmd->t_state_lock);
552 
553 	__target_execute_cmd(cmd, false);
554 
555 	return ret;
556 
557 out:
558 	/*
559 	 * In the MISCOMPARE or failure case, unlock ->caw_sem obtained in
560 	 * sbc_compare_and_write() before the original READ I/O submission.
561 	 */
562 	up(&dev->caw_sem);
563 	sg_free_table(&write_tbl);
564 	return ret;
565 }
566 
567 static sense_reason_t
568 sbc_compare_and_write(struct se_cmd *cmd)
569 {
570 	struct exec_cmd_ops *ops = cmd->protocol_data;
571 	struct se_device *dev = cmd->se_dev;
572 	sense_reason_t ret;
573 	int rc;
574 	/*
575 	 * Submit the READ first for COMPARE_AND_WRITE to perform the
576 	 * comparision using SGLs at cmd->t_bidi_data_sg..
577 	 */
578 	rc = down_interruptible(&dev->caw_sem);
579 	if (rc != 0) {
580 		cmd->transport_complete_callback = NULL;
581 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
582 	}
583 	/*
584 	 * Reset cmd->data_length to individual block_size in order to not
585 	 * confuse backend drivers that depend on this value matching the
586 	 * size of the I/O being submitted.
587 	 */
588 	cmd->data_length = cmd->t_task_nolb * dev->dev_attrib.block_size;
589 
590 	ret = ops->execute_rw(cmd, cmd->t_bidi_data_sg, cmd->t_bidi_data_nents,
591 			      DMA_FROM_DEVICE);
592 	if (ret) {
593 		cmd->transport_complete_callback = NULL;
594 		up(&dev->caw_sem);
595 		return ret;
596 	}
597 	/*
598 	 * Unlock of dev->caw_sem to occur in compare_and_write_callback()
599 	 * upon MISCOMPARE, or in compare_and_write_done() upon completion
600 	 * of WRITE instance user-data.
601 	 */
602 	return TCM_NO_SENSE;
603 }
604 
605 static int
606 sbc_set_prot_op_checks(u8 protect, bool fabric_prot, enum target_prot_type prot_type,
607 		       bool is_write, struct se_cmd *cmd)
608 {
609 	if (is_write) {
610 		cmd->prot_op = fabric_prot ? TARGET_PROT_DOUT_STRIP :
611 			       protect ? TARGET_PROT_DOUT_PASS :
612 			       TARGET_PROT_DOUT_INSERT;
613 		switch (protect) {
614 		case 0x0:
615 		case 0x3:
616 			cmd->prot_checks = 0;
617 			break;
618 		case 0x1:
619 		case 0x5:
620 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
621 			if (prot_type == TARGET_DIF_TYPE1_PROT)
622 				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
623 			break;
624 		case 0x2:
625 			if (prot_type == TARGET_DIF_TYPE1_PROT)
626 				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
627 			break;
628 		case 0x4:
629 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
630 			break;
631 		default:
632 			pr_err("Unsupported protect field %d\n", protect);
633 			return -EINVAL;
634 		}
635 	} else {
636 		cmd->prot_op = fabric_prot ? TARGET_PROT_DIN_INSERT :
637 			       protect ? TARGET_PROT_DIN_PASS :
638 			       TARGET_PROT_DIN_STRIP;
639 		switch (protect) {
640 		case 0x0:
641 		case 0x1:
642 		case 0x5:
643 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
644 			if (prot_type == TARGET_DIF_TYPE1_PROT)
645 				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
646 			break;
647 		case 0x2:
648 			if (prot_type == TARGET_DIF_TYPE1_PROT)
649 				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
650 			break;
651 		case 0x3:
652 			cmd->prot_checks = 0;
653 			break;
654 		case 0x4:
655 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
656 			break;
657 		default:
658 			pr_err("Unsupported protect field %d\n", protect);
659 			return -EINVAL;
660 		}
661 	}
662 
663 	return 0;
664 }
665 
666 static sense_reason_t
