xref: /linux/drivers/target/target_core_iblock.c (revision e8d235d4d8fb8957bae5f6ed4521115203a00d8b)
1 /*******************************************************************************
2  * Filename:  target_core_iblock.c
3  *
4  * This file contains the Storage Engine  <-> Linux BlockIO transport
5  * specific functions.
6  *
7  * (c) Copyright 2003-2013 Datera, Inc.
8  *
9  * Nicholas A. Bellinger <nab@kernel.org>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24  *
25  ******************************************************************************/
26 
27 #include <linux/string.h>
28 #include <linux/parser.h>
29 #include <linux/timer.h>
30 #include <linux/fs.h>
31 #include <linux/blkdev.h>
32 #include <linux/slab.h>
33 #include <linux/spinlock.h>
34 #include <linux/bio.h>
35 #include <linux/genhd.h>
36 #include <linux/file.h>
37 #include <linux/module.h>
38 #include <scsi/scsi.h>
39 #include <scsi/scsi_host.h>
40 #include <asm/unaligned.h>
41 
42 #include <target/target_core_base.h>
43 #include <target/target_core_backend.h>
44 #include <target/target_core_backend_configfs.h>
45 
46 #include "target_core_iblock.h"
47 
48 #define IBLOCK_MAX_BIO_PER_TASK	 32	/* max # of bios to submit at a time */
49 #define IBLOCK_BIO_POOL_SIZE	128
50 
51 static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
52 {
53 	return container_of(dev, struct iblock_dev, dev);
54 }
55 
56 
57 static struct se_subsystem_api iblock_template;
58 
59 /*	iblock_attach_hba(): (Part of se_subsystem_api_t template)
60  *
61  *
62  */
63 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
64 {
65 	pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
66 		" Generic Target Core Stack %s\n", hba->hba_id,
67 		IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
68 	return 0;
69 }
70 
71 static void iblock_detach_hba(struct se_hba *hba)
72 {
73 }
74 
75 static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
76 {
77 	struct iblock_dev *ib_dev = NULL;
78 
79 	ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
80 	if (!ib_dev) {
81 		pr_err("Unable to allocate struct iblock_dev\n");
82 		return NULL;
83 	}
84 
85 	pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
86 
87 	return &ib_dev->dev;
88 }
89 
90 static int iblock_configure_device(struct se_device *dev)
91 {
92 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
93 	struct request_queue *q;
94 	struct block_device *bd = NULL;
95 	struct blk_integrity *bi;
96 	fmode_t mode;
97 	int ret = -ENOMEM;
98 
99 	if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
100 		pr_err("Missing udev_path= parameters for IBLOCK\n");
101 		return -EINVAL;
102 	}
103 
104 	ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
105 	if (!ib_dev->ibd_bio_set) {
106 		pr_err("IBLOCK: Unable to create bioset\n");
107 		goto out;
108 	}
109 
110 	pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
111 			ib_dev->ibd_udev_path);
112 
113 	mode = FMODE_READ|FMODE_EXCL;
114 	if (!ib_dev->ibd_readonly)
115 		mode |= FMODE_WRITE;
116 
117 	bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
118 	if (IS_ERR(bd)) {
119 		ret = PTR_ERR(bd);
120 		goto out_free_bioset;
121 	}
122 	ib_dev->ibd_bd = bd;
123 
124 	q = bdev_get_queue(bd);
125 
126 	dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
127 	dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
128 	dev->dev_attrib.hw_queue_depth = q->nr_requests;
129 
130 	/*
131 	 * Check if the underlying struct block_device request_queue supports
132 	 * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
133 	 * in ATA and we need to set TPE=1
134 	 */
135 	if (blk_queue_discard(q)) {
136 		dev->dev_attrib.max_unmap_lba_count =
137 				q->limits.max_discard_sectors;
138 
139 		/*
140 		 * Currently hardcoded to 1 in Linux/SCSI code..
141 		 */
142 		dev->dev_attrib.max_unmap_block_desc_count = 1;
143 		dev->dev_attrib.unmap_granularity =
144 				q->limits.discard_granularity >> 9;
145 		dev->dev_attrib.unmap_granularity_alignment =
146 				q->limits.discard_alignment;
147 
148 		pr_debug("IBLOCK: BLOCK Discard support available,"
149 				" disabled by default\n");
150 	}
151 	/*
152 	 * Enable write same emulation for IBLOCK and use 0xFFFF as
153 	 * the smaller WRITE_SAME(10) only has a two-byte block count.
