[RFC 16/22] tcm: Add IBLOCK subsystem plugin

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

This patch adds the TCM/IBLOCK subsystem plugin for accessing struct block_device
with an emulated SPC-3 control path from Linux/BLOCK code using struct bio.  The
also includes WriteCache and FUA Write emulation to struct block_device using
block/blk-barrier.c:blkdev_issue_flush()

Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
---
 drivers/target/target_core_iblock.c | 1173 +++++++++++++++++++++++++++++++++++
 drivers/target/target_core_iblock.h |   44 ++
 2 files changed, 1217 insertions(+), 0 deletions(-)
 create mode 100644 drivers/target/target_core_iblock.c
 create mode 100644 drivers/target/target_core_iblock.h

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
new file mode 100644
index 0000000..b08c341
--- /dev/null
+++ b/drivers/target/target_core_iblock.c
@@ -0,0 +1,1173 @@
+/*******************************************************************************
+ * 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@xxxxxxxxxx>
+ *
+ * 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/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_get_dev_info(struct iblock_dev *, char *, int *);
+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;
+}
+
+/*	iblock_detach_hba(): (Part of se_subsystem_api_t template)
+ *
+ *
+ */
+static int iblock_detach_hba(struct se_hba *hba)
+{
+	struct iblock_hba *ib_host;
+
+	if (!hba->hba_ptr) {
+		printk(KERN_ERR "hba->hba_ptr is NULL!\n");
+		return -1;
+	}
+	ib_host = (struct iblock_hba *) 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;
+
+	return 0;
+}
+
+static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
+{
+	struct iblock_dev *ib_dev = NULL;
+	struct iblock_hba *ib_host = (struct iblock_hba *) 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 int __iblock_do_sync_cache(struct se_device *);
+
+static struct se_device *iblock_create_virtdevice(
+	struct se_hba *hba,
+	struct se_subsystem_dev *se_dev,
+	void *p)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *) p;
+	struct se_device *dev;
+	struct block_device *bd = NULL;
+	u32 dev_flags = 0;
+
+	if (!(ib_dev)) {
+		printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
+		return 0;
+	}
+	/*
+	 * 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");
+	/*
+	 * Check if we have an open file descritpor passed through configfs
+	 * $TARGET/iblock_0/some_bd/fd pointing to an underlying.
+	 * struct block_device.  If so, claim it with the pointer from
+	 * iblock_create_virtdevice_from_fd()
+	 *
+	 * Otherwise, assume that parameters through 'control' attribute
+	 * have set ib_dev->ibd_[major,minor]
+	 */
+	if (ib_dev->ibd_bd) {
+		printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %p\n",
+			 ib_dev->ibd_bd);
+
+		ib_dev->ibd_major = MAJOR(ib_dev->ibd_bd->bd_dev);
+		ib_dev->ibd_minor = MINOR(ib_dev->ibd_bd->bd_dev);
+
+		bd = linux_blockdevice_claim(ib_dev->ibd_major,
+				ib_dev->ibd_minor, ib_dev);
+		if (!(bd)) {
+			printk(KERN_INFO "IBLOCK: Unable to claim"
+					" struct block_device\n");
+			goto failed;
+		}
+		dev_flags = DF_CLAIMED_BLOCKDEV;
+	} else {
+		/*
+		 * 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 = open_bdev_exclusive(ib_dev->ibd_udev_path,
+				FMODE_WRITE|FMODE_READ, ib_dev);
+		if (!(bd))
+			goto failed;
+
+		dev_flags = DF_CLAIMED_BLOCKDEV;
+		ib_dev->ibd_major = MAJOR(bd->bd_dev);
+		ib_dev->ibd_minor = MINOR(bd->bd_dev);
+		ib_dev->ibd_bd = bd;
+		ib_dev->ibd_flags |= IBDF_BDEV_EXCLUSIVE;
+	}
+	/*
+	 * Pass dev_flags for linux_blockdevice_claim() or
+	 * linux_blockdevice_claim() from the usage above.
+	 *
+	 * Note that transport_add_device_to_core_hba() will call
+	 * linux_blockdevice_release() internally on failure to
+	 * call bd_release() on the referenced struct block_device.
