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target/iblock: Add iblock_do_unmap() helper
[deliverable/linux.git] / drivers / target / target_core_iblock.c
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 2003-2012 RisingTide Systems LLC.
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
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 fmode_t mode;
95 int ret = -ENOMEM;
96
97 if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
98 pr_err("Missing udev_path= parameters for IBLOCK\n");
99 return -EINVAL;
100 }
101
102 ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
103 if (!ib_dev->ibd_bio_set) {
104 pr_err("IBLOCK: Unable to create bioset\n");
105 goto out;
106 }
107
108 pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
109 ib_dev->ibd_udev_path);
110
111 mode = FMODE_READ|FMODE_EXCL;
112 if (!ib_dev->ibd_readonly)
113 mode |= FMODE_WRITE;
114
115 bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
116 if (IS_ERR(bd)) {
117 ret = PTR_ERR(bd);
118 goto out_free_bioset;
119 }
120 ib_dev->ibd_bd = bd;
121
122 q = bdev_get_queue(bd);
123
124 dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
125 dev->dev_attrib.hw_max_sectors = UINT_MAX;
126 dev->dev_attrib.hw_queue_depth = q->nr_requests;
127
128 /*
129 * Check if the underlying struct block_device request_queue supports
130 * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
131 * in ATA and we need to set TPE=1
132 */
133 if (blk_queue_discard(q)) {
134 dev->dev_attrib.max_unmap_lba_count =
135 q->limits.max_discard_sectors;
136
137 /*
138 * Currently hardcoded to 1 in Linux/SCSI code..
139 */
140 dev->dev_attrib.max_unmap_block_desc_count = 1;
141 dev->dev_attrib.unmap_granularity =
142 q->limits.discard_granularity >> 9;
143 dev->dev_attrib.unmap_granularity_alignment =
144 q->limits.discard_alignment;
145
146 pr_debug("IBLOCK: BLOCK Discard support available,"
147 " disabled by default\n");
148 }
149 /*
150 * Enable write same emulation for IBLOCK and use 0xFFFF as
151 * the smaller WRITE_SAME(10) only has a two-byte block count.
152 */
153 dev->dev_attrib.max_write_same_len = 0xFFFF;
154
155 if (blk_queue_nonrot(q))
156 dev->dev_attrib.is_nonrot = 1;
157
158 return 0;
159
160 out_free_bioset:
161 bioset_free(ib_dev->ibd_bio_set);
162 ib_dev->ibd_bio_set = NULL;
163 out:
164 return ret;
165 }
166
167 static void iblock_free_device(struct se_device *dev)
168 {
169 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
170
171 if (ib_dev->ibd_bd != NULL)
172 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
173 if (ib_dev->ibd_bio_set != NULL)
174 bioset_free(ib_dev->ibd_bio_set);
175 kfree(ib_dev);
176 }
177
178 static unsigned long long iblock_emulate_read_cap_with_block_size(
179 struct se_device *dev,
180 struct block_device *bd,
181 struct request_queue *q)
182 {
183 unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
184 bdev_logical_block_size(bd)) - 1);
185 u32 block_size = bdev_logical_block_size(bd);
186
187 if (block_size == dev->dev_attrib.block_size)
188 return blocks_long;
189
190 switch (block_size) {
191 case 4096:
192 switch (dev->dev_attrib.block_size) {
193 case 2048:
194 blocks_long <<= 1;
195 break;
196 case 1024:
197 blocks_long <<= 2;
198 break;
199 case 512:
200 blocks_long <<= 3;
201 default:
202 break;
203 }
204 break;
205 case 2048:
206 switch (dev->dev_attrib.block_size) {
207 case 4096:
208 blocks_long >>= 1;
209 break;
210 case 1024:
211 blocks_long <<= 1;
212 break;
213 case 512:
214 blocks_long <<= 2;
215 break;
216 default:
217 break;
218 }
219 break;
220 case 1024:
221 switch (dev->dev_attrib.block_size) {
222 case 4096:
223 blocks_long >>= 2;
224 break;
225 case 2048:
226 blocks_long >>= 1;
227 break;
228 case 512:
229 blocks_long <<= 1;
230 break;
231 default:
232 break;
233 }
234 break;
235 case 512:
236 switch (dev->dev_attrib.block_size) {
237 case 4096:
238 blocks_long >>= 3;
239 break;
240 case 2048:
241 blocks_long >>= 2;
242 break;
243 case 1024:
244 blocks_long >>= 1;
245 break;
246 default:
247 break;
248 }
249 break;
250 default:
251 break;
252 }
253
254 return blocks_long;
255 }
256
257 static void iblock_complete_cmd(struct se_cmd *cmd)
258 {
259 struct iblock_req *ibr = cmd->priv;
260 u8 status;
261
262 if (!atomic_dec_and_test(&ibr->pending))
263 return;
264
265 if (atomic_read(&ibr->ib_bio_err_cnt))
266 status = SAM_STAT_CHECK_CONDITION;
267 else
268 status = SAM_STAT_GOOD;
269
270 target_complete_cmd(cmd, status);
271 kfree(ibr);
272 }
273
274 static void iblock_bio_done(struct bio *bio, int err)
275 {
276 struct se_cmd *cmd = bio->bi_private;
277 struct iblock_req *ibr = cmd->priv;
278
279 /*
280 * Set -EIO if !BIO_UPTODATE and the passed is still err=0
281 */
282 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
283 err = -EIO;
284
285 if (err != 0) {
286 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
287 " err: %d\n", bio, err);
288 /*
289 * Bump the ib_bio_err_cnt and release bio.
