1 files changed, 930 insertions, 0 deletions

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
new file mode 100644
index 000000000..d9266cf55
--- /dev/null
+++ b/drivers/target/target_core_iblock.c
@@ -0,0 +1,930 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*******************************************************************************
+ * Filename:  target_core_iblock.c
+ *
+ * This file contains the Storage Engine  <-> Linux BlockIO transport
+ * specific functions.
+ *
+ * (c) Copyright 2003-2013 Datera, Inc.
+ *
+ * Nicholas A. Bellinger <nab@kernel.org>
+ *
+ ******************************************************************************/
+
+#include <linux/string.h>
+#include <linux/parser.h>
+#include <linux/timer.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/blk-integrity.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/bio.h>
+#include <linux/file.h>
+#include <linux/module.h>
+#include <linux/scatterlist.h>
+#include <scsi/scsi_proto.h>
+#include <asm/unaligned.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_backend.h>
+
+#include "target_core_iblock.h"
+
+#define IBLOCK_MAX_BIO_PER_TASK	 32	/* max # of bios to submit at a time */
+#define IBLOCK_BIO_POOL_SIZE	128
+
+static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
+{
+	return container_of(dev, struct iblock_dev, dev);
+}
+
+
+static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
+{
+	pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
+		" Generic Target Core Stack %s\n", hba->hba_id,
+		IBLOCK_VERSION, TARGET_CORE_VERSION);
+	return 0;
+}
+
+static void iblock_detach_hba(struct se_hba *hba)
+{
+}
+
+static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
+{
+	struct iblock_dev *ib_dev = NULL;
+
+	ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
+	if (!ib_dev) {
+		pr_err("Unable to allocate struct iblock_dev\n");
+		return NULL;
+	}
+
+	ib_dev->ibd_plug = kcalloc(nr_cpu_ids, sizeof(*ib_dev->ibd_plug),
+				   GFP_KERNEL);
+	if (!ib_dev->ibd_plug)
+		goto free_dev;
+
+	pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
+
+	return &ib_dev->dev;
+
+free_dev:
+	kfree(ib_dev);
+	return NULL;
+}
+
+static bool iblock_configure_unmap(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+
+	return target_configure_unmap_from_queue(&dev->dev_attrib,
+						 ib_dev->ibd_bd);
+}
+
+static int iblock_configure_device(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	struct request_queue *q;
+	struct block_device *bd = NULL;
+	struct blk_integrity *bi;
+	fmode_t mode;
+	unsigned int max_write_zeroes_sectors;
+	int ret;
+
+	if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
+		pr_err("Missing udev_path= parameters for IBLOCK\n");
+		return -EINVAL;
+	}
+
+	ret = bioset_init(&ib_dev->ibd_bio_set, IBLOCK_BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
+	if (ret) {
+		pr_err("IBLOCK: Unable to create bioset\n");
+		goto out;
+	}
+
+	pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
+			ib_dev->ibd_udev_path);
+
+	mode = FMODE_READ|FMODE_EXCL;
+	if (!ib_dev->ibd_readonly)
+		mode |= FMODE_WRITE;
+	else
+		dev->dev_flags |= DF_READ_ONLY;
+
+	bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
+	if (IS_ERR(bd)) {
+		ret = PTR_ERR(bd);
+		goto out_free_bioset;
+	}
+	ib_dev->ibd_bd = bd;
+
+	q = bdev_get_queue(bd);
+
+	dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
+	dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
+	dev->dev_attrib.hw_queue_depth = q->nr_requests;
+
+	/*
+	 * Enable write same emulation for IBLOCK and use 0xFFFF as
+	 * the smaller WRITE_SAME(10) only has a two-byte block count.
