1 /*
2  * SCSI Block Commands (SBC) parsing and emulation.
3  *
4  * (c) Copyright 2002-2013 Datera, Inc.
5  *
6  * Nicholas A. Bellinger <nab@kernel.org>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21  */
22 
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/ratelimit.h>
26 #include <linux/crc-t10dif.h>
27 #include <asm/unaligned.h>
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_tcq.h>
30 
31 #include <target/target_core_base.h>
32 #include <target/target_core_backend.h>
33 #include <target/target_core_fabric.h>
34 
35 #include "target_core_internal.h"
36 #include "target_core_ua.h"
37 #include "target_core_alua.h"
38 
39 static sense_reason_t
40 sbc_emulate_readcapacity(struct se_cmd *cmd)
41 {
42 	struct se_device *dev = cmd->se_dev;
43 	unsigned char *cdb = cmd->t_task_cdb;
44 	unsigned long long blocks_long = dev->transport->get_blocks(dev);
45 	unsigned char *rbuf;
46 	unsigned char buf[8];
47 	u32 blocks;
48 
49 	/*
50 	 * SBC-2 says:
51 	 *   If the PMI bit is set to zero and the LOGICAL BLOCK
52 	 *   ADDRESS field is not set to zero, the device server shall
53 	 *   terminate the command with CHECK CONDITION status with
54 	 *   the sense key set to ILLEGAL REQUEST and the additional
55 	 *   sense code set to INVALID FIELD IN CDB.
56 	 *
57 	 * In SBC-3, these fields are obsolete, but some SCSI
58 	 * compliance tests actually check this, so we might as well
59 	 * follow SBC-2.
60 	 */
61 	if (!(cdb[8] & 1) && !!(cdb[2] | cdb[3] | cdb[4] | cdb[5]))
62 		return TCM_INVALID_CDB_FIELD;
63 
64 	if (blocks_long >= 0x00000000ffffffff)
65 		blocks = 0xffffffff;
66 	else
67 		blocks = (u32)blocks_long;
68 
69 	buf[0] = (blocks >> 24) & 0xff;
70 	buf[1] = (blocks >> 16) & 0xff;
71 	buf[2] = (blocks >> 8) & 0xff;
72 	buf[3] = blocks & 0xff;
73 	buf[4] = (dev->dev_attrib.block_size >> 24) & 0xff;
74 	buf[5] = (dev->dev_attrib.block_size >> 16) & 0xff;
75 	buf[6] = (dev->dev_attrib.block_size >> 8) & 0xff;
76 	buf[7] = dev->dev_attrib.block_size & 0xff;
77 
78 	rbuf = transport_kmap_data_sg(cmd);
79 	if (rbuf) {
80 		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
81 		transport_kunmap_data_sg(cmd);
82 	}
83 
84 	target_complete_cmd_with_length(cmd, GOOD, 8);
85 	return 0;
86 }
87 
88 static sense_reason_t
89 sbc_emulate_readcapacity_16(struct se_cmd *cmd)
90 {
91 	struct se_device *dev = cmd->se_dev;
92 	struct se_session *sess = cmd->se_sess;
93 	unsigned char *rbuf;
94 	unsigned char buf[32];
95 	unsigned long long blocks = dev->transport->get_blocks(dev);
96 
97 	memset(buf, 0, sizeof(buf));
98 	buf[0] = (blocks >> 56) & 0xff;
99 	buf[1] = (blocks >> 48) & 0xff;
100 	buf[2] = (blocks >> 40) & 0xff;
101 	buf[3] = (blocks >> 32) & 0xff;
102 	buf[4] = (blocks >> 24) & 0xff;
103 	buf[5] = (blocks >> 16) & 0xff;
104 	buf[6] = (blocks >> 8) & 0xff;
105 	buf[7] = blocks & 0xff;
106 	buf[8] = (dev->dev_attrib.block_size >> 24) & 0xff;
107 	buf[9] = (dev->dev_attrib.block_size >> 16) & 0xff;
108 	buf[10] = (dev->dev_attrib.block_size >> 8) & 0xff;
109 	buf[11] = dev->dev_attrib.block_size & 0xff;
110 	/*
111 	 * Set P_TYPE and PROT_EN bits for DIF support
112 	 */
113 	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
114 		if (dev->dev_attrib.pi_prot_type)
115 			buf[12] = (dev->dev_attrib.pi_prot_type - 1) << 1 | 0x1;
116 	}
117 
118 	if (dev->transport->get_lbppbe)
119 		buf[13] = dev->transport->get_lbppbe(dev) & 0x0f;
120 
121 	if (dev->transport->get_alignment_offset_lbas) {
122 		u16 lalba = dev->transport->get_alignment_offset_lbas(dev);
123 		buf[14] = (lalba >> 8) & 0x3f;
124 		buf[15] = lalba & 0xff;
125 	}
126 
127 	/*
128 	 * Set Thin Provisioning Enable bit following sbc3r22 in section
129 	 * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
130 	 */
131 	if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws)
132 		buf[14] |= 0x80;
133 
134 	rbuf = transport_kmap_data_sg(cmd);
135 	if (rbuf) {
136 		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
137 		transport_kunmap_data_sg(cmd);
138 	}
139 
140 	target_complete_cmd_with_length(cmd, GOOD, 32);
141 	return 0;
142 }
143 
144 sector_t sbc_get_write_same_sectors(struct se_cmd *cmd)
145 {
146 	u32 num_blocks;
147 
148 	if (cmd->t_task_cdb[0] == WRITE_SAME)
149 		num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
150 	else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
151 		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
152 	else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
153 		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
154 
155 	/*
156 	 * Use the explicit range when non zero is supplied, otherwise calculate
157 	 * the remaining range based on ->get_blocks() - starting LBA.
