Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/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 iblock_dev *ibd = (struct iblock_dev *)req->ib_dev;
396         struct request_queue *q = bdev_get_queue(ibd->ibd_bd);
397         struct bio *bio = req->ib_bio, *nbio = NULL;
398         int rw;
399 
400         if (task->task_data_direction == DMA_TO_DEVICE) {
401                 /*
402                  * Force data to disk if we pretend to not have a volatile
403                  * write cache, or the initiator set the Force Unit Access bit.
404                  */
405                 if (DEV_ATTRIB(dev)->emulate_write_cache == 0 ||
406                     (DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
407                      T_TASK(task->task_se_cmd)->t_tasks_fua))
408                         rw = WRITE_FUA;
409                 else
410                         rw = WRITE;
411         } else {
412                 rw = READ;
413         }
414 
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 
425         if (q->unplug_fn)
426                 q->unplug_fn(q);
427         return PYX_TRANSPORT_SENT_TO_TRANSPORT;
428 }
429 
430 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
431 {
432         struct iblock_dev *ibd = dev->dev_ptr;
433         struct block_device *bd = ibd->ibd_bd;
434         int barrier = 0;
435 
436         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
437 }
438 
439 static void iblock_free_task(struct se_task *task)
440 {
441         struct iblock_req *req = IBLOCK_REQ(task);
442         struct bio *bio, *hbio = req->ib_bio;
443         /*
444          * We only release the bio(s) here if iblock_bio_done() has not called
445          * bio_put() -> iblock_bio_destructor().
446          */
447         while (hbio != NULL) {
448                 bio = hbio;
449                 hbio = hbio->bi_next;
450                 bio->bi_next = NULL;
451                 bio_put(bio);
452         }
453 
454         kfree(req);
455 }
456 
457 enum {
458         Opt_udev_path, Opt_force, Opt_err
459 };
460 
461 static match_table_t tokens = {
462         {Opt_udev_path, "udev_path=%s"},
463         {Opt_force, "force=%d"},
464         {Opt_err, NULL}
465 };
466 
467 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
468                                                struct se_subsystem_dev *se_dev,
469                                                const char *page, ssize_t count)
470 {
471         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
472         char *orig, *ptr, *opts;
473         substring_t args[MAX_OPT_ARGS];
474         int ret = 0, arg, token;
475 
476         opts = kstrdup(page, GFP_KERNEL);
477         if (!opts)
478                 return -ENOMEM;
479 
480         orig = opts;
481 
482         while ((ptr = strsep(&opts, ",")) != NULL) {
483                 if (!*ptr)
484                         continue;
485 
486                 token = match_token(ptr, tokens, args);
487                 switch (token) {
488                 case Opt_udev_path:
489                         if (ib_dev->ibd_bd) {
490                                 printk(KERN_ERR "Unable to set udev_path= while"
491                                         " ib_dev->ibd_bd exists\n");
492                                 ret = -EEXIST;
493                                 goto out;
494                         }
495 
496                         ret = snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
497                                 "%s", match_strdup(&args[0]));
498                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
499                                         ib_dev->ibd_udev_path);
500                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
501                         break;
502                 case Opt_force:
503                         match_int(args, &arg);
504                         ib_dev->ibd_force = arg;
505                         printk(KERN_INFO "IBLOCK: Set force=%d\n",
506                                 ib_dev->ibd_force);
507                         break;
508                 default:
509                         break;
510                 }
511         }
512 
513 out:
514         kfree(orig);
515         return (!ret) ? count : ret;
516 }
517 
518 static ssize_t iblock_check_configfs_dev_params(
519         struct se_hba *hba,
520         struct se_subsystem_dev *se_dev)
521 {
522         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
523 
524         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
525                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
526                 return -1;
527         }
528 
529         return 0;
530 }
531 
532 static ssize_t iblock_show_configfs_dev_params(
533         struct se_hba *hba,
534         struct se_subsystem_dev *se_dev,
535         char *b)
536 {
537         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
538         struct block_device *bd = ibd->ibd_bd;
539         char buf[BDEVNAME_SIZE];
540         ssize_t bl = 0;
541 
542         if (bd)
543                 bl += sprintf(b + bl, "iBlock device: %s",
544                                 bdevname(bd, buf));
545         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
546                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
547                                 ibd->ibd_udev_path);
