[SCSI] target: Add LIO target core v4.0.0-rc6
[linux-2.6.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/smp_lock.h>
39 #include <linux/bio.h>
40 #include <linux/genhd.h>
41 #include <linux/file.h>
42 #include <scsi/scsi.h>
43 #include <scsi/scsi_host.h>
44
45 #include <target/target_core_base.h>
46 #include <target/target_core_device.h>
47 #include <target/target_core_transport.h>
48
49 #include "target_core_iblock.h"
50
51 #if 0
52 #define DEBUG_IBLOCK(x...) printk(x)
53 #else
54 #define DEBUG_IBLOCK(x...)
55 #endif
56
57 static struct se_subsystem_api iblock_template;
58
59 static void iblock_bio_done(struct bio *, int);
60
61 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
62  *
63  *
64  */
65 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
66 {
67         struct iblock_hba *ib_host;
68
69         ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
70         if (!(ib_host)) {
71                 printk(KERN_ERR "Unable to allocate memory for"
72                                 " struct iblock_hba\n");
73                 return -ENOMEM;
74         }
75
76         ib_host->iblock_host_id = host_id;
77
78         atomic_set(&hba->left_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
79         atomic_set(&hba->max_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
80         hba->hba_ptr = (void *) ib_host;
81
82         printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
83                 " Generic Target Core Stack %s\n", hba->hba_id,
84                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
85
86         printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic"
87                 " Target Core TCQ Depth: %d\n", hba->hba_id,
88                 ib_host->iblock_host_id, atomic_read(&hba->max_queue_depth));
89
90         return 0;
91 }
92
93 static void iblock_detach_hba(struct se_hba *hba)
94 {
95         struct iblock_hba *ib_host = hba->hba_ptr;
96
97         printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
98                 " Target Core\n", hba->hba_id, ib_host->iblock_host_id);
99
100         kfree(ib_host);
101         hba->hba_ptr = NULL;
102 }
103
104 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
105 {
106         struct iblock_dev *ib_dev = NULL;
107         struct iblock_hba *ib_host = hba->hba_ptr;
108
109         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
110         if (!(ib_dev)) {
111                 printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
112                 return NULL;
113         }
114         ib_dev->ibd_host = ib_host;
115
116         printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);
117
118         return ib_dev;
119 }
120
121 static struct se_device *iblock_create_virtdevice(
122         struct se_hba *hba,
123         struct se_subsystem_dev *se_dev,
124         void *p)
125 {
126         struct iblock_dev *ib_dev = p;
127         struct se_device *dev;
128         struct se_dev_limits dev_limits;
129         struct block_device *bd = NULL;
130         struct request_queue *q;
131         struct queue_limits *limits;
132         u32 dev_flags = 0;
133
134         if (!(ib_dev)) {
135                 printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
136                 return 0;
137         }
138         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
139         /*
140          * These settings need to be made tunable..
141          */
142         ib_dev->ibd_bio_set = bioset_create(32, 64);
143         if (!(ib_dev->ibd_bio_set)) {
144                 printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
145                 return 0;
146         }
147         printk(KERN_INFO "IBLOCK: Created bio_set()\n");
148         /*
149          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
150          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
151          */
152         printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
153                         ib_dev->ibd_udev_path);
154
155         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
156                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
157         if (!(bd))
158                 goto failed;
159         /*
160          * Setup the local scope queue_limits from struct request_queue->limits
161          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
162          */
163         q = bdev_get_queue(bd);
164         limits = &dev_limits.limits;
165         limits->logical_block_size = bdev_logical_block_size(bd);
166         limits->max_hw_sectors = queue_max_hw_sectors(q);
167         limits->max_sectors = queue_max_sectors(q);
168         dev_limits.hw_queue_depth = IBLOCK_MAX_DEVICE_QUEUE_DEPTH;
169         dev_limits.queue_depth = IBLOCK_DEVICE_QUEUE_DEPTH;
170
171         ib_dev->ibd_major = MAJOR(bd->bd_dev);
172         ib_dev->ibd_minor = MINOR(bd->bd_dev);
173         ib_dev->ibd_bd = bd;
174
175         dev = transport_add_device_to_core_hba(hba,
176                         &iblock_template, se_dev, dev_flags, (void *)ib_dev,
177                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
178         if (!(dev))
179                 goto failed;
180
181         ib_dev->ibd_depth = dev->queue_depth;
182
183         /*
184          * Check if the underlying struct block_device request_queue supports
185          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
186          * in ATA and we need to set TPE=1
187          */
188         if (blk_queue_discard(bdev_get_queue(bd))) {
189                 struct request_queue *q = bdev_get_queue(bd);
190
191                 DEV_ATTRIB(dev)->max_unmap_lba_count =
192                                 q->limits.max_discard_sectors;
193                 /*
194                  * Currently hardcoded to 1 in Linux/SCSI code..