158 	 */
159 	if (num_blocks)
160 		return num_blocks;
161 
162 	return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
163 		cmd->t_task_lba + 1;
164 }
165 EXPORT_SYMBOL(sbc_get_write_same_sectors);
166 
167 static sense_reason_t
168 sbc_emulate_noop(struct se_cmd *cmd)
169 {
170 	target_complete_cmd(cmd, GOOD);
171 	return 0;
172 }
173 
174 static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
175 {
176 	return cmd->se_dev->dev_attrib.block_size * sectors;
177 }
178 
179 static inline u32 transport_get_sectors_6(unsigned char *cdb)
180 {
181 	/*
182 	 * Use 8-bit sector value.  SBC-3 says:
183 	 *
184 	 *   A TRANSFER LENGTH field set to zero specifies that 256
185 	 *   logical blocks shall be written.  Any other value
186 	 *   specifies the number of logical blocks that shall be
187 	 *   written.
188 	 */
189 	return cdb[4] ? : 256;
190 }
191 
192 static inline u32 transport_get_sectors_10(unsigned char *cdb)
193 {
194 	return (u32)(cdb[7] << 8) + cdb[8];
195 }
196 
197 static inline u32 transport_get_sectors_12(unsigned char *cdb)
198 {
199 	return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
200 }
201 
202 static inline u32 transport_get_sectors_16(unsigned char *cdb)
203 {
204 	return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
205 		    (cdb[12] << 8) + cdb[13];
206 }
207 
208 /*
209  * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
210  */
211 static inline u32 transport_get_sectors_32(unsigned char *cdb)
212 {
213 	return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
214 		    (cdb[30] << 8) + cdb[31];
215 
216 }
217 
218 static inline u32 transport_lba_21(unsigned char *cdb)
219 {
220 	return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
221 }
222 
223 static inline u32 transport_lba_32(unsigned char *cdb)
224 {
225 	return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
226 }
227 
228 static inline unsigned long long transport_lba_64(unsigned char *cdb)
229 {
230 	unsigned int __v1, __v2;
231 
232 	__v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
233 	__v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
234 
235 	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
236 }
237 
238 /*
239  * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
240  */
241 static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
242 {
243 	unsigned int __v1, __v2;
244 
245 	__v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
246 	__v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
247 
248 	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
249 }
250 
251 static sense_reason_t
252 sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *ops)
253 {
254 	unsigned int sectors = sbc_get_write_same_sectors(cmd);
255 
256 	if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
257 		pr_err("WRITE_SAME PBDATA and LBDATA"
258 			" bits not supported for Block Discard"
259 			" Emulation\n");
260 		return TCM_UNSUPPORTED_SCSI_OPCODE;
261 	}
262 	if (sectors > cmd->se_dev->dev_attrib.max_write_same_len) {
263 		pr_warn("WRITE_SAME sectors: %u exceeds max_write_same_len: %u\n",
264 			sectors, cmd->se_dev->dev_attrib.max_write_same_len);
265 		return TCM_INVALID_CDB_FIELD;
266 	}
267 	/* We always have ANC_SUP == 0 so setting ANCHOR is always an error */
268 	if (flags[0] & 0x10) {
269 		pr_warn("WRITE SAME with ANCHOR not supported\n");
270 		return TCM_INVALID_CDB_FIELD;
271 	}
272 	/*
273 	 * Special case for WRITE_SAME w/ UNMAP=1 that ends up getting
274 	 * translated into block discard requests within backend code.
275 	 */
276 	if (flags[0] & 0x08) {
277 		if (!ops->execute_write_same_unmap)
278 			return TCM_UNSUPPORTED_SCSI_OPCODE;
279 
280 		cmd->execute_cmd = ops->execute_write_same_unmap;
281 		return 0;
282 	}
283 	if (!ops->execute_write_same)
284 		return TCM_UNSUPPORTED_SCSI_OPCODE;
285 
286 	cmd->execute_cmd = ops->execute_write_same;
287 	return 0;
288 }
289 
290 static sense_reason_t xdreadwrite_callback(struct se_cmd *cmd)
291 {
292 	unsigned char *buf, *addr;
293 	struct scatterlist *sg;
294 	unsigned int offset;
295 	sense_reason_t ret = TCM_NO_SENSE;
296 	int i, count;
297 	/*
298 	 * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
299 	 *
300 	 * 1) read the specified logical block(s);
301 	 * 2) transfer logical blocks from the data-out buffer;
302 	 * 3) XOR the logical blocks transferred from the data-out buffer with
303 	 *    the logical blocks read, storing the resulting XOR data in a buffer;
304 	 * 4) if the DISABLE WRITE bit is set to zero, then write the logical
305 	 *    blocks transferred from the data-out buffer; and
306 	 * 5) transfer the resulting XOR data to the data-in buffer.
307 	 */
308 	buf = kmalloc(cmd->data_length, GFP_KERNEL);
309 	if (!buf) {
310 		pr_err("Unable to allocate xor_callback buf\n");
311 		return TCM_OUT_OF_RESOURCES;
312 	}
313 	/*
314 	 * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
315 	 * into the locally allocated *buf
316 	 */
317 	sg_copy_to_buffer(cmd->t_data_sg,
318 			  cmd->t_data_nents,
319 			  buf,
320 			  cmd->data_length);
321 
322 	/*
323 	 * Now perform the XOR against the BIDI read memory located at
324 	 * cmd->t_mem_bidi_list
325 	 */
326 
327 	offset = 0;
328 	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
329 		addr = kmap_atomic(sg_page(sg));
330 		if (!addr) {
331 			ret = TCM_OUT_OF_RESOURCES;
332 			goto out;
333 		}
334 
335 		for (i = 0; i < sg->length; i++)
336 			*(addr + sg->offset + i) ^= *(buf + offset + i);
337 
338 		offset += sg->length;
339 		kunmap_atomic(addr);
340 	}
341 
342 out:
343 	kfree(buf);
344 	return ret;
345 }
346 
347 static sense_reason_t
348 sbc_execute_rw(struct se_cmd *cmd)
349 {
350 	return cmd->execute_rw(cmd, cmd->t_data_sg, cmd->t_data_nents,
351 			       cmd->data_direction);
352 }
353 
354 static sense_reason_t compare_and_write_post(struct se_cmd *cmd)
355 {
356 	struct se_device *dev = cmd->se_dev;
357 
358 	/*
359 	 * Only set SCF_COMPARE_AND_WRITE_POST to force a response fall-through
360 	 * within target_complete_ok_work() if the command was successfully
361 	 * sent to the backend driver.