667 sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char protect,
668 	       u32 sectors, bool is_write)
669 {
670 	int sp_ops = cmd->se_sess->sup_prot_ops;
671 	int pi_prot_type = dev->dev_attrib.pi_prot_type;
672 	bool fabric_prot = false;
673 
674 	if (!cmd->t_prot_sg || !cmd->t_prot_nents) {
675 		if (unlikely(protect &&
676 		    !dev->dev_attrib.pi_prot_type && !cmd->se_sess->sess_prot_type)) {
677 			pr_err("CDB contains protect bit, but device + fabric does"
678 			       " not advertise PROTECT=1 feature bit\n");
679 			return TCM_INVALID_CDB_FIELD;
680 		}
681 		if (cmd->prot_pto)
682 			return TCM_NO_SENSE;
683 	}
684 
685 	switch (dev->dev_attrib.pi_prot_type) {
686 	case TARGET_DIF_TYPE3_PROT:
687 		cmd->reftag_seed = 0xffffffff;
688 		break;
689 	case TARGET_DIF_TYPE2_PROT:
690 		if (protect)
691 			return TCM_INVALID_CDB_FIELD;
692 
693 		cmd->reftag_seed = cmd->t_task_lba;
694 		break;
695 	case TARGET_DIF_TYPE1_PROT:
696 		cmd->reftag_seed = cmd->t_task_lba;
697 		break;
698 	case TARGET_DIF_TYPE0_PROT:
699 		/*
700 		 * See if the fabric supports T10-PI, and the session has been
701 		 * configured to allow export PROTECT=1 feature bit with backend
702 		 * devices that don't support T10-PI.
703 		 */
704 		fabric_prot = is_write ?
705 			      !!(sp_ops & (TARGET_PROT_DOUT_PASS | TARGET_PROT_DOUT_STRIP)) :
706 			      !!(sp_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DIN_INSERT));
707 
708 		if (fabric_prot && cmd->se_sess->sess_prot_type) {
709 			pi_prot_type = cmd->se_sess->sess_prot_type;
710 			break;
711 		}
712 		if (!protect)
713 			return TCM_NO_SENSE;
714 		fallthrough;
715 	default:
716 		pr_err("Unable to determine pi_prot_type for CDB: 0x%02x "
717 		       "PROTECT: 0x%02x\n", cmd->t_task_cdb[0], protect);
718 		return TCM_INVALID_CDB_FIELD;
719 	}
720 
721 	if (sbc_set_prot_op_checks(protect, fabric_prot, pi_prot_type, is_write, cmd))
722 		return TCM_INVALID_CDB_FIELD;
723 
724 	cmd->prot_type = pi_prot_type;
725 	cmd->prot_length = dev->prot_length * sectors;
726 
727 	/**
728 	 * In case protection information exists over the wire
729 	 * we modify command data length to describe pure data.
730 	 * The actual transfer length is data length + protection
731 	 * length
732 	 **/
733 	if (protect)
734 		cmd->data_length = sectors * dev->dev_attrib.block_size;
735 
736 	pr_debug("%s: prot_type=%d, data_length=%d, prot_length=%d "
737 		 "prot_op=%d prot_checks=%d\n",
738 		 __func__, cmd->prot_type, cmd->data_length, cmd->prot_length,
739 		 cmd->prot_op, cmd->prot_checks);
740 
741 	return TCM_NO_SENSE;
742 }
743 
744 static int
745 sbc_check_dpofua(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb)
746 {
747 	if (cdb[1] & 0x10) {
748 		/* see explanation in spc_emulate_modesense */
749 		if (!target_check_fua(dev)) {
750 			pr_err("Got CDB: 0x%02x with DPO bit set, but device"
751 			       " does not advertise support for DPO\n", cdb[0]);
752 			return -EINVAL;
753 		}
754 	}
755 	if (cdb[1] & 0x8) {
756 		if (!target_check_fua(dev)) {
757 			pr_err("Got CDB: 0x%02x with FUA bit set, but device"
758 			       " does not advertise support for FUA write\n",
759 			       cdb[0]);
760 			return -EINVAL;
761 		}
762 		cmd->se_cmd_flags |= SCF_FUA;
763 	}
764 	return 0;
765 }
766 
767 sense_reason_t
768 sbc_parse_cdb(struct se_cmd *cmd, struct exec_cmd_ops *ops)
769 {
770 	struct se_device *dev = cmd->se_dev;