548         } else
549                 bl += sprintf(b + bl, "\n");
550 
551         bl += sprintf(b + bl, "        ");
552         if (bd) {
553                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
554                         ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
555                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
556                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
557         } else {
558                 bl += sprintf(b + bl, "Major: %d Minor: %d\n",
559                         ibd->ibd_major, ibd->ibd_minor);
560         }
561 
562         return bl;
563 }
564 
565 static void iblock_bio_destructor(struct bio *bio)
566 {
567         struct se_task *task = bio->bi_private;
568         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
569 
570         bio_free(bio, ib_dev->ibd_bio_set);
571 }
572 
573 static struct bio *iblock_get_bio(
574         struct se_task *task,
575         struct iblock_req *ib_req,
576         struct iblock_dev *ib_dev,
577         int *ret,
578         sector_t lba,
579         u32 sg_num)
580 {
581         struct bio *bio;
582 
583         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
584         if (!(bio)) {
585                 printk(KERN_ERR "Unable to allocate memory for bio\n");
586                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
587                 return NULL;
588         }
589 
590         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
591                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
592         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
593 
594         bio->bi_bdev = ib_dev->ibd_bd;
595         bio->bi_private = (void *) task;
596         bio->bi_destructor = iblock_bio_destructor;
597         bio->bi_end_io = &iblock_bio_done;
598         bio->bi_sector = lba;
599         atomic_inc(&ib_req->ib_bio_cnt);
600 
601         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
602         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
603                         atomic_read(&ib_req->ib_bio_cnt));
604         return bio;
605 }
606 
607 static int iblock_map_task_SG(struct se_task *task)
608 {
609         struct se_cmd *cmd = task->task_se_cmd;
610         struct se_device *dev = SE_DEV(cmd);
611         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
612         struct iblock_req *ib_req = IBLOCK_REQ(task);
613         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
614         struct scatterlist *sg;
615         int ret = 0;
616         u32 i, sg_num = task->task_sg_num;
617         sector_t block_lba;
618         /*
619          * Do starting conversion up from non 512-byte blocksize with
620          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
621          */
622         if (DEV_ATTRIB(dev)->block_size == 4096)
623                 block_lba = (task->task_lba << 3);
624         else if (DEV_ATTRIB(dev)->block_size == 2048)
625                 block_lba = (task->task_lba << 2);
626         else if (DEV_ATTRIB(dev)->block_size == 1024)
627                 block_lba = (task->task_lba << 1);
628         else if (DEV_ATTRIB(dev)->block_size == 512)
629                 block_lba = task->task_lba;
630         else {
631                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
632                                 " %u\n", DEV_ATTRIB(dev)->block_size);
633                 return PYX_TRANSPORT_LU_COMM_FAILURE;
634         }
635 
636         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
637         if (!(bio))
638                 return ret;
639 
640         ib_req->ib_bio = bio;
641         hbio = tbio = bio;
642         /*
643          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
644          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
645          */
646         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
647                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
648                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
649                                 sg->length, sg->offset);
650 again:
651                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
652                 if (ret != sg->length) {
653 
654                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
655                                         bio->bi_sector);
656                         DEBUG_IBLOCK("** task->task_size: %u\n",
657                                         task->task_size);
658                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
659                                         bio->bi_max_vecs);
660                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
661                                         bio->bi_vcnt);
662 
663                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
664                                                 block_lba, sg_num);
665                         if (!(bio))
666                                 goto fail;
667 
668                         tbio = tbio->bi_next = bio;
669                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
670                                 " list, Going to again\n", bio);
671                         goto again;
672                 }
673                 /* Always in 512 byte units for Linux/Block */
674                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