290 */
291 atomic_inc(&ibr->ib_bio_err_cnt);
292 smp_mb__after_atomic_inc();
293 }
294
295 bio_put(bio);
296
297 iblock_complete_cmd(cmd);
298 }
299
300 static struct bio *
301 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
302 {
303 struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
304 struct bio *bio;
305
306 /*
307 * Only allocate as many vector entries as the bio code allows us to,
308 * we'll loop later on until we have handled the whole request.
309 */
310 if (sg_num > BIO_MAX_PAGES)
311 sg_num = BIO_MAX_PAGES;
312
313 bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
314 if (!bio) {
315 pr_err("Unable to allocate memory for bio\n");
316 return NULL;
317 }
318
319 bio->bi_bdev = ib_dev->ibd_bd;
320 bio->bi_private = cmd;
321 bio->bi_end_io = &iblock_bio_done;
322 bio->bi_sector = lba;
323
324 return bio;
325 }
326
327 static void iblock_submit_bios(struct bio_list *list, int rw)
328 {
329 struct blk_plug plug;
330 struct bio *bio;
331
332 blk_start_plug(&plug);
333 while ((bio = bio_list_pop(list)))
334 submit_bio(rw, bio);
335 blk_finish_plug(&plug);
336 }
337
338 static void iblock_end_io_flush(struct bio *bio, int err)
339 {
340 struct se_cmd *cmd = bio->bi_private;
341
342 if (err)
343 pr_err("IBLOCK: cache flush failed: %d\n", err);
344
345 if (cmd) {
346 if (err)
347 target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
348 else
349 target_complete_cmd(cmd, SAM_STAT_GOOD);
350 }
351
352 bio_put(bio);
353 }
354
355 /*
356 * Implement SYCHRONIZE CACHE. Note that we can't handle lba ranges and must
357 * always flush the whole cache.
358 */
359 static sense_reason_t
360 iblock_execute_sync_cache(struct se_cmd *cmd)
361 {
362 struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
363 int immed = (cmd->t_task_cdb[1] & 0x2);
364 struct bio *bio;
365
366 /*
367 * If the Immediate bit is set, queue up the GOOD response
368 * for this SYNCHRONIZE_CACHE op.