+	 */
+	dev = transport_add_device_to_core_hba(hba,
+			&iblock_template, se_dev, dev_flags, (void *)ib_dev);
+	if (!(dev))
+		goto failed;
+
+	ib_dev->ibd_depth = dev->queue_depth;
+	/*
+	 * Check if the underlying struct block_device supports the
+	 * block/blk-barrier.c:blkdev_issue_flush() call, depending upon
+	 * which the SCSI mode page bits for WriteCache=1 and DPOFUA=1
+	 * will be enabled by TCM Core.
+	 */
+	if (__iblock_do_sync_cache(dev) == 0)
+		ib_dev->ibd_flags |= IBDF_BDEV_ISSUE_FLUSH;
+
+	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;
+}
+
+/*	iblock_activate_device(): (Part of se_subsystem_api_t template)
+ *
+ *
+ */
+static int iblock_activate_device(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *) dev->dev_ptr;
+	struct iblock_hba *ib_hba = ib_dev->ibd_host;
+
+	printk(KERN_INFO "CORE_iBLOCK[%u] - Activating Device with TCQ: %d at"
+		" Major: %d Minor %d\n", ib_hba->iblock_host_id,
+		ib_dev->ibd_depth, ib_dev->ibd_major, ib_dev->ibd_minor);
+
+	return 0;
+}
+
+/*	iblock_deactivate_device(): (Part of se_subsystem_api_t template)
+ *
+ *
+ */
+static void iblock_deactivate_device(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *) dev->dev_ptr;
+	struct iblock_hba *ib_hba = ib_dev->ibd_host;
+
+	printk(KERN_INFO "CORE_iBLOCK[%u] - Deactivating Device with TCQ: %d"
+		" at Major: %d Minor %d\n", ib_hba->iblock_host_id,
+		ib_dev->ibd_depth, ib_dev->ibd_major, ib_dev->ibd_minor);
+}
+
+static void iblock_free_device(void *p)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *) p;
+
+	if (ib_dev->ibd_bd) {
+		printk(KERN_INFO "IBLOCK: Releasing Major:Minor - %d:%d\n",
+			ib_dev->ibd_major, ib_dev->ibd_minor);
+
+		if (ib_dev->ibd_flags & IBDF_BDEV_EXCLUSIVE)
+			close_bdev_exclusive(ib_dev->ibd_bd,
+				FMODE_WRITE|FMODE_READ);
+		else
+			linux_blockdevice_release(ib_dev->ibd_major,
+					ib_dev->ibd_minor, ib_dev->ibd_bd);
+		ib_dev->ibd_bd = NULL;
+	}
+
+	if (ib_dev->ibd_bio_set) {
+		DEBUG_IBLOCK("Calling bioset_free ib_dev->ibd_bio_set: %p\n",
+				ib_dev->ibd_bio_set);
+		bioset_free(ib_dev->ibd_bio_set);
+	}
+
+	kfree(ib_dev);
+}
+
+static int iblock_transport_complete(struct se_task *task)
+{
+	return 0;
+}
+
+/*	iblock_allocate_request(): (Part of se_subsystem_api_t template)
+ *
+ *
+ */
+static void *iblock_allocate_request(
+	struct se_task *task,
+	struct se_device *dev)
+{
+	struct iblock_req *ib_req;
+
+	ib_req = kmalloc(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 = (struct iblock_dev *) dev->dev_ptr;
+	return (void *)ib_req;
+}
+
+static int iblock_emulate_inquiry(struct se_task *task)
+{
+	unsigned char prod[64], se_location[128];
+	struct se_cmd *cmd = TASK_CMD(task);
+	struct iblock_dev *ibd = (struct iblock_dev *) task->se_dev->dev_ptr;
+	struct se_hba *hba = task->se_dev->se_hba;
+
+	memset(prod, 0, 64);
+	memset(se_location, 0, 128);
+
+	sprintf(prod, "IBLOCK");
+	sprintf(se_location, "%u_%u_%u", hba->hba_id, ibd->ibd_major,
+		ibd->ibd_minor);
+
+	return transport_generic_emulate_inquiry(cmd, TYPE_DISK, prod,
+		IBLOCK_VERSION, se_location);
+}
+
+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;
+}
+
+static int iblock_emulate_read_cap(struct se_task *task)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) task->se_dev->dev_ptr;
+	struct block_device *bd = ibd->ibd_bd;
+	struct request_queue *q = bdev_get_queue(bd);
+	unsigned long long blocks_long = 0;
+	u32 blocks = 0;
