96d98cc8f85bdbb92ece2a51116fb572eadb4cc4
[linux-3.10.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  * 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/version.h>
31 #include <linux/string.h>
32 #include <linux/parser.h>
33 #include <linux/timer.h>
34 #include <linux/fs.h>
35 #include <linux/blkdev.h>
36 #include <linux/slab.h>
37 #include <linux/spinlock.h>
38 #include <linux/bio.h>
39 #include <linux/genhd.h>
40 #include <linux/file.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_device.h>
46 #include <target/target_core_transport.h>
47
48 #include "target_core_iblock.h"
49
50 #if 0
51 #define DEBUG_IBLOCK(x...) printk(x)
52 #else
53 #define DEBUG_IBLOCK(x...)
54 #endif
55
56 static struct se_subsystem_api iblock_template;
57
58 static void iblock_bio_done(struct bio *, int);
59
60 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
61  *
62  *
63  */
64 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
65 {
66         struct iblock_hba *ib_host;
67
68         ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
69         if (!(ib_host)) {
70                 printk(KERN_ERR "Unable to allocate memory for"
71                                 " struct iblock_hba\n");
72                 return -ENOMEM;
73         }
74
75         ib_host->iblock_host_id = host_id;
76
77         atomic_set(&hba->left_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
78         atomic_set(&hba->max_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
79         hba->hba_ptr = (void *) ib_host;
80
81         printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
82                 " Generic Target Core Stack %s\n", hba->hba_id,
83                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
84
85         printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic"
86                 " Target Core TCQ Depth: %d\n", hba->hba_id,
87                 ib_host->iblock_host_id, atomic_read(&hba->max_queue_depth));
88
89         return 0;
90 }
91
92 static void iblock_detach_hba(struct se_hba *hba)
93 {
94         struct iblock_hba *ib_host = hba->hba_ptr;
95
96         printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
97                 " Target Core\n", hba->hba_id, ib_host->iblock_host_id);
98
99         kfree(ib_host);
100         hba->hba_ptr = NULL;
101 }
102
103 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
104 {
105         struct iblock_dev *ib_dev = NULL;
106         struct iblock_hba *ib_host = hba->hba_ptr;
107
108         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
109         if (!(ib_dev)) {
110                 printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
111                 return NULL;
112         }
113         ib_dev->ibd_host = ib_host;
114
115         printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);
116
117         return ib_dev;
118 }
119
120 static struct se_device *iblock_create_virtdevice(
121         struct se_hba *hba,
122         struct se_subsystem_dev *se_dev,
123         void *p)
124 {
125         struct iblock_dev *ib_dev = p;
126         struct se_device *dev;
127         struct se_dev_limits dev_limits;
128         struct block_device *bd = NULL;
129         struct request_queue *q;
130         struct queue_limits *limits;
131         u32 dev_flags = 0;
132
133         if (!(ib_dev)) {
134                 printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
135                 return 0;
136         }
137         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
138         /*
139          * These settings need to be made tunable..
140          */
141         ib_dev->ibd_bio_set = bioset_create(32, 64);
142         if (!(ib_dev->ibd_bio_set)) {
143                 printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
144                 return 0;
145         }
146         printk(KERN_INFO "IBLOCK: Created bio_set()\n");
147         /*
148          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
149          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
150          */
151         printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
152                         ib_dev->ibd_udev_path);
153
154         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
155                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
156         if (IS_ERR(bd))
157                 goto failed;
158         /*
159          * Setup the local scope queue_limits from struct request_queue->limits
160          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
161          */
162         q = bdev_get_queue(bd);
163         limits = &dev_limits.limits;
164         limits->logical_block_size = bdev_logical_block_size(bd);
165         limits->max_hw_sectors = queue_max_hw_sectors(q);
166         limits->max_sectors = queue_max_sectors(q);
167         dev_limits.hw_queue_depth = IBLOCK_MAX_DEVICE_QUEUE_DEPTH;
168         dev_limits.queue_depth = IBLOCK_DEVICE_QUEUE_DEPTH;
169
170         ib_dev->ibd_major = MAJOR(bd->bd_dev);
171         ib_dev->ibd_minor = MINOR(bd->bd_dev);
172         ib_dev->ibd_bd = bd;
173
174         dev = transport_add_device_to_core_hba(hba,
175                         &iblock_template, se_dev, dev_flags, (void *)ib_dev,
176                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
177         if (!(dev))
178                 goto failed;
179
180         ib_dev->ibd_depth = dev->queue_depth;
181
182         /*
183          * Check if the underlying struct block_device request_queue supports
184          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
185          * in ATA and we need to set TPE=1
186          */
187         if (blk_queue_discard(bdev_get_queue(bd))) {
188                 struct request_queue *q = bdev_get_queue(bd);
189
190                 DEV_ATTRIB(dev)->max_unmap_lba_count =
191                                 q->limits.max_discard_sectors;
192                 /*
193                  * Currently hardcoded to 1 in Linux/SCSI code..