195                  */
196                 DEV_ATTRIB(dev)->max_unmap_block_desc_count = 1;
197                 DEV_ATTRIB(dev)->unmap_granularity =
198                                 q->limits.discard_granularity;
199                 DEV_ATTRIB(dev)->unmap_granularity_alignment =
200                                 q->limits.discard_alignment;
201
202                 printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
203                                 " disabled by default\n");
204         }
205
206         return dev;
207
208 failed:
209         if (ib_dev->ibd_bio_set) {
210                 bioset_free(ib_dev->ibd_bio_set);
211                 ib_dev->ibd_bio_set = NULL;
212         }
213         ib_dev->ibd_bd = NULL;
214         ib_dev->ibd_major = 0;
215         ib_dev->ibd_minor = 0;
216         return NULL;
217 }
218
219 static void iblock_free_device(void *p)
220 {
221         struct iblock_dev *ib_dev = p;
222
223         blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
224         bioset_free(ib_dev->ibd_bio_set);
225         kfree(ib_dev);
226 }
227
228 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
229 {
230         return container_of(task, struct iblock_req, ib_task);
231 }
232
233 static struct se_task *
234 iblock_alloc_task(struct se_cmd *cmd)
235 {
236         struct iblock_req *ib_req;
237
238         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
239         if (!(ib_req)) {
240                 printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
241                 return NULL;
242         }
243
244         ib_req->ib_dev = SE_DEV(cmd)->dev_ptr;
245         atomic_set(&ib_req->ib_bio_cnt, 0);
246         return &ib_req->ib_task;
247 }
248
249 static unsigned long long iblock_emulate_read_cap_with_block_size(
250         struct se_device *dev,
251         struct block_device *bd,
252         struct request_queue *q)
253 {
254         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
255                                         bdev_logical_block_size(bd)) - 1);
256         u32 block_size = bdev_logical_block_size(bd);
257
258         if (block_size == DEV_ATTRIB(dev)->block_size)
259                 return blocks_long;
260
261         switch (block_size) {
262         case 4096:
263                 switch (DEV_ATTRIB(dev)->block_size) {
264                 case 2048:
265                         blocks_long <<= 1;
266                         break;
267                 case 1024:
268                         blocks_long <<= 2;
269                         break;
270                 case 512:
271                         blocks_long <<= 3;
272                 default:
273                         break;
274                 }
275                 break;
276         case 2048:
277                 switch (DEV_ATTRIB(dev)->block_size) {
278                 case 4096:
279                         blocks_long >>= 1;
280                         break;
281                 case 1024:
282                         blocks_long <<= 1;
283                         break;
284                 case 512:
285                         blocks_long <<= 2;
286                         break;
287                 default:
288                         break;
289                 }
290                 break;
291         case 1024:
292                 switch (DEV_ATTRIB(dev)->block_size) {
293                 case 4096:
294                         blocks_long >>= 2;
295                         break;
296                 case 2048:
297                         blocks_long >>= 1;
298                         break;
299                 case 512:
300                         blocks_long <<= 1;
301                         break;
302                 default:
303                         break;
304                 }
305                 break;
306         case 512:
307                 switch (DEV_ATTRIB(dev)->block_size) {
308                 case 4096:
309                         blocks_long >>= 3;
310                         break;
311                 case 2048:
312                         blocks_long >>= 2;
313                         break;
314                 case 1024:
315                         blocks_long >>= 1;
316                         break;
317                 default:
318                         break;
319                 }
320                 break;
321         default:
322                 break;
323         }
324
325         return blocks_long;
326 }
327
328 /*
329  * Emulate SYCHRONIZE_CACHE_*
330  */
331 static void iblock_emulate_sync_cache(struct se_task *task)
332 {
333         struct se_cmd *cmd = TASK_CMD(task);
334         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
335         int immed = (T_TASK(cmd)->t_task_cdb[1] & 0x2);
336         sector_t error_sector;
337         int ret;
338
339         /*
340          * If the Immediate bit is set, queue up the GOOD response
341          * for this SYNCHRONIZE_CACHE op
342          */
343         if (immed)
344                 transport_complete_sync_cache(cmd, 1);
345
346         /*
347          * blkdev_issue_flush() does not support a specifying a range, so
348          * we have to flush the entire cache.