154 	 */
155 	dev->dev_attrib.max_write_same_len = 0xFFFF;
156 
157 	if (blk_queue_nonrot(q))
158 		dev->dev_attrib.is_nonrot = 1;
159 
160 	bi = bdev_get_integrity(bd);
161 	if (bi) {
162 		struct bio_set *bs = ib_dev->ibd_bio_set;
163 
164 		if (!strcmp(bi->name, "T10-DIF-TYPE3-IP") ||
165 		    !strcmp(bi->name, "T10-DIF-TYPE1-IP")) {
166 			pr_err("IBLOCK export of blk_integrity: %s not"
167 			       " supported\n", bi->name);
168 			ret = -ENOSYS;
169 			goto out_blkdev_put;
170 		}
171 
172 		if (!strcmp(bi->name, "T10-DIF-TYPE3-CRC")) {
173 			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
174 		} else if (!strcmp(bi->name, "T10-DIF-TYPE1-CRC")) {
175 			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
176 		}
177 
178 		if (dev->dev_attrib.pi_prot_type) {
179 			if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
180 				pr_err("Unable to allocate bioset for PI\n");
181 				ret = -ENOMEM;
182 				goto out_blkdev_put;
183 			}
184 			pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
185 				 bs->bio_integrity_pool);
186 		}
187 		dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
188 	}
189 
190 	return 0;
191 
192 out_blkdev_put:
193 	blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
194 out_free_bioset:
195 	bioset_free(ib_dev->ibd_bio_set);
196 	ib_dev->ibd_bio_set = NULL;
197 out:
198 	return ret;
199 }
200 
201 static void iblock_free_device(struct se_device *dev)
202 {
203 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
204 
205 	if (ib_dev->ibd_bd != NULL)
206 		blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
207 	if (ib_dev->ibd_bio_set != NULL)
208 		bioset_free(ib_dev->ibd_bio_set);
209 
210 	kfree(ib_dev);
211 }
212 
213 static unsigned long long iblock_emulate_read_cap_with_block_size(
214 	struct se_device *dev,
215 	struct block_device *bd,
216 	struct request_queue *q)
217 {
218 	unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
219 					bdev_logical_block_size(bd)) - 1);
220 	u32 block_size = bdev_logical_block_size(bd);
221 
222 	if (block_size == dev->dev_attrib.block_size)
223 		return blocks_long;
224 
225 	switch (block_size) {
226 	case 4096:
227 		switch (dev->dev_attrib.block_size) {
228 		case 2048:
229 			blocks_long <<= 1;
230 			break;
231 		case 1024:
232 			blocks_long <<= 2;
233 			break;
234 		case 512:
235 			blocks_long <<= 3;
236 		default:
237 			break;
238 		}
239 		break;
240 	case 2048:
241 		switch (dev->dev_attrib.block_size) {
242 		case 4096:
243 			blocks_long >>= 1;
244 			break;
245 		case 1024:
246 			blocks_long <<= 1;
247 			break;
248 		case 512:
249 			blocks_long <<= 2;
250 			break;
251 		default:
252 			break;
253 		}
254 		break;
255 	case 1024:
256 		switch (dev->dev_attrib.block_size) {
257 		case 4096:
258 			blocks_long >>= 2;
259 			break;
260 		case 2048:
261 			blocks_long >>= 1;
262 			break;
263 		case 512:
264 			blocks_long <<= 1;
265 			break;
266 		default:
267 			break;
268 		}
269 		break;
270 	case 512:
271 		switch (dev->dev_attrib.block_size) {
272 		case 4096:
273 			blocks_long >>= 3;
274 			break;
275 		case 2048:
276 			blocks_long >>= 2;
277 			break;
278 		case 1024:
279 			blocks_long >>= 1;
280 			break;
281 		default:
282 			break;
283 		}
284 		break;
285 	default:
286 		break;
287 	}
288 
289 	return blocks_long;
290 }
291 
292 static void iblock_complete_cmd(struct se_cmd *cmd)
293 {
294 	struct iblock_req *ibr = cmd->priv;
295 	u8 status;
296 
297 	if (!atomic_dec_and_test(&ibr->pending))
298 		return;
299 
300 	if (atomic_read(&ibr->ib_bio_err_cnt))
301 		status = SAM_STAT_CHECK_CONDITION;
302 	else
303 		status = SAM_STAT_GOOD;
304 
305 	target_complete_cmd(cmd, status);
306 	kfree(ibr);
307 }
308 
309 static void iblock_bio_done(struct bio *bio, int err)
310 {
311 	struct se_cmd *cmd = bio->bi_private;
312 	struct iblock_req *ibr = cmd->priv;
313 
314 	/*
315 	 * Set -EIO if !BIO_UPTODATE and the passed is still err=0
316 	 */
317 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
318 		err = -EIO;
319 
320 	if (err != 0) {
321 		pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
322 			" err: %d\n", bio, err);
323 		/*
324 		 * Bump the ib_bio_err_cnt and release bio.