362 	 */
363 	spin_lock_irq(&cmd->t_state_lock);
364 	if ((cmd->transport_state & CMD_T_SENT) && !cmd->scsi_status)
365 		cmd->se_cmd_flags |= SCF_COMPARE_AND_WRITE_POST;
366 	spin_unlock_irq(&cmd->t_state_lock);
367 
368 	/*
369 	 * Unlock ->caw_sem originally obtained during sbc_compare_and_write()
370 	 * before the original READ I/O submission.
371 	 */
372 	up(&dev->caw_sem);
373 
374 	return TCM_NO_SENSE;
375 }
376 
377 static sense_reason_t compare_and_write_callback(struct se_cmd *cmd)
378 {
379 	struct se_device *dev = cmd->se_dev;
380 	struct scatterlist *write_sg = NULL, *sg;
381 	unsigned char *buf = NULL, *addr;
382 	struct sg_mapping_iter m;
383 	unsigned int offset = 0, len;
384 	unsigned int nlbas = cmd->t_task_nolb;
385 	unsigned int block_size = dev->dev_attrib.block_size;
386 	unsigned int compare_len = (nlbas * block_size);
387 	sense_reason_t ret = TCM_NO_SENSE;
388 	int rc, i;
389 
390 	/*
391 	 * Handle early failure in transport_generic_request_failure(),
392 	 * which will not have taken ->caw_mutex yet..
393 	 */
394 	if (!cmd->t_data_sg || !cmd->t_bidi_data_sg)
395 		return TCM_NO_SENSE;
396 	/*
397 	 * Immediately exit + release dev->caw_sem if command has already
398 	 * been failed with a non-zero SCSI status.
399 	 */
400 	if (cmd->scsi_status) {
401 		pr_err("compare_and_write_callback: non zero scsi_status:"
402 			" 0x%02x\n", cmd->scsi_status);
403 		goto out;
404 	}
405 
406 	buf = kzalloc(cmd->data_length, GFP_KERNEL);
407 	if (!buf) {
408 		pr_err("Unable to allocate compare_and_write buf\n");
409 		ret = TCM_OUT_OF_RESOURCES;
410 		goto out;
411 	}
412 
413 	write_sg = kmalloc(sizeof(struct scatterlist) * cmd->t_data_nents,
414 			   GFP_KERNEL);
415 	if (!write_sg) {
416 		pr_err("Unable to allocate compare_and_write sg\n");
417 		ret = TCM_OUT_OF_RESOURCES;
418 		goto out;
419 	}
420 	sg_init_table(write_sg, cmd->t_data_nents);
421 	/*
422 	 * Setup verify and write data payloads from total NumberLBAs.
423 	 */
424 	rc = sg_copy_to_buffer(cmd->t_data_sg, cmd->t_data_nents, buf,
425 			       cmd->data_length);
426 	if (!rc) {
427 		pr_err("sg_copy_to_buffer() failed for compare_and_write\n");
428 		ret = TCM_OUT_OF_RESOURCES;
429 		goto out;
430 	}
431 	/*
432 	 * Compare against SCSI READ payload against verify payload
433 	 */
434 	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, i) {
435 		addr = (unsigned char *)kmap_atomic(sg_page(sg));
436 		if (!addr) {
437 			ret = TCM_OUT_OF_RESOURCES;
438 			goto out;
439 		}
440 
441 		len = min(sg->length, compare_len);
442 
443 		if (memcmp(addr, buf + offset, len)) {
444 			pr_warn("Detected MISCOMPARE for addr: %p buf: %p\n",
445 				addr, buf + offset);
446 			kunmap_atomic(addr);
447 			goto miscompare;
448 		}
449 		kunmap_atomic(addr);
450 
451 		offset += len;
452 		compare_len -= len;
453 		if (!compare_len)
454 			break;
455 	}
456 
457 	i = 0;
458 	len = cmd->t_task_nolb * block_size;
459 	sg_miter_start(&m, cmd->t_data_sg, cmd->t_data_nents, SG_MITER_TO_SG);
460 	/*
461 	 * Currently assumes NoLB=1 and SGLs are PAGE_SIZE..
462 	 */
463 	while (len) {
464 		sg_miter_next(&m);
465 
466 		if (block_size < PAGE_SIZE) {
467 			sg_set_page(&write_sg[i], m.page, block_size,
468 				    block_size);
469 		} else {
470 			sg_miter_next(&m);
471 			sg_set_page(&write_sg[i], m.page, block_size,
472 				    0);
473 		}
474 		len -= block_size;
475 		i++;
476 	}
477 	sg_miter_stop(&m);
478 	/*
479 	 * Save the original SGL + nents values before updating to new
480 	 * assignments, to be released in transport_free_pages() ->
481 	 * transport_reset_sgl_orig()
482 	 */
483 	cmd->t_data_sg_orig = cmd->t_data_sg;
484 	cmd->t_data_sg = write_sg;
485 	cmd->t_data_nents_orig = cmd->t_data_nents;
486 	cmd->t_data_nents = 1;
487 
488 	cmd->sam_task_attr = MSG_HEAD_TAG;
489 	cmd->transport_complete_callback = compare_and_write_post;
490 	/*
491 	 * Now reset ->execute_cmd() to the normal sbc_execute_rw() handler
492 	 * for submitting the adjusted SGL to write instance user-data.
493 	 */
494 	cmd->execute_cmd = sbc_execute_rw;
495 
496 	spin_lock_irq(&cmd->t_state_lock);
497 	cmd->t_state = TRANSPORT_PROCESSING;
498 	cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
499 	spin_unlock_irq(&cmd->t_state_lock);
500 
501 	__target_execute_cmd(cmd);
502 
503 	kfree(buf);
504 	return ret;
505 
506 miscompare:
507 	pr_warn("Target/%s: Send MISCOMPARE check condition and sense\n",
508 		dev->transport->name);
509 	ret = TCM_MISCOMPARE_VERIFY;
510 out:
511 	/*
512 	 * In the MISCOMPARE or failure case, unlock ->caw_sem obtained in
513 	 * sbc_compare_and_write() before the original READ I/O submission.