771 	unsigned char *cdb = cmd->t_task_cdb;
772 	unsigned int size;
773 	u32 sectors = 0;
774 	sense_reason_t ret;
775 
776 	cmd->protocol_data = ops;
777 
778 	switch (cdb[0]) {
779 	case READ_6:
780 		sectors = transport_get_sectors_6(cdb);
781 		cmd->t_task_lba = transport_lba_21(cdb);
782 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
783 		cmd->execute_cmd = sbc_execute_rw;
784 		break;
785 	case READ_10:
786 		sectors = transport_get_sectors_10(cdb);
787 		cmd->t_task_lba = transport_lba_32(cdb);
788 
789 		if (sbc_check_dpofua(dev, cmd, cdb))
790 			return TCM_INVALID_CDB_FIELD;
791 
792 		ret = sbc_check_prot(dev, cmd, cdb[1] >> 5, sectors, false);
793 		if (ret)
794 			return ret;
795 
796 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
797 		cmd->execute_cmd = sbc_execute_rw;
798 		break;
799 	case READ_12:
800 		sectors = transport_get_sectors_12(cdb);
801 		cmd->t_task_lba = transport_lba_32(cdb);
802 
803 		if (sbc_check_dpofua(dev, cmd, cdb))
804 			return TCM_INVALID_CDB_FIELD;
805 
806 		ret = sbc_check_prot(dev, cmd, cdb[1] >> 5, sectors, false);
807 		if (ret)
808 			return ret;
809 
810 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
811 		cmd->execute_cmd = sbc_execute_rw;
812 		break;
813 	case READ_16:
814 		sectors = transport_get_sectors_16(cdb);
815 		cmd->t_task_lba = transport_lba_64(cdb);
816 
817 		if (sbc_check_dpofua(dev, cmd, cdb))
818 			return TCM_INVALID_CDB_FIELD;
819 
820 		ret = sbc_check_prot(dev, cmd, cdb[1] >> 5, sectors, false);
821 		if (ret)
822 			return ret;
823 
824 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
825 		cmd->execute_cmd = sbc_execute_rw;
826 		break;
827 	case WRITE_6:
828 		sectors = transport_get_sectors_6(cdb);
829 		cmd->t_task_lba = transport_lba_21(cdb);
830 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
831 		cmd->execute_cmd = sbc_execute_rw;
832 		break;
833 	case WRITE_10:
834 	case WRITE_VERIFY:
835 		sectors = transport_get_sectors_10(cdb);
836 		cmd->t_task_lba = transport_lba_32(cdb);
837 
838 		if (sbc_check_dpofua(dev, cmd, cdb))
839 			return TCM_INVALID_CDB_FIELD;
840 
841 		ret = sbc_check_prot(dev, cmd, cdb[1] >> 5, sectors, true);
842 		if (ret)
843 			return ret;
844 
845 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
846 		cmd->execute_cmd = sbc_execute_rw;
847 		break;
848 	case WRITE_12:
849 		sectors = transport_get_sectors_12(cdb);
850 		cmd->t_task_lba = transport_lba_32(cdb);
851 
852 		if (sbc_check_dpofua(dev, cmd, cdb))
853 			return TCM_INVALID_CDB_FIELD;
854 
855 		ret = sbc_check_prot(dev, cmd, cdb[1] >> 5, sectors, true);
856 		if (ret)
857 			return ret;
858 
859 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
860 		cmd->execute_cmd = sbc_execute_rw;
861 		break;
862 	case WRITE_16:
863 	case WRITE_VERIFY_16:
864 		sectors = transport_get_sectors_16(cdb);
865 		cmd->t_task_lba = transport_lba_64(cdb);
866 
867 		if (sbc_check_dpofua(dev, cmd, cdb))
868 			return TCM_INVALID_CDB_FIELD;
869 
870 		ret = sbc_check_prot(dev, cmd, cdb[1] >> 5, sectors, true);
871 		if (ret)
872 			return ret;
873 
874 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
875 		cmd->execute_cmd = sbc_execute_rw;
876 		break;
877 	case VARIABLE_LENGTH_CMD:
878 	{
879 		u16 service_action = get_unaligned_be16(&cdb[8]);
880 		switch (service_action) {
881 		case WRITE_SAME_32:
882 			sectors = transport_get_sectors_32(cdb);
883 			if (!sectors) {
