xref: /linux/drivers/target/target_core_iblock.c (revision 3e44c471a2dab210f7e9b1e5f7d4d54d52df59eb)
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_proto.h>
39 #include <asm/unaligned.h>
40 
41 #include <target/target_core_base.h>
42 #include <target/target_core_backend.h>
43 #include <target/target_core_backend_configfs.h>
44 
45 #include "target_core_iblock.h"
46 
47 #define IBLOCK_MAX_BIO_PER_TASK	 32	/* max # of bios to submit at a time */
48 #define IBLOCK_BIO_POOL_SIZE	128
49 
50 static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
51 {
52 	return container_of(dev, struct iblock_dev, dev);
53 }
54 
55 
56 static struct se_subsystem_api iblock_template;
57 
58 /*	iblock_attach_hba(): (Part of se_subsystem_api_t template)
59  *
60  *
61  */
62 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
63 {
64 	pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
65 		" Generic Target Core Stack %s\n", hba->hba_id,
66 		IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
67 	return 0;
68 }
69 
70 static void iblock_detach_hba(struct se_hba *hba)
71 {
72 }
73 
74 static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
75 {
76 	struct iblock_dev *ib_dev = NULL;
77 
78 	ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
79 	if (!ib_dev) {
80 		pr_err("Unable to allocate struct iblock_dev\n");
81 		return NULL;
82 	}
83 
84 	pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
85 
86 	return &ib_dev->dev;
87 }
88 
89 static int iblock_configure_device(struct se_device *dev)
90 {
91 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
92 	struct request_queue *q;
93 	struct block_device *bd = NULL;
94 	struct blk_integrity *bi;
95 	fmode_t mode;
96 	int ret = -ENOMEM;
97 
98 	if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
99 		pr_err("Missing udev_path= parameters for IBLOCK\n");
100 		return -EINVAL;
101 	}
102 
103 	ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
104 	if (!ib_dev->ibd_bio_set) {
105 		pr_err("IBLOCK: Unable to create bioset\n");
106 		goto out;
107 	}
108 
109 	pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
110 			ib_dev->ibd_udev_path);
111 
112 	mode = FMODE_READ|FMODE_EXCL;
113 	if (!ib_dev->ibd_readonly)
114 		mode |= FMODE_WRITE;
115 
116 	bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
117 	if (IS_ERR(bd)) {
118 		ret = PTR_ERR(bd);
119 		goto out_free_bioset;
120 	}
121 	ib_dev->ibd_bd = bd;
122 
123 	q = bdev_get_queue(bd);
124 
125 	dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
126 	dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
127 	dev->dev_attrib.hw_queue_depth = q->nr_requests;
128 
129 	/*
130 	 * Check if the underlying struct block_device request_queue supports
131 	 * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
132 	 * in ATA and we need to set TPE=1
133 	 */
134 	if (blk_queue_discard(q)) {
135 		dev->dev_attrib.max_unmap_lba_count =
136 				q->limits.max_discard_sectors;
137 
138 		/*
139 		 * Currently hardcoded to 1 in Linux/SCSI code..
140 		 */
141 		dev->dev_attrib.max_unmap_block_desc_count = 1;
142 		dev->dev_attrib.unmap_granularity =
143 				q->limits.discard_granularity >> 9;
144 		dev->dev_attrib.unmap_granularity_alignment =
145 				q->limits.discard_alignment;
146 
147 		pr_debug("IBLOCK: BLOCK Discard support available,"
148 				" disabled by default\n");
149 	}
150 	/*
151 	 * Enable write same emulation for IBLOCK and use 0xFFFF as
152 	 * the smaller WRITE_SAME(10) only has a two-byte block count.