369 */
370 if (immed)
371 target_complete_cmd(cmd, SAM_STAT_GOOD);
372
373 bio = bio_alloc(GFP_KERNEL, 0);
374 bio->bi_end_io = iblock_end_io_flush;
375 bio->bi_bdev = ib_dev->ibd_bd;
376 if (!immed)
377 bio->bi_private = cmd;
378 submit_bio(WRITE_FLUSH, bio);
379 return 0;
380 }
381
382 static sense_reason_t
383 iblock_do_unmap(struct se_cmd *cmd, struct block_device *bdev,
384 sector_t lba, sector_t nolb)
385 {
386 int ret;
387
388 ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
389 if (ret < 0) {
390 pr_err("blkdev_issue_discard() failed: %d\n", ret);
391 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
392 }
393
394 return 0;
395 }
396
397 static sense_reason_t
398 iblock_execute_unmap(struct se_cmd *cmd)
399 {
400 struct se_device *dev = cmd->se_dev;
401 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
402 unsigned char *buf, *ptr = NULL;
403 sector_t lba;
404 int size;
405 u32 range;
406 sense_reason_t ret = 0;
407 int dl, bd_dl;
408
409 /* We never set ANC_SUP */
410 if (cmd->t_task_cdb[1])
411 return TCM_INVALID_CDB_FIELD;
412
413 if (cmd->data_length == 0) {
414 target_complete_cmd(cmd, SAM_STAT_GOOD);
415 return 0;
416 }
417
418 if (cmd->data_length < 8) {
419 pr_warn("UNMAP parameter list length %u too small\n",
420 cmd->data_length);
421 return TCM_PARAMETER_LIST_LENGTH_ERROR;
422 }
423
424 buf = transport_kmap_data_sg(cmd);
425 if (!buf)
426 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
427
428 dl = get_unaligned_be16(&buf[0]);
429 bd_dl = get_unaligned_be16(&buf[2]);
430
431 size = cmd->data_length - 8;
432 if (bd_dl > size)
433 pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
434 cmd->data_length, bd_dl);
435 else
436 size = bd_dl;
437
438 if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
439 ret = TCM_INVALID_PARAMETER_LIST;
440 goto err;
441 }
442
443 /* First UNMAP block descriptor starts at 8 byte offset */
444 ptr = &buf[8];
445 pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
446 " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
447
448 while (size >= 16) {
449 lba = get_unaligned_be64(&ptr[0]);
450 range = get_unaligned_be32(&ptr[8]);
451 pr_debug("UNMAP: Using lba: %llu and range: %u\n",
452 (unsigned long long)lba, range);
453
454 if (range > dev->dev_attrib.max_unmap_lba_count) {
455 ret = TCM_INVALID_PARAMETER_LIST;
456 goto err;
457 }
458
459 if (lba + range > dev->transport->get_blocks(dev) + 1) {
460 ret = TCM_ADDRESS_OUT_OF_RANGE;
461 goto err;
462 }
463
464 ret = iblock_do_unmap(cmd, ib_dev->ibd_bd, lba, range);
465 if (ret)
466 goto err;
467
468 ptr += 16;
469 size -= 16;
470 }
471
472 err:
473 transport_kunmap_data_sg(cmd);
474 if (!ret)
475 target_complete_cmd(cmd, GOOD);
476 return ret;
477 }
478
479 static sense_reason_t
480 iblock_execute_write_same_unmap(struct se_cmd *cmd)
481 {
482 struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
483 sector_t lba = cmd->t_task_lba;
484 sector_t nolb = sbc_get_write_same_sectors(cmd);
485 int ret;
486
487 ret = iblock_do_unmap(cmd, bdev, lba, nolb);
488 if (ret)
489 return ret;
490
491 target_complete_cmd(cmd, GOOD);
492 return 0;
493 }
494
495 static sense_reason_t
496 iblock_execute_write_same(struct se_cmd *cmd)
497 {
498 struct iblock_req *ibr;
499 struct scatterlist *sg;
500 struct bio *bio;
501 struct bio_list list;
502 sector_t block_lba = cmd->t_task_lba;
503 sector_t sectors = sbc_get_write_same_sectors(cmd);
504
505 sg = &cmd->t_data_sg[0];
506
507 if (cmd->t_data_nents > 1 ||
508 sg->length != cmd->se_dev->dev_attrib.block_size) {
509 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
510 " block_size: %u\n", cmd->t_data_nents, sg->length,
511 cmd->se_dev->dev_attrib.block_size);
512 return TCM_INVALID_CDB_FIELD;
513 }
514
515 ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
516 if (!ibr)
517 goto fail;
518 cmd->priv = ibr;
519
520 bio = iblock_get_bio(cmd, block_lba, 1);
521 if (!bio)
522 goto fail_free_ibr;
523
524 bio_list_init(&list);
525 bio_list_add(&list, bio);
526
527 atomic_set(&ibr->pending, 1);
528
529 while (sectors) {
530 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
531 != sg->length) {
532
533 bio = iblock_get_bio(cmd, block_lba, 1);
534 if (!bio)
535 goto fail_put_bios;
