]> git.karo-electronics.de Git - mv-sheeva.git/blobdiff - drivers/target/target_core_iblock.c
Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[mv-sheeva.git] / drivers / target / target_core_iblock.c
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
new file mode 100644 (file)
index 0000000..67f0c09
--- /dev/null
@@ -0,0 +1,810 @@
+/*******************************************************************************
+ * Filename:  target_core_iblock.c
+ *
+ * This file contains the Storage Engine  <-> Linux BlockIO transport
+ * specific functions.
+ *
+ * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
+ * Copyright (c) 2005, 2006, 2007 SBE, Inc.
+ * Copyright (c) 2007-2010 Rising Tide Systems
+ * Copyright (c) 2008-2010 Linux-iSCSI.org
+ *
+ * Nicholas A. Bellinger <nab@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ ******************************************************************************/
+
+#include <linux/version.h>
+#include <linux/string.h>
+#include <linux/parser.h>
+#include <linux/timer.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/smp_lock.h>
+#include <linux/bio.h>
+#include <linux/genhd.h>
+#include <linux/file.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_device.h>
+#include <target/target_core_transport.h>
+
+#include "target_core_iblock.h"
+
+#if 0
+#define DEBUG_IBLOCK(x...) printk(x)
+#else
+#define DEBUG_IBLOCK(x...)
+#endif
+
+static struct se_subsystem_api iblock_template;
+
+static void iblock_bio_done(struct bio *, int);
+
+/*     iblock_attach_hba(): (Part of se_subsystem_api_t template)
+ *
+ *
+ */
+static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
+{
+       struct iblock_hba *ib_host;
+
+       ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
+       if (!(ib_host)) {
+               printk(KERN_ERR "Unable to allocate memory for"
+                               " struct iblock_hba\n");
+               return -ENOMEM;
+       }
+
+       ib_host->iblock_host_id = host_id;
+
+       atomic_set(&hba->left_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
+       atomic_set(&hba->max_queue_depth, IBLOCK_HBA_QUEUE_DEPTH);
+       hba->hba_ptr = (void *) ib_host;
+
+       printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
+               " Generic Target Core Stack %s\n", hba->hba_id,
+               IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
+
+       printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic"
+               " Target Core TCQ Depth: %d\n", hba->hba_id,
+               ib_host->iblock_host_id, atomic_read(&hba->max_queue_depth));
+
+       return 0;
+}
+
+static void iblock_detach_hba(struct se_hba *hba)
+{
+       struct iblock_hba *ib_host = hba->hba_ptr;
+
+       printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
+               " Target Core\n", hba->hba_id, ib_host->iblock_host_id);
+
+       kfree(ib_host);
+       hba->hba_ptr = NULL;
+}
+
+static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
+{
+       struct iblock_dev *ib_dev = NULL;
+       struct iblock_hba *ib_host = hba->hba_ptr;
+
+       ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
+       if (!(ib_dev)) {
+               printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
+               return NULL;
+       }
+       ib_dev->ibd_host = ib_host;
+
+       printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);
+
+       return ib_dev;
+}
+
+static struct se_device *iblock_create_virtdevice(
+       struct se_hba *hba,
+       struct se_subsystem_dev *se_dev,
+       void *p)
+{
+       struct iblock_dev *ib_dev = p;
+       struct se_device *dev;
+       struct se_dev_limits dev_limits;
+       struct block_device *bd = NULL;
+       struct request_queue *q;
+       struct queue_limits *limits;
+       u32 dev_flags = 0;
+
+       if (!(ib_dev)) {
+               printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
+               return 0;
+       }
+       memset(&dev_limits, 0, sizeof(struct se_dev_limits));
+       /*
+        * These settings need to be made tunable..