153 	 */
154 	dev->dev_attrib.max_write_same_len = 0xFFFF;
155 
156 	if (blk_queue_nonrot(q))
157 		dev->dev_attrib.is_nonrot = 1;
158 
159 	bi = bdev_get_integrity(bd);
160 	if (bi) {
161 		struct bio_set *bs = ib_dev->ibd_bio_set;
162 
163 		if (!strcmp(bi->name, "T10-DIF-TYPE3-IP") ||
164 		    !strcmp(bi->name, "T10-DIF-TYPE1-IP")) {
165 			pr_err("IBLOCK export of blk_integrity: %s not"
166 			       " supported\n", bi->name);
167 			ret = -ENOSYS;
168 			goto out_blkdev_put;
169 		}
170 
171 		if (!strcmp(bi->name, "T10-DIF-TYPE3-CRC")) {
172 			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
173 		} else if (!strcmp(bi->name, "T10-DIF-TYPE1-CRC")) {
174 			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
175 		}
176 
177 		if (dev->dev_attrib.pi_prot_type) {
178 			if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
179 				pr_err("Unable to allocate bioset for PI\n");
180 				ret = -ENOMEM;
181 				goto out_blkdev_put;
182 			}
183 			pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
184 				 bs->bio_integrity_pool);
185 		}
186 		dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
187 	}
188 
189 	return 0;
190 
191 out_blkdev_put:
192 	blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
193 out_free_bioset:
194 	bioset_free(ib_dev->ibd_bio_set);
195 	ib_dev->ibd_bio_set = NULL;
196 out:
197 	return ret;
198 }
199 
200 static void iblock_free_device(struct se_device *dev)
201 {
202 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
203 
204 	if (ib_dev->ibd_bd != NULL)
205 		blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
206 	if (ib_dev->ibd_bio_set != NULL)
207 		bioset_free(ib_dev->ibd_bio_set);
208 
209 	kfree(ib_dev);
210 }
211 
212 static unsigned long long iblock_emulate_read_cap_with_block_size(
213 	struct se_device *dev,
214 	struct block_device *bd,
215 	struct request_queue *q)
216 {
217 	unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
218 					bdev_logical_block_size(bd)) - 1);
219 	u32 block_size = bdev_logical_block_size(bd);
220 
221 	if (block_size == dev->dev_attrib.block_size)
222 		return blocks_long;
223 
224 	switch (block_size) {
225 	case 4096:
226 		switch (dev->dev_attrib.block_size) {
227 		case 2048:
228 			blocks_long <<= 1;
229 			break;
230 		case 1024:
231 			blocks_long <<= 2;
232 			break;
233 		case 512:
234 			blocks_long <<= 3;
235 		default:
236 			break;
237 		}
238 		break;
239 	case 2048:
240 		switch (dev->dev_attrib.block_size) {
241 		case 4096:
242 			blocks_long >>= 1;
243 			break;
244 		case 1024:
245 			blocks_long <<= 1;
246 			break;
247 		case 512:
248 			blocks_long <<= 2;
249 			break;
250 		default:
251 			break;
252 		}
253 		break;
254 	case 1024:
255 		switch (dev->dev_attrib.block_size) {
256 		case 4096:
257 			blocks_long >>= 2;
258 			break;
259 		case 2048:
260 			blocks_long >>= 1;
261 			break;
262 		case 512:
263 			blocks_long <<= 1;
264 			break;
265 		default:
266 			break;
267 		}
268 		break;
269 	case 512:
270 		switch (dev->dev_attrib.block_size) {
271 		case 4096:
272 			blocks_long >>= 3;
273 			break;
274 		case 2048:
275 			blocks_long >>= 2;
276 			break;
277 		case 1024:
278 			blocks_long >>= 1;
279 			break;
280 		default:
281 			break;
282 		}
283 		break;
284 	default:
285 		break;
286 	}
287 
288 	return blocks_long;
289 }
290 
291 static void iblock_complete_cmd(struct se_cmd *cmd)
292 {
293 	struct iblock_req *ibr = cmd->priv;
294 	u8 status;
295 
296 	if (!atomic_dec_and_test(&ibr->pending))
297 		return;
298 
299 	if (atomic_read(&ibr->ib_bio_err_cnt))
300 		status = SAM_STAT_CHECK_CONDITION;
301 	else
302 		status = SAM_STAT_GOOD;
303 
304 	target_complete_cmd(cmd, status);
305 	kfree(ibr);
306 }
307 
308 static void iblock_bio_done(struct bio *bio, int err)
309 {
310 	struct se_cmd *cmd = bio->bi_private;
311 	struct iblock_req *ibr = cmd->priv;
312 
313 	/*
314 	 * Set -EIO if !BIO_UPTODATE and the passed is still err=0
315 	 */
316 	if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
317 		err = -EIO;
318 
319 	if (err != 0) {
320 		pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
321 			" err: %d\n", bio, err);
322 		/*
323 		 * Bump the ib_bio_err_cnt and release bio.
