1 files changed, 808 insertions, 0 deletions

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
new file mode 100644
index 000000000000..c6e0d757e76e
--- /dev/null
+++ b/drivers/target/target_core_iblock.c
@@ -0,0 +1,808 @@
+/*******************************************************************************
+ * 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 (!(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;
+
+	blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
+	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);