+        */
+       ib_dev->ibd_bio_set = bioset_create(32, 64);
+       if (!(ib_dev->ibd_bio_set)) {
+               printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
+               return 0;
+       }
+       printk(KERN_INFO "IBLOCK: Created bio_set()\n");
+       /*
+        * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
+        * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
+        */
+       printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
+                       ib_dev->ibd_udev_path);
+
+       bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
+                               FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
+       if (IS_ERR(bd))
+               goto failed;
+       /*
+        * Setup the local scope queue_limits from struct request_queue->limits
+        * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
+        */
+       q = bdev_get_queue(bd);
+       limits = &dev_limits.limits;
+       limits->logical_block_size = bdev_logical_block_size(bd);
+       limits->max_hw_sectors = queue_max_hw_sectors(q);
+       limits->max_sectors = queue_max_sectors(q);
+       dev_limits.hw_queue_depth = IBLOCK_MAX_DEVICE_QUEUE_DEPTH;
+       dev_limits.queue_depth = IBLOCK_DEVICE_QUEUE_DEPTH;
+
+       ib_dev->ibd_major = MAJOR(bd->bd_dev);
+       ib_dev->ibd_minor = MINOR(bd->bd_dev);
+       ib_dev->ibd_bd = bd;
+
+       dev = transport_add_device_to_core_hba(hba,
+                       &iblock_template, se_dev, dev_flags, (void *)ib_dev,
+                       &dev_limits, "IBLOCK", IBLOCK_VERSION);
+       if (!(dev))
+               goto failed;
+
+       ib_dev->ibd_depth = dev->queue_depth;
+
+       /*
+        * Check if the underlying struct block_device request_queue supports
+        * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
+        * in ATA and we need to set TPE=1
+        */
+       if (blk_queue_discard(bdev_get_queue(bd))) {
+               struct request_queue *q = bdev_get_queue(bd);
+
+               DEV_ATTRIB(dev)->max_unmap_lba_count =
+                               q->limits.max_discard_sectors;
+               /*
+                * Currently hardcoded to 1 in Linux/SCSI code..
+                */
+               DEV_ATTRIB(dev)->max_unmap_block_desc_count = 1;
+               DEV_ATTRIB(dev)->unmap_granularity =
+                               q->limits.discard_granularity;
+               DEV_ATTRIB(dev)->unmap_granularity_alignment =
+                               q->limits.discard_alignment;
+
+               printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
+                               " disabled by default\n");
+       }
+
+       return dev;
+
+failed:
+       if (ib_dev->ibd_bio_set) {
+               bioset_free(ib_dev->ibd_bio_set);
+               ib_dev->ibd_bio_set = NULL;
+       }
+       ib_dev->ibd_bd = NULL;
+       ib_dev->ibd_major = 0;
+       ib_dev->ibd_minor = 0;
+       return NULL;
+}
+
+static void iblock_free_device(void *p)
+{
+       struct iblock_dev *ib_dev = p;
+
+       if (ib_dev->ibd_bd != NULL)
+               blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
+       if (ib_dev->ibd_bio_set != NULL)
+               bioset_free(ib_dev->ibd_bio_set);
+       kfree(ib_dev);
+}
+
+static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
+{
+       return container_of(task, struct iblock_req, ib_task);
+}
+
+static struct se_task *
+iblock_alloc_task(struct se_cmd *cmd)
+{
+       struct iblock_req *ib_req;
+
+       ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
+       if (!(ib_req)) {
+               printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
+               return NULL;
+       }
+
+       ib_req->ib_dev = SE_DEV(cmd)->dev_ptr;
+       atomic_set(&ib_req->ib_bio_cnt, 0);
+       return &ib_req->ib_task;
+}
+
+static unsigned long long iblock_emulate_read_cap_with_block_size(
+       struct se_device *dev,
+       struct block_device *bd,
+       struct request_queue *q)
+{
+       unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
+                                       bdev_logical_block_size(bd)) - 1);
+       u32 block_size = bdev_logical_block_size(bd);
+
