block: remove per-queue plugging
[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 (IS_ERR(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         if (ib_dev->ibd_bd != NULL)
224                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
225         if (ib_dev->ibd_bio_set != NULL)
226                 bioset_free(ib_dev->ibd_bio_set);
227         kfree(ib_dev);
228 }
229
230 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
231 {
232         return container_of(task, struct iblock_req, ib_task);
233 }
234
235 static struct se_task *
236 iblock_alloc_task(struct se_cmd *cmd)
237 {
238         struct iblock_req *ib_req;
239
240         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
241         if (!(ib_req)) {
242                 printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
243                 return NULL;
244         }
245
246         ib_req->ib_dev = SE_DEV(cmd)->dev_ptr;
247         atomic_set(&ib_req->ib_bio_cnt, 0);
248         return &ib_req->ib_task;
249 }
250
251 static unsigned long long iblock_emulate_read_cap_with_block_size(
252         struct se_device *dev,
253         struct block_device *bd,
254         struct request_queue *q)
255 {
256         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
257                                         bdev_logical_block_size(bd)) - 1);
258         u32 block_size = bdev_logical_block_size(bd);
259
260         if (block_size == DEV_ATTRIB(dev)->block_size)
261                 return blocks_long;
262
263         switch (block_size) {
264         case 4096:
265                 switch (DEV_ATTRIB(dev)->block_size) {
266                 case 2048:
267                         blocks_long <<= 1;
268                         break;
269                 case 1024:
270                         blocks_long <<= 2;
271                         break;
272                 case 512:
273                         blocks_long <<= 3;
274                 default:
275                         break;
276                 }
277                 break;
278         case 2048:
279                 switch (DEV_ATTRIB(dev)->block_size) {
280                 case 4096:
281                         blocks_long >>= 1;
282                         break;
283                 case 1024:
284                         blocks_long <<= 1;
285                         break;
286                 case 512:
287                         blocks_long <<= 2;
288                         break;
289                 default:
290                         break;
291                 }
292                 break;
293         case 1024:
294                 switch (DEV_ATTRIB(dev)->block_size) {
295                 case 4096:
296                         blocks_long >>= 2;
297                         break;
298                 case 2048:
299                         blocks_long >>= 1;
300                         break;
301                 case 512:
302                         blocks_long <<= 1;
303                         break;
304                 default:
305                         break;
306                 }
307                 break;
308         case 512:
309                 switch (DEV_ATTRIB(dev)->block_size) {
310                 case 4096:
311                         blocks_long >>= 3;
312                         break;
313                 case 2048:
314                         blocks_long >>= 2;
315                         break;
316                 case 1024:
317                         blocks_long >>= 1;
318                         break;
319                 default:
320                         break;
321                 }
322                 break;
323         default:
324                 break;
325         }
326
327         return blocks_long;
328 }
329
330 /*
331  * Emulate SYCHRONIZE_CACHE_*
332  */
333 static void iblock_emulate_sync_cache(struct se_task *task)
334 {
335         struct se_cmd *cmd = TASK_CMD(task);
336         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
337         int immed = (T_TASK(cmd)->t_task_cdb[1] & 0x2);
338         sector_t error_sector;
339         int ret;
340
341         /*
342          * If the Immediate bit is set, queue up the GOOD response
343          * for this SYNCHRONIZE_CACHE op
344          */
345         if (immed)
346                 transport_complete_sync_cache(cmd, 1);
347
348         /*
349          * blkdev_issue_flush() does not support a specifying a range, so
350          * we have to flush the entire cache.
351          */
352         ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
353         if (ret != 0) {
354                 printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
355                         " error_sector: %llu\n", ret,
356                         (unsigned long long)error_sector);
357         }
358
359         if (!immed)
360                 transport_complete_sync_cache(cmd, ret == 0);
361 }
362
363 /*
364  * Tell TCM Core that we are capable of WriteCache emulation for
365  * an underlying struct se_device.
366  */
367 static int iblock_emulated_write_cache(struct se_device *dev)
368 {
369         return 1;
370 }
371
372 static int iblock_emulated_dpo(struct se_device *dev)
373 {
374         return 0;
375 }
376
377 /*
378  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
379  * for TYPE_DISK.