514 	 */
515 	up(&dev->caw_sem);
516 	kfree(write_sg);
517 	kfree(buf);
518 	return ret;
519 }
520 
521 static sense_reason_t
522 sbc_compare_and_write(struct se_cmd *cmd)
523 {
524 	struct se_device *dev = cmd->se_dev;
525 	sense_reason_t ret;
526 	int rc;
527 	/*
528 	 * Submit the READ first for COMPARE_AND_WRITE to perform the
529 	 * comparision using SGLs at cmd->t_bidi_data_sg..
530 	 */
531 	rc = down_interruptible(&dev->caw_sem);
532 	if ((rc != 0) || signal_pending(current)) {
533 		cmd->transport_complete_callback = NULL;
534 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
535 	}
536 	/*
537 	 * Reset cmd->data_length to individual block_size in order to not
538 	 * confuse backend drivers that depend on this value matching the
539 	 * size of the I/O being submitted.
540 	 */
541 	cmd->data_length = cmd->t_task_nolb * dev->dev_attrib.block_size;
542 
543 	ret = cmd->execute_rw(cmd, cmd->t_bidi_data_sg, cmd->t_bidi_data_nents,
544 			      DMA_FROM_DEVICE);
545 	if (ret) {
546 		cmd->transport_complete_callback = NULL;
547 		up(&dev->caw_sem);
548 		return ret;
549 	}
550 	/*
551 	 * Unlock of dev->caw_sem to occur in compare_and_write_callback()
552 	 * upon MISCOMPARE, or in compare_and_write_done() upon completion
553 	 * of WRITE instance user-data.
554 	 */
555 	return TCM_NO_SENSE;
556 }
557 
558 static int
559 sbc_set_prot_op_checks(u8 protect, enum target_prot_type prot_type,
560 		       bool is_write, struct se_cmd *cmd)
561 {
562 	if (is_write) {
563 		cmd->prot_op = protect ? TARGET_PROT_DOUT_PASS :
564 					 TARGET_PROT_DOUT_INSERT;
565 		switch (protect) {
566 		case 0x0:
567 		case 0x3:
568 			cmd->prot_checks = 0;
569 			break;
570 		case 0x1:
571 		case 0x5:
572 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
573 			if (prot_type == TARGET_DIF_TYPE1_PROT)
574 				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
575 			break;
576 		case 0x2:
577 			if (prot_type == TARGET_DIF_TYPE1_PROT)
578 				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
579 			break;
580 		case 0x4:
581 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
582 			break;
583 		default:
584 			pr_err("Unsupported protect field %d\n", protect);
585 			return -EINVAL;
586 		}
587 	} else {
588 		cmd->prot_op = protect ? TARGET_PROT_DIN_PASS :
589 					 TARGET_PROT_DIN_STRIP;
590 		switch (protect) {
591 		case 0x0:
592 		case 0x1:
593 		case 0x5:
594 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
595 			if (prot_type == TARGET_DIF_TYPE1_PROT)
596 				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
597 			break;
598 		case 0x2:
599 			if (prot_type == TARGET_DIF_TYPE1_PROT)
600 				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
601 			break;
602 		case 0x3:
603 			cmd->prot_checks = 0;
604 			break;
605 		case 0x4:
606 			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
607 			break;
608 		default:
609 			pr_err("Unsupported protect field %d\n", protect);
610 			return -EINVAL;
611 		}
612 	}
613 
614 	return 0;
615 }
616 
617 static bool
618 sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
619 	       u32 sectors, bool is_write)
620 {
621 	u8 protect = cdb[1] >> 5;
622 
623 	if ((!cmd->t_prot_sg || !cmd->t_prot_nents) && cmd->prot_pto)
624 		return true;
625 
626 	switch (dev->dev_attrib.pi_prot_type) {
627 	case TARGET_DIF_TYPE3_PROT:
628 		cmd->reftag_seed = 0xffffffff;
629 		break;
630 	case TARGET_DIF_TYPE2_PROT:
631 		if (protect)
632 			return false;
633 
634 		cmd->reftag_seed = cmd->t_task_lba;
635 		break;
636 	case TARGET_DIF_TYPE1_PROT:
637 		cmd->reftag_seed = cmd->t_task_lba;
638 		break;
639 	case TARGET_DIF_TYPE0_PROT:
640 	default:
641 		return true;
642 	}
643 
644 	if (sbc_set_prot_op_checks(protect, dev->dev_attrib.pi_prot_type,
645 				   is_write, cmd))
646 		return false;
647 
648 	cmd->prot_type = dev->dev_attrib.pi_prot_type;
649 	cmd->prot_length = dev->prot_length * sectors;
650 
651 	/**
652 	 * In case protection information exists over the wire
653 	 * we modify command data length to describe pure data.