325 		 */
326 		atomic_inc(&ibr->ib_bio_err_cnt);
327 		smp_mb__after_atomic();
328 	}
329 
330 	bio_put(bio);
331 
332 	iblock_complete_cmd(cmd);
333 }
334 
335 static struct bio *
336 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
337 {
338 	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
339 	struct bio *bio;
340 
341 	/*
342 	 * Only allocate as many vector entries as the bio code allows us to,
343 	 * we'll loop later on until we have handled the whole request.
344 	 */
345 	if (sg_num > BIO_MAX_PAGES)
346 		sg_num = BIO_MAX_PAGES;
347 
348 	bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
349 	if (!bio) {
350 		pr_err("Unable to allocate memory for bio\n");
351 		return NULL;
352 	}
353 
354 	bio->bi_bdev = ib_dev->ibd_bd;
355 	bio->bi_private = cmd;
356 	bio->bi_end_io = &iblock_bio_done;
357 	bio->bi_iter.bi_sector = lba;
358 
359 	return bio;
360 }
361 
362 static void iblock_submit_bios(struct bio_list *list, int rw)
363 {
364 	struct blk_plug plug;
365 	struct bio *bio;
366 
367 	blk_start_plug(&plug);
368 	while ((bio = bio_list_pop(list)))
369 		submit_bio(rw, bio);
370 	blk_finish_plug(&plug);
371 }
372 
373 static void iblock_end_io_flush(struct bio *bio, int err)
374 {
375 	struct se_cmd *cmd = bio->bi_private;
376 
377 	if (err)
378 		pr_err("IBLOCK: cache flush failed: %d\n", err);
379 
380 	if (cmd) {
381 		if (err)
382 			target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
383 		else
384 			target_complete_cmd(cmd, SAM_STAT_GOOD);
385 	}
386 
387 	bio_put(bio);
388 }
389 
390 /*
391  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
392  * always flush the whole cache.
393  */
394 static sense_reason_t
395 iblock_execute_sync_cache(struct se_cmd *cmd)
396 {
397 	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
398 	int immed = (cmd->t_task_cdb[1] & 0x2);
399 	struct bio *bio;
400 
401 	/*
402 	 * If the Immediate bit is set, queue up the GOOD response
403 	 * for this SYNCHRONIZE_CACHE op.