884 				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
885 				       " supported\n");
886 				return TCM_INVALID_CDB_FIELD;
887 			}
888 
889 			size = sbc_get_size(cmd, 1);
890 			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
891 
892 			ret = sbc_setup_write_same(cmd, cdb[10], ops);
893 			if (ret)
894 				return ret;
895 			break;
896 		default:
897 			pr_err("VARIABLE_LENGTH_CMD service action"
898 				" 0x%04x not supported\n", service_action);
899 			return TCM_UNSUPPORTED_SCSI_OPCODE;
900 		}
901 		break;
902 	}
903 	case COMPARE_AND_WRITE:
904 		if (!dev->dev_attrib.emulate_caw) {
905 			pr_err_ratelimited("se_device %s/%s (vpd_unit_serial %s) reject COMPARE_AND_WRITE\n",
906 					   dev->se_hba->backend->ops->name,
907 					   config_item_name(&dev->dev_group.cg_item),
908 					   dev->t10_wwn.unit_serial);
909 			return TCM_UNSUPPORTED_SCSI_OPCODE;
910 		}
911 		sectors = cdb[13];
912 		/*
913 		 * Currently enforce COMPARE_AND_WRITE for a single sector
914 		 */
915 		if (sectors > 1) {
916 			pr_err("COMPARE_AND_WRITE contains NoLB: %u greater"
917 			       " than 1\n", sectors);
918 			return TCM_INVALID_CDB_FIELD;
919 		}
920 		if (sbc_check_dpofua(dev, cmd, cdb))
921 			return TCM_INVALID_CDB_FIELD;
922 
923 		/*
924 		 * Double size because we have two buffers, note that
925 		 * zero is not an error..
926 		 */
927 		size = 2 * sbc_get_size(cmd, sectors);
928 		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
929 		cmd->t_task_nolb = sectors;
930 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB | SCF_COMPARE_AND_WRITE;
931 		cmd->execute_cmd = sbc_compare_and_write;
932 		cmd->transport_complete_callback = compare_and_write_callback;
933 		break;
934 	case READ_CAPACITY:
935 		size = READ_CAP_LEN;
936 		cmd->execute_cmd = sbc_emulate_readcapacity;
937 		break;
938 	case SERVICE_ACTION_IN_16:
939 		switch (cmd->t_task_cdb[1] & 0x1f) {
940 		case SAI_READ_CAPACITY_16:
941 			cmd->execute_cmd = sbc_emulate_readcapacity_16;
942 			break;
943 		case SAI_REPORT_REFERRALS:
944 			cmd->execute_cmd = target_emulate_report_referrals;
945 			break;
946 		default:
947 			pr_err("Unsupported SA: 0x%02x\n",
948 				cmd->t_task_cdb[1] & 0x1f);
949 			return TCM_INVALID_CDB_FIELD;
950 		}
951 		size = get_unaligned_be32(&cdb[10]);
952 		break;
953 	case SYNCHRONIZE_CACHE:
954 	case SYNCHRONIZE_CACHE_16:
955 		if (cdb[0] == SYNCHRONIZE_CACHE) {
956 			sectors = transport_get_sectors_10(cdb);
957 			cmd->t_task_lba = transport_lba_32(cdb);
958 		} else {
959 			sectors = transport_get_sectors_16(cdb);
960 			cmd->t_task_lba = transport_lba_64(cdb);
961 		}
962 		if (ops->execute_sync_cache) {
963 			cmd->execute_cmd = ops->execute_sync_cache;
964 			goto check_lba;
965 		}
966 		size = 0;
967 		cmd->execute_cmd = sbc_emulate_noop;
968 		break;
969 	case UNMAP:
970 		if (!ops->execute_unmap)
971 			return TCM_UNSUPPORTED_SCSI_OPCODE;
972 
973 		if (!dev->dev_attrib.emulate_tpu) {
974 			pr_err("Got UNMAP, but backend device has"
975 			       " emulate_tpu disabled\n");
976 			return TCM_UNSUPPORTED_SCSI_OPCODE;
977 		}
978 		size = get_unaligned_be16(&cdb[7]);
979 		cmd->execute_cmd = sbc_execute_unmap;
980 		break;
981 	case WRITE_SAME_16:
982 		sectors = transport_get_sectors_16(cdb);
983 		if (!sectors) {
984 			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
985 			return TCM_INVALID_CDB_FIELD;
986 		}
987 
988 		size = sbc_get_size(cmd, 1);