654 	 * The actual transfer length is data length + protection
655 	 * length
656 	 **/
657 	if (protect)
658 		cmd->data_length = sectors * dev->dev_attrib.block_size;
659 
660 	pr_debug("%s: prot_type=%d, data_length=%d, prot_length=%d "
661 		 "prot_op=%d prot_checks=%d\n",
662 		 __func__, cmd->prot_type, cmd->data_length, cmd->prot_length,
663 		 cmd->prot_op, cmd->prot_checks);
664 
665 	return true;
666 }
667 
668 sense_reason_t
669 sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
670 {
671 	struct se_device *dev = cmd->se_dev;
672 	unsigned char *cdb = cmd->t_task_cdb;
673 	unsigned int size;
674 	u32 sectors = 0;
675 	sense_reason_t ret;
676 
677 	switch (cdb[0]) {
678 	case READ_6:
679 		sectors = transport_get_sectors_6(cdb);
680 		cmd->t_task_lba = transport_lba_21(cdb);
681 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
682 		cmd->execute_rw = ops->execute_rw;
683 		cmd->execute_cmd = sbc_execute_rw;
684 		break;
685 	case READ_10:
686 		sectors = transport_get_sectors_10(cdb);
687 		cmd->t_task_lba = transport_lba_32(cdb);
688 
689 		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
690 			return TCM_UNSUPPORTED_SCSI_OPCODE;
691 
692 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
693 		cmd->execute_rw = ops->execute_rw;
694 		cmd->execute_cmd = sbc_execute_rw;
695 		break;
696 	case READ_12:
697 		sectors = transport_get_sectors_12(cdb);
698 		cmd->t_task_lba = transport_lba_32(cdb);
699 
700 		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
701 			return TCM_UNSUPPORTED_SCSI_OPCODE;
702 
703 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
704 		cmd->execute_rw = ops->execute_rw;
705 		cmd->execute_cmd = sbc_execute_rw;
706 		break;
707 	case READ_16:
708 		sectors = transport_get_sectors_16(cdb);
709 		cmd->t_task_lba = transport_lba_64(cdb);
710 
711 		if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
712 			return TCM_UNSUPPORTED_SCSI_OPCODE;
713 
714 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
715 		cmd->execute_rw = ops->execute_rw;
716 		cmd->execute_cmd = sbc_execute_rw;
717 		break;
718 	case WRITE_6:
719 		sectors = transport_get_sectors_6(cdb);
720 		cmd->t_task_lba = transport_lba_21(cdb);
721 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
722 		cmd->execute_rw = ops->execute_rw;
723 		cmd->execute_cmd = sbc_execute_rw;
724 		break;
725 	case WRITE_10:
726 	case WRITE_VERIFY:
727 		sectors = transport_get_sectors_10(cdb);
728 		cmd->t_task_lba = transport_lba_32(cdb);
729 
730 		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
731 			return TCM_UNSUPPORTED_SCSI_OPCODE;
732 
733 		if (cdb[1] & 0x8)
734 			cmd->se_cmd_flags |= SCF_FUA;
735 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
736 		cmd->execute_rw = ops->execute_rw;
737 		cmd->execute_cmd = sbc_execute_rw;
738 		break;
739 	case WRITE_12:
740 		sectors = transport_get_sectors_12(cdb);
741 		cmd->t_task_lba = transport_lba_32(cdb);
742 
743 		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
744 			return TCM_UNSUPPORTED_SCSI_OPCODE;
745 
746 		if (cdb[1] & 0x8)
747 			cmd->se_cmd_flags |= SCF_FUA;
748 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
749 		cmd->execute_rw = ops->execute_rw;
750 		cmd->execute_cmd = sbc_execute_rw;
751 		break;
752 	case WRITE_16:
753 		sectors = transport_get_sectors_16(cdb);
754 		cmd->t_task_lba = transport_lba_64(cdb);
755 
756 		if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
757 			return TCM_UNSUPPORTED_SCSI_OPCODE;
758 
759 		if (cdb[1] & 0x8)
760 			cmd->se_cmd_flags |= SCF_FUA;
761 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
762 		cmd->execute_rw = ops->execute_rw;
763 		cmd->execute_cmd = sbc_execute_rw;
764 		break;
765 	case XDWRITEREAD_10:
766 		if (cmd->data_direction != DMA_TO_DEVICE ||
767 		    !(cmd->se_cmd_flags & SCF_BIDI))
768 			return TCM_INVALID_CDB_FIELD;
769 		sectors = transport_get_sectors_10(cdb);
770 
771 		cmd->t_task_lba = transport_lba_32(cdb);
772 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
773 
774 		/*
775 		 * Setup BIDI XOR callback to be run after I/O completion.
776 		 */
777 		cmd->execute_rw = ops->execute_rw;
778 		cmd->execute_cmd = sbc_execute_rw;
779 		cmd->transport_complete_callback = &xdreadwrite_callback;
780 		if (cdb[1] & 0x8)
781 			cmd->se_cmd_flags |= SCF_FUA;
782 		break;
783 	case VARIABLE_LENGTH_CMD:
784 	{
785 		u16 service_action = get_unaligned_be16(&cdb[8]);
786 		switch (service_action) {
787 		case XDWRITEREAD_32:
788 			sectors = transport_get_sectors_32(cdb);
789 
790 			/*
791 			 * Use WRITE_32 and READ_32 opcodes for the emulated
792 			 * XDWRITE_READ_32 logic.
793 			 */
794 			cmd->t_task_lba = transport_lba_64_ext(cdb);
795 			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
796 
797 			/*
798 			 * Setup BIDI XOR callback to be run during after I/O
799 			 * completion.
800 			 */
801 			cmd->execute_rw = ops->execute_rw;
802 			cmd->execute_cmd = sbc_execute_rw;
803 			cmd->transport_complete_callback = &xdreadwrite_callback;
804 			if (cdb[1] & 0x8)
805 				cmd->se_cmd_flags |= SCF_FUA;
806 			break;
807 		case WRITE_SAME_32:
808 			sectors = transport_get_sectors_32(cdb);
809 			if (!sectors) {
810 				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
811 				       " supported\n");
812 				return TCM_INVALID_CDB_FIELD;
813 			}
814 
815 			size = sbc_get_size(cmd, 1);
816 			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
817 
818 			ret = sbc_setup_write_same(cmd, &cdb[10], ops);
819 			if (ret)
820 				return ret;
821 			break;
822 		default:
823 			pr_err("VARIABLE_LENGTH_CMD service action"
824 				" 0x%04x not supported\n", service_action);
825 			return TCM_UNSUPPORTED_SCSI_OPCODE;
826 		}
827 		break;
828 	}
829 	case COMPARE_AND_WRITE:
830 		sectors = cdb[13];
831 		/*
832 		 * Currently enforce COMPARE_AND_WRITE for a single sector
833 		 */
834 		if (sectors > 1) {
835 			pr_err("COMPARE_AND_WRITE contains NoLB: %u greater"
836 			       " than 1\n", sectors);
837 			return TCM_INVALID_CDB_FIELD;
838 		}
839 		/*
840 		 * Double size because we have two buffers, note that
841 		 * zero is not an error..