+       if (block_size == DEV_ATTRIB(dev)->block_size)
+               return blocks_long;
+
+       switch (block_size) {
+       case 4096:
+               switch (DEV_ATTRIB(dev)->block_size) {
+               case 2048:
+                       blocks_long <<= 1;
+                       break;
+               case 1024:
+                       blocks_long <<= 2;
+                       break;
+               case 512:
+                       blocks_long <<= 3;
+               default:
+                       break;
+               }
+               break;
+       case 2048:
+               switch (DEV_ATTRIB(dev)->block_size) {
+               case 4096:
+                       blocks_long >>= 1;
+                       break;
+               case 1024:
+                       blocks_long <<= 1;
+                       break;
+               case 512:
+                       blocks_long <<= 2;
+                       break;
+               default:
+                       break;
+               }
+               break;
+       case 1024:
+               switch (DEV_ATTRIB(dev)->block_size) {
+               case 4096:
+                       blocks_long >>= 2;
+                       break;
+               case 2048:
+                       blocks_long >>= 1;
+                       break;
+               case 512:
+                       blocks_long <<= 1;
+                       break;
+               default:
+                       break;
+               }
+               break;
+       case 512:
+               switch (DEV_ATTRIB(dev)->block_size) {
+               case 4096:
+                       blocks_long >>= 3;
+                       break;
+               case 2048:
+                       blocks_long >>= 2;
+                       break;
+               case 1024:
+                       blocks_long >>= 1;
+                       break;
+               default:
+                       break;
+               }
+               break;
+       default:
+               break;
+       }
+
+       return blocks_long;
+}
+
+/*
+ * Emulate SYCHRONIZE_CACHE_*
+ */
+static void iblock_emulate_sync_cache(struct se_task *task)
+{
+       struct se_cmd *cmd = TASK_CMD(task);
+       struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
+       int immed = (T_TASK(cmd)->t_task_cdb[1] & 0x2);
+       sector_t error_sector;
+       int ret;
+
+       /*
+        * If the Immediate bit is set, queue up the GOOD response
+        * for this SYNCHRONIZE_CACHE op
+        */
+       if (immed)
+               transport_complete_sync_cache(cmd, 1);
+
+       /*
+        * blkdev_issue_flush() does not support a specifying a range, so
+        * we have to flush the entire cache.
+        */
+       ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
+       if (ret != 0) {
+               printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
+                       " error_sector: %llu\n", ret,
+                       (unsigned long long)error_sector);
+       }
+
+       if (!immed)
+               transport_complete_sync_cache(cmd, ret == 0);
+}
+
+/*
+ * Tell TCM Core that we are capable of WriteCache emulation for
+ * an underlying struct se_device.
+ */
+static int iblock_emulated_write_cache(struct se_device *dev)
+{
+       return 1;
+}
+
+static int iblock_emulated_dpo(struct se_device *dev)
+{
+       return 0;
+}
+
+/*
+ * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
+ * for TYPE_DISK.
+ */
+static int iblock_emulated_fua_write(struct se_device *dev)
+{
+       return 1;
+}
+
+static int iblock_emulated_fua_read(struct se_device *dev)
+{
+       return 0;
+}
+
+static int iblock_do_task(struct se_task *task)
+{
+       struct se_device *dev = task->task_se_cmd->se_dev;
+       struct iblock_req *req = IBLOCK_REQ(task);
+       struct iblock_dev *ibd = (struct iblock_dev *)req->ib_dev;
+       struct request_queue *q = bdev_get_queue(ibd->ibd_bd);
+       struct bio *bio = req->ib_bio, *nbio = NULL;
+       int rw;
+
+       if (task->task_data_direction == DMA_TO_DEVICE) {
+               /*
+                * Force data to disk if we pretend to not have a volatile
+                * write cache, or the initiator set the Force Unit Access bit.