194                  */
195                 DEV_ATTRIB(dev)->max_unmap_block_desc_count = 1;
196                 DEV_ATTRIB(dev)->unmap_granularity =
197                                 q->limits.discard_granularity;
198                 DEV_ATTRIB(dev)->unmap_granularity_alignment =
199                                 q->limits.discard_alignment;
200
201                 printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
202                                 " disabled by default\n");
203         }
204
205         return dev;
206
207 failed:
208         if (ib_dev->ibd_bio_set) {
209                 bioset_free(ib_dev->ibd_bio_set);
210                 ib_dev->ibd_bio_set = NULL;
211         }
212         ib_dev->ibd_bd = NULL;
213         ib_dev->ibd_major = 0;
214         ib_dev->ibd_minor = 0;
215         return NULL;
216 }
217
218 static void iblock_free_device(void *p)
219 {
220         struct iblock_dev *ib_dev = p;
221
222         if (ib_dev->ibd_bd != NULL)
223                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
224         if (ib_dev->ibd_bio_set != NULL)
225                 bioset_free(ib_dev->ibd_bio_set);
226         kfree(ib_dev);
227 }
228
229 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
230 {
231         return container_of(task, struct iblock_req, ib_task);
232 }
233
234 static struct se_task *
235 iblock_alloc_task(struct se_cmd *cmd)
236 {
237         struct iblock_req *ib_req;
238
239         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
240         if (!(ib_req)) {
241                 printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
242                 return NULL;
243         }
244
245         ib_req->ib_dev = SE_DEV(cmd)->dev_ptr;
246         atomic_set(&ib_req->ib_bio_cnt, 0);
247         return &ib_req->ib_task;
248 }
249
250 static unsigned long long iblock_emulate_read_cap_with_block_size(
251         struct se_device *dev,
252         struct block_device *bd,
253         struct request_queue *q)
254 {
255         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
256                                         bdev_logical_block_size(bd)) - 1);
257         u32 block_size = bdev_logical_block_size(bd);
258
259         if (block_size == DEV_ATTRIB(dev)->block_size)
260                 return blocks_long;
261
262         switch (block_size) {
263         case 4096:
264                 switch (DEV_ATTRIB(dev)->block_size) {
265                 case 2048:
266                         blocks_long <<= 1;
267                         break;
268                 case 1024:
269                         blocks_long <<= 2;
270                         break;
271                 case 512:
272                         blocks_long <<= 3;
273                 default:
274                         break;
275                 }
276                 break;
277         case 2048:
278                 switch (DEV_ATTRIB(dev)->block_size) {
279                 case 4096:
280                         blocks_long >>= 1;
281                         break;
282                 case 1024:
283                         blocks_long <<= 1;
284                         break;
285                 case 512:
286                         blocks_long <<= 2;
287                         break;
288                 default:
289                         break;
290                 }
291                 break;
292         case 1024:
293                 switch (DEV_ATTRIB(dev)->block_size) {
294                 case 4096:
295                         blocks_long >>= 2;
296                         break;
297                 case 2048:
298                         blocks_long >>= 1;
299                         break;
300                 case 512:
301                         blocks_long <<= 1;
302                         break;
303                 default:
304                         break;
305                 }
306                 break;
307         case 512:
308                 switch (DEV_ATTRIB(dev)->block_size) {
309                 case 4096:
310                         blocks_long >>= 3;
311                         break;
312                 case 2048:
313                         blocks_long >>= 2;
314                         break;
315                 case 1024:
316                         blocks_long >>= 1;
317                         break;
318                 default:
319                         break;
320                 }
321                 break;
322         default:
323                 break;
324         }
325
326         return blocks_long;
327 }
328
329 /*
330  * Emulate SYCHRONIZE_CACHE_*
331  */
332 static void iblock_emulate_sync_cache(struct se_task *task)
333 {
334         struct se_cmd *cmd = TASK_CMD(task);
335         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
336         int immed = (T_TASK(cmd)->t_task_cdb[1] & 0x2);
337         sector_t error_sector;
338         int ret;
339
340         /*
341          * If the Immediate bit is set, queue up the GOOD response
342          * for this SYNCHRONIZE_CACHE op
343          */
344         if (immed)
345                 transport_complete_sync_cache(cmd, 1);
346
347         /*
348          * blkdev_issue_flush() does not support a specifying a range, so
349          * we have to flush the entire cache.
