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1/*******************************************************************************
2 * Filename: target_core_iblock.c
3 *
4 * This file contains the Storage Engine <-> Linux BlockIO transport
5 * specific functions.
6 *
7 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
8 * Copyright (c) 2005, 2006, 2007 SBE, Inc.
9 * Copyright (c) 2007-2010 Rising Tide Systems
10 * Copyright (c) 2008-2010 Linux-iSCSI.org
11 *
12 * Nicholas A. Bellinger <nab@kernel.org>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 *
28 ******************************************************************************/
29
30#include <linux/string.h>
31#include <linux/parser.h>
32#include <linux/timer.h>
33#include <linux/fs.h>
34#include <linux/blkdev.h>
35#include <linux/slab.h>
36#include <linux/spinlock.h>
37#include <linux/bio.h>
38#include <linux/genhd.h>
39#include <linux/file.h>
40#include <linux/module.h>
41#include <scsi/scsi.h>
42#include <scsi/scsi_host.h>
43
44#include <target/target_core_base.h>
45#include <target/target_core_backend.h>
46
47#include "target_core_iblock.h"
48
49#define IBLOCK_MAX_BIO_PER_TASK 32 /* max # of bios to submit at a time */
50#define IBLOCK_BIO_POOL_SIZE 128
51
52static struct se_subsystem_api iblock_template;
53
54static void iblock_bio_done(struct bio *, int);
55
56/* iblock_attach_hba(): (Part of se_subsystem_api_t template)
57 *
58 *
59 */
60static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
61{
62 pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
63 " Generic Target Core Stack %s\n", hba->hba_id,
64 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
65 return 0;
66}
67
68static void iblock_detach_hba(struct se_hba *hba)
69{
70}
71
72static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
73{
74 struct iblock_dev *ib_dev = NULL;
75
76 ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
77 if (!ib_dev) {
78 pr_err("Unable to allocate struct iblock_dev\n");
79 return NULL;
80 }
81
82 pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
83
84 return ib_dev;
85}
86
87static struct se_device *iblock_create_virtdevice(
88 struct se_hba *hba,
89 struct se_subsystem_dev *se_dev,
90 void *p)
91{
92 struct iblock_dev *ib_dev = p;
93 struct se_device *dev;
94 struct se_dev_limits dev_limits;
95 struct block_device *bd = NULL;
96 struct request_queue *q;
97 struct queue_limits *limits;
98 u32 dev_flags = 0;
99 int ret = -EINVAL;
100
101 if (!ib_dev) {
102 pr_err("Unable to locate struct iblock_dev parameter\n");
103 return ERR_PTR(ret);
104 }
105 memset(&dev_limits, 0, sizeof(struct se_dev_limits));
106
107 ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
108 if (!ib_dev->ibd_bio_set) {
109 pr_err("IBLOCK: Unable to create bioset()\n");
110 return ERR_PTR(-ENOMEM);
111 }
112 pr_debug("IBLOCK: Created bio_set()\n");
113 /*
114 * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
115 * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
116 */
117 pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
118 ib_dev->ibd_udev_path);
119
120 bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
121 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
122 if (IS_ERR(bd)) {
123 ret = PTR_ERR(bd);
124 goto failed;
125 }
126 /*
127 * Setup the local scope queue_limits from struct request_queue->limits
128 * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
129 */
130 q = bdev_get_queue(bd);
131 limits = &dev_limits.limits;
132 limits->logical_block_size = bdev_logical_block_size(bd);
133 limits->max_hw_sectors = UINT_MAX;
134 limits->max_sectors = UINT_MAX;
135 dev_limits.hw_queue_depth = q->nr_requests;
136 dev_limits.queue_depth = q->nr_requests;
137
138 ib_dev->ibd_bd = bd;
139
140 dev = transport_add_device_to_core_hba(hba,
141 &iblock_template, se_dev, dev_flags, ib_dev,
142 &dev_limits, "IBLOCK", IBLOCK_VERSION);
143 if (!dev)
144 goto failed;
145
146 /*
147 * Check if the underlying struct block_device request_queue supports
148 * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
149 * in ATA and we need to set TPE=1
150 */
151 if (blk_queue_discard(q)) {
152 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
153 q->limits.max_discard_sectors;
154 /*
155 * Currently hardcoded to 1 in Linux/SCSI code..