380  */
381 static int iblock_emulated_fua_write(struct se_device *dev)
382 {
383         return 1;
384 }
385
386 static int iblock_emulated_fua_read(struct se_device *dev)
387 {
388         return 0;
389 }
390
391 static int iblock_do_task(struct se_task *task)
392 {
393         struct se_device *dev = task->task_se_cmd->se_dev;
394         struct iblock_req *req = IBLOCK_REQ(task);
395         struct bio *bio = req->ib_bio, *nbio = NULL;
396         struct blk_plug plug;
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         blk_start_plug(&plug);
415         while (bio) {
416                 nbio = bio->bi_next;
417                 bio->bi_next = NULL;
418                 DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
419                         " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
420
421                 submit_bio(rw, bio);
422                 bio = nbio;
423         }
424         blk_finish_plug(&plug);
425
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, *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
495                         ret = snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
496                                 "%s", match_strdup(&args[0]));
497                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
498                                         ib_dev->ibd_udev_path);
499                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
500                         break;
501                 case Opt_force:
502                         match_int(args, &arg);
503                         ib_dev->ibd_force = arg;
504                         printk(KERN_INFO "IBLOCK: Set force=%d\n",
505                                 ib_dev->ibd_force);
506                         break;
507                 default:
508                         break;
509                 }
510         }
511
512 out:
513         kfree(orig);
514         return (!ret) ? count : ret;
515 }
516
517 static ssize_t iblock_check_configfs_dev_params(
518         struct se_hba *hba,
519         struct se_subsystem_dev *se_dev)
520 {
521         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
522
523         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
524                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
525                 return -1;
526         }
527
528         return 0;
529 }
530
531 static ssize_t iblock_show_configfs_dev_params(
532         struct se_hba *hba,
533         struct se_subsystem_dev *se_dev,
534         char *b)
535 {
536         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
537         struct block_device *bd = ibd->ibd_bd;
538         char buf[BDEVNAME_SIZE];
539         ssize_t bl = 0;
540
541         if (bd)
542                 bl += sprintf(b + bl, "iBlock device: %s",
543                                 bdevname(bd, buf));
544         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
545                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
546                                 ibd->ibd_udev_path);
547         } else
548                 bl += sprintf(b + bl, "\n");
549
550         bl += sprintf(b + bl, "        ");
551         if (bd) {
552                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
553                         ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
554                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
555                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
556         } else {
557                 bl += sprintf(b + bl, "Major: %d Minor: %d\n",
558                         ibd->ibd_major, ibd->ibd_minor);
559         }
560
561         return bl;
562 }
563
564 static void iblock_bio_destructor(struct bio *bio)
565 {
566         struct se_task *task = bio->bi_private;
567         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
568
569         bio_free(bio, ib_dev->ibd_bio_set);
570 }
571
572 static struct bio *iblock_get_bio(
573         struct se_task *task,
574         struct iblock_req *ib_req,
575         struct iblock_dev *ib_dev,
576         int *ret,
577         sector_t lba,
578         u32 sg_num)
579 {
580         struct bio *bio;
581
582         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
583         if (!(bio)) {
584                 printk(KERN_ERR "Unable to allocate memory for bio\n");
585                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
586                 return NULL;
587         }
588
589         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
590                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
591         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
592
593         bio->bi_bdev = ib_dev->ibd_bd;
594         bio->bi_private = (void *) task;
595         bio->bi_destructor = iblock_bio_destructor;
596         bio->bi_end_io = &iblock_bio_done;
597         bio->bi_sector = lba;
598         atomic_inc(&ib_req->ib_bio_cnt);
599
600         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
601         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
602                         atomic_read(&ib_req->ib_bio_cnt));
603         return bio;
604 }
605
606 static int iblock_map_task_SG(struct se_task *task)
607 {
608         struct se_cmd *cmd = task->task_se_cmd;
609         struct se_device *dev = SE_DEV(cmd);
610         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
611         struct iblock_req *ib_req = IBLOCK_REQ(task);
612         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
613         struct scatterlist *sg;
614         int ret = 0;
615         u32 i, sg_num = task->task_sg_num;
616         sector_t block_lba;
617         /*
618          * Do starting conversion up from non 512-byte blocksize with
619          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
620          */
621         if (DEV_ATTRIB(dev)->block_size == 4096)
622                 block_lba = (task->task_lba << 3);
623         else if (DEV_ATTRIB(dev)->block_size == 2048)
624                 block_lba = (task->task_lba << 2);
625         else if (DEV_ATTRIB(dev)->block_size == 1024)
626                 block_lba = (task->task_lba << 1);
627         else if (DEV_ATTRIB(dev)->block_size == 512)
628                 block_lba = task->task_lba;
629         else {
630                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
631                                 " %u\n", DEV_ATTRIB(dev)->block_size);
632                 return PYX_TRANSPORT_LU_COMM_FAILURE;
633         }
634
635         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
636         if (!(bio))
637                 return ret;
638
639         ib_req->ib_bio = bio;
640         hbio = tbio = bio;
641         /*
642          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
643          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