350          */
351         ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
352         if (ret != 0) {
353                 printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
354                         " error_sector: %llu\n", ret,
355                         (unsigned long long)error_sector);
356         }
357
358         if (!immed)
359                 transport_complete_sync_cache(cmd, ret == 0);
360 }
361
362 /*
363  * Tell TCM Core that we are capable of WriteCache emulation for
364  * an underlying struct se_device.
365  */
366 static int iblock_emulated_write_cache(struct se_device *dev)
367 {
368         return 1;
369 }
370
371 static int iblock_emulated_dpo(struct se_device *dev)
372 {
373         return 0;
374 }
375
376 /*
377  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
378  * for TYPE_DISK.
379  */
380 static int iblock_emulated_fua_write(struct se_device *dev)
381 {
382         return 1;
383 }
384
385 static int iblock_emulated_fua_read(struct se_device *dev)
386 {
387         return 0;
388 }
389
390 static int iblock_do_task(struct se_task *task)
391 {
392         struct se_device *dev = task->task_se_cmd->se_dev;
393         struct iblock_req *req = IBLOCK_REQ(task);
394         struct iblock_dev *ibd = (struct iblock_dev *)req->ib_dev;
395         struct request_queue *q = bdev_get_queue(ibd->ibd_bd);
396         struct bio *bio = req->ib_bio, *nbio = NULL;
397         int rw;
398
399         if (task->task_data_direction == DMA_TO_DEVICE) {
400                 /*
401                  * Force data to disk if we pretend to not have a volatile
402                  * write cache, or the initiator set the Force Unit Access bit.
403                  */
404                 if (DEV_ATTRIB(dev)->emulate_write_cache == 0 ||
405                     (DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
406                      T_TASK(task->task_se_cmd)->t_tasks_fua))
407                         rw = WRITE_FUA;
408                 else
409                         rw = WRITE;
410         } else {
411                 rw = READ;
412         }
413
414         while (bio) {
415                 nbio = bio->bi_next;
416                 bio->bi_next = NULL;
417                 DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
418                         " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
419
420                 submit_bio(rw, bio);
421                 bio = nbio;
422         }
423
424         if (q->unplug_fn)
425                 q->unplug_fn(q);
426         return PYX_TRANSPORT_SENT_TO_TRANSPORT;
427 }
428
429 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
430 {
431         struct iblock_dev *ibd = dev->dev_ptr;
432         struct block_device *bd = ibd->ibd_bd;
433         int barrier = 0;
434
435         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
436 }
437
438 static void iblock_free_task(struct se_task *task)
439 {
440         struct iblock_req *req = IBLOCK_REQ(task);
441         struct bio *bio, *hbio = req->ib_bio;
442         /*
443          * We only release the bio(s) here if iblock_bio_done() has not called
444          * bio_put() -> iblock_bio_destructor().
445          */
446         while (hbio != NULL) {
447                 bio = hbio;
448                 hbio = hbio->bi_next;
449                 bio->bi_next = NULL;
450                 bio_put(bio);
451         }
452
453         kfree(req);
454 }
455
456 enum {
457         Opt_udev_path, Opt_force, Opt_err
458 };
459
460 static match_table_t tokens = {
461         {Opt_udev_path, "udev_path=%s"},
462         {Opt_force, "force=%d"},
463         {Opt_err, NULL}
464 };
465
466 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
467                                                struct se_subsystem_dev *se_dev,
468                                                const char *page, ssize_t count)
469 {
470         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
471         char *orig, *ptr, *arg_p, *opts;
472         substring_t args[MAX_OPT_ARGS];
473         int ret = 0, arg, token;
474
475         opts = kstrdup(page, GFP_KERNEL);
476         if (!opts)
477                 return -ENOMEM;
478
479         orig = opts;
480
481         while ((ptr = strsep(&opts, ",")) != NULL) {
482                 if (!*ptr)
483                         continue;
484
485                 token = match_token(ptr, tokens, args);
486                 switch (token) {
487                 case Opt_udev_path:
488                         if (ib_dev->ibd_bd) {
489                                 printk(KERN_ERR "Unable to set udev_path= while"
490                                         " ib_dev->ibd_bd exists\n");
491                                 ret = -EEXIST;
492                                 goto out;
493                         }
494                         arg_p = match_strdup(&args[0]);
495                         if (!arg_p) {
496                                 ret = -ENOMEM;
497                                 break;
498                         }
499                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
500                                         "%s", arg_p);
501                         kfree(arg_p);
502                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
503                                         ib_dev->ibd_udev_path);
504                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
505                         break;
506                 case Opt_force:
507                         match_int(args, &arg);
508                         ib_dev->ibd_force = arg;
509                         printk(KERN_INFO "IBLOCK: Set force=%d\n",
510                                 ib_dev->ibd_force);
511                         break;
512                 default:
513                         break;
514                 }
515         }
516
517 out:
518         kfree(orig);