349          */
350         ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
351         if (ret != 0) {
352                 printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
353                         " error_sector: %llu\n", ret,
354                         (unsigned long long)error_sector);
355         }
356
357         if (!immed)
358                 transport_complete_sync_cache(cmd, ret == 0);
359 }
360
361 /*
362  * Tell TCM Core that we are capable of WriteCache emulation for
363  * an underlying struct se_device.
364  */
365 static int iblock_emulated_write_cache(struct se_device *dev)
366 {
367         return 1;
368 }
369
370 static int iblock_emulated_dpo(struct se_device *dev)
371 {
372         return 0;
373 }
374
375 /*
376  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
377  * for TYPE_DISK.
378  */
379 static int iblock_emulated_fua_write(struct se_device *dev)
380 {
381         return 1;
382 }
383
384 static int iblock_emulated_fua_read(struct se_device *dev)
385 {
386         return 0;
387 }
388
389 static int iblock_do_task(struct se_task *task)
390 {
391         struct se_device *dev = task->task_se_cmd->se_dev;
392         struct iblock_req *req = IBLOCK_REQ(task);
393         struct iblock_dev *ibd = (struct iblock_dev *)req->ib_dev;
394         struct request_queue *q = bdev_get_queue(ibd->ibd_bd);
395         struct bio *bio = req->ib_bio, *nbio = NULL;
396         int rw;
397
398         if (task->task_data_direction == DMA_TO_DEVICE) {
399                 /*
400                  * Force data to disk if we pretend to not have a volatile
401                  * write cache, or the initiator set the Force Unit Access bit.
402                  */
403                 if (DEV_ATTRIB(dev)->emulate_write_cache == 0 ||
404                     (DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
405                      T_TASK(task->task_se_cmd)->t_tasks_fua))
406                         rw = WRITE_FUA;
407                 else
408                         rw = WRITE;
409         } else {
410                 rw = READ;
411         }
412
413         while (bio) {
414                 nbio = bio->bi_next;
415                 bio->bi_next = NULL;
416                 DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
417                         " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
418
419                 submit_bio(rw, bio);
420                 bio = nbio;
421         }
422
423         if (q->unplug_fn)
424                 q->unplug_fn(q);
425         return PYX_TRANSPORT_SENT_TO_TRANSPORT;
426 }
427
428 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
429 {
430         struct iblock_dev *ibd = dev->dev_ptr;
431         struct block_device *bd = ibd->ibd_bd;
432         int barrier = 0;
433
434         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
435 }
436
437 static void iblock_free_task(struct se_task *task)
438 {
439         struct iblock_req *req = IBLOCK_REQ(task);
440         struct bio *bio, *hbio = req->ib_bio;
441         /*
442          * We only release the bio(s) here if iblock_bio_done() has not called
443          * bio_put() -> iblock_bio_destructor().
444          */
445         while (hbio != NULL) {
446                 bio = hbio;
447                 hbio = hbio->bi_next;
448                 bio->bi_next = NULL;
449                 bio_put(bio);
450         }
451
452         kfree(req);
453 }
454
455 enum {
456         Opt_udev_path, Opt_force, Opt_err
457 };
458
459 static match_table_t tokens = {
460         {Opt_udev_path, "udev_path=%s"},
461         {Opt_force, "force=%d"},
462         {Opt_err, NULL}
463 };
464
465 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
466                                                struct se_subsystem_dev *se_dev,
467                                                const char *page, ssize_t count)
468 {
469         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
470         char *orig, *ptr, *opts;
471         substring_t args[MAX_OPT_ARGS];
472         int ret = 0, arg, token;
473
474         opts = kstrdup(page, GFP_KERNEL);
475         if (!opts)
476                 return -ENOMEM;
477
478         orig = opts;
479
480         while ((ptr = strsep(&opts, ",")) != NULL) {
481                 if (!*ptr)
482                         continue;
483
484                 token = match_token(ptr, tokens, args);
485                 switch (token) {
486                 case Opt_udev_path:
487                         if (ib_dev->ibd_bd) {
488                                 printk(KERN_ERR "Unable to set udev_path= while"
489                                         " ib_dev->ibd_bd exists\n");
490                                 ret = -EEXIST;
491                                 goto out;
492                         }
493
494                         ret = snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
495                                 "%s", match_strdup(&args[0]));
496                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
497                                         ib_dev->ibd_udev_path);
498                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
499                         break;
500                 case Opt_force:
501                         match_int(args, &arg);
502                         ib_dev->ibd_force = arg;
503                         printk(KERN_INFO "IBLOCK: Set force=%d\n",
504                                 ib_dev->ibd_force);
505                         break;
506                 default:
507                         break;
508                 }
509         }
510
511 out:
512         kfree(orig);
513         return (!ret) ? count : ret;
514 }
515
516 static ssize_t iblock_check_configfs_dev_params(
517         struct se_hba *hba,
518         struct se_subsystem_dev *se_dev)