324 		 */
325 		atomic_inc(&ibr->ib_bio_err_cnt);
326 		smp_mb__after_atomic();
327 	}
328 
329 	bio_put(bio);
330 
331 	iblock_complete_cmd(cmd);
332 }
333 
334 static struct bio *
335 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
336 {
337 	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
338 	struct bio *bio;
339 
340 	/*
341 	 * Only allocate as many vector entries as the bio code allows us to,
342 	 * we'll loop later on until we have handled the whole request.
343 	 */
344 	if (sg_num > BIO_MAX_PAGES)
345 		sg_num = BIO_MAX_PAGES;
346 
347 	bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
348 	if (!bio) {
349 		pr_err("Unable to allocate memory for bio\n");
350 		return NULL;
351 	}
352 
353 	bio->bi_bdev = ib_dev->ibd_bd;
354 	bio->bi_private = cmd;
355 	bio->bi_end_io = &iblock_bio_done;
356 	bio->bi_iter.bi_sector = lba;
357 
358 	return bio;
359 }
360 
361 static void iblock_submit_bios(struct bio_list *list, int rw)
362 {
363 	struct blk_plug plug;
364 	struct bio *bio;
365 
366 	blk_start_plug(&plug);
367 	while ((bio = bio_list_pop(list)))
368 		submit_bio(rw, bio);
369 	blk_finish_plug(&plug);
370 }
371 
372 static void iblock_end_io_flush(struct bio *bio, int err)
373 {
374 	struct se_cmd *cmd = bio->bi_private;
375 
376 	if (err)
377 		pr_err("IBLOCK: cache flush failed: %d\n", err);
378 
379 	if (cmd) {
380 		if (err)
381 			target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
382 		else
383 			target_complete_cmd(cmd, SAM_STAT_GOOD);
384 	}
385 
386 	bio_put(bio);
387 }
388 
389 /*
390  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
391  * always flush the whole cache.
392  */
393 static sense_reason_t
394 iblock_execute_sync_cache(struct se_cmd *cmd)
395 {
396 	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
397 	int immed = (cmd->t_task_cdb[1] & 0x2);
398 	struct bio *bio;
399 
400 	/*
401 	 * If the Immediate bit is set, queue up the GOOD response
402 	 * for this SYNCHRONIZE_CACHE op.
403 	 */
404 	if (immed)
405 		target_complete_cmd(cmd, SAM_STAT_GOOD);
406 
407 	bio = bio_alloc(GFP_KERNEL, 0);
408 	bio->bi_end_io = iblock_end_io_flush;
409 	bio->bi_bdev = ib_dev->ibd_bd;
410 	if (!immed)
411 		bio->bi_private = cmd;
412 	submit_bio(WRITE_FLUSH, bio);
413 	return 0;
414 }
415 
416 static sense_reason_t
417 iblock_do_unmap(struct se_cmd *cmd, void *priv,
418 		sector_t lba, sector_t nolb)
419 {
420 	struct block_device *bdev = priv;
421 	int ret;
422 
423 	ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
424 	if (ret < 0) {
425 		pr_err("blkdev_issue_discard() failed: %d\n", ret);
426 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
427 	}
428 
429 	return 0;
430 }
431 
432 static sense_reason_t
433 iblock_execute_unmap(struct se_cmd *cmd)
434 {
435 	struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
436 
437 	return sbc_execute_unmap(cmd, iblock_do_unmap, bdev);
438 }
439 
440 static sense_reason_t
441 iblock_execute_write_same_unmap(struct se_cmd *cmd)
442 {
443 	struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
444 	sector_t lba = cmd->t_task_lba;
445 	sector_t nolb = sbc_get_write_same_sectors(cmd);
446 	sense_reason_t ret;
447 
448 	ret = iblock_do_unmap(cmd, bdev, lba, nolb);
449 	if (ret)
450 		return ret;
451 
452 	target_complete_cmd(cmd, GOOD);
453 	return 0;
454 }
455 
456 static sense_reason_t
457 iblock_execute_write_same(struct se_cmd *cmd)
458 {
459 	struct iblock_req *ibr;
460 	struct scatterlist *sg;
461 	struct bio *bio;
462 	struct bio_list list;
463 	sector_t block_lba = cmd->t_task_lba;
464 	sector_t sectors = sbc_get_write_same_sectors(cmd);
465 
466 	if (cmd->prot_op) {
467 		pr_err("WRITE_SAME: Protection information with IBLOCK"
468 		       " backends not supported\n");
469 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
470 	}
471 	sg = &cmd->t_data_sg[0];
472 
473 	if (cmd->t_data_nents > 1 ||