+	 */
+	max_write_zeroes_sectors = bdev_write_zeroes_sectors(bd);
+	if (max_write_zeroes_sectors)
+		dev->dev_attrib.max_write_same_len = max_write_zeroes_sectors;
+	else
+		dev->dev_attrib.max_write_same_len = 0xFFFF;
+
+	if (bdev_nonrot(bd))
+		dev->dev_attrib.is_nonrot = 1;
+
+	bi = bdev_get_integrity(bd);
+	if (bi) {
+		struct bio_set *bs = &ib_dev->ibd_bio_set;
+
+		if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-IP") ||
+		    !strcmp(bi->profile->name, "T10-DIF-TYPE1-IP")) {
+			pr_err("IBLOCK export of blk_integrity: %s not"
+			       " supported\n", bi->profile->name);
+			ret = -ENOSYS;
+			goto out_blkdev_put;
+		}
+
+		if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-CRC")) {
+			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
+		} else if (!strcmp(bi->profile->name, "T10-DIF-TYPE1-CRC")) {
+			dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
+		}
+
+		if (dev->dev_attrib.pi_prot_type) {
+			if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
+				pr_err("Unable to allocate bioset for PI\n");
+				ret = -ENOMEM;
+				goto out_blkdev_put;
+			}
+			pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
+				 &bs->bio_integrity_pool);
+		}
+		dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
+	}
+
+	return 0;
+
+out_blkdev_put:
+	blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
+out_free_bioset:
+	bioset_exit(&ib_dev->ibd_bio_set);
+out:
+	return ret;
+}
+
+static void iblock_dev_call_rcu(struct rcu_head *p)
+{
+	struct se_device *dev = container_of(p, struct se_device, rcu_head);
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+
+	kfree(ib_dev->ibd_plug);
+	kfree(ib_dev);
+}
+
+static void iblock_free_device(struct se_device *dev)
+{
+	call_rcu(&dev->rcu_head, iblock_dev_call_rcu);
+}
+
+static void iblock_destroy_device(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+
+	if (ib_dev->ibd_bd != NULL)
+		blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
+	bioset_exit(&ib_dev->ibd_bio_set);
+}
+
+static struct se_dev_plug *iblock_plug_device(struct se_device *se_dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(se_dev);
+	struct iblock_dev_plug *ib_dev_plug;
+
+	/*
+	 * Each se_device has a per cpu work this can be run from. We
+	 * shouldn't have multiple threads on the same cpu calling this
+	 * at the same time.
+	 */
+	ib_dev_plug = &ib_dev->ibd_plug[raw_smp_processor_id()];
+	if (test_and_set_bit(IBD_PLUGF_PLUGGED, &ib_dev_plug->flags))
+		return NULL;
+
+	blk_start_plug(&ib_dev_plug->blk_plug);
+	return &ib_dev_plug->se_plug;
+}
+
+static void iblock_unplug_device(struct se_dev_plug *se_plug)
+{
+	struct iblock_dev_plug *ib_dev_plug = container_of(se_plug,
+					struct iblock_dev_plug, se_plug);
+
+	blk_finish_plug(&ib_dev_plug->blk_plug);
+	clear_bit(IBD_PLUGF_PLUGGED, &ib_dev_plug->flags);
+}
+
+static sector_t iblock_get_blocks(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	u32 block_size = bdev_logical_block_size(ib_dev->ibd_bd);
+	unsigned long long blocks_long =
+		div_u64(bdev_nr_bytes(ib_dev->ibd_bd), block_size) - 1;
+
+	if (block_size == dev->dev_attrib.block_size)
+		return blocks_long;
+
+	switch (block_size) {
+	case 4096:
+		switch (dev->dev_attrib.block_size) {
+		case 2048:
+			blocks_long <<= 1;
+			break;
+		case 1024:
+			blocks_long <<= 2;
+			break;
+		case 512:
+			blocks_long <<= 3;
+			break;
+		default:
+			break;
+		}
+		break;
+	case 2048:
+		switch (dev->dev_attrib.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->dev_attrib.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->dev_attrib.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 void iblock_complete_cmd(struct se_cmd *cmd)
+{
+	struct iblock_req *ibr = cmd->priv;
+	u8 status;
+
+	if (!refcount_dec_and_test(&ibr->pending))
+		return;
+
+	if (atomic_read(&ibr->ib_bio_err_cnt))
+		status = SAM_STAT_CHECK_CONDITION;
+	else
+		status = SAM_STAT_GOOD;
+
+	target_complete_cmd(cmd, status);
+	kfree(ibr);
+}
+
+static void iblock_bio_done(struct bio *bio)
+{
+	struct se_cmd *cmd = bio->bi_private;
+	struct iblock_req *ibr = cmd->priv;
+
+	if (bio->bi_status) {
+		pr_err("bio error: %p,  err: %d\n", bio, bio->bi_status);
+		/*
+		 * Bump the ib_bio_err_cnt and release bio.