404 	 */
405 	if (immed)
406 		target_complete_cmd(cmd, SAM_STAT_GOOD);
407 
408 	bio = bio_alloc(GFP_KERNEL, 0);
409 	bio->bi_end_io = iblock_end_io_flush;
410 	bio->bi_bdev = ib_dev->ibd_bd;
411 	if (!immed)
412 		bio->bi_private = cmd;
413 	submit_bio(WRITE_FLUSH, bio);
414 	return 0;
415 }
416 
417 static sense_reason_t
418 iblock_do_unmap(struct se_cmd *cmd, void *priv,
419 		sector_t lba, sector_t nolb)
420 {
421 	struct block_device *bdev = priv;
422 	int ret;
423 
424 	ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
425 	if (ret < 0) {
426 		pr_err("blkdev_issue_discard() failed: %d\n", ret);
427 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
428 	}
429 
430 	return 0;
431 }
432 
433 static sense_reason_t
434 iblock_execute_unmap(struct se_cmd *cmd)
435 {
436 	struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
437 
438 	return sbc_execute_unmap(cmd, iblock_do_unmap, bdev);
439 }
440 
441 static sense_reason_t
442 iblock_execute_write_same_unmap(struct se_cmd *cmd)
443 {
444 	struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
445 	sector_t lba = cmd->t_task_lba;
446 	sector_t nolb = sbc_get_write_same_sectors(cmd);
447 	sense_reason_t ret;
448 
449 	ret = iblock_do_unmap(cmd, bdev, lba, nolb);
450 	if (ret)
451 		return ret;
452 
453 	target_complete_cmd(cmd, GOOD);
454 	return 0;
455 }
456 
457 static sense_reason_t
458 iblock_execute_write_same(struct se_cmd *cmd)
459 {
460 	struct iblock_req *ibr;
461 	struct scatterlist *sg;
462 	struct bio *bio;
463 	struct bio_list list;
464 	sector_t block_lba = cmd->t_task_lba;
465 	sector_t sectors = sbc_get_write_same_sectors(cmd);
466 
467 	if (cmd->prot_op) {
468 		pr_err("WRITE_SAME: Protection information with IBLOCK"
469 		       " backends not supported\n");
470 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
471 	}
472 	sg = &cmd->t_data_sg[0];
473 
474 	if (cmd->t_data_nents > 1 ||
475 	    sg->length != cmd->se_dev->dev_attrib.block_size) {
476 		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
477 			" block_size: %u\n", cmd->t_data_nents, sg->length,
478 			cmd->se_dev->dev_attrib.block_size);
479 		return TCM_INVALID_CDB_FIELD;
480 	}
481 
482 	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
483 	if (!ibr)
484 		goto fail;
485 	cmd->priv = ibr;
486 
487 	bio = iblock_get_bio(cmd, block_lba, 1);
488 	if (!bio)
489 		goto fail_free_ibr;
490 
491 	bio_list_init(&list);
492 	bio_list_add(&list, bio);
493 
494 	atomic_set(&ibr->pending, 1);
495 
496 	while (sectors) {
497 		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
498 				!= sg->length) {
499 
500 			bio = iblock_get_bio(cmd, block_lba, 1);
501 			if (!bio)
502 				goto fail_put_bios;
503 
504 			atomic_inc(&ibr->pending);
505 			bio_list_add(&list, bio);
506 		}
507 
508 		/* Always in 512 byte units for Linux/Block */
509 		block_lba += sg->length >> IBLOCK_LBA_SHIFT;
510 		sectors -= 1;
511 	}
512 
513 	iblock_submit_bios(&list, WRITE);
514 	return 0;
515 
516 fail_put_bios:
517 	while ((bio = bio_list_pop(&list)))
518 		bio_put(bio);
519 fail_free_ibr:
520 	kfree(ibr);
521 fail:
522 	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
523 }
524 
525 enum {
526 	Opt_udev_path, Opt_readonly, Opt_force, Opt_err
527 };
528 
529 static match_table_t tokens = {
530 	{Opt_udev_path, "udev_path=%s"},
531 	{Opt_readonly, "readonly=%d"},
532 	{Opt_force, "force=%d"},
533 	{Opt_err, NULL}
534 };
535 
536 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
537 		const char *page, ssize_t count)
538 {
539 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
540 	char *orig, *ptr, *arg_p, *opts;
541 	substring_t args[MAX_OPT_ARGS];
542 	int ret = 0, token;
543 	unsigned long tmp_readonly;
544 
545 	opts = kstrdup(page, GFP_KERNEL);
546 	if (!opts)
547 		return -ENOMEM;
548 
549 	orig = opts;
550 
551 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
552 		if (!*ptr)
553 			continue;
554 
555 		token = match_token(ptr, tokens, args);
556 		switch (token) {
557 		case Opt_udev_path:
558 			if (ib_dev->ibd_bd) {
559 				pr_err("Unable to set udev_path= while"
560 					" ib_dev->ibd_bd exists\n");
561 				ret = -EEXIST;
562 				goto out;
563 			}
564 			if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
565 				SE_UDEV_PATH_LEN) == 0) {
566 				ret = -EINVAL;
567 				break;
568 			}
569 			pr_debug("IBLOCK: Referencing UDEV path: %s\n",
570 					ib_dev->ibd_udev_path);
571 			ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
572 			break;
573 		case Opt_readonly:
574 			arg_p = match_strdup(&args[0]);
575 			if (!arg_p) {
576 				ret = -ENOMEM;
577 				break;
578 			}
579 			ret = kstrtoul(arg_p, 0, &tmp_readonly);
580 			kfree(arg_p);
581 			if (ret < 0) {
582 				pr_err("kstrtoul() failed for"
583 						" readonly=\n");
584 				goto out;
585 			}
586 			ib_dev->ibd_readonly = tmp_readonly;
587 			pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
588 			break;
589 		case Opt_force:
590 			break;
591 		default:
592 			break;
593 		}
594 	}
595 
596 out:
597 	kfree(orig);
598 	return (!ret) ? count : ret;
599 }
600 
601 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
602 {
603 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
604 	struct block_device *bd = ib_dev->ibd_bd;
605 	char buf[BDEVNAME_SIZE];
606 	ssize_t bl = 0;
607 
608 	if (bd)
609 		bl += sprintf(b + bl, "iBlock device: %s",
610 				bdevname(bd, buf));
611 	if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
612 		bl += sprintf(b + bl, "  UDEV PATH: %s",
613 				ib_dev->ibd_udev_path);
614 	bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
615 
616 	bl += sprintf(b + bl, "        ");
617 	if (bd) {
618 		bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
619 			MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
620 			"" : (bd->bd_holder == ib_dev) ?