519         return (!ret) ? count : ret;
520 }
521
522 static ssize_t iblock_check_configfs_dev_params(
523         struct se_hba *hba,
524         struct se_subsystem_dev *se_dev)
525 {
526         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
527
528         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
529                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
530                 return -1;
531         }
532
533         return 0;
534 }
535
536 static ssize_t iblock_show_configfs_dev_params(
537         struct se_hba *hba,
538         struct se_subsystem_dev *se_dev,
539         char *b)
540 {
541         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
542         struct block_device *bd = ibd->ibd_bd;
543         char buf[BDEVNAME_SIZE];
544         ssize_t bl = 0;
545
546         if (bd)
547                 bl += sprintf(b + bl, "iBlock device: %s",
548                                 bdevname(bd, buf));
549         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
550                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
551                                 ibd->ibd_udev_path);
552         } else
553                 bl += sprintf(b + bl, "\n");
554
555         bl += sprintf(b + bl, "        ");
556         if (bd) {
557                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
558                         ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
559                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
560                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
561         } else {
562                 bl += sprintf(b + bl, "Major: %d Minor: %d\n",
563                         ibd->ibd_major, ibd->ibd_minor);
564         }
565
566         return bl;
567 }
568
569 static void iblock_bio_destructor(struct bio *bio)
570 {
571         struct se_task *task = bio->bi_private;
572         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
573
574         bio_free(bio, ib_dev->ibd_bio_set);
575 }
576
577 static struct bio *iblock_get_bio(
578         struct se_task *task,
579         struct iblock_req *ib_req,
580         struct iblock_dev *ib_dev,
581         int *ret,
582         sector_t lba,
583         u32 sg_num)
584 {
585         struct bio *bio;
586
587         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
588         if (!(bio)) {
589                 printk(KERN_ERR "Unable to allocate memory for bio\n");
590                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
591                 return NULL;
592         }
593
594         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
595                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
596         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
597
598         bio->bi_bdev = ib_dev->ibd_bd;
599         bio->bi_private = (void *) task;
600         bio->bi_destructor = iblock_bio_destructor;
601         bio->bi_end_io = &iblock_bio_done;
602         bio->bi_sector = lba;
603         atomic_inc(&ib_req->ib_bio_cnt);
604
605         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
606         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
607                         atomic_read(&ib_req->ib_bio_cnt));
608         return bio;
609 }
610
611 static int iblock_map_task_SG(struct se_task *task)
612 {
613         struct se_cmd *cmd = task->task_se_cmd;
614         struct se_device *dev = SE_DEV(cmd);
615         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
616         struct iblock_req *ib_req = IBLOCK_REQ(task);
617         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
618         struct scatterlist *sg;
619         int ret = 0;
620         u32 i, sg_num = task->task_sg_num;
621         sector_t block_lba;
622         /*
623          * Do starting conversion up from non 512-byte blocksize with
624          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
625          */
626         if (DEV_ATTRIB(dev)->block_size == 4096)
627                 block_lba = (task->task_lba << 3);
628         else if (DEV_ATTRIB(dev)->block_size == 2048)
629                 block_lba = (task->task_lba << 2);
630         else if (DEV_ATTRIB(dev)->block_size == 1024)
631                 block_lba = (task->task_lba << 1);
632         else if (DEV_ATTRIB(dev)->block_size == 512)
633                 block_lba = task->task_lba;
634         else {
635                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
636                                 " %u\n", DEV_ATTRIB(dev)->block_size);
637                 return PYX_TRANSPORT_LU_COMM_FAILURE;
638         }
639
640         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
641         if (!(bio))
642                 return ret;
643
644         ib_req->ib_bio = bio;
645         hbio = tbio = bio;
646         /*
647          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
648          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
649          */
650         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
651                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
652                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
653                                 sg->length, sg->offset);
654 again:
655                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
656                 if (ret != sg->length) {
657
658                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
659                                         bio->bi_sector);
660                         DEBUG_IBLOCK("** task->task_size: %u\n",
661                                         task->task_size);
662                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
663                                         bio->bi_max_vecs);
664                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
665                                         bio->bi_vcnt);
666