+		 */
+		atomic_inc(&ibr->ib_bio_err_cnt);
+		smp_mb__after_atomic();
+	}
+
+	bio_put(bio);
+
+	iblock_complete_cmd(cmd);
+}
+
+static struct bio *iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num,
+				  blk_opf_t opf)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
+	struct bio *bio;
+
+	/*
+	 * Only allocate as many vector entries as the bio code allows us to,
+	 * we'll loop later on until we have handled the whole request.
+	 */
+	bio = bio_alloc_bioset(ib_dev->ibd_bd, bio_max_segs(sg_num), opf,
+			       GFP_NOIO, &ib_dev->ibd_bio_set);
+	if (!bio) {
+		pr_err("Unable to allocate memory for bio\n");
+		return NULL;
+	}
+
+	bio->bi_private = cmd;
+	bio->bi_end_io = &iblock_bio_done;
+	bio->bi_iter.bi_sector = lba;
+
+	return bio;
+}
+
+static void iblock_submit_bios(struct bio_list *list)
+{
+	struct blk_plug plug;
+	struct bio *bio;
+	/*
+	 * The block layer handles nested plugs, so just plug/unplug to handle
+	 * fabric drivers that didn't support batching and multi bio cmds.
+	 */
+	blk_start_plug(&plug);
+	while ((bio = bio_list_pop(list)))
+		submit_bio(bio);
+	blk_finish_plug(&plug);
+}
+
+static void iblock_end_io_flush(struct bio *bio)
+{
+	struct se_cmd *cmd = bio->bi_private;
+
+	if (bio->bi_status)
+		pr_err("IBLOCK: cache flush failed: %d\n", bio->bi_status);
+
+	if (cmd) {
+		if (bio->bi_status)
+			target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
+		else
+			target_complete_cmd(cmd, SAM_STAT_GOOD);
+	}
+
+	bio_put(bio);
+}
+
+/*
+ * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
+ * always flush the whole cache.
+ */
+static sense_reason_t
+iblock_execute_sync_cache(struct se_cmd *cmd)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
+	int immed = (cmd->t_task_cdb[1] & 0x2);
+	struct bio *bio;
+
+	/*
+	 * If the Immediate bit is set, queue up the GOOD response
+	 * for this SYNCHRONIZE_CACHE op.
+	 */
+	if (immed)
+		target_complete_cmd(cmd, SAM_STAT_GOOD);
+
+	bio = bio_alloc(ib_dev->ibd_bd, 0, REQ_OP_WRITE | REQ_PREFLUSH,
+			GFP_KERNEL);
+	bio->bi_end_io = iblock_end_io_flush;
+	if (!immed)
+		bio->bi_private = cmd;
+	submit_bio(bio);
+	return 0;
+}
+
+static sense_reason_t
+iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
+{
+	struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
+	struct se_device *dev = cmd->se_dev;
+	int ret;
+
+	ret = blkdev_issue_discard(bdev,
+				   target_to_linux_sector(dev, lba),
+				   target_to_linux_sector(dev,  nolb),
+				   GFP_KERNEL);
+	if (ret < 0) {
+		pr_err("blkdev_issue_discard() failed: %d\n", ret);
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	}
+
+	return 0;
+}
+
+static sense_reason_t
+iblock_execute_zero_out(struct block_device *bdev, struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct scatterlist *sg = &cmd->t_data_sg[0];
+	unsigned char *buf, *not_zero;
+	int ret;
+
+	buf = kmap(sg_page(sg)) + sg->offset;
+	if (!buf)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	/*
+	 * Fall back to block_execute_write_same() slow-path if
+	 * incoming WRITE_SAME payload does not contain zeros.