+                */
+               if (DEV_ATTRIB(dev)->emulate_write_cache == 0 ||
+                   (DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
+                    T_TASK(task->task_se_cmd)->t_tasks_fua))
+                       rw = WRITE_FUA;
+               else
+                       rw = WRITE;
+       } else {
+               rw = READ;
+       }
+
+       while (bio) {
+               nbio = bio->bi_next;
+               bio->bi_next = NULL;
+               DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
+                       " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
+
+               submit_bio(rw, bio);
+               bio = nbio;
+       }
+
+       if (q->unplug_fn)
+               q->unplug_fn(q);
+       return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+}
+
+static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
+{
+       struct iblock_dev *ibd = dev->dev_ptr;
+       struct block_device *bd = ibd->ibd_bd;
+       int barrier = 0;
+
+       return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
+}
+
+static void iblock_free_task(struct se_task *task)
+{
+       struct iblock_req *req = IBLOCK_REQ(task);
+       struct bio *bio, *hbio = req->ib_bio;
+       /*
+        * We only release the bio(s) here if iblock_bio_done() has not called
+        * bio_put() -> iblock_bio_destructor().
+        */
+       while (hbio != NULL) {
+               bio = hbio;
+               hbio = hbio->bi_next;
+               bio->bi_next = NULL;
+               bio_put(bio);
+       }
+
+       kfree(req);
+}
+
+enum {
+       Opt_udev_path, Opt_force, Opt_err
+};
+
+static match_table_t tokens = {
+       {Opt_udev_path, "udev_path=%s"},
+       {Opt_force, "force=%d"},
+       {Opt_err, NULL}
+};
+
+static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
+                                              struct se_subsystem_dev *se_dev,
+                                              const char *page, ssize_t count)
+{
+       struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
+       char *orig, *ptr, *opts;
+       substring_t args[MAX_OPT_ARGS];
+       int ret = 0, arg, token;
+
+       opts = kstrdup(page, GFP_KERNEL);
+       if (!opts)
+               return -ENOMEM;
+
+       orig = opts;
+
+       while ((ptr = strsep(&opts, ",")) != NULL) {
+               if (!*ptr)
+                       continue;
+
+               token = match_token(ptr, tokens, args);
+               switch (token) {
+               case Opt_udev_path:
+                       if (ib_dev->ibd_bd) {
+                               printk(KERN_ERR "Unable to set udev_path= while"
+                                       " ib_dev->ibd_bd exists\n");
+                               ret = -EEXIST;
+                               goto out;
+                       }
+
+                       ret = snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
+                               "%s", match_strdup(&args[0]));
+                       printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
+                                       ib_dev->ibd_udev_path);
+                       ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
+                       break;
+               case Opt_force:
+                       match_int(args, &arg);
+                       ib_dev->ibd_force = arg;
+                       printk(KERN_INFO "IBLOCK: Set force=%d\n",
+                               ib_dev->ibd_force);
+                       break;
+               default:
+                       break;
+               }
+       }
+
+out:
+       kfree(orig);
+       return (!ret) ? count : ret;
+}
+
+static ssize_t iblock_check_configfs_dev_params(
+       struct se_hba *hba,
+       struct se_subsystem_dev *se_dev)
+{
+       struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
+
+       if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
+               printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
+               return -1;
+       }
+
+       return 0;
+}
+
+static ssize_t iblock_show_configfs_dev_params(
+       struct se_hba *hba,
+       struct se_subsystem_dev *se_dev,
+       char *b)
+{
+       struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
+       struct block_device *bd = ibd->ibd_bd;
+       char buf[BDEVNAME_SIZE];
+       ssize_t bl = 0;
+
+       if (bd)
+               bl += sprintf(b + bl, "iBlock device: %s",
+                               bdevname(bd, buf));
+       if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
+               bl += sprintf(b + bl, "  UDEV PATH: %s\n",
+                               ibd->ibd_udev_path);
+       } else
+               bl += sprintf(b + bl, "\n");
+
+       bl += sprintf(b + bl, "        ");
+       if (bd) {
+               bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