842 		 */
843 		size = 2 * sbc_get_size(cmd, sectors);
844 		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
845 		cmd->t_task_nolb = sectors;
846 		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB | SCF_COMPARE_AND_WRITE;
847 		cmd->execute_rw = ops->execute_rw;
848 		cmd->execute_cmd = sbc_compare_and_write;
849 		cmd->transport_complete_callback = compare_and_write_callback;
850 		break;
851 	case READ_CAPACITY:
852 		size = READ_CAP_LEN;
853 		cmd->execute_cmd = sbc_emulate_readcapacity;
854 		break;
855 	case SERVICE_ACTION_IN:
856 		switch (cmd->t_task_cdb[1] & 0x1f) {
857 		case SAI_READ_CAPACITY_16:
858 			cmd->execute_cmd = sbc_emulate_readcapacity_16;
859 			break;
860 		case SAI_REPORT_REFERRALS:
861 			cmd->execute_cmd = target_emulate_report_referrals;
862 			break;
863 		default:
864 			pr_err("Unsupported SA: 0x%02x\n",
865 				cmd->t_task_cdb[1] & 0x1f);
866 			return TCM_INVALID_CDB_FIELD;
867 		}
868 		size = (cdb[10] << 24) | (cdb[11] << 16) |
869 		       (cdb[12] << 8) | cdb[13];
870 		break;
871 	case SYNCHRONIZE_CACHE:
872 	case SYNCHRONIZE_CACHE_16:
873 		if (cdb[0] == SYNCHRONIZE_CACHE) {
874 			sectors = transport_get_sectors_10(cdb);
875 			cmd->t_task_lba = transport_lba_32(cdb);
876 		} else {
877 			sectors = transport_get_sectors_16(cdb);
878 			cmd->t_task_lba = transport_lba_64(cdb);
879 		}
880 		if (ops->execute_sync_cache) {
881 			cmd->execute_cmd = ops->execute_sync_cache;
882 			goto check_lba;
883 		}
884 		size = 0;
885 		cmd->execute_cmd = sbc_emulate_noop;
886 		break;
887 	case UNMAP:
888 		if (!ops->execute_unmap)
889 			return TCM_UNSUPPORTED_SCSI_OPCODE;
890 
891 		size = get_unaligned_be16(&cdb[7]);
892 		cmd->execute_cmd = ops->execute_unmap;
893 		break;
894 	case WRITE_SAME_16:
895 		sectors = transport_get_sectors_16(cdb);
896 		if (!sectors) {
897 			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
898 			return TCM_INVALID_CDB_FIELD;
899 		}
900 
901 		size = sbc_get_size(cmd, 1);
902 		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
903 
904 		ret = sbc_setup_write_same(cmd, &cdb[1], ops);
905 		if (ret)
906 			return ret;
907 		break;
908 	case WRITE_SAME:
909 		sectors = transport_get_sectors_10(cdb);
910 		if (!sectors) {
911 			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
912 			return TCM_INVALID_CDB_FIELD;
913 		}
914 
915 		size = sbc_get_size(cmd, 1);
916 		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
917 
918 		/*
919 		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
920 		 * of byte 1 bit 3 UNMAP instead of original reserved field
921 		 */
922 		ret = sbc_setup_write_same(cmd, &cdb[1], ops);
923 		if (ret)
924 			return ret;
925 		break;
926 	case VERIFY:
927 		size = 0;
928 		sectors = transport_get_sectors_10(cdb);
929 		cmd->t_task_lba = transport_lba_32(cdb);
930 		cmd->execute_cmd = sbc_emulate_noop;
931 		goto check_lba;
932 	case REZERO_UNIT:
933 	case SEEK_6:
934 	case SEEK_10:
935 		/*
936 		 * There are still clients out there which use these old SCSI-2
937 		 * commands. This mainly happens when running VMs with legacy
938 		 * guest systems, connected via SCSI command pass-through to
939 		 * iSCSI targets. Make them happy and return status GOOD.
940 		 */
941 		size = 0;
942 		cmd->execute_cmd = sbc_emulate_noop;
943 		break;
944 	default:
945 		ret = spc_parse_cdb(cmd, &size);
946 		if (ret)
947 			return ret;
948 	}
949 
950 	/* reject any command that we don't have a handler for */
951 	if (!cmd->execute_cmd)
952 		return TCM_UNSUPPORTED_SCSI_OPCODE;
953 
954 	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
955 		unsigned long long end_lba;
956 
957 		if (sectors > dev->dev_attrib.fabric_max_sectors) {
958 			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
959 				" big sectors %u exceeds fabric_max_sectors:"
960 				" %u\n", cdb[0], sectors,
961 				dev->dev_attrib.fabric_max_sectors);
962 			return TCM_INVALID_CDB_FIELD;
963 		}
964 		if (sectors > dev->dev_attrib.hw_max_sectors) {
965 			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
966 				" big sectors %u exceeds backend hw_max_sectors:"
967 				" %u\n", cdb[0], sectors,
968 				dev->dev_attrib.hw_max_sectors);
969 			return TCM_INVALID_CDB_FIELD;
970 		}
971 check_lba:
972 		end_lba = dev->transport->get_blocks(dev) + 1;
973 		if (cmd->t_task_lba + sectors > end_lba) {
974 			pr_err("cmd exceeds last lba %llu "
975 				"(lba %llu, sectors %u)\n",
976 				end_lba, cmd->t_task_lba, sectors);
977 			return TCM_ADDRESS_OUT_OF_RANGE;
978 		}
979 
980 		if (!(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE))
981 			size = sbc_get_size(cmd, sectors);
982 	}
983 
984 	return target_cmd_size_check(cmd, size);
985 }
986 EXPORT_SYMBOL(sbc_parse_cdb);
987 
988 u32 sbc_get_device_type(struct se_device *dev)
989 {
990 	return TYPE_DISK;
991 }
992 EXPORT_SYMBOL(sbc_get_device_type);
993 
994 sense_reason_t
995 sbc_execute_unmap(struct se_cmd *cmd,
996 	sense_reason_t (*do_unmap_fn)(struct se_cmd *, void *,
997 				      sector_t, sector_t),
998 	void *priv)
999 {
1000 	struct se_device *dev = cmd->se_dev;
1001 	unsigned char *buf, *ptr = NULL;