+	 */
+	not_zero = memchr_inv(buf, 0x00, cmd->data_length);
+	kunmap(sg_page(sg));
+
+	if (not_zero)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+	ret = blkdev_issue_zeroout(bdev,
+				target_to_linux_sector(dev, cmd->t_task_lba),
+				target_to_linux_sector(dev,
+					sbc_get_write_same_sectors(cmd)),
+				GFP_KERNEL, BLKDEV_ZERO_NOUNMAP);
+	if (ret)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+	target_complete_cmd(cmd, SAM_STAT_GOOD);
+	return 0;
+}
+
+static sense_reason_t
+iblock_execute_write_same(struct se_cmd *cmd)
+{
+	struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
+	struct iblock_req *ibr;
+	struct scatterlist *sg;
+	struct bio *bio;
+	struct bio_list list;
+	struct se_device *dev = cmd->se_dev;
+	sector_t block_lba = target_to_linux_sector(dev, cmd->t_task_lba);
+	sector_t sectors = target_to_linux_sector(dev,
+					sbc_get_write_same_sectors(cmd));
+
+	if (cmd->prot_op) {
+		pr_err("WRITE_SAME: Protection information with IBLOCK"
+		       " backends not supported\n");
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	}
+
+	if (!cmd->t_data_nents)
+		return TCM_INVALID_CDB_FIELD;
+
+	sg = &cmd->t_data_sg[0];
+
+	if (cmd->t_data_nents > 1 ||
+	    sg->length != cmd->se_dev->dev_attrib.block_size) {
+		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
+			" block_size: %u\n", cmd->t_data_nents, sg->length,
+			cmd->se_dev->dev_attrib.block_size);
+		return TCM_INVALID_CDB_FIELD;
+	}
+
+	if (bdev_write_zeroes_sectors(bdev)) {
+		if (!iblock_execute_zero_out(bdev, cmd))
+			return 0;
+	}
+
+	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
+	if (!ibr)
+		goto fail;
+	cmd->priv = ibr;
+
+	bio = iblock_get_bio(cmd, block_lba, 1, REQ_OP_WRITE);
+	if (!bio)
+		goto fail_free_ibr;
+
+	bio_list_init(&list);
+	bio_list_add(&list, bio);
+
+	refcount_set(&ibr->pending, 1);
+
+	while (sectors) {
+		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
+				!= sg->length) {
+
+			bio = iblock_get_bio(cmd, block_lba, 1, REQ_OP_WRITE);
+			if (!bio)
+				goto fail_put_bios;
+
+			refcount_inc(&ibr->pending);
+			bio_list_add(&list, bio);
+		}
+
+		/* Always in 512 byte units for Linux/Block */
+		block_lba += sg->length >> SECTOR_SHIFT;
+		sectors -= sg->length >> SECTOR_SHIFT;
+	}
+
+	iblock_submit_bios(&list);
+	return 0;
+
+fail_put_bios:
+	while ((bio = bio_list_pop(&list)))
+		bio_put(bio);
+fail_free_ibr:
+	kfree(ibr);
+fail:
+	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+}
+
+enum {
+	Opt_udev_path, Opt_readonly, Opt_force, Opt_err
+};
+
+static match_table_t tokens = {
+	{Opt_udev_path, "udev_path=%s"},
+	{Opt_readonly, "readonly=%d"},
+	{Opt_force, "force=%d"},
+	{Opt_err, NULL}
+};
+
+static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
+		const char *page, ssize_t count)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	char *orig, *ptr, *arg_p, *opts;
+	substring_t args[MAX_OPT_ARGS];
+	int ret = 0, token;
+	unsigned long tmp_readonly;
+
+	opts = kstrdup(page, GFP_KERNEL);
+	if (!opts)
+		return -ENOMEM;
+
+	orig = opts;
+
+	while ((ptr = strsep(&opts, ",\n")) != NULL) {
+		if (!*ptr)
+			continue;
+