536
537 atomic_inc(&ibr->pending);
538 bio_list_add(&list, bio);
539 }
540
541 /* Always in 512 byte units for Linux/Block */
542 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
543 sectors -= 1;
544 }
545
546 iblock_submit_bios(&list, WRITE);
547 return 0;
548
549 fail_put_bios:
550 while ((bio = bio_list_pop(&list)))
551 bio_put(bio);
552 fail_free_ibr:
553 kfree(ibr);
554 fail:
555 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
556 }
557
558 enum {
559 Opt_udev_path, Opt_readonly, Opt_force, Opt_err
560 };
561
562 static match_table_t tokens = {
563 {Opt_udev_path, "udev_path=%s"},
564 {Opt_readonly, "readonly=%d"},
565 {Opt_force, "force=%d"},
566 {Opt_err, NULL}
567 };
568
569 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
570 const char *page, ssize_t count)
571 {
572 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
573 char *orig, *ptr, *arg_p, *opts;
574 substring_t args[MAX_OPT_ARGS];
575 int ret = 0, token;
576 unsigned long tmp_readonly;
577
578 opts = kstrdup(page, GFP_KERNEL);
579 if (!opts)
580 return -ENOMEM;
581
582 orig = opts;
583
584 while ((ptr = strsep(&opts, ",\n")) != NULL) {
585 if (!*ptr)
586 continue;
587
588 token = match_token(ptr, tokens, args);
589 switch (token) {
590 case Opt_udev_path:
591 if (ib_dev->ibd_bd) {
592 pr_err("Unable to set udev_path= while"
593 " ib_dev->ibd_bd exists\n");
594 ret = -EEXIST;
595 goto out;
596 }
597 if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
598 SE_UDEV_PATH_LEN) == 0) {
599 ret = -EINVAL;
600 break;
601 }
602 pr_debug("IBLOCK: Referencing UDEV path: %s\n",
603 ib_dev->ibd_udev_path);
604 ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
605 break;
606 case Opt_readonly:
607 arg_p = match_strdup(&args[0]);
608 if (!arg_p) {
609 ret = -ENOMEM;
610 break;
611 }
612 ret = strict_strtoul(arg_p, 0, &tmp_readonly);
613 kfree(arg_p);
614 if (ret < 0) {
615 pr_err("strict_strtoul() failed for"
616 " readonly=\n");
617 goto out;
618 }
619 ib_dev->ibd_readonly = tmp_readonly;
620 pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
621 break;
622 case Opt_force:
623 break;
624 default:
625 break;
626 }
627 }
628
629 out:
630 kfree(orig);
631 return (!ret) ? count : ret;
632 }
633
634 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
635 {
636 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
637 struct block_device *bd = ib_dev->ibd_bd;
638 char buf[BDEVNAME_SIZE];
639 ssize_t bl = 0;
640
641 if (bd)
642 bl += sprintf(b + bl, "iBlock device: %s",
643 bdevname(bd, buf));
644 if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
645 bl += sprintf(b + bl, " UDEV PATH: %s",
646 ib_dev->ibd_udev_path);
647 bl += sprintf(b + bl, " readonly: %d\n", ib_dev->ibd_readonly);
648
649 bl += sprintf(b + bl, " ");
650 if (bd) {
651 bl += sprintf(b + bl, "Major: %d Minor: %d %s\n",
652 MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
653 "" : (bd->bd_holder == ib_dev) ?
654 "CLAIMED: IBLOCK" : "CLAIMED: OS");
655 } else {
656 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
657 }
658
659 return bl;
660 }
661
662 static sense_reason_t
663 iblock_execute_rw(struct se_cmd *cmd)
664 {
665 struct scatterlist *sgl = cmd->t_data_sg;
666 u32 sgl_nents = cmd->t_data_nents;
667 enum dma_data_direction data_direction = cmd->data_direction;
668 struct se_device *dev = cmd->se_dev;
669 struct iblock_req *ibr;
670 struct bio *bio;
671 struct bio_list list;
672 struct scatterlist *sg;
673 u32 sg_num = sgl_nents;
674 sector_t block_lba;
675 unsigned bio_cnt;
676 int rw = 0;
677 int i;
678
679 if (data_direction == DMA_TO_DEVICE) {
680 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
681 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
682 /*
683 * Force writethrough using WRITE_FUA if a volatile write cache
684 * is not enabled, or if initiator set the Force Unit Access bit.
685 */
686 if (q->flush_flags & REQ_FUA) {
687 if (cmd->se_cmd_flags & SCF_FUA)
688 rw = WRITE_FUA;
689 else if (!(q->flush_flags & REQ_FLUSH))
690 rw = WRITE_FUA;
691 } else {
692 rw = WRITE;
693 }
694 } else {
695 rw = READ;
696 }
697
698 /*
699 * Convert the blocksize advertised to the initiator to the 512 byte
700 * units unconditionally used by the Linux block layer.