519 {
520         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
521
522         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
523                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
524                 return -1;
525         }
526
527         return 0;
528 }
529
530 static ssize_t iblock_show_configfs_dev_params(
531         struct se_hba *hba,
532         struct se_subsystem_dev *se_dev,
533         char *b)
534 {
535         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
536         struct block_device *bd = ibd->ibd_bd;
537         char buf[BDEVNAME_SIZE];
538         ssize_t bl = 0;
539
540         if (bd)
541                 bl += sprintf(b + bl, "iBlock device: %s",
542                                 bdevname(bd, buf));
543         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
544                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
545                                 ibd->ibd_udev_path);
546         } else
547                 bl += sprintf(b + bl, "\n");
548
549         bl += sprintf(b + bl, "        ");
550         if (bd) {
551                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
552                         ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
553                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
554                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
555         } else {
556                 bl += sprintf(b + bl, "Major: %d Minor: %d\n",
557                         ibd->ibd_major, ibd->ibd_minor);
558         }
559
560         return bl;
561 }
562
563 static void iblock_bio_destructor(struct bio *bio)
564 {
565         struct se_task *task = bio->bi_private;
566         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
567
568         bio_free(bio, ib_dev->ibd_bio_set);
569 }
570
571 static struct bio *iblock_get_bio(
572         struct se_task *task,
573         struct iblock_req *ib_req,
574         struct iblock_dev *ib_dev,
575         int *ret,
576         sector_t lba,
577         u32 sg_num)
578 {
579         struct bio *bio;
580
581         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
582         if (!(bio)) {
583                 printk(KERN_ERR "Unable to allocate memory for bio\n");
584                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
585                 return NULL;
586         }
587
588         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
589                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
590         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
591
592         bio->bi_bdev = ib_dev->ibd_bd;
593         bio->bi_private = (void *) task;
594         bio->bi_destructor = iblock_bio_destructor;
595         bio->bi_end_io = &iblock_bio_done;
596         bio->bi_sector = lba;
597         atomic_inc(&ib_req->ib_bio_cnt);
598
599         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
600         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
601                         atomic_read(&ib_req->ib_bio_cnt));
602         return bio;
603 }
604
605 static int iblock_map_task_SG(struct se_task *task)
606 {
607         struct se_cmd *cmd = task->task_se_cmd;
608         struct se_device *dev = SE_DEV(cmd);
609         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
610         struct iblock_req *ib_req = IBLOCK_REQ(task);
611         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
612         struct scatterlist *sg;
613         int ret = 0;
614         u32 i, sg_num = task->task_sg_num;
615         sector_t block_lba;
616         /*
617          * Do starting conversion up from non 512-byte blocksize with
618          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
619          */
620         if (DEV_ATTRIB(dev)->block_size == 4096)
621                 block_lba = (task->task_lba << 3);
622         else if (DEV_ATTRIB(dev)->block_size == 2048)
623                 block_lba = (task->task_lba << 2);
624         else if (DEV_ATTRIB(dev)->block_size == 1024)
625                 block_lba = (task->task_lba << 1);
626         else if (DEV_ATTRIB(dev)->block_size == 512)
627                 block_lba = task->task_lba;
628         else {
629                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
630                                 " %u\n", DEV_ATTRIB(dev)->block_size);
631                 return PYX_TRANSPORT_LU_COMM_FAILURE;
632         }
633
634         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
635         if (!(bio))
636                 return ret;
637
638         ib_req->ib_bio = bio;
639         hbio = tbio = bio;
640         /*
641          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
642          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
643          */
644         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
645                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
646                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
647                                 sg->length, sg->offset);
648 again:
649                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
650                 if (ret != sg->length) {
651
652                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
653                                         bio->bi_sector);
654                         DEBUG_IBLOCK("** task->task_size: %u\n",
655                                         task->task_size);
656                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
657                                         bio->bi_max_vecs);
658                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
659                                         bio->bi_vcnt);
660
661                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