474 	    sg->length != cmd->se_dev->dev_attrib.block_size) {
475 		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
476 			" block_size: %u\n", cmd->t_data_nents, sg->length,
477 			cmd->se_dev->dev_attrib.block_size);
478 		return TCM_INVALID_CDB_FIELD;
479 	}
480 
481 	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
482 	if (!ibr)
483 		goto fail;
484 	cmd->priv = ibr;
485 
486 	bio = iblock_get_bio(cmd, block_lba, 1);
487 	if (!bio)
488 		goto fail_free_ibr;
489 
490 	bio_list_init(&list);
491 	bio_list_add(&list, bio);
492 
493 	atomic_set(&ibr->pending, 1);
494 
495 	while (sectors) {
496 		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
497 				!= sg->length) {
498 
499 			bio = iblock_get_bio(cmd, block_lba, 1);
500 			if (!bio)
501 				goto fail_put_bios;
502 
503 			atomic_inc(&ibr->pending);
504 			bio_list_add(&list, bio);
505 		}
506 
507 		/* Always in 512 byte units for Linux/Block */
508 		block_lba += sg->length >> IBLOCK_LBA_SHIFT;
509 		sectors -= 1;
510 	}
511 
512 	iblock_submit_bios(&list, WRITE);
513 	return 0;
514 
515 fail_put_bios:
516 	while ((bio = bio_list_pop(&list)))
517 		bio_put(bio);
518 fail_free_ibr:
519 	kfree(ibr);
520 fail:
521 	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
522 }
523 
524 enum {
525 	Opt_udev_path, Opt_readonly, Opt_force, Opt_err
526 };
527 
528 static match_table_t tokens = {
529 	{Opt_udev_path, "udev_path=%s"},
530 	{Opt_readonly, "readonly=%d"},
531 	{Opt_force, "force=%d"},
532 	{Opt_err, NULL}
533 };
534 
535 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
536 		const char *page, ssize_t count)
537 {
538 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
539 	char *orig, *ptr, *arg_p, *opts;
540 	substring_t args[MAX_OPT_ARGS];
541 	int ret = 0, token;
542 	unsigned long tmp_readonly;
543 
544 	opts = kstrdup(page, GFP_KERNEL);
545 	if (!opts)
546 		return -ENOMEM;
547 
548 	orig = opts;
549 
550 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
551 		if (!*ptr)
552 			continue;
553 
554 		token = match_token(ptr, tokens, args);
555 		switch (token) {
556 		case Opt_udev_path:
557 			if (ib_dev->ibd_bd) {
558 				pr_err("Unable to set udev_path= while"
559 					" ib_dev->ibd_bd exists\n");
560 				ret = -EEXIST;
561 				goto out;
562 			}
563 			if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
564 				SE_UDEV_PATH_LEN) == 0) {
565 				ret = -EINVAL;
566 				break;
567 			}
568 			pr_debug("IBLOCK: Referencing UDEV path: %s\n",
569 					ib_dev->ibd_udev_path);
570 			ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
571 			break;
572 		case Opt_readonly:
573 			arg_p = match_strdup(&args[0]);
574 			if (!arg_p) {
575 				ret = -ENOMEM;
576 				break;
577 			}
578 			ret = kstrtoul(arg_p, 0, &tmp_readonly);
579 			kfree(arg_p);
580 			if (ret < 0) {
581 				pr_err("kstrtoul() failed for"
582 						" readonly=\n");
583 				goto out;
584 			}
585 			ib_dev->ibd_readonly = tmp_readonly;
586 			pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
587 			break;
588 		case Opt_force:
589 			break;
590 		default:
591 			break;
592 		}
593 	}
594 
595 out:
596 	kfree(orig);
597 	return (!ret) ? count : ret;
598 }
599 
600 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
601 {
602 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
603 	struct block_device *bd = ib_dev->ibd_bd;
604 	char buf[BDEVNAME_SIZE];
605 	ssize_t bl = 0;
606 
607 	if (bd)
608 		bl += sprintf(b + bl, "iBlock device: %s",
609 				bdevname(bd, buf));
610 	if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
611 		bl += sprintf(b + bl, "  UDEV PATH: %s",
612 				ib_dev->ibd_udev_path);
613 	bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
614 
615 	bl += sprintf(b + bl, "        ");
616 	if (bd) {
617 		bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
618 			MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
619 			"" : (bd->bd_holder == ib_dev) ?