989 		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
990 
991 		ret = sbc_setup_write_same(cmd, cdb[1], ops);
992 		if (ret)
993 			return ret;
994 		break;
995 	case WRITE_SAME:
996 		sectors = transport_get_sectors_10(cdb);
997 		if (!sectors) {
998 			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
999 			return TCM_INVALID_CDB_FIELD;
1000 		}
1001 
1002 		size = sbc_get_size(cmd, 1);
1003 		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
1004 
1005 		/*
1006 		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
1007 		 * of byte 1 bit 3 UNMAP instead of original reserved field
1008 		 */
1009 		ret = sbc_setup_write_same(cmd, cdb[1], ops);
1010 		if (ret)
1011 			return ret;
1012 		break;
1013 	case VERIFY:
1014 	case VERIFY_16:
1015 		size = 0;
1016 		if (cdb[0] == VERIFY) {
1017 			sectors = transport_get_sectors_10(cdb);
1018 			cmd->t_task_lba = transport_lba_32(cdb);
1019 		} else {
1020 			sectors = transport_get_sectors_16(cdb);
1021 			cmd->t_task_lba = transport_lba_64(cdb);
1022 		}
1023 		cmd->execute_cmd = sbc_emulate_noop;
1024 		goto check_lba;
1025 	case REZERO_UNIT:
1026 	case SEEK_6:
1027 	case SEEK_10:
1028 		/*
1029 		 * There are still clients out there which use these old SCSI-2
1030 		 * commands. This mainly happens when running VMs with legacy
1031 		 * guest systems, connected via SCSI command pass-through to
1032 		 * iSCSI targets. Make them happy and return status GOOD.
1033 		 */
1034 		size = 0;
1035 		cmd->execute_cmd = sbc_emulate_noop;
1036 		break;
1037 	case START_STOP:
1038 		size = 0;
1039 		cmd->execute_cmd = sbc_emulate_startstop;
1040 		break;
1041 	default:
1042 		ret = spc_parse_cdb(cmd, &size);
1043 		if (ret)
1044 			return ret;
1045 	}
1046 
1047 	/* reject any command that we don't have a handler for */
1048 	if (!cmd->execute_cmd)
1049 		return TCM_UNSUPPORTED_SCSI_OPCODE;
1050 
1051 	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1052 		unsigned long long end_lba;
1053 check_lba:
1054 		end_lba = dev->transport->get_blocks(dev) + 1;
1055 		if (((cmd->t_task_lba + sectors) < cmd->t_task_lba) ||
1056 		    ((cmd->t_task_lba + sectors) > end_lba)) {
1057 			pr_err("cmd exceeds last lba %llu "
1058 				"(lba %llu, sectors %u)\n",
1059 				end_lba, cmd->t_task_lba, sectors);
1060 			return TCM_ADDRESS_OUT_OF_RANGE;
1061 		}
1062 
1063 		if (!(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE))
1064 			size = sbc_get_size(cmd, sectors);
1065 	}
1066 
1067 	return target_cmd_size_check(cmd, size);
1068 }
1069 EXPORT_SYMBOL(sbc_parse_cdb);
1070 
1071 u32 sbc_get_device_type(struct se_device *dev)
1072 {
1073 	return TYPE_DISK;
1074 }
1075 EXPORT_SYMBOL(sbc_get_device_type);
1076 
1077 static sense_reason_t
1078 sbc_execute_unmap(struct se_cmd *cmd)
1079 {
1080 	struct exec_cmd_ops *ops = cmd->protocol_data;
1081 	struct se_device *dev = cmd->se_dev;
1082 	unsigned char *buf, *ptr = NULL;
1083 	sector_t lba;
1084 	int size;
1085 	u32 range;
1086 	sense_reason_t ret = 0;
1087 	int dl, bd_dl;
1088 
1089 	/* We never set ANC_SUP */
1090 	if (cmd->t_task_cdb[1])
1091 		return TCM_INVALID_CDB_FIELD;
1092 
1093 	if (cmd->data_length == 0) {
1094 		target_complete_cmd(cmd, SAM_STAT_GOOD);
1095 		return 0;
1096 	}
1097 
1098 	if (cmd->data_length < 8) {
1099 		pr_warn("UNMAP parameter list length %u too small\n",
1100 			cmd->data_length);
1101 		return TCM_PARAMETER_LIST_LENGTH_ERROR;
1102 	}
1103 