644          */
645         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
646                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
647                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
648                                 sg->length, sg->offset);
649 again:
650                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
651                 if (ret != sg->length) {
652
653                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
654                                         bio->bi_sector);
655                         DEBUG_IBLOCK("** task->task_size: %u\n",
656                                         task->task_size);
657                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
658                                         bio->bi_max_vecs);
659                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
660                                         bio->bi_vcnt);
661
662                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
663                                                 block_lba, sg_num);
664                         if (!(bio))
665                                 goto fail;
666
667                         tbio = tbio->bi_next = bio;
668                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
669                                 " list, Going to again\n", bio);
670                         goto again;
671                 }
672                 /* Always in 512 byte units for Linux/Block */
673                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
674                 sg_num--;
675                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
676                         " sg_num to %u\n", task, sg_num);
677                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
678                                 " to %llu\n", task, block_lba);
679                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
680                                 " %u\n", task, bio->bi_vcnt);
681         }
682
683         return 0;
684 fail:
685         while (hbio) {
686                 bio = hbio;
687                 hbio = hbio->bi_next;
688                 bio->bi_next = NULL;
689                 bio_put(bio);
690         }
691         return ret;
692 }
693
694 static unsigned char *iblock_get_cdb(struct se_task *task)
695 {
696         return IBLOCK_REQ(task)->ib_scsi_cdb;
697 }
698
699 static u32 iblock_get_device_rev(struct se_device *dev)
700 {
701         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
702 }
703
704 static u32 iblock_get_device_type(struct se_device *dev)
705 {
706         return TYPE_DISK;
707 }
708
709 static sector_t iblock_get_blocks(struct se_device *dev)
710 {
711         struct iblock_dev *ibd = dev->dev_ptr;
712         struct block_device *bd = ibd->ibd_bd;
713         struct request_queue *q = bdev_get_queue(bd);
714
715         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
716 }
717
718 static void iblock_bio_done(struct bio *bio, int err)
719 {
720         struct se_task *task = bio->bi_private;
721         struct iblock_req *ibr = IBLOCK_REQ(task);
722         /*
723          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
724          */
725         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
726                 err = -EIO;
727
728         if (err != 0) {
729                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
730                         " err: %d\n", bio, err);
731                 /*
732                  * Bump the ib_bio_err_cnt and release bio.
733                  */
734                 atomic_inc(&ibr->ib_bio_err_cnt);
735                 smp_mb__after_atomic_inc();
736                 bio_put(bio);
737                 /*
738                  * Wait to complete the task until the last bio as completed.
739                  */
740                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
741                         return;
742
743                 ibr->ib_bio = NULL;
744                 transport_complete_task(task, 0);
745                 return;
746         }
747         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
748                 task, bio, task->task_lba, bio->bi_sector, err);
749         /*
750          * bio_put() will call iblock_bio_destructor() to release the bio back
751          * to ibr->ib_bio_set.
752          */
753         bio_put(bio);
754         /*
755          * Wait to complete the task until the last bio as completed.
756          */
757         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
758                 return;
759         /*
760          * Return GOOD status for task if zero ib_bio_err_cnt exists.
761          */
762         ibr->ib_bio = NULL;
763         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
764 }
765
766 static struct se_subsystem_api iblock_template = {
767         .name                   = "iblock",
768         .owner                  = THIS_MODULE,
769         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
770         .map_task_SG            = iblock_map_task_SG,
771         .attach_hba             = iblock_attach_hba,
772         .detach_hba             = iblock_detach_hba,
773         .allocate_virtdevice    = iblock_allocate_virtdevice,
774         .create_virtdevice      = iblock_create_virtdevice,
775         .free_device            = iblock_free_device,
776         .dpo_emulated           = iblock_emulated_dpo,
777         .fua_write_emulated     = iblock_emulated_fua_write,
778         .fua_read_emulated      = iblock_emulated_fua_read,
779         .write_cache_emulated   = iblock_emulated_write_cache,
780         .alloc_task             = iblock_alloc_task,
781         .do_task                = iblock_do_task,
782         .do_discard             = iblock_do_discard,
783         .do_sync_cache          = iblock_emulate_sync_cache,
784         .free_task              = iblock_free_task,
785         .check_configfs_dev_params = iblock_check_configfs_dev_params,
786         .set_configfs_dev_params = iblock_set_configfs_dev_params,
787         .show_configfs_dev_params = iblock_show_configfs_dev_params,
788         .get_cdb                = iblock_get_cdb,
789         .get_device_rev         = iblock_get_device_rev,
790         .get_device_type        = iblock_get_device_type,
791         .get_blocks             = iblock_get_blocks,
792 };
793
794 static int __init iblock_module_init(void)
795 {
796         return transport_subsystem_register(&iblock_template);
797 }
798
799 static void iblock_module_exit(void)
800 {
801         transport_subsystem_release(&iblock_template);
802 }
803
804 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
805 MODULE_AUTHOR("nab@Linux-iSCSI.org");
806 MODULE_LICENSE("GPL");
807
808 module_init(iblock_module_init);
809 module_exit(iblock_module_exit);