620 			"CLAIMED: IBLOCK" : "CLAIMED: OS");
621 	} else {
622 		bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
623 	}
624 
625 	return bl;
626 }
627 
628 static int
629 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
630 {
631 	struct se_device *dev = cmd->se_dev;
632 	struct blk_integrity *bi;
633 	struct bio_integrity_payload *bip;
634 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
635 	struct scatterlist *sg;
636 	int i, rc;
637 
638 	bi = bdev_get_integrity(ib_dev->ibd_bd);
639 	if (!bi) {
640 		pr_err("Unable to locate bio_integrity\n");
641 		return -ENODEV;
642 	}
643 
644 	bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
645 	if (!bip) {
646 		pr_err("Unable to allocate bio_integrity_payload\n");
647 		return -ENOMEM;
648 	}
649 
650 	bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
651 			 dev->prot_length;
652 	bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
653 
654 	pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
655 		 (unsigned long long)bip->bip_iter.bi_sector);
656 
657 	for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
658 
659 		rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
660 					    sg->offset);
661 		if (rc != sg->length) {
662 			pr_err("bio_integrity_add_page() failed; %d\n", rc);
663 			return -ENOMEM;
664 		}
665 
666 		pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
667 			 sg_page(sg), sg->length, sg->offset);
668 	}
669 
670 	return 0;
671 }
672 
673 static sense_reason_t
674 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
675 		  enum dma_data_direction data_direction)
676 {
677 	struct se_device *dev = cmd->se_dev;
678 	struct iblock_req *ibr;
679 	struct bio *bio, *bio_start;
680 	struct bio_list list;
681 	struct scatterlist *sg;
682 	u32 sg_num = sgl_nents;
683 	sector_t block_lba;
684 	unsigned bio_cnt;
685 	int rw = 0;
686 	int i;
687 
688 	if (data_direction == DMA_TO_DEVICE) {
689 		struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
690 		struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
691 		/*
692 		 * Force writethrough using WRITE_FUA if a volatile write cache
693 		 * is not enabled, or if initiator set the Force Unit Access bit.
694 		 */
695 		if (q->flush_flags & REQ_FUA) {
696 			if (cmd->se_cmd_flags & SCF_FUA)
697 				rw = WRITE_FUA;
698 			else if (!(q->flush_flags & REQ_FLUSH))
699 				rw = WRITE_FUA;
700 			else
701 				rw = WRITE;
702 		} else {
703 			rw = WRITE;
704 		}
705 	} else {
706 		rw = READ;
707 	}
708 
709 	/*
710 	 * Convert the blocksize advertised to the initiator to the 512 byte
711 	 * units unconditionally used by the Linux block layer.