+
+	blocks_long = iblock_emulate_read_cap_with_block_size(
+				task->se_dev, bd, q);
+	if (blocks_long >= 0x00000000ffffffff)
+		blocks = 0xffffffff;
+	else
+		blocks = (u32)blocks_long;
+
+	return transport_generic_emulate_readcapacity(TASK_CMD(task), blocks);
+}
+
+static int iblock_emulate_read_cap16(struct se_task *task)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) task->se_dev->dev_ptr;
+	struct block_device *bd = ibd->ibd_bd;
+	struct request_queue *q = bdev_get_queue(bd);
+	unsigned long long blocks_long;
+
+	blocks_long = iblock_emulate_read_cap_with_block_size(
+				task->se_dev, bd, q);
+	return transport_generic_emulate_readcapacity_16(
+				TASK_CMD(task), blocks_long);
+}
+
+static int iblock_emulate_scsi_cdb(struct se_task *task)
+{
+	int ret;
+	struct se_cmd *cmd = TASK_CMD(task);
+
+	switch (T_TASK(cmd)->t_task_cdb[0]) {
+	case INQUIRY:
+		if (iblock_emulate_inquiry(task) < 0)
+			return PYX_TRANSPORT_INVALID_CDB_FIELD;
+		break;
+	case READ_CAPACITY:
+		ret = iblock_emulate_read_cap(task);
+		if (ret < 0)
+			return ret;
+		break;
+	case MODE_SENSE:
+		ret = transport_generic_emulate_modesense(TASK_CMD(task),
+				T_TASK(cmd)->t_task_cdb,
+				T_TASK(cmd)->t_task_buf, 0, TYPE_DISK);
+		if (ret < 0)
+			return ret;
+		break;
+	case MODE_SENSE_10:
+		ret = transport_generic_emulate_modesense(TASK_CMD(task),
+				T_TASK(cmd)->t_task_cdb,
+			T_TASK(cmd)->t_task_buf, 1, TYPE_DISK);
+		if (ret < 0)
+			return ret;
+		break;
+	case SERVICE_ACTION_IN:
+		if ((T_TASK(cmd)->t_task_cdb[1] & 0x1f) !=
+		     SAI_READ_CAPACITY_16) {
+			printk(KERN_ERR "Unsupported SA: 0x%02x\n",
+				T_TASK(cmd)->t_task_cdb[1] & 0x1f);
+			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		}
+		ret = iblock_emulate_read_cap16(task);
+		if (ret < 0)
+			return ret;
+		break;
+	case REQUEST_SENSE:
+		ret = transport_generic_emulate_request_sense(cmd,
+				T_TASK(cmd)->t_task_cdb);
+		if (ret < 0)
+			return ret;
+		break;
+	case ALLOW_MEDIUM_REMOVAL:
+	case ERASE:
+	case REZERO_UNIT:
+	case SEEK_10:
+	case SPACE:
+	case START_STOP:
+	case SYNCHRONIZE_CACHE:
+	case TEST_UNIT_READY:
+	case VERIFY:
+	case WRITE_FILEMARKS:
+	case RESERVE:
+	case RESERVE_10:
+	case RELEASE:
+	case RELEASE_10:
+		break;
+	default:
+		printk(KERN_ERR "Unsupported SCSI Opcode: 0x%02x for iBlock\n",
+				T_TASK(cmd)->t_task_cdb[0]);
+		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+	}
+
+	task->task_scsi_status = GOOD;
+	transport_complete_task(task, 1);
+
+	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+}
+
+static int __iblock_do_sync_cache(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *)dev->dev_ptr;
+	int ret;
+
+	ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, NULL,
+				BLKDEV_IFL_WAIT);
+	if (ret != 0) {
+		printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d\n", ret);
+		return -1;
+	}
+	DEBUG_IBLOCK("IBLOCK: Called block_issue_flush()\n");
+	return 0;
+}
+
+void iblock_do_sync_cache_range(
+	struct se_cmd *cmd,
+	unsigned long long lba,
+	u32 size_in_bytes)
+{
+	int ret, immed = (T_TASK(cmd)->t_task_cdb[1] & 0x2);
+	/*
+	 * If the Immediate bit is set, queue up the GOOD response
+	 * for this SYNCHRONIZE_CACHE op
+	 */
+	if (immed)
+		transport_complete_sync_cache(cmd, 1);
+	/*
+	 * block/blk-barrier.c:block_issue_flush() does not support a
+	 * LBA + Range synchronization method, so for this case we
+	 * have to flush the entire cache.