662                                                 block_lba, sg_num);
663                         if (!(bio))
664                                 goto fail;
665
666                         tbio = tbio->bi_next = bio;
667                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
668                                 " list, Going to again\n", bio);
669                         goto again;
670                 }
671                 /* Always in 512 byte units for Linux/Block */
672                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
673                 sg_num--;
674                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
675                         " sg_num to %u\n", task, sg_num);
676                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
677                                 " to %llu\n", task, block_lba);
678                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
679                                 " %u\n", task, bio->bi_vcnt);
680         }
681
682         return 0;
683 fail:
684         while (hbio) {
685                 bio = hbio;
686                 hbio = hbio->bi_next;
687                 bio->bi_next = NULL;
688                 bio_put(bio);
689         }
690         return ret;
691 }
692
693 static unsigned char *iblock_get_cdb(struct se_task *task)
694 {
695         return IBLOCK_REQ(task)->ib_scsi_cdb;
696 }
697
698 static u32 iblock_get_device_rev(struct se_device *dev)
699 {
700         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
701 }
702
703 static u32 iblock_get_device_type(struct se_device *dev)
704 {
705         return TYPE_DISK;
706 }
707
708 static sector_t iblock_get_blocks(struct se_device *dev)
709 {
710         struct iblock_dev *ibd = dev->dev_ptr;
711         struct block_device *bd = ibd->ibd_bd;
712         struct request_queue *q = bdev_get_queue(bd);
713
714         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
715 }
716
717 static void iblock_bio_done(struct bio *bio, int err)
718 {
719         struct se_task *task = bio->bi_private;
720         struct iblock_req *ibr = IBLOCK_REQ(task);
721         /*
722          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
723          */
724         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
725                 err = -EIO;
726
727         if (err != 0) {
728                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
729                         " err: %d\n", bio, err);
730                 /*
731                  * Bump the ib_bio_err_cnt and release bio.
732                  */
733                 atomic_inc(&ibr->ib_bio_err_cnt);
734                 smp_mb__after_atomic_inc();
735                 bio_put(bio);
736                 /*
737                  * Wait to complete the task until the last bio as completed.
738                  */
739                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
740                         return;
741
742                 ibr->ib_bio = NULL;
743                 transport_complete_task(task, 0);
744                 return;
745         }
746         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
747                 task, bio, task->task_lba, bio->bi_sector, err);
748         /*
749          * bio_put() will call iblock_bio_destructor() to release the bio back
750          * to ibr->ib_bio_set.
751          */
752         bio_put(bio);
753         /*
754          * Wait to complete the task until the last bio as completed.
755          */
756         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
757                 return;
758         /*
759          * Return GOOD status for task if zero ib_bio_err_cnt exists.
760          */
761         ibr->ib_bio = NULL;
762         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
763 }
764
765 static struct se_subsystem_api iblock_template = {
766         .name                   = "iblock",
767         .owner                  = THIS_MODULE,
768         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
769         .map_task_SG            = iblock_map_task_SG,
770         .attach_hba             = iblock_attach_hba,
771         .detach_hba             = iblock_detach_hba,
772         .allocate_virtdevice    = iblock_allocate_virtdevice,
773         .create_virtdevice      = iblock_create_virtdevice,
774         .free_device            = iblock_free_device,
775         .dpo_emulated           = iblock_emulated_dpo,
776         .fua_write_emulated     = iblock_emulated_fua_write,
777         .fua_read_emulated      = iblock_emulated_fua_read,
778         .write_cache_emulated   = iblock_emulated_write_cache,
779         .alloc_task             = iblock_alloc_task,
780         .do_task                = iblock_do_task,
781         .do_discard             = iblock_do_discard,
782         .do_sync_cache          = iblock_emulate_sync_cache,
783         .free_task              = iblock_free_task,
784         .check_configfs_dev_params = iblock_check_configfs_dev_params,
785         .set_configfs_dev_params = iblock_set_configfs_dev_params,
786         .show_configfs_dev_params = iblock_show_configfs_dev_params,
787         .get_cdb                = iblock_get_cdb,
788         .get_device_rev         = iblock_get_device_rev,
789         .get_device_type        = iblock_get_device_type,
790         .get_blocks             = iblock_get_blocks,
791 };
792
793 static int __init iblock_module_init(void)
794 {
795         return transport_subsystem_register(&iblock_template);
796 }
797
798 static void iblock_module_exit(void)
799 {
800         transport_subsystem_release(&iblock_template);
801 }
802
803 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
804 MODULE_AUTHOR("nab@Linux-iSCSI.org");
805 MODULE_LICENSE("GPL");
806
807 module_init(iblock_module_init);
808 module_exit(iblock_module_exit);