156 */
157 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
158 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
159 q->limits.discard_granularity >> 9;
160 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
161 q->limits.discard_alignment;
162
163 pr_debug("IBLOCK: BLOCK Discard support available,"
164 " disabled by default\n");
165 }
166
167 if (blk_queue_nonrot(q))
168 dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
169
170 return dev;
171
172failed:
173 if (ib_dev->ibd_bio_set) {
174 bioset_free(ib_dev->ibd_bio_set);
175 ib_dev->ibd_bio_set = NULL;
176 }
177 ib_dev->ibd_bd = NULL;
178 return ERR_PTR(ret);
179}
180
181static void iblock_free_device(void *p)
182{
183 struct iblock_dev *ib_dev = p;
184
185 if (ib_dev->ibd_bd != NULL)
186 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
187 if (ib_dev->ibd_bio_set != NULL)
188 bioset_free(ib_dev->ibd_bio_set);
189 kfree(ib_dev);
190}
191
192static unsigned long long iblock_emulate_read_cap_with_block_size(
193 struct se_device *dev,
194 struct block_device *bd,
195 struct request_queue *q)
196{
197 unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
198 bdev_logical_block_size(bd)) - 1);
199 u32 block_size = bdev_logical_block_size(bd);
200
201 if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
202 return blocks_long;
203
204 switch (block_size) {
205 case 4096:
206 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
207 case 2048:
208 blocks_long <<= 1;
209 break;
210 case 1024:
211 blocks_long <<= 2;
212 break;
213 case 512:
214 blocks_long <<= 3;
215 default:
216 break;
217 }
218 break;
219 case 2048:
220 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
221 case 4096:
222 blocks_long >>= 1;
223 break;
224 case 1024:
225 blocks_long <<= 1;
226 break;
227 case 512:
228 blocks_long <<= 2;
229 break;
230 default:
231 break;
232 }
233 break;
234 case 1024:
235 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
236 case 4096:
237 blocks_long >>= 2;
238 break;
239 case 2048:
240 blocks_long >>= 1;
241 break;
242 case 512:
243 blocks_long <<= 1;
244 break;
245 default:
246 break;
247 }
248 break;
249 case 512:
250 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
251 case 4096:
252 blocks_long >>= 3;
253 break;
254 case 2048:
255 blocks_long >>= 2;
256 break;
257 case 1024:
258 blocks_long >>= 1;
259 break;
260 default:
261 break;
262 }
263 break;
264 default:
265 break;
266 }
267
268 return blocks_long;
269}
270
271static void iblock_end_io_flush(struct bio *bio, int err)
272{
273 struct se_cmd *cmd = bio->bi_private;
274
275 if (err)
276 pr_err("IBLOCK: cache flush failed: %d\n", err);
277
278 if (cmd) {
279 if (err) {
280 cmd->scsi_sense_reason =
281 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
282 target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
283 } else {
284 target_complete_cmd(cmd, SAM_STAT_GOOD);
285 }
286 }
287
288 bio_put(bio);
289}
290
291/*
292 * Implement SYCHRONIZE CACHE. Note that we can't handle lba ranges and must
293 * always flush the whole cache.
294 */
295static void iblock_emulate_sync_cache(struct se_cmd *cmd)
296{
297 struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
298 int immed = (cmd->t_task_cdb[1] & 0x2);
299 struct bio *bio;
300
301 /*
302 * If the Immediate bit is set, queue up the GOOD response
303 * for this SYNCHRONIZE_CACHE op.
304 */
305 if (immed)
306 target_complete_cmd(cmd, SAM_STAT_GOOD);
307
308 bio = bio_alloc(GFP_KERNEL, 0);
309 bio->bi_end_io = iblock_end_io_flush;
310 bio->bi_bdev = ib_dev->ibd_bd;
311 if (!immed)
312 bio->bi_private = cmd;
313 submit_bio(WRITE_FLUSH, bio);
314}
315
316static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
317{
318 struct iblock_dev *ibd = dev->dev_ptr;
319 struct block_device *bd = ibd->ibd_bd;
320 int barrier = 0;
321
322 return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
323}
324
325enum {
326 Opt_udev_path, Opt_force, Opt_err
327};
328
329static match_table_t tokens = {
330 {Opt_udev_path, "udev_path=%s"},
331 {Opt_force, "force=%d"},
332 {Opt_err, NULL}
333};
334
335static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
336 struct se_subsystem_dev *se_dev,
337 const char *page, ssize_t count)
338{
339 struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
340 char *orig, *ptr, *arg_p, *opts;
341 substring_t args[MAX_OPT_ARGS];
342 int ret = 0, token;
343
344 opts = kstrdup(page, GFP_KERNEL);
345 if (!opts)
346 return -ENOMEM;
347
348 orig = opts;
349
350 while ((ptr = strsep(&opts, ",\n")) != NULL) {