+	 */
+	ret = __iblock_do_sync_cache(cmd->se_dev);
+	if (ret < 0) {
+		if (!(immed))
+			transport_complete_sync_cache(cmd, 0);
+		return;
+	}
+
+	if (!(immed))
+		transport_complete_sync_cache(cmd, 1);
+}
+
+/*
+ * Tell TCM Core that we are capable of WriteCache emulation for
+ * an underlying struct se_device.
+ */
+int iblock_emulated_write_cache(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *)dev->dev_ptr;
+	/*
+	 * Only return WCE if ISSUE_FLUSH is supported
+	 */	
+	return (ib_dev->ibd_flags & IBDF_BDEV_ISSUE_FLUSH) ? 1 : 0;
+}
+
+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.
+ */
+int iblock_emulated_fua_write(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = (struct iblock_dev *)dev->dev_ptr;
+	/*
+	 * Only return FUA WRITE if ISSUE_FLUSH is supported
+	 */
+	return (ib_dev->ibd_flags & IBDF_BDEV_ISSUE_FLUSH) ? 1 : 0;
+}
+
+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 = (struct iblock_req *)task->transport_req;
+	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 write = (TASK_CMD(task)->data_direction == SE_DIRECTION_WRITE);
+	int ret;
+
+	if (!(TASK_CMD(task)->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB))
+		return iblock_emulate_scsi_cdb(task);
+
+	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(write, bio);
+		bio = nbio;
+	}
+
+	if (q->unplug_fn)
+		q->unplug_fn(q);
+	/*
+	 * Check for Forced Unit Access WRITE emulation
+	 */
+	if ((DEV_ATTRIB(dev)->emulate_write_cache > 0) &&
+	    (DEV_ATTRIB(dev)->emulate_fua_write > 0) &&
+	    write && T_TASK(task->task_se_cmd)->t_task_fua) {
+		/*
+		 * We might need to be a bit smarter here
+		 * and return some sense data to let the initiator
+		 * know the FUA WRITE cache sync failed..?
+		 */
+		ret = __iblock_do_sync_cache(dev);
+		if (ret < 0) {
+			printk(KERN_ERR "__iblock_do_sync_cache()"
+				" failed for FUA Write\n");
+		}
+	}
+
+	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+}
+
+static void iblock_free_task(struct se_task *task)
+{
+	struct iblock_req *req = (struct iblock_req *) task->transport_req;
+
+	/*
+	 * We do not release the bio(s) here associated with this task, as
+	 * this is handled by bio_put() and iblock_bio_destructor().