1104 	buf = transport_kmap_data_sg(cmd);
1105 	if (!buf)
1106 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1107 
1108 	dl = get_unaligned_be16(&buf[0]);
1109 	bd_dl = get_unaligned_be16(&buf[2]);
1110 
1111 	size = cmd->data_length - 8;
1112 	if (bd_dl > size)
1113 		pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
1114 			cmd->data_length, bd_dl);
1115 	else
1116 		size = bd_dl;
1117 
1118 	if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
1119 		ret = TCM_INVALID_PARAMETER_LIST;
1120 		goto err;
1121 	}
1122 
1123 	/* First UNMAP block descriptor starts at 8 byte offset */
1124 	ptr = &buf[8];
1125 	pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
1126 		" ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
1127 
1128 	while (size >= 16) {
1129 		lba = get_unaligned_be64(&ptr[0]);
1130 		range = get_unaligned_be32(&ptr[8]);
1131 		pr_debug("UNMAP: Using lba: %llu and range: %u\n",
1132 				 (unsigned long long)lba, range);
1133 
1134 		if (range > dev->dev_attrib.max_unmap_lba_count) {
1135 			ret = TCM_INVALID_PARAMETER_LIST;
1136 			goto err;
1137 		}
1138 
1139 		if (lba + range > dev->transport->get_blocks(dev) + 1) {
1140 			ret = TCM_ADDRESS_OUT_OF_RANGE;
1141 			goto err;
1142 		}
1143 
1144 		if (range) {
1145 			ret = ops->execute_unmap(cmd, lba, range);
1146 			if (ret)
1147 				goto err;
1148 		}
1149 
1150 		ptr += 16;
1151 		size -= 16;
1152 	}
1153 
1154 err:
1155 	transport_kunmap_data_sg(cmd);
1156 	if (!ret)
1157 		target_complete_cmd(cmd, SAM_STAT_GOOD);
1158 	return ret;
1159 }
1160 
1161 void
1162 sbc_dif_generate(struct se_cmd *cmd)
1163 {
1164 	struct se_device *dev = cmd->se_dev;
1165 	struct t10_pi_tuple *sdt;
1166 	struct scatterlist *dsg = cmd->t_data_sg, *psg;
1167 	sector_t sector = cmd->t_task_lba;
1168 	void *daddr, *paddr;
1169 	int i, j, offset = 0;
1170 	unsigned int block_size = dev->dev_attrib.block_size;
1171 
1172 	for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) {
1173 		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1174 		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1175 
1176 		for (j = 0; j < psg->length;
1177 				j += sizeof(*sdt)) {
1178 			__u16 crc;
1179 			unsigned int avail;
1180 
1181 			if (offset >= dsg->length) {
1182 				offset -= dsg->length;
1183 				kunmap_atomic(daddr - dsg->offset);
1184 				dsg = sg_next(dsg);
1185 				if (!dsg) {
1186 					kunmap_atomic(paddr - psg->offset);
1187 					return;
1188 				}
1189 				daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1190 			}
1191 
1192 			sdt = paddr + j;
1193 			avail = min(block_size, dsg->length - offset);
1194 			crc = crc_t10dif(daddr + offset, avail);
1195 			if (avail < block_size) {
1196 				kunmap_atomic(daddr - dsg->offset);
1197 				dsg = sg_next(dsg);
1198 				if (!dsg) {
1199 					kunmap_atomic(paddr - psg->offset);
1200 					return;
1201 				}
1202 				daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1203 				offset = block_size - avail;
1204 				crc = crc_t10dif_update(crc, daddr, offset);
1205 			} else {
1206 				offset += block_size;
1207 			}
1208 
1209 			sdt->guard_tag = cpu_to_be16(crc);
1210 			if (cmd->prot_type == TARGET_DIF_TYPE1_PROT)
1211 				sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
1212 			sdt->app_tag = 0;
1213 
1214 			pr_debug("DIF %s INSERT sector: %llu guard_tag: 0x%04x"
1215 				 " app_tag: 0x%04x ref_tag: %u\n",
1216 				 (cmd->data_direction == DMA_TO_DEVICE) ?