621 			"CLAIMED: IBLOCK" : "CLAIMED: OS");
622 	} else {
623 		bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
624 	}
625 
626 	return bl;
627 }
628 
629 static int
630 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
631 {
632 	struct se_device *dev = cmd->se_dev;
633 	struct blk_integrity *bi;
634 	struct bio_integrity_payload *bip;
635 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
636 	struct scatterlist *sg;
637 	int i, rc;
638 
639 	bi = bdev_get_integrity(ib_dev->ibd_bd);
640 	if (!bi) {
641 		pr_err("Unable to locate bio_integrity\n");
642 		return -ENODEV;
643 	}
644 
645 	bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
646 	if (!bip) {
647 		pr_err("Unable to allocate bio_integrity_payload\n");
648 		return -ENOMEM;
649 	}
650 
651 	bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
652 			 dev->prot_length;
653 	bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
654 
655 	pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
656 		 (unsigned long long)bip->bip_iter.bi_sector);
657 
658 	for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
659 
660 		rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
661 					    sg->offset);
662 		if (rc != sg->length) {
663 			pr_err("bio_integrity_add_page() failed; %d\n", rc);
664 			return -ENOMEM;
665 		}
666 
667 		pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
668 			 sg_page(sg), sg->length, sg->offset);
669 	}
670 
671 	return 0;
672 }
673 
674 static sense_reason_t
675 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
676 		  enum dma_data_direction data_direction)
677 {
678 	struct se_device *dev = cmd->se_dev;
679 	struct iblock_req *ibr;
680 	struct bio *bio, *bio_start;
681 	struct bio_list list;
682 	struct scatterlist *sg;
683 	u32 sg_num = sgl_nents;
684 	sector_t block_lba;
685 	unsigned bio_cnt;
686 	int rw = 0;
687 	int i;
688 
689 	if (data_direction == DMA_TO_DEVICE) {
690 		struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
691 		struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
692 		/*
693 		 * Force writethrough using WRITE_FUA if a volatile write cache
694 		 * is not enabled, or if initiator set the Force Unit Access bit.
695 		 */
696 		if (q->flush_flags & REQ_FUA) {
697 			if (cmd->se_cmd_flags & SCF_FUA)
698 				rw = WRITE_FUA;
699 			else if (!(q->flush_flags & REQ_FLUSH))
700 				rw = WRITE_FUA;
701 			else
702 				rw = WRITE;
703 		} else {
704 			rw = WRITE;
705 		}
706 	} else {
707 		rw = READ;
708 	}
709 
710 	/*
711 	 * Convert the blocksize advertised to the initiator to the 512 byte
712 	 * units unconditionally used by the Linux block layer.