+	 */
+
+	kfree(req);
+	task->transport_req = 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 = (struct iblock_dev *) se_dev->se_dev_su_ptr;
+	char *buf, *cur, *ptr, *ptr2;
+	unsigned long force;
+	int params = 0, ret = 0;
+
+	buf = kzalloc(count, GFP_KERNEL);
+	if (!(buf)) {
+		printk(KERN_ERR "Unable to allocate memory for temporary"
+			" buffer\n");
+		return 0;
+	}
+	memcpy(buf, page, count);
+	cur = buf;
+
+	while (cur) {
+		ptr = strstr(cur, "=");
+		if (!(ptr))
+			goto out;
+
+		*ptr = '\0';
+		ptr++;
+
+		ptr2 = strstr(cur, "udev_path");
+		if ((ptr2)) {
+			transport_check_dev_params_delim(ptr, &cur);
+			ptr = strstrip(ptr);
+			if (ib_dev->ibd_bd) {
+				printk(KERN_ERR "Unable to set udev_path= while"
+					" ib_dev->ibd_bd exists\n");
+				params = 0;
+				goto out;
+			}
+
+			ret = snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
+				"%s", ptr);
+			printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
+					ib_dev->ibd_udev_path);
+			ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
+			params++;
+			continue;
+		}
+		ptr2 = strstr(cur, "force");
+		if ((ptr2)) {
+			transport_check_dev_params_delim(ptr, &cur);
+			ret = strict_strtoul(ptr, 0, &force);
+			if (ret < 0) {
+				printk(KERN_ERR "strict_strtoul() failed"
+					" for force=\n");
+				break;
+			}
+			ib_dev->ibd_force = (int)force;
+			printk(KERN_INFO "IBLOCK: Set force=%d\n",
+				ib_dev->ibd_force);
+			params++;
+		} else
+			cur = NULL;
+	}
+
+out:
+	kfree(buf);
+	return (params) ? count : -EINVAL;
+}
+
+static ssize_t iblock_check_configfs_dev_params(
+	struct se_hba *hba,
+	struct se_subsystem_dev *se_dev)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) 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 *page)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) se_dev->se_dev_su_ptr;
+	int bl = 0;
+
+	__iblock_get_dev_info(ibd, page, &bl);
+	return (ssize_t)bl;
+}
+
+static struct se_device *iblock_create_virtdevice_from_fd(
+	struct se_subsystem_dev *se_dev,
+	const char *page)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) se_dev->se_dev_su_ptr;
+	struct se_device *dev = NULL;
+	struct file *filp;
+	struct inode *inode;
+	char *p = (char *)page;
+	unsigned long long fd;
+	int ret;
+
+	ret = strict_strtoull(p, 0, (unsigned long long *)&fd);
+	if (ret < 0) {
+		printk(KERN_ERR "strict_strtol() failed for fd\n");
+		return ERR_PTR(-EINVAL);
+	}
+	if ((fd < 3 || fd > 7)) {
+		printk(KERN_ERR "IBLOCK: Illegal value of file descriptor:"
+				" %llu\n", fd);
+		return ERR_PTR(-EINVAL);
+	}
+	filp = fget(fd);
+	if (!(filp)) {
+		printk(KERN_ERR "IBLOCK: Unable to fget() fd: %llu\n", fd);
+		return ERR_PTR(-EBADF);
+	}
+	inode = igrab(filp->f_mapping->host);
+	if (!(inode)) {
+		printk(KERN_ERR "IBLOCK: Unable to locate struct inode for"
+			" struct block_device fd\n");
+		fput(filp);
+		return ERR_PTR(-EINVAL);
+	}
+	if (!(S_ISBLK(inode->i_mode))) {
+		printk(KERN_ERR "IBLOCK: S_ISBLK(inode->i_mode) failed for file"
+				" descriptor: %llu\n", fd);
+		iput(inode);
+		fput(filp);
+		return ERR_PTR(-ENODEV);
+	}
+	ibd->ibd_bd = I_BDEV(filp->f_mapping->host);
+	if (!(ibd->ibd_bd)) {
+		printk(KERN_ERR "IBLOCK: Unable to locate struct block_device"
+				" from I_BDEV()\n");
+		iput(inode);
+		fput(filp);
+		return ERR_PTR(-EINVAL);
+	}
+	/*
+	 * iblock_create_virtdevice() will call linux_blockdevice_claim()
+	 * to claim struct block_device.