1002 	sector_t lba;
1003 	int size;
1004 	u32 range;
1005 	sense_reason_t ret = 0;
1006 	int dl, bd_dl;
1007 
1008 	/* We never set ANC_SUP */
1009 	if (cmd->t_task_cdb[1])
1010 		return TCM_INVALID_CDB_FIELD;
1011 
1012 	if (cmd->data_length == 0) {
1013 		target_complete_cmd(cmd, SAM_STAT_GOOD);
1014 		return 0;
1015 	}
1016 
1017 	if (cmd->data_length < 8) {
1018 		pr_warn("UNMAP parameter list length %u too small\n",
1019 			cmd->data_length);
1020 		return TCM_PARAMETER_LIST_LENGTH_ERROR;
1021 	}
1022 
1023 	buf = transport_kmap_data_sg(cmd);
1024 	if (!buf)
1025 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1026 
1027 	dl = get_unaligned_be16(&buf[0]);
1028 	bd_dl = get_unaligned_be16(&buf[2]);
1029 
1030 	size = cmd->data_length - 8;
1031 	if (bd_dl > size)
1032 		pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
1033 			cmd->data_length, bd_dl);
1034 	else
1035 		size = bd_dl;
1036 
1037 	if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
1038 		ret = TCM_INVALID_PARAMETER_LIST;
1039 		goto err;
1040 	}
1041 
1042 	/* First UNMAP block descriptor starts at 8 byte offset */
1043 	ptr = &buf[8];
1044 	pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
1045 		" ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
1046 
1047 	while (size >= 16) {
1048 		lba = get_unaligned_be64(&ptr[0]);
1049 		range = get_unaligned_be32(&ptr[8]);
1050 		pr_debug("UNMAP: Using lba: %llu and range: %u\n",
1051 				 (unsigned long long)lba, range);
1052 
1053 		if (range > dev->dev_attrib.max_unmap_lba_count) {
1054 			ret = TCM_INVALID_PARAMETER_LIST;
1055 			goto err;
1056 		}
1057 
1058 		if (lba + range > dev->transport->get_blocks(dev) + 1) {
1059 			ret = TCM_ADDRESS_OUT_OF_RANGE;
1060 			goto err;
1061 		}
1062 
1063 		ret = do_unmap_fn(cmd, priv, lba, range);
1064 		if (ret)
1065 			goto err;
1066 
1067 		ptr += 16;
1068 		size -= 16;
1069 	}
1070 
1071 err:
1072 	transport_kunmap_data_sg(cmd);
1073 	if (!ret)
1074 		target_complete_cmd(cmd, GOOD);
1075 	return ret;
1076 }
1077 EXPORT_SYMBOL(sbc_execute_unmap);
1078 
1079 void
1080 sbc_dif_generate(struct se_cmd *cmd)
1081 {
1082 	struct se_device *dev = cmd->se_dev;
1083 	struct se_dif_v1_tuple *sdt;
1084 	struct scatterlist *dsg, *psg = cmd->t_prot_sg;
1085 	sector_t sector = cmd->t_task_lba;
1086 	void *daddr, *paddr;
1087 	int i, j, offset = 0;
1088 
1089 	for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
1090 		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1091 		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1092 
1093 		for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
1094 
1095 			if (offset >= psg->length) {
1096 				kunmap_atomic(paddr);
1097 				psg = sg_next(psg);
1098 				paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1099 				offset = 0;
1100 			}
1101 
1102 			sdt = paddr + offset;
1103 			sdt->guard_tag = cpu_to_be16(crc_t10dif(daddr + j,
1104 						dev->dev_attrib.block_size));
1105 			if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT)
1106 				sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
1107 			sdt->app_tag = 0;
1108 
1109 			pr_debug("DIF WRITE INSERT sector: %llu guard_tag: 0x%04x"
1110 				 " app_tag: 0x%04x ref_tag: %u\n",
1111 				 (unsigned long long)sector, sdt->guard_tag,
1112 				 sdt->app_tag, be32_to_cpu(sdt->ref_tag));
1113 
1114 			sector++;
1115 			offset += sizeof(struct se_dif_v1_tuple);
1116 		}
1117 
1118 		kunmap_atomic(paddr);
1119 		kunmap_atomic(daddr);
1120 	}
1121 }
1122 
1123 static sense_reason_t
1124 sbc_dif_v1_verify(struct se_device *dev, struct se_dif_v1_tuple *sdt,
1125 		  const void *p, sector_t sector, unsigned int ei_lba)
1126 {
1127 	int block_size = dev->dev_attrib.block_size;
1128 	__be16 csum;
1129 
1130 	csum = cpu_to_be16(crc_t10dif(p, block_size));
1131 
1132 	if (sdt->guard_tag != csum) {
1133 		pr_err("DIFv1 checksum failed on sector %llu guard tag 0x%04x"
1134 			" csum 0x%04x\n", (unsigned long long)sector,
1135 			be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
1136 		return TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED;
1137 	}
1138 
1139 	if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT &&
1140 	    be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
1141 		pr_err("DIFv1 Type 1 reference failed on sector: %llu tag: 0x%08x"
1142 		       " sector MSB: 0x%08x\n", (unsigned long long)sector,
1143 		       be32_to_cpu(sdt->ref_tag), (u32)(sector & 0xffffffff));
1144 		return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
1145 	}
1146 
1147 	if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE2_PROT &&
1148 	    be32_to_cpu(sdt->ref_tag) != ei_lba) {
1149 		pr_err("DIFv1 Type 2 reference failed on sector: %llu tag: 0x%08x"
1150 		       " ei_lba: 0x%08x\n", (unsigned long long)sector,
1151 			be32_to_cpu(sdt->ref_tag), ei_lba);
1152 		return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
1153 	}
1154 
1155 	return 0;
1156 }
1157 
1158 static void
1159 sbc_dif_copy_prot(struct se_cmd *cmd, unsigned int sectors, bool read,
1160 		  struct scatterlist *sg, int sg_off)
1161 {