351 if (!*ptr)
352 continue;
353
354 token = match_token(ptr, tokens, args);
355 switch (token) {
356 case Opt_udev_path:
357 if (ib_dev->ibd_bd) {
358 pr_err("Unable to set udev_path= while"
359 " ib_dev->ibd_bd exists\n");
360 ret = -EEXIST;
361 goto out;
362 }
363 arg_p = match_strdup(&args[0]);
364 if (!arg_p) {
365 ret = -ENOMEM;
366 break;
367 }
368 snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
369 "%s", arg_p);
370 kfree(arg_p);
371 pr_debug("IBLOCK: Referencing UDEV path: %s\n",
372 ib_dev->ibd_udev_path);
373 ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
374 break;
375 case Opt_force:
376 break;
377 default:
378 break;
379 }
380 }
381
382out:
383 kfree(orig);
384 return (!ret) ? count : ret;
385}
386
387static ssize_t iblock_check_configfs_dev_params(
388 struct se_hba *hba,
389 struct se_subsystem_dev *se_dev)
390{
391 struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
392
393 if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
394 pr_err("Missing udev_path= parameters for IBLOCK\n");
395 return -EINVAL;
396 }
397
398 return 0;
399}
400
401static ssize_t iblock_show_configfs_dev_params(
402 struct se_hba *hba,
403 struct se_subsystem_dev *se_dev,
404 char *b)
405{
406 struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
407 struct block_device *bd = ibd->ibd_bd;
408 char buf[BDEVNAME_SIZE];
409 ssize_t bl = 0;
410
411 if (bd)
412 bl += sprintf(b + bl, "iBlock device: %s",
413 bdevname(bd, buf));
414 if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
415 bl += sprintf(b + bl, " UDEV PATH: %s\n",
416 ibd->ibd_udev_path);
417 } else
418 bl += sprintf(b + bl, "\n");
419
420 bl += sprintf(b + bl, " ");
421 if (bd) {
422 bl += sprintf(b + bl, "Major: %d Minor: %d %s\n",
423 MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
424 "" : (bd->bd_holder == ibd) ?
425 "CLAIMED: IBLOCK" : "CLAIMED: OS");
426 } else {
427 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
428 }
429
430 return bl;
431}
432
433static void iblock_complete_cmd(struct se_cmd *cmd)
434{
435 struct iblock_req *ibr = cmd->priv;
436 u8 status;
437
438 if (!atomic_dec_and_test(&ibr->pending))
439 return;
440
441 if (atomic_read(&ibr->ib_bio_err_cnt))
442 status = SAM_STAT_CHECK_CONDITION;
443 else
444 status = SAM_STAT_GOOD;
445
446 target_complete_cmd(cmd, status);
447 kfree(ibr);
448}
449
450static void iblock_bio_destructor(struct bio *bio)
451{
452 struct se_cmd *cmd = bio->bi_private;
453 struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
454
455 bio_free(bio, ib_dev->ibd_bio_set);
456}
457
458static struct bio *
459iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
460{
461 struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
462 struct bio *bio;
463
464 /*
465 * Only allocate as many vector entries as the bio code allows us to,
466 * we'll loop later on until we have handled the whole request.
467 */
468 if (sg_num > BIO_MAX_PAGES)
469 sg_num = BIO_MAX_PAGES;
470
471 bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
472 if (!bio) {
473 pr_err("Unable to allocate memory for bio\n");
474 return NULL;
475 }
476
477 bio->bi_bdev = ib_dev->ibd_bd;
478 bio->bi_private = cmd;
479 bio->bi_destructor = iblock_bio_destructor;
480 bio->bi_end_io = &iblock_bio_done;
481 bio->bi_sector = lba;
482 return bio;
483}
484
485static void iblock_submit_bios(struct bio_list *list, int rw)
486{
487 struct blk_plug plug;
488 struct bio *bio;
489
490 blk_start_plug(&plug);
491 while ((bio = bio_list_pop(list)))
492 submit_bio(rw, bio);
493 blk_finish_plug(&plug);
494}
495
496static int iblock_execute_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
497 u32 sgl_nents, enum dma_data_direction data_direction)
498{
499 struct se_device *dev = cmd->se_dev;
500 struct iblock_req *ibr;
501 struct bio *bio;
502 struct bio_list list;
503 struct scatterlist *sg;
504 u32 sg_num = sgl_nents;
505 sector_t block_lba;
506 unsigned bio_cnt;
507 int rw;
508 int i;
509
510 if (data_direction == DMA_TO_DEVICE) {
511 /*
512 * Force data to disk if we pretend to not have a volatile
513 * write cache, or the initiator set the Force Unit Access bit.
514 */
515 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
516 (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
517 (cmd->se_cmd_flags & SCF_FUA)))
518 rw = WRITE_FUA;
519 else
520 rw = WRITE;
521 } else {
522 rw = READ;
523 }
524
525 /*
526 * Convert the blocksize advertised to the initiator to the 512 byte
527 * units unconditionally used by the Linux block layer.