+	 */
+	dev = iblock_create_virtdevice(se_dev->se_dev_hba, se_dev, (void *)ibd);
+
+	iput(inode);
+	fput(filp);
+	return dev;
+}
+
+static void iblock_get_plugin_info(void *p, char *b, int *bl)
+{
+	*bl += sprintf(b + *bl, "TCM iBlock Plugin %s\n", IBLOCK_VERSION);
+}
+
+static void iblock_get_hba_info(struct se_hba *hba, char *b, int *bl)
+{
+	struct iblock_hba *ib_host = (struct iblock_hba *)hba->hba_ptr;
+
+	*bl += sprintf(b + *bl, "SE Host ID: %u  iBlock Host ID: %u\n",
+		hba->hba_id, ib_host->iblock_host_id);
+	*bl += sprintf(b + *bl, "        TCM iBlock HBA\n");
+}
+
+static void iblock_get_dev_info(struct se_device *dev, char *b, int *bl)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) dev->dev_ptr;
+
+	__iblock_get_dev_info(ibd, b, bl);
+}
+
+static void __iblock_get_dev_info(struct iblock_dev *ibd, char *b, int *bl)
+{
+	char buf[BDEVNAME_SIZE];
+	struct block_device *bd = ibd->ibd_bd;
+
+	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);
+	}
+}
+
+static void iblock_bio_destructor(struct bio *bio)
+{
+	struct se_task *task = (struct se_task *)bio->bi_private;
+	struct iblock_dev *ib_dev = (struct iblock_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 = (struct iblock_dev *) task->se_dev->dev_ptr;
+	struct iblock_req *ib_req = (struct iblock_req *) task->transport_req;
+	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;
+	}
+
+	atomic_set(&ib_req->ib_bio_cnt, 0);
+
+	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 task->task_sg_num;
+fail:
+	while (hbio) {
+		bio = hbio;
+		hbio = hbio->bi_next;
+		bio->bi_next = NULL;
+		bio_put(bio);
+	}
+	return ret;
+}
+
+static int iblock_CDB_none(struct se_task *task, u32 size)
+{
+	return 0;
+}
+
+static int iblock_CDB_read_non_SG(struct se_task *task, u32 size)
+{
+	return 0;
+}
+
+static int iblock_CDB_read_SG(struct se_task *task, u32 size)
+{
+	return iblock_map_task_SG(task);
+}
+
+static int iblock_CDB_write_non_SG(struct se_task *task, u32 size)
+{
+	return 0;
+}
+
+static int iblock_CDB_write_SG(struct se_task *task, u32 size)
+{
+	return iblock_map_task_SG(task);
+}
+
+static int iblock_check_lba(unsigned long long lba, struct se_device *dev)
+{
+	return 0;
+}
+
+static int iblock_check_for_SG(struct se_task *task)
+{
+	return task->task_sg_num;
+}
+
+static unsigned char *iblock_get_cdb(struct se_task *task)
+{
+	struct iblock_req *req = (struct iblock_req *) task->transport_req;
+
+	return req->ib_scsi_cdb;
+}
+
+static u32 iblock_get_blocksize(struct se_device *dev)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) dev->dev_ptr;
+
+	return bdev_logical_block_size(ibd->ibd_bd);
+}
+
+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 u32 iblock_get_dma_length(u32 task_size, struct se_device *dev)
+{
+	return PAGE_SIZE;
+}
+
+static u32 iblock_get_max_sectors(struct se_device *dev)
+{
+	struct iblock_dev *ibd = (struct iblock_dev *) dev->dev_ptr;
+	struct request_queue *q = bdev_get_queue(ibd->ibd_bd);
+
+	return q->limits.max_sectors;
+}
+
+static u32 iblock_get_queue_depth(struct se_device *dev)
+{
+	return IBLOCK_DEVICE_QUEUE_DEPTH;
+}
+
+static u32 iblock_get_max_queue_depth(struct se_device *dev)
+{
+	return IBLOCK_MAX_DEVICE_QUEUE_DEPTH;
+}
+
+static void iblock_bio_done(struct bio *bio, int err)
+{
+	struct se_task *task = (struct se_task *)bio->bi_private;
+	struct iblock_req *ibr = (struct iblock_req *)task->transport_req;
+
+	err = test_bit(BIO_UPTODATE, &bio->bi_flags) ? err : -EIO;
+	if (err != 0) {
+		printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
+			" err: %d\n", bio, err);
+		transport_complete_task(task, 0);