701 */
702 if (dev->dev_attrib.block_size == 4096)
703 block_lba = (cmd->t_task_lba << 3);
704 else if (dev->dev_attrib.block_size == 2048)
705 block_lba = (cmd->t_task_lba << 2);
706 else if (dev->dev_attrib.block_size == 1024)
707 block_lba = (cmd->t_task_lba << 1);
708 else if (dev->dev_attrib.block_size == 512)
709 block_lba = cmd->t_task_lba;
710 else {
711 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
712 " %u\n", dev->dev_attrib.block_size);
713 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
714 }
715
716 ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
717 if (!ibr)
718 goto fail;
719 cmd->priv = ibr;
720
721 if (!sgl_nents) {
722 atomic_set(&ibr->pending, 1);
723 iblock_complete_cmd(cmd);
724 return 0;
725 }
726
727 bio = iblock_get_bio(cmd, block_lba, sgl_nents);
728 if (!bio)
729 goto fail_free_ibr;
730
731 bio_list_init(&list);
732 bio_list_add(&list, bio);
733
734 atomic_set(&ibr->pending, 2);
735 bio_cnt = 1;
736
737 for_each_sg(sgl, sg, sgl_nents, i) {
738 /*
739 * XXX: if the length the device accepts is shorter than the
740 * length of the S/G list entry this will cause and
741 * endless loop. Better hope no driver uses huge pages.
742 */
743 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
744 != sg->length) {
745 if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
746 iblock_submit_bios(&list, rw);
747 bio_cnt = 0;
748 }
749
750 bio = iblock_get_bio(cmd, block_lba, sg_num);
751 if (!bio)
752 goto fail_put_bios;
753
754 atomic_inc(&ibr->pending);
755 bio_list_add(&list, bio);
756 bio_cnt++;
757 }
758
759 /* Always in 512 byte units for Linux/Block */
760 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
761 sg_num--;
762 }
763
764 iblock_submit_bios(&list, rw);
765 iblock_complete_cmd(cmd);
766 return 0;
767
768 fail_put_bios:
769 while ((bio = bio_list_pop(&list)))
770 bio_put(bio);
771 fail_free_ibr:
772 kfree(ibr);
773 fail:
774 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
775 }
776
777 static sector_t iblock_get_blocks(struct se_device *dev)
778 {
779 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
780 struct block_device *bd = ib_dev->ibd_bd;
781 struct request_queue *q = bdev_get_queue(bd);
782
783 return iblock_emulate_read_cap_with_block_size(dev, bd, q);
784 }
785
786 static struct sbc_ops iblock_sbc_ops = {
787 .execute_rw = iblock_execute_rw,
788 .execute_sync_cache = iblock_execute_sync_cache,
789 .execute_write_same = iblock_execute_write_same,
790 .execute_write_same_unmap = iblock_execute_write_same_unmap,
791 .execute_unmap = iblock_execute_unmap,
792 };
793
794 static sense_reason_t
795 iblock_parse_cdb(struct se_cmd *cmd)
796 {
797 return sbc_parse_cdb(cmd, &iblock_sbc_ops);
798 }
799
800 bool iblock_get_write_cache(struct se_device *dev)
801 {
802 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
803 struct block_device *bd = ib_dev->ibd_bd;
804 struct request_queue *q = bdev_get_queue(bd);
805
806 return q->flush_flags & REQ_FLUSH;
807 }
808
809 static struct se_subsystem_api iblock_template = {
810 .name = "iblock",
811 .inquiry_prod = "IBLOCK",
812 .inquiry_rev = IBLOCK_VERSION,
813 .owner = THIS_MODULE,
814 .transport_type = TRANSPORT_PLUGIN_VHBA_PDEV,
815 .attach_hba = iblock_attach_hba,
816 .detach_hba = iblock_detach_hba,
817 .alloc_device = iblock_alloc_device,
818 .configure_device = iblock_configure_device,
819 .free_device = iblock_free_device,
820 .parse_cdb = iblock_parse_cdb,
821 .set_configfs_dev_params = iblock_set_configfs_dev_params,
822 .show_configfs_dev_params = iblock_show_configfs_dev_params,
823 .get_device_type = sbc_get_device_type,
824 .get_blocks = iblock_get_blocks,
825 .get_write_cache = iblock_get_write_cache,
826 };
827
828 static int __init iblock_module_init(void)
829 {
830 return transport_subsystem_register(&iblock_template);
831 }
832
833 static void __exit iblock_module_exit(void)
834 {
835 transport_subsystem_release(&iblock_template);
836 }
837
838 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
839 MODULE_AUTHOR("nab@Linux-iSCSI.org");
840 MODULE_LICENSE("GPL");
841
842 module_init(iblock_module_init);
843 module_exit(iblock_module_exit);
Linux kernel - Deliverables
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