+                       ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
+                       "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
+                       "CLAIMED: IBLOCK" : "CLAIMED: OS");
+       } else {
+               bl += sprintf(b + bl, "Major: %d Minor: %d\n",
+                       ibd->ibd_major, ibd->ibd_minor);
+       }
+
+       return bl;
+}
+
+static void iblock_bio_destructor(struct bio *bio)
+{
+       struct se_task *task = bio->bi_private;
+       struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
+
+       bio_free(bio, ib_dev->ibd_bio_set);
+}
+
+static struct bio *iblock_get_bio(
+       struct se_task *task,
+       struct iblock_req *ib_req,
+       struct iblock_dev *ib_dev,
+       int *ret,
+       sector_t lba,
+       u32 sg_num)
+{
+       struct bio *bio;
+
+       bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
+       if (!(bio)) {
+               printk(KERN_ERR "Unable to allocate memory for bio\n");
+               *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
+               return NULL;
+       }
+
+       DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
+               " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
+       DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
+
+       bio->bi_bdev = ib_dev->ibd_bd;
+       bio->bi_private = (void *) task;
+       bio->bi_destructor = iblock_bio_destructor;
+       bio->bi_end_io = &iblock_bio_done;
+       bio->bi_sector = lba;
+       atomic_inc(&ib_req->ib_bio_cnt);
+
+       DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
+       DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
+                       atomic_read(&ib_req->ib_bio_cnt));
+       return bio;
+}
+
+static int iblock_map_task_SG(struct se_task *task)
+{
+       struct se_cmd *cmd = task->task_se_cmd;
+       struct se_device *dev = SE_DEV(cmd);
+       struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
+       struct iblock_req *ib_req = IBLOCK_REQ(task);
+       struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
+       struct scatterlist *sg;
+       int ret = 0;
+       u32 i, sg_num = task->task_sg_num;
+       sector_t block_lba;
+       /*
+        * Do starting conversion up from non 512-byte blocksize with
+        * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
+        */
+       if (DEV_ATTRIB(dev)->block_size == 4096)
+               block_lba = (task->task_lba << 3);
+       else if (DEV_ATTRIB(dev)->block_size == 2048)
+               block_lba = (task->task_lba << 2);
+       else if (DEV_ATTRIB(dev)->block_size == 1024)
+               block_lba = (task->task_lba << 1);
+       else if (DEV_ATTRIB(dev)->block_size == 512)
+               block_lba = task->task_lba;
+       else {
+               printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
+                               " %u\n", DEV_ATTRIB(dev)->block_size);
+               return PYX_TRANSPORT_LU_COMM_FAILURE;
+       }
+
+       bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
+       if (!(bio))
+               return ret;
+
+       ib_req->ib_bio = bio;
+       hbio = tbio = bio;
+       /*
+        * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
+        * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
+        */
+       for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
+               DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
+                       " %p len: %u offset: %u\n", task, bio, sg_page(sg),
+                               sg->length, sg->offset);
+again:
+               ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
+               if (ret != sg->length) {
+
+                       DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
+                                       bio->bi_sector);
+                       DEBUG_IBLOCK("** task->task_size: %u\n",
+                                       task->task_size);
+                       DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
+                                       bio->bi_max_vecs);
+                       DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
+                                       bio->bi_vcnt);
+
+                       bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
+                                               block_lba, sg_num);
+                       if (!(bio))
+                               goto fail;
+
+                       tbio = tbio->bi_next = bio;
+                       DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
+                               " list, Going to again\n", bio);
+                       goto again;
+               }
+               /* Always in 512 byte units for Linux/Block */
+               block_lba += sg->length >> IBLOCK_LBA_SHIFT;