675                 sg_num--;
676                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
677                         " sg_num to %u\n", task, sg_num);
678                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
679                                 " to %llu\n", task, block_lba);
680                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
681                                 " %u\n", task, bio->bi_vcnt);
682         }
683 
684         return 0;
685 fail:
686         while (hbio) {
687                 bio = hbio;
688                 hbio = hbio->bi_next;
689                 bio->bi_next = NULL;
690                 bio_put(bio);
691         }
692         return ret;
693 }
694 
695 static unsigned char *iblock_get_cdb(struct se_task *task)
696 {
697         return IBLOCK_REQ(task)->ib_scsi_cdb;
698 }
699 
700 static u32 iblock_get_device_rev(struct se_device *dev)
701 {
702         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
703 }
704 
705 static u32 iblock_get_device_type(struct se_device *dev)
706 {
707         return TYPE_DISK;
708 }
709 
710 static sector_t iblock_get_blocks(struct se_device *dev)
711 {
712         struct iblock_dev *ibd = dev->dev_ptr;
713         struct block_device *bd = ibd->ibd_bd;
714         struct request_queue *q = bdev_get_queue(bd);
715 
716         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
717 }
718 
719 static void iblock_bio_done(struct bio *bio, int err)
720 {
721         struct se_task *task = bio->bi_private;
722         struct iblock_req *ibr = IBLOCK_REQ(task);
723         /*
724          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
725          */
726         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
727                 err = -EIO;
728 
729         if (err != 0) {
730                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
731                         " err: %d\n", bio, err);
732                 /*
733                  * Bump the ib_bio_err_cnt and release bio.
734                  */
735                 atomic_inc(&ibr->ib_bio_err_cnt);
736                 smp_mb__after_atomic_inc();
737                 bio_put(bio);
738                 /*
739                  * Wait to complete the task until the last bio as completed.
740                  */
741                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
742                         return;
743 
744                 ibr->ib_bio = NULL;
745                 transport_complete_task(task, 0);
746                 return;
747         }
748         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
749                 task, bio, task->task_lba, bio->bi_sector, err);
750         /*
751          * bio_put() will call iblock_bio_destructor() to release the bio back
752          * to ibr->ib_bio_set.
753          */
754         bio_put(bio);
755         /*
756          * Wait to complete the task until the last bio as completed.
757          */
758         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
759                 return;
760         /*
761          * Return GOOD status for task if zero ib_bio_err_cnt exists.
762          */
763         ibr->ib_bio = NULL;
764         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
765 }
766 
767 static struct se_subsystem_api iblock_template = {
768         .name                   = "iblock",
769         .owner                  = THIS_MODULE,
770         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
771         .map_task_SG            = iblock_map_task_SG,
772         .attach_hba             = iblock_attach_hba,
773         .detach_hba             = iblock_detach_hba,
774         .allocate_virtdevice    = iblock_allocate_virtdevice,
775         .create_virtdevice      = iblock_create_virtdevice,
776         .free_device            = iblock_free_device,
777         .dpo_emulated           = iblock_emulated_dpo,
778         .fua_write_emulated     = iblock_emulated_fua_write,
779         .fua_read_emulated      = iblock_emulated_fua_read,
780         .write_cache_emulated   = iblock_emulated_write_cache,
781         .alloc_task             = iblock_alloc_task,
782         .do_task                = iblock_do_task,
783         .do_discard             = iblock_do_discard,
784         .do_sync_cache          = iblock_emulate_sync_cache,
785         .free_task              = iblock_free_task,
786         .check_configfs_dev_params = iblock_check_configfs_dev_params,
787         .set_configfs_dev_params = iblock_set_configfs_dev_params,
788         .show_configfs_dev_params = iblock_show_configfs_dev_params,
789         .get_cdb                = iblock_get_cdb,
790         .get_device_rev         = iblock_get_device_rev,
791         .get_device_type        = iblock_get_device_type,
792         .get_blocks             = iblock_get_blocks,
793 };
794 
795 static int __init iblock_module_init(void)
796 {
797         return transport_subsystem_register(&iblock_template);
798 }
799 
800 static void iblock_module_exit(void)
801 {
802         transport_subsystem_release(&iblock_template);
803 }
804 
805 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
806 MODULE_AUTHOR("nab@Linux-iSCSI.org");
807 MODULE_LICENSE("GPL");
808 
809 module_init(iblock_module_init);
810 module_exit(iblock_module_exit);
811 

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