712 	 */
713 	if (dev->dev_attrib.block_size == 4096)
714 		block_lba = (cmd->t_task_lba << 3);
715 	else if (dev->dev_attrib.block_size == 2048)
716 		block_lba = (cmd->t_task_lba << 2);
717 	else if (dev->dev_attrib.block_size == 1024)
718 		block_lba = (cmd->t_task_lba << 1);
719 	else if (dev->dev_attrib.block_size == 512)
720 		block_lba = cmd->t_task_lba;
721 	else {
722 		pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
723 				" %u\n", dev->dev_attrib.block_size);
724 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
725 	}
726 
727 	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
728 	if (!ibr)
729 		goto fail;
730 	cmd->priv = ibr;
731 
732 	if (!sgl_nents) {
733 		atomic_set(&ibr->pending, 1);
734 		iblock_complete_cmd(cmd);
735 		return 0;
736 	}
737 
738 	bio = iblock_get_bio(cmd, block_lba, sgl_nents);
739 	if (!bio)
740 		goto fail_free_ibr;
741 
742 	bio_start = bio;
743 	bio_list_init(&list);
744 	bio_list_add(&list, bio);
745 
746 	atomic_set(&ibr->pending, 2);
747 	bio_cnt = 1;
748 
749 	for_each_sg(sgl, sg, sgl_nents, i) {
750 		/*
751 		 * XXX: if the length the device accepts is shorter than the
752 		 *	length of the S/G list entry this will cause and
753 		 *	endless loop.  Better hope no driver uses huge pages.
754 		 */
755 		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
756 				!= sg->length) {
757 			if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
758 				iblock_submit_bios(&list, rw);
759 				bio_cnt = 0;
760 			}
761 
762 			bio = iblock_get_bio(cmd, block_lba, sg_num);
763 			if (!bio)
764 				goto fail_put_bios;
765 
766 			atomic_inc(&ibr->pending);
767 			bio_list_add(&list, bio);
768 			bio_cnt++;
769 		}
770 
771 		/* Always in 512 byte units for Linux/Block */
772 		block_lba += sg->length >> IBLOCK_LBA_SHIFT;
773 		sg_num--;
774 	}
775 
776 	if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
777 		int rc = iblock_alloc_bip(cmd, bio_start);
778 		if (rc)
779 			goto fail_put_bios;
780 	}
781 
782 	iblock_submit_bios(&list, rw);
783 	iblock_complete_cmd(cmd);
784 	return 0;
785 
786 fail_put_bios:
787 	while ((bio = bio_list_pop(&list)))
788 		bio_put(bio);
789 fail_free_ibr:
790 	kfree(ibr);
791 fail:
792 	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
793 }
794 
795 static sector_t iblock_get_blocks(struct se_device *dev)
796 {
797 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
798 	struct block_device *bd = ib_dev->ibd_bd;
799 	struct request_queue *q = bdev_get_queue(bd);
800 
801 	return iblock_emulate_read_cap_with_block_size(dev, bd, q);
802 }
803 
804 static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
805 {
806 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
807 	struct block_device *bd = ib_dev->ibd_bd;
808 	int ret;
809 
810 	ret = bdev_alignment_offset(bd);
811 	if (ret == -1)
812 		return 0;
813 
814 	/* convert offset-bytes to offset-lbas */
815 	return ret / bdev_logical_block_size(bd);
816 }
817 
818 static unsigned int iblock_get_lbppbe(struct se_device *dev)
819 {
820 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
821 	struct block_device *bd = ib_dev->ibd_bd;
822 	int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
823 
824 	return ilog2(logs_per_phys);
825 }
826 
827 static unsigned int iblock_get_io_min(struct se_device *dev)
828 {
829 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
830 	struct block_device *bd = ib_dev->ibd_bd;
831 
832 	return bdev_io_min(bd);
833 }
834 
835 static unsigned int iblock_get_io_opt(struct se_device *dev)
836 {
837 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
838 	struct block_device *bd = ib_dev->ibd_bd;
839 
840 	return bdev_io_opt(bd);
841 }
842 