713 	 */
714 	if (dev->dev_attrib.block_size == 4096)
715 		block_lba = (cmd->t_task_lba << 3);
716 	else if (dev->dev_attrib.block_size == 2048)
717 		block_lba = (cmd->t_task_lba << 2);
718 	else if (dev->dev_attrib.block_size == 1024)
719 		block_lba = (cmd->t_task_lba << 1);
720 	else if (dev->dev_attrib.block_size == 512)
721 		block_lba = cmd->t_task_lba;
722 	else {
723 		pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
724 				" %u\n", dev->dev_attrib.block_size);
725 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
726 	}
727 
728 	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
729 	if (!ibr)
730 		goto fail;
731 	cmd->priv = ibr;
732 
733 	if (!sgl_nents) {
734 		atomic_set(&ibr->pending, 1);
735 		iblock_complete_cmd(cmd);
736 		return 0;
737 	}
738 
739 	bio = iblock_get_bio(cmd, block_lba, sgl_nents);
740 	if (!bio)
741 		goto fail_free_ibr;
742 
743 	bio_start = bio;
744 	bio_list_init(&list);
745 	bio_list_add(&list, bio);
746 
747 	atomic_set(&ibr->pending, 2);
748 	bio_cnt = 1;
749 
750 	for_each_sg(sgl, sg, sgl_nents, i) {
751 		/*
752 		 * XXX: if the length the device accepts is shorter than the
753 		 *	length of the S/G list entry this will cause and
754 		 *	endless loop.  Better hope no driver uses huge pages.
755 		 */
756 		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
757 				!= sg->length) {
758 			if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
759 				iblock_submit_bios(&list, rw);
760 				bio_cnt = 0;
761 			}
762 
763 			bio = iblock_get_bio(cmd, block_lba, sg_num);
764 			if (!bio)
765 				goto fail_put_bios;
766 
767 			atomic_inc(&ibr->pending);
768 			bio_list_add(&list, bio);
769 			bio_cnt++;
770 		}
771 
772 		/* Always in 512 byte units for Linux/Block */
773 		block_lba += sg->length >> IBLOCK_LBA_SHIFT;
774 		sg_num--;
775 	}
776 
777 	if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
778 		int rc = iblock_alloc_bip(cmd, bio_start);
779 		if (rc)
780 			goto fail_put_bios;
781 	}
782 
783 	iblock_submit_bios(&list, rw);
784 	iblock_complete_cmd(cmd);
785 	return 0;
786 
787 fail_put_bios:
788 	while ((bio = bio_list_pop(&list)))
789 		bio_put(bio);
790 fail_free_ibr:
791 	kfree(ibr);
792 fail:
793 	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
794 }
795 
796 static sector_t iblock_get_blocks(struct se_device *dev)
797 {
798 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
799 	struct block_device *bd = ib_dev->ibd_bd;
800 	struct request_queue *q = bdev_get_queue(bd);
801 
802 	return iblock_emulate_read_cap_with_block_size(dev, bd, q);
803 }
804 
805 static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
806 {
807 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
808 	struct block_device *bd = ib_dev->ibd_bd;
809 	int ret;
810 
811 	ret = bdev_alignment_offset(bd);
812 	if (ret == -1)
813 		return 0;
814 
815 	/* convert offset-bytes to offset-lbas */
816 	return ret / bdev_logical_block_size(bd);
817 }
818 
819 static unsigned int iblock_get_lbppbe(struct se_device *dev)
820 {
821 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
822 	struct block_device *bd = ib_dev->ibd_bd;
823 	int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
824 
825 	return ilog2(logs_per_phys);
826 }
827 
828 static unsigned int iblock_get_io_min(struct se_device *dev)
829 {
830 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
831 	struct block_device *bd = ib_dev->ibd_bd;
832 
833 	return bdev_io_min(bd);
834 }
835 
836 static unsigned int iblock_get_io_opt(struct se_device *dev)
837 {
838 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
839 	struct block_device *bd = ib_dev->ibd_bd;
840 
841 	return bdev_io_opt(bd);
842 }
843 
844 static struct sbc_ops iblock_sbc_ops = {