1217 				 "WRITE" : "READ", (unsigned long long)sector,
1218 				 sdt->guard_tag, sdt->app_tag,
1219 				 be32_to_cpu(sdt->ref_tag));
1220 
1221 			sector++;
1222 		}
1223 
1224 		kunmap_atomic(daddr - dsg->offset);
1225 		kunmap_atomic(paddr - psg->offset);
1226 	}
1227 }
1228 
1229 static sense_reason_t
1230 sbc_dif_v1_verify(struct se_cmd *cmd, struct t10_pi_tuple *sdt,
1231 		  __u16 crc, sector_t sector, unsigned int ei_lba)
1232 {
1233 	__be16 csum;
1234 
1235 	if (!(cmd->prot_checks & TARGET_DIF_CHECK_GUARD))
1236 		goto check_ref;
1237 
1238 	csum = cpu_to_be16(crc);
1239 
1240 	if (sdt->guard_tag != csum) {
1241 		pr_err("DIFv1 checksum failed on sector %llu guard tag 0x%04x"
1242 			" csum 0x%04x\n", (unsigned long long)sector,
1243 			be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
1244 		return TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED;
1245 	}
1246 
1247 check_ref:
1248 	if (!(cmd->prot_checks & TARGET_DIF_CHECK_REFTAG))
1249 		return 0;
1250 
1251 	if (cmd->prot_type == TARGET_DIF_TYPE1_PROT &&
1252 	    be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
1253 		pr_err("DIFv1 Type 1 reference failed on sector: %llu tag: 0x%08x"
1254 		       " sector MSB: 0x%08x\n", (unsigned long long)sector,
1255 		       be32_to_cpu(sdt->ref_tag), (u32)(sector & 0xffffffff));
1256 		return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
1257 	}
1258 
1259 	if (cmd->prot_type == TARGET_DIF_TYPE2_PROT &&
1260 	    be32_to_cpu(sdt->ref_tag) != ei_lba) {
1261 		pr_err("DIFv1 Type 2 reference failed on sector: %llu tag: 0x%08x"
1262 		       " ei_lba: 0x%08x\n", (unsigned long long)sector,
1263 			be32_to_cpu(sdt->ref_tag), ei_lba);
1264 		return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
1265 	}
1266 
1267 	return 0;
1268 }
1269 
1270 void sbc_dif_copy_prot(struct se_cmd *cmd, unsigned int sectors, bool read,
1271 		       struct scatterlist *sg, int sg_off)
1272 {
1273 	struct se_device *dev = cmd->se_dev;
1274 	struct scatterlist *psg;
1275 	void *paddr, *addr;
1276 	unsigned int i, len, left;
1277 	unsigned int offset = sg_off;
1278 
1279 	if (!sg)
1280 		return;
1281 
1282 	left = sectors * dev->prot_length;
1283 
1284 	for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) {
1285 		unsigned int psg_len, copied = 0;
1286 
1287 		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1288 		psg_len = min(left, psg->length);
1289 		while (psg_len) {
1290 			len = min(psg_len, sg->length - offset);
1291 			addr = kmap_atomic(sg_page(sg)) + sg->offset + offset;
1292 
1293 			if (read)
1294 				memcpy(paddr + copied, addr, len);
1295 			else
1296 				memcpy(addr, paddr + copied, len);
1297 
1298 			left -= len;
1299 			offset += len;
1300 			copied += len;
1301 			psg_len -= len;
1302 