667                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
668                                                 block_lba, sg_num);
669                         if (!(bio))
670                                 goto fail;
671
672                         tbio = tbio->bi_next = bio;
673                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
674                                 " list, Going to again\n", bio);
675                         goto again;
676                 }
677                 /* Always in 512 byte units for Linux/Block */
678                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
679                 sg_num--;
680                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
681                         " sg_num to %u\n", task, sg_num);
682                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
683                                 " to %llu\n", task, block_lba);
684                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
685                                 " %u\n", task, bio->bi_vcnt);
686         }
687
688         return 0;
689 fail:
690         while (hbio) {
691                 bio = hbio;
692                 hbio = hbio->bi_next;
693                 bio->bi_next = NULL;
694                 bio_put(bio);
695         }
696         return ret;
697 }
698
699 static unsigned char *iblock_get_cdb(struct se_task *task)
700 {
701         return IBLOCK_REQ(task)->ib_scsi_cdb;
702 }
703
704 static u32 iblock_get_device_rev(struct se_device *dev)
705 {
706         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
707 }
708
709 static u32 iblock_get_device_type(struct se_device *dev)
710 {
711         return TYPE_DISK;
712 }
713
714 static sector_t iblock_get_blocks(struct se_device *dev)
715 {
716         struct iblock_dev *ibd = dev->dev_ptr;
717         struct block_device *bd = ibd->ibd_bd;
718         struct request_queue *q = bdev_get_queue(bd);
719
720         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
721 }
722
723 static void iblock_bio_done(struct bio *bio, int err)
724 {
725         struct se_task *task = bio->bi_private;
726         struct iblock_req *ibr = IBLOCK_REQ(task);
727         /*
728          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
729          */
730         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
731                 err = -EIO;
732
733         if (err != 0) {
734                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
735                         " err: %d\n", bio, err);
736                 /*
737                  * Bump the ib_bio_err_cnt and release bio.
738                  */
739                 atomic_inc(&ibr->ib_bio_err_cnt);
740                 smp_mb__after_atomic_inc();
741                 bio_put(bio);
742                 /*
743                  * Wait to complete the task until the last bio as completed.
744                  */
745                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
746                         return;
747
748                 ibr->ib_bio = NULL;
749                 transport_complete_task(task, 0);
750                 return;
751         }
752         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
753                 task, bio, task->task_lba, bio->bi_sector, err);
754         /*
755          * bio_put() will call iblock_bio_destructor() to release the bio back
756          * to ibr->ib_bio_set.
757          */
758         bio_put(bio);
759         /*
760          * Wait to complete the task until the last bio as completed.
761          */
762         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
763                 return;
764         /*
765          * Return GOOD status for task if zero ib_bio_err_cnt exists.
766          */
767         ibr->ib_bio = NULL;
768         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
769 }
770
771 static struct se_subsystem_api iblock_template = {
772         .name                   = "iblock",
773         .owner                  = THIS_MODULE,
774         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
775         .map_task_SG            = iblock_map_task_SG,
776         .attach_hba             = iblock_attach_hba,
777         .detach_hba             = iblock_detach_hba,
778         .allocate_virtdevice    = iblock_allocate_virtdevice,
779         .create_virtdevice      = iblock_create_virtdevice,
780         .free_device            = iblock_free_device,
781         .dpo_emulated           = iblock_emulated_dpo,
782         .fua_write_emulated     = iblock_emulated_fua_write,
783         .fua_read_emulated      = iblock_emulated_fua_read,
784         .write_cache_emulated   = iblock_emulated_write_cache,
785         .alloc_task             = iblock_alloc_task,
786         .do_task                = iblock_do_task,
787         .do_discard             = iblock_do_discard,
788         .do_sync_cache          = iblock_emulate_sync_cache,
789         .free_task              = iblock_free_task,
790         .check_configfs_dev_params = iblock_check_configfs_dev_params,
791         .set_configfs_dev_params = iblock_set_configfs_dev_params,
792         .show_configfs_dev_params = iblock_show_configfs_dev_params,
793         .get_cdb                = iblock_get_cdb,
794         .get_device_rev         = iblock_get_device_rev,
795         .get_device_type        = iblock_get_device_type,
796         .get_blocks             = iblock_get_blocks,
797 };
798
799 static int __init iblock_module_init(void)
800 {
801         return transport_subsystem_register(&iblock_template);
802 }
803
804 static void iblock_module_exit(void)
805 {
806         transport_subsystem_release(&iblock_template);
807 }
808
809 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
810 MODULE_AUTHOR("nab@Linux-iSCSI.org");
811 MODULE_LICENSE("GPL");
812
813 module_init(iblock_module_init);
814 module_exit(iblock_module_exit);