845 	.execute_rw		= iblock_execute_rw,
846 	.execute_sync_cache	= iblock_execute_sync_cache,
847 	.execute_write_same	= iblock_execute_write_same,
848 	.execute_write_same_unmap = iblock_execute_write_same_unmap,
849 	.execute_unmap		= iblock_execute_unmap,
850 };
851 
852 static sense_reason_t
853 iblock_parse_cdb(struct se_cmd *cmd)
854 {
855 	return sbc_parse_cdb(cmd, &iblock_sbc_ops);
856 }
857 
858 static bool iblock_get_write_cache(struct se_device *dev)
859 {
860 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
861 	struct block_device *bd = ib_dev->ibd_bd;
862 	struct request_queue *q = bdev_get_queue(bd);
863 
864 	return q->flush_flags & REQ_FLUSH;
865 }
866 
867 DEF_TB_DEFAULT_ATTRIBS(iblock);
868 
869 static struct configfs_attribute *iblock_backend_dev_attrs[] = {
870 	&iblock_dev_attrib_emulate_model_alias.attr,
871 	&iblock_dev_attrib_emulate_dpo.attr,
872 	&iblock_dev_attrib_emulate_fua_write.attr,
873 	&iblock_dev_attrib_emulate_fua_read.attr,
874 	&iblock_dev_attrib_emulate_write_cache.attr,
875 	&iblock_dev_attrib_emulate_ua_intlck_ctrl.attr,
876 	&iblock_dev_attrib_emulate_tas.attr,
877 	&iblock_dev_attrib_emulate_tpu.attr,
878 	&iblock_dev_attrib_emulate_tpws.attr,
879 	&iblock_dev_attrib_emulate_caw.attr,
880 	&iblock_dev_attrib_emulate_3pc.attr,
881 	&iblock_dev_attrib_pi_prot_type.attr,
882 	&iblock_dev_attrib_hw_pi_prot_type.attr,
883 	&iblock_dev_attrib_pi_prot_format.attr,
884 	&iblock_dev_attrib_enforce_pr_isids.attr,
885 	&iblock_dev_attrib_is_nonrot.attr,
886 	&iblock_dev_attrib_emulate_rest_reord.attr,
887 	&iblock_dev_attrib_force_pr_aptpl.attr,
888 	&iblock_dev_attrib_hw_block_size.attr,
889 	&iblock_dev_attrib_block_size.attr,
890 	&iblock_dev_attrib_hw_max_sectors.attr,
891 	&iblock_dev_attrib_optimal_sectors.attr,
892 	&iblock_dev_attrib_hw_queue_depth.attr,
893 	&iblock_dev_attrib_queue_depth.attr,
894 	&iblock_dev_attrib_max_unmap_lba_count.attr,
895 	&iblock_dev_attrib_max_unmap_block_desc_count.attr,
896 	&iblock_dev_attrib_unmap_granularity.attr,
897 	&iblock_dev_attrib_unmap_granularity_alignment.attr,
898 	&iblock_dev_attrib_max_write_same_len.attr,
899 	NULL,
900 };
901 
902 static struct se_subsystem_api iblock_template = {
903 	.name			= "iblock",
904 	.inquiry_prod		= "IBLOCK",
905 	.inquiry_rev		= IBLOCK_VERSION,
906 	.owner			= THIS_MODULE,
907 	.transport_type		= TRANSPORT_PLUGIN_VHBA_PDEV,
908 	.attach_hba		= iblock_attach_hba,
909 	.detach_hba		= iblock_detach_hba,
910 	.alloc_device		= iblock_alloc_device,
911 	.configure_device	= iblock_configure_device,
912 	.free_device		= iblock_free_device,
913 	.parse_cdb		= iblock_parse_cdb,
914 	.set_configfs_dev_params = iblock_set_configfs_dev_params,
915 	.show_configfs_dev_params = iblock_show_configfs_dev_params,
916 	.get_device_type	= sbc_get_device_type,
917 	.get_blocks		= iblock_get_blocks,
918 	.get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
919 	.get_lbppbe		= iblock_get_lbppbe,
920 	.get_io_min		= iblock_get_io_min,
921 	.get_io_opt		= iblock_get_io_opt,
922 	.get_write_cache	= iblock_get_write_cache,
923 };
924 
925 static int __init iblock_module_init(void)
926 {
927 	struct target_backend_cits *tbc = &iblock_template.tb_cits;
928 
929 	target_core_setup_sub_cits(&iblock_template);
930 	tbc->tb_dev_attrib_cit.ct_attrs = iblock_backend_dev_attrs;
931 
932 	return transport_subsystem_register(&iblock_template);
933 }
934 
935 static void __exit iblock_module_exit(void)
936 {
937 	transport_subsystem_release(&iblock_template);
938 }
939 
940 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
941 MODULE_AUTHOR("nab@Linux-iSCSI.org");
942 MODULE_LICENSE("GPL");
943 
944 module_init(iblock_module_init);
945 module_exit(iblock_module_exit);
946