1162 	struct se_device *dev = cmd->se_dev;
1163 	struct scatterlist *psg;
1164 	void *paddr, *addr;
1165 	unsigned int i, len, left;
1166 	unsigned int offset = sg_off;
1167 
1168 	left = sectors * dev->prot_length;
1169 
1170 	for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) {
1171 		unsigned int psg_len, copied = 0;
1172 
1173 		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1174 		psg_len = min(left, psg->length);
1175 		while (psg_len) {
1176 			len = min(psg_len, sg->length - offset);
1177 			addr = kmap_atomic(sg_page(sg)) + sg->offset + offset;
1178 
1179 			if (read)
1180 				memcpy(paddr + copied, addr, len);
1181 			else
1182 				memcpy(addr, paddr + copied, len);
1183 
1184 			left -= len;
1185 			offset += len;
1186 			copied += len;
1187 			psg_len -= len;
1188 
1189 			if (offset >= sg->length) {
1190 				sg = sg_next(sg);
1191 				offset = 0;
1192 			}
1193 			kunmap_atomic(addr);
1194 		}
1195 		kunmap_atomic(paddr);
1196 	}
1197 }
1198 
1199 sense_reason_t
1200 sbc_dif_verify_write(struct se_cmd *cmd, sector_t start, unsigned int sectors,
1201 		     unsigned int ei_lba, struct scatterlist *sg, int sg_off)
1202 {
1203 	struct se_device *dev = cmd->se_dev;
1204 	struct se_dif_v1_tuple *sdt;
1205 	struct scatterlist *dsg, *psg = cmd->t_prot_sg;
1206 	sector_t sector = start;
1207 	void *daddr, *paddr;
1208 	int i, j, offset = 0;
1209 	sense_reason_t rc;
1210 
1211 	for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
1212 		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1213 		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1214 
1215 		for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
1216 
1217 			if (offset >= psg->length) {
1218 				kunmap_atomic(paddr);
1219 				psg = sg_next(psg);
1220 				paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1221 				offset = 0;
1222 			}
1223 
1224 			sdt = paddr + offset;
1225 
1226 			pr_debug("DIF WRITE sector: %llu guard_tag: 0x%04x"
1227 				 " app_tag: 0x%04x ref_tag: %u\n",
1228 				 (unsigned long long)sector, sdt->guard_tag,
1229 				 sdt->app_tag, be32_to_cpu(sdt->ref_tag));
1230 
1231 			rc = sbc_dif_v1_verify(dev, sdt, daddr + j, sector,
1232 					       ei_lba);
1233 			if (rc) {
1234 				kunmap_atomic(paddr);
1235 				kunmap_atomic(daddr);
1236 				cmd->bad_sector = sector;
1237 				return rc;
1238 			}
1239 
1240 			sector++;
1241 			ei_lba++;
1242 			offset += sizeof(struct se_dif_v1_tuple);
1243 		}
1244 
1245 		kunmap_atomic(paddr);
1246 		kunmap_atomic(daddr);
1247 	}
1248 	sbc_dif_copy_prot(cmd, sectors, false, sg, sg_off);
1249 
1250 	return 0;
1251 }
1252 EXPORT_SYMBOL(sbc_dif_verify_write);
1253 
1254 static sense_reason_t
1255 __sbc_dif_verify_read(struct se_cmd *cmd, sector_t start, unsigned int sectors,
1256 		      unsigned int ei_lba, struct scatterlist *sg, int sg_off)
1257 {
1258 	struct se_device *dev = cmd->se_dev;
1259 	struct se_dif_v1_tuple *sdt;
1260 	struct scatterlist *dsg, *psg = sg;
1261 	sector_t sector = start;
1262 	void *daddr, *paddr;
1263 	int i, j, offset = sg_off;
1264 	sense_reason_t rc;
1265 
1266 	for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
1267 		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
1268 		paddr = kmap_atomic(sg_page(psg)) + sg->offset;
1269 
1270 		for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
1271 
1272 			if (offset >= psg->length) {
1273 				kunmap_atomic(paddr);
1274 				psg = sg_next(psg);
1275 				paddr = kmap_atomic(sg_page(psg)) + psg->offset;
1276 				offset = 0;
1277 			}
1278 
1279 			sdt = paddr + offset;
1280 
1281 			pr_debug("DIF READ sector: %llu guard_tag: 0x%04x"
1282 				 " app_tag: 0x%04x ref_tag: %u\n",
1283 				 (unsigned long long)sector, sdt->guard_tag,
1284 				 sdt->app_tag, be32_to_cpu(sdt->ref_tag));
1285 
1286 			if (sdt->app_tag == cpu_to_be16(0xffff)) {
1287 				sector++;
1288 				offset += sizeof(struct se_dif_v1_tuple);
1289 				continue;
1290 			}
1291 
1292 			rc = sbc_dif_v1_verify(dev, sdt, daddr + j, sector,
1293 					       ei_lba);
1294 			if (rc) {
1295 				kunmap_atomic(paddr);
1296 				kunmap_atomic(daddr);
1297 				cmd->bad_sector = sector;
1298 				return rc;
1299 			}
1300 
1301 			sector++;
1302 			ei_lba++;
1303 			offset += sizeof(struct se_dif_v1_tuple);
1304 		}
1305 
1306 		kunmap_atomic(paddr);
1307 		kunmap_atomic(daddr);
1308 	}
1309 
1310 	return 0;
1311 }
1312 
1313 sense_reason_t
1314 sbc_dif_read_strip(struct se_cmd *cmd)
1315 {
1316 	struct se_device *dev = cmd->se_dev;
1317 	u32 sectors = cmd->prot_length / dev->prot_length;
1318 
1319 	return __sbc_dif_verify_read(cmd, cmd->t_task_lba, sectors, 0,
1320 				     cmd->t_prot_sg, 0);
1321 }
1322 
1323 sense_reason_t
1324 sbc_dif_verify_read(struct se_cmd *cmd, sector_t start, unsigned int sectors,
1325 		    unsigned int ei_lba, struct scatterlist *sg, int sg_off)
1326 {
1327 	sense_reason_t rc;
1328 
1329 	rc = __sbc_dif_verify_read(cmd, start, sectors, ei_lba, sg, sg_off);
1330 	if (rc)
1331 		return rc;
1332 
1333 	sbc_dif_copy_prot(cmd, sectors, true, sg, sg_off);
1334 	return 0;
1335 }
1336 EXPORT_SYMBOL(sbc_dif_verify_read);
1337