528 */
529 if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
530 block_lba = (cmd->t_task_lba << 3);
531 else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
532 block_lba = (cmd->t_task_lba << 2);
533 else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
534 block_lba = (cmd->t_task_lba << 1);
535 else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
536 block_lba = cmd->t_task_lba;
537 else {
538 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
539 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
540 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
541 return -ENOSYS;
542 }
543
544 ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
545 if (!ibr)
546 goto fail;
547 cmd->priv = ibr;
548
549 bio = iblock_get_bio(cmd, block_lba, sgl_nents);
550 if (!bio)
551 goto fail_free_ibr;
552
553 bio_list_init(&list);
554 bio_list_add(&list, bio);
555
556 atomic_set(&ibr->pending, 2);
557 bio_cnt = 1;
558
559 for_each_sg(sgl, sg, sgl_nents, i) {
560 /*
561 * XXX: if the length the device accepts is shorter than the
562 * length of the S/G list entry this will cause and
563 * endless loop. Better hope no driver uses huge pages.
564 */
565 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
566 != sg->length) {
567 if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
568 iblock_submit_bios(&list, rw);
569 bio_cnt = 0;
570 }
571
572 bio = iblock_get_bio(cmd, block_lba, sg_num);
573 if (!bio)
574 goto fail_put_bios;
575
576 atomic_inc(&ibr->pending);
577 bio_list_add(&list, bio);
578 bio_cnt++;
579 }
580
581 /* Always in 512 byte units for Linux/Block */
582 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
583 sg_num--;
584 }
585
586 iblock_submit_bios(&list, rw);
587 iblock_complete_cmd(cmd);
588 return 0;
589
590fail_put_bios:
591 while ((bio = bio_list_pop(&list)))
592 bio_put(bio);
593fail_free_ibr:
594 kfree(ibr);
595 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
596fail:
597 return -ENOMEM;
598}
599
600static u32 iblock_get_device_rev(struct se_device *dev)
601{
602 return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
603}
604
605static u32 iblock_get_device_type(struct se_device *dev)
606{
607 return TYPE_DISK;
608}
609
610static sector_t iblock_get_blocks(struct se_device *dev)
611{
612 struct iblock_dev *ibd = dev->dev_ptr;
613 struct block_device *bd = ibd->ibd_bd;
614 struct request_queue *q = bdev_get_queue(bd);
615
616 return iblock_emulate_read_cap_with_block_size(dev, bd, q);
617}
618
619static void iblock_bio_done(struct bio *bio, int err)
620{
621 struct se_cmd *cmd = bio->bi_private;
622 struct iblock_req *ibr = cmd->priv;
623
624 /*
625 * Set -EIO if !BIO_UPTODATE and the passed is still err=0
626 */
627 if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
628 err = -EIO;
629
630 if (err != 0) {
631 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
632 " err: %d\n", bio, err);
633 /*
634 * Bump the ib_bio_err_cnt and release bio.
635 */
636 atomic_inc(&ibr->ib_bio_err_cnt);
637 smp_mb__after_atomic_inc();
638 }
639
640 bio_put(bio);
641
642 iblock_complete_cmd(cmd);
643}
644
645static struct se_subsystem_api iblock_template = {
646 .name = "iblock",
647 .owner = THIS_MODULE,
648 .transport_type = TRANSPORT_PLUGIN_VHBA_PDEV,
649 .write_cache_emulated = 1,
650 .fua_write_emulated = 1,
651 .attach_hba = iblock_attach_hba,
652 .detach_hba = iblock_detach_hba,
653 .allocate_virtdevice = iblock_allocate_virtdevice,
654 .create_virtdevice = iblock_create_virtdevice,
655 .free_device = iblock_free_device,
656 .execute_cmd = iblock_execute_cmd,
657 .do_discard = iblock_do_discard,
658 .do_sync_cache = iblock_emulate_sync_cache,
659 .check_configfs_dev_params = iblock_check_configfs_dev_params,
660 .set_configfs_dev_params = iblock_set_configfs_dev_params,
661 .show_configfs_dev_params = iblock_show_configfs_dev_params,
662 .get_device_rev = iblock_get_device_rev,
663 .get_device_type = iblock_get_device_type,
664 .get_blocks = iblock_get_blocks,
665};
666
667static int __init iblock_module_init(void)
668{
669 return transport_subsystem_register(&iblock_template);
670}
671
672static void iblock_module_exit(void)
673{
674 transport_subsystem_release(&iblock_template);
675}
676
677MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
678MODULE_AUTHOR("nab@Linux-iSCSI.org");
679MODULE_LICENSE("GPL");
680
681module_init(iblock_module_init);
682module_exit(iblock_module_exit);