+               sg_num--;
+               DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
+                       " sg_num to %u\n", task, sg_num);
+               DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
+                               " to %llu\n", task, block_lba);
+               DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
+                               " %u\n", task, bio->bi_vcnt);
+       }
+
+       return 0;
+fail:
+       while (hbio) {
+               bio = hbio;
+               hbio = hbio->bi_next;
+               bio->bi_next = NULL;
+               bio_put(bio);
+       }
+       return ret;
+}
+
+static unsigned char *iblock_get_cdb(struct se_task *task)
+{
+       return IBLOCK_REQ(task)->ib_scsi_cdb;
+}
+
+static u32 iblock_get_device_rev(struct se_device *dev)
+{
+       return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
+}
+
+static u32 iblock_get_device_type(struct se_device *dev)
+{
+       return TYPE_DISK;
+}
+
+static sector_t iblock_get_blocks(struct se_device *dev)
+{
+       struct iblock_dev *ibd = dev->dev_ptr;
+       struct block_device *bd = ibd->ibd_bd;
+       struct request_queue *q = bdev_get_queue(bd);
+
+       return iblock_emulate_read_cap_with_block_size(dev, bd, q);
+}
+
+static void iblock_bio_done(struct bio *bio, int err)
+{
+       struct se_task *task = bio->bi_private;
+       struct iblock_req *ibr = IBLOCK_REQ(task);
+       /*
+        * Set -EIO if !BIO_UPTODATE and the passed is still err=0
+        */
+       if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
+               err = -EIO;
+
+       if (err != 0) {
+               printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
+                       " err: %d\n", bio, err);
+               /*
+                * Bump the ib_bio_err_cnt and release bio.
+                */
+               atomic_inc(&ibr->ib_bio_err_cnt);
+               smp_mb__after_atomic_inc();
+               bio_put(bio);
+               /*
+                * Wait to complete the task until the last bio as completed.
+                */
+               if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
+                       return;
+
+               ibr->ib_bio = NULL;
+               transport_complete_task(task, 0);
+               return;
+       }
+       DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
+               task, bio, task->task_lba, bio->bi_sector, err);
+       /*
+        * bio_put() will call iblock_bio_destructor() to release the bio back
+        * to ibr->ib_bio_set.
+        */
+       bio_put(bio);
+       /*
+        * Wait to complete the task until the last bio as completed.
+        */
+       if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
+               return;
+       /*
+        * Return GOOD status for task if zero ib_bio_err_cnt exists.
+        */
+       ibr->ib_bio = NULL;
+       transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
+}
+
+static struct se_subsystem_api iblock_template = {
+       .name                   = "iblock",
+       .owner                  = THIS_MODULE,
+       .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
+       .map_task_SG            = iblock_map_task_SG,
+       .attach_hba             = iblock_attach_hba,
+       .detach_hba             = iblock_detach_hba,
+       .allocate_virtdevice    = iblock_allocate_virtdevice,
+       .create_virtdevice      = iblock_create_virtdevice,
+       .free_device            = iblock_free_device,
+       .dpo_emulated           = iblock_emulated_dpo,
+       .fua_write_emulated     = iblock_emulated_fua_write,
+       .fua_read_emulated      = iblock_emulated_fua_read,
+       .write_cache_emulated   = iblock_emulated_write_cache,
+       .alloc_task             = iblock_alloc_task,
+       .do_task                = iblock_do_task,
+       .do_discard             = iblock_do_discard,
+       .do_sync_cache          = iblock_emulate_sync_cache,
+       .free_task              = iblock_free_task,
+       .check_configfs_dev_params = iblock_check_configfs_dev_params,
+       .set_configfs_dev_params = iblock_set_configfs_dev_params,
+       .show_configfs_dev_params = iblock_show_configfs_dev_params,
+       .get_cdb                = iblock_get_cdb,
+       .get_device_rev         = iblock_get_device_rev,
+       .get_device_type        = iblock_get_device_type,
+       .get_blocks             = iblock_get_blocks,
+};
+
+static int __init iblock_module_init(void)
+{
+       return transport_subsystem_register(&iblock_template);
+}
+
+static void iblock_module_exit(void)
+{
+       transport_subsystem_release(&iblock_template);
+}
+
+MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
+MODULE_AUTHOR("nab@Linux-iSCSI.org");
+MODULE_LICENSE("GPL");
+
+module_init(iblock_module_init);
+module_exit(iblock_module_exit);