843 static struct sbc_ops iblock_sbc_ops = {
844 	.execute_rw		= iblock_execute_rw,
845 	.execute_sync_cache	= iblock_execute_sync_cache,
846 	.execute_write_same	= iblock_execute_write_same,
847 	.execute_write_same_unmap = iblock_execute_write_same_unmap,
848 	.execute_unmap		= iblock_execute_unmap,
849 };
850 
851 static sense_reason_t
852 iblock_parse_cdb(struct se_cmd *cmd)
853 {
854 	return sbc_parse_cdb(cmd, &iblock_sbc_ops);
855 }
856 
857 static bool iblock_get_write_cache(struct se_device *dev)
858 {
859 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
860 	struct block_device *bd = ib_dev->ibd_bd;
861 	struct request_queue *q = bdev_get_queue(bd);
862 
863 	return q->flush_flags & REQ_FLUSH;
864 }
865 
866 DEF_TB_DEFAULT_ATTRIBS(iblock);
867 
868 static struct configfs_attribute *iblock_backend_dev_attrs[] = {
869 	&iblock_dev_attrib_emulate_model_alias.attr,
870 	&iblock_dev_attrib_emulate_dpo.attr,
871 	&iblock_dev_attrib_emulate_fua_write.attr,
872 	&iblock_dev_attrib_emulate_fua_read.attr,
873 	&iblock_dev_attrib_emulate_write_cache.attr,
874 	&iblock_dev_attrib_emulate_ua_intlck_ctrl.attr,
875 	&iblock_dev_attrib_emulate_tas.attr,
876 	&iblock_dev_attrib_emulate_tpu.attr,
877 	&iblock_dev_attrib_emulate_tpws.attr,
878 	&iblock_dev_attrib_emulate_caw.attr,
879 	&iblock_dev_attrib_emulate_3pc.attr,
880 	&iblock_dev_attrib_pi_prot_type.attr,
881 	&iblock_dev_attrib_hw_pi_prot_type.attr,
882 	&iblock_dev_attrib_pi_prot_format.attr,
883 	&iblock_dev_attrib_enforce_pr_isids.attr,
884 	&iblock_dev_attrib_is_nonrot.attr,
885 	&iblock_dev_attrib_emulate_rest_reord.attr,
886 	&iblock_dev_attrib_force_pr_aptpl.attr,
887 	&iblock_dev_attrib_hw_block_size.attr,
888 	&iblock_dev_attrib_block_size.attr,
889 	&iblock_dev_attrib_hw_max_sectors.attr,
890 	&iblock_dev_attrib_optimal_sectors.attr,
891 	&iblock_dev_attrib_hw_queue_depth.attr,
892 	&iblock_dev_attrib_queue_depth.attr,
893 	&iblock_dev_attrib_max_unmap_lba_count.attr,
894 	&iblock_dev_attrib_max_unmap_block_desc_count.attr,
895 	&iblock_dev_attrib_unmap_granularity.attr,
896 	&iblock_dev_attrib_unmap_granularity_alignment.attr,
897 	&iblock_dev_attrib_max_write_same_len.attr,
898 	NULL,
899 };
900 
901 static struct se_subsystem_api iblock_template = {
902 	.name			= "iblock",
903 	.inquiry_prod		= "IBLOCK",
904 	.inquiry_rev		= IBLOCK_VERSION,
905 	.owner			= THIS_MODULE,
906 	.attach_hba		= iblock_attach_hba,
907 	.detach_hba		= iblock_detach_hba,
908 	.alloc_device		= iblock_alloc_device,
909 	.configure_device	= iblock_configure_device,
910 	.free_device		= iblock_free_device,
911 	.parse_cdb		= iblock_parse_cdb,
912 	.set_configfs_dev_params = iblock_set_configfs_dev_params,
913 	.show_configfs_dev_params = iblock_show_configfs_dev_params,
914 	.get_device_type	= sbc_get_device_type,
915 	.get_blocks		= iblock_get_blocks,
916 	.get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
917 	.get_lbppbe		= iblock_get_lbppbe,
918 	.get_io_min		= iblock_get_io_min,
919 	.get_io_opt		= iblock_get_io_opt,
920 	.get_write_cache	= iblock_get_write_cache,
921 };
922 
923 static int __init iblock_module_init(void)
924 {
925 	struct target_backend_cits *tbc = &iblock_template.tb_cits;
926 
927 	target_core_setup_sub_cits(&iblock_template);
928 	tbc->tb_dev_attrib_cit.ct_attrs = iblock_backend_dev_attrs;
929 
930 	return transport_subsystem_register(&iblock_template);
931 }
932 
933 static void __exit iblock_module_exit(void)
934 {
935 	transport_subsystem_release(&iblock_template);
936 }
937 
938 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
939 MODULE_AUTHOR("nab@Linux-iSCSI.org");
940 MODULE_LICENSE("GPL");
941 
942 module_init(iblock_module_init);
943 module_exit(iblock_module_exit);
944