+		goto out;
+	}
+	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)))
+		goto out;
+
+	ibr->ib_bio = NULL;
+	transport_complete_task(task, (!err));
+out:
+	return;
+}
+
+static struct se_subsystem_api iblock_template = {
+	.name			= "iblock",
+	.type			= IBLOCK,
+	.transport_type		= TRANSPORT_PLUGIN_VHBA_PDEV,
+	.external_submod	= 1,
+	.cdb_none		= iblock_CDB_none,
+	.cdb_read_non_SG	= iblock_CDB_read_non_SG,
+	.cdb_read_SG		= iblock_CDB_read_SG,
+	.cdb_write_non_SG	= iblock_CDB_write_non_SG,
+	.cdb_write_SG		= iblock_CDB_write_SG,
+	.attach_hba		= iblock_attach_hba,
+	.detach_hba		= iblock_detach_hba,
+	.allocate_virtdevice	= iblock_allocate_virtdevice,
+	.create_virtdevice	= iblock_create_virtdevice,
+	.activate_device	= iblock_activate_device,
+	.deactivate_device	= iblock_deactivate_device,
+	.free_device		= iblock_free_device,
+	.do_sync_cache_range	= iblock_do_sync_cache_range,
+	.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,
+	.transport_complete	= iblock_transport_complete,
+	.allocate_request	= iblock_allocate_request,
+	.do_task		= iblock_do_task,
+	.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,
+	.create_virtdevice_from_fd = iblock_create_virtdevice_from_fd,
+	.get_plugin_info	= iblock_get_plugin_info,
+	.get_hba_info		= iblock_get_hba_info,
+	.get_dev_info		= iblock_get_dev_info,
+	.check_lba		= iblock_check_lba,
+	.check_for_SG		= iblock_check_for_SG,
+	.get_cdb		= iblock_get_cdb,
+	.get_blocksize		= iblock_get_blocksize,
+	.get_device_rev		= iblock_get_device_rev,
+	.get_device_type	= iblock_get_device_type,
+	.get_dma_length		= iblock_get_dma_length,
+	.get_max_sectors	= iblock_get_max_sectors,
+	.get_queue_depth	= iblock_get_queue_depth,
+	.get_max_queue_depth	= iblock_get_max_queue_depth,
+	.write_pending		= NULL,
+};
+
+int __init iblock_module_init(void)
+{
+	int ret;
+
+	INIT_LIST_HEAD(&iblock_template.sub_api_list);
+
+	ret = transport_subsystem_register(&iblock_template, THIS_MODULE);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+void iblock_module_exit(void)
+{
+	transport_subsystem_release(&iblock_template);
+}
+
+MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
+MODULE_AUTHOR("nab@xxxxxxxxxxxxxxx");
+MODULE_LICENSE("GPL");
+
+module_init(iblock_module_init);
+module_exit(iblock_module_exit);
diff --git a/drivers/target/target_core_iblock.h b/drivers/target/target_core_iblock.h
new file mode 100644
index 0000000..d2a7c4a
--- /dev/null
+++ b/drivers/target/target_core_iblock.h
@@ -0,0 +1,44 @@
+#ifndef TARGET_CORE_IBLOCK_H
+#define TARGET_CORE_IBLOCK_H
+
+#define IBLOCK_VERSION		"4.0"
+
+#define IBLOCK_HBA_QUEUE_DEPTH	512
+#define IBLOCK_DEVICE_QUEUE_DEPTH	32
+#define IBLOCK_MAX_DEVICE_QUEUE_DEPTH	128
+#define IBLOCK_MAX_CDBS		16
+#define IBLOCK_LBA_SHIFT	9
+
+extern struct se_global *se_global;
+
+struct iblock_req {
+	unsigned char ib_scsi_cdb[SCSI_CDB_SIZE];
+	atomic_t ib_bio_cnt;
+	u32	ib_sg_count;
+	void	*ib_buf;
+	struct bio *ib_bio;
+	struct iblock_dev *ib_dev;
+} ____cacheline_aligned;
+
+#define IBDF_HAS_UDEV_PATH		0x01
+#define IBDF_HAS_FORCE			0x02
+#define IBDF_BDEV_EXCLUSIVE		0x04
+#define IBDF_BDEV_ISSUE_FLUSH		0x08
+
+struct iblock_dev {
+	unsigned char ibd_udev_path[SE_UDEV_PATH_LEN];
+	int	ibd_force;
+	int	ibd_major;
+	int	ibd_minor;
+	u32	ibd_depth;
+	u32	ibd_flags;
+	struct bio_set	*ibd_bio_set;
+	struct block_device *ibd_bd;
+	struct iblock_hba *ibd_host;
+} ____cacheline_aligned;
+
+struct iblock_hba {
+	int		iblock_host_id;
+} ____cacheline_aligned;
+
+#endif /* TARGET_CORE_IBLOCK_H */
-- 
1.7.2.2

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