1303 			kunmap_atomic(addr - sg->offset - offset);
1304 
1305 			if (offset >= sg->length) {
1306 				sg = sg_next(sg);
1307 				offset = 0;
1308 			}
1309 		}
1310 		kunmap_atomic(paddr - psg->offset);
1311 	}
1312 }
1313 EXPORT_SYMBOL(sbc_dif_copy_prot);
1314 
1315 sense_reason_t
1316 sbc_dif_verify(struct se_cmd *cmd, sector_t start, unsigned int sectors,
1317 	       unsigned int ei_lba, struct scatterlist *psg, int psg_off)
1318 {
1319 	struct se_device *dev = cmd->se_dev;
1320 	struct t10_pi_tuple *sdt;
1321 	struct scatterlist *dsg = cmd->t_data_sg;
1322 	sector_t sector = start;
1323 	void *daddr, *paddr;
1324 	int i;
1325 	sense_reason_t rc;
1326 	int dsg_off = 0;
1327 	unsigned int block_size = dev->dev_attrib.block_size;
1328 
1329 	for (; psg && sector < start + sectors; psg = sg_next(psg)) {
1330 		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1331 		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1332 
1333 		for (i = psg_off; i < psg->length &&
1334 				sector < start + sectors;
1335 				i += sizeof(*sdt)) {
1336 			__u16 crc;
1337 			unsigned int avail;
1338 
1339 			if (dsg_off >= dsg->length) {
1340 				dsg_off -= dsg->length;
1341 				kunmap_atomic(daddr - dsg->offset);
1342 				dsg = sg_next(dsg);
1343 				if (!dsg) {
1344 					kunmap_atomic(paddr - psg->offset);
1345 					return 0;
1346 				}
1347 				daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1348 			}
1349 
1350 			sdt = paddr + i;
1351 
1352 			pr_debug("DIF READ sector: %llu guard_tag: 0x%04x"
1353 				 " app_tag: 0x%04x ref_tag: %u\n",
1354 				 (unsigned long long)sector, sdt->guard_tag,
1355 				 sdt->app_tag, be32_to_cpu(sdt->ref_tag));
1356 
1357 			if (sdt->app_tag == T10_PI_APP_ESCAPE) {
1358 				dsg_off += block_size;
1359 				goto next;
1360 			}
1361 
1362 			avail = min(block_size, dsg->length - dsg_off);
1363 			crc = crc_t10dif(daddr + dsg_off, avail);
1364 			if (avail < block_size) {
1365 				kunmap_atomic(daddr - dsg->offset);
1366 				dsg = sg_next(dsg);
1367 				if (!dsg) {
1368 					kunmap_atomic(paddr - psg->offset);
1369 					return 0;
1370 				}
1371 				daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1372 				dsg_off = block_size - avail;
1373 				crc = crc_t10dif_update(crc, daddr, dsg_off);
1374 			} else {
1375 				dsg_off += block_size;
1376 			}
1377 
1378 			rc = sbc_dif_v1_verify(cmd, sdt, crc, sector, ei_lba);
1379 			if (rc) {
1380 				kunmap_atomic(daddr - dsg->offset);
1381 				kunmap_atomic(paddr - psg->offset);
1382 				cmd->sense_info = sector;
1383 				return rc;
1384 			}
1385 next:
1386 			sector++;
1387 			ei_lba++;
1388 		}
1389 
1390 		psg_off = 0;
1391 		kunmap_atomic(daddr - dsg->offset);
1392 		kunmap_atomic(paddr - psg->offset);
1393 	}
1394 
1395 	return 0;
1396 }
1397 EXPORT_SYMBOL(sbc_dif_verify);
1398