+		token = match_token(ptr, tokens, args);
+		switch (token) {
+		case Opt_udev_path:
+			if (ib_dev->ibd_bd) {
+				pr_err("Unable to set udev_path= while"
+					" ib_dev->ibd_bd exists\n");
+				ret = -EEXIST;
+				goto out;
+			}
+			if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
+				SE_UDEV_PATH_LEN) == 0) {
+				ret = -EINVAL;
+				break;
+			}
+			pr_debug("IBLOCK: Referencing UDEV path: %s\n",
+					ib_dev->ibd_udev_path);
+			ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
+			break;
+		case Opt_readonly:
+			arg_p = match_strdup(&args[0]);
+			if (!arg_p) {
+				ret = -ENOMEM;
+				break;
+			}
+			ret = kstrtoul(arg_p, 0, &tmp_readonly);
+			kfree(arg_p);
+			if (ret < 0) {
+				pr_err("kstrtoul() failed for"
+						" readonly=\n");
+				goto out;
+			}
+			ib_dev->ibd_readonly = tmp_readonly;
+			pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
+			break;
+		case Opt_force:
+			break;
+		default:
+			break;
+		}
+	}
+
+out:
+	kfree(orig);
+	return (!ret) ? count : ret;
+}
+
+static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	struct block_device *bd = ib_dev->ibd_bd;
+	ssize_t bl = 0;
+
+	if (bd)
+		bl += sprintf(b + bl, "iBlock device: %pg", bd);
+	if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
+		bl += sprintf(b + bl, "  UDEV PATH: %s",
+				ib_dev->ibd_udev_path);
+	bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
+
+	bl += sprintf(b + bl, "        ");
+	if (bd) {
+		bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
+			MAJOR(bd->bd_dev), MINOR(bd->bd_dev),
+			"CLAIMED: IBLOCK");
+	} else {
+		bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
+	}
+
+	return bl;
+}
+
+static int
+iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio,
+		 struct sg_mapping_iter *miter)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct blk_integrity *bi;
+	struct bio_integrity_payload *bip;
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	int rc;
+	size_t resid, len;
+
+	bi = bdev_get_integrity(ib_dev->ibd_bd);
+	if (!bi) {
+		pr_err("Unable to locate bio_integrity\n");
+		return -ENODEV;
+	}
+
+	bip = bio_integrity_alloc(bio, GFP_NOIO, bio_max_segs(cmd->t_prot_nents));
+	if (IS_ERR(bip)) {
+		pr_err("Unable to allocate bio_integrity_payload\n");
+		return PTR_ERR(bip);
+	}
+
+	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
+	/* virtual start sector must be in integrity interval units */
+	bip_set_seed(bip, bio->bi_iter.bi_sector >>
+				  (bi->interval_exp - SECTOR_SHIFT));
+
+	pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
+		 (unsigned long long)bip->bip_iter.bi_sector);
+
+	resid = bip->bip_iter.bi_size;
+	while (resid > 0 && sg_miter_next(miter)) {
+
+		len = min_t(size_t, miter->length, resid);
+		rc = bio_integrity_add_page(bio, miter->page, len,
+					    offset_in_page(miter->addr));
+		if (rc != len) {
+			pr_err("bio_integrity_add_page() failed; %d\n", rc);
+			sg_miter_stop(miter);
+			return -ENOMEM;
+		}
+
+		pr_debug("Added bio integrity page: %p length: %zu offset: %lu\n",
+			  miter->page, len, offset_in_page(miter->addr));
+
+		resid -= len;
+		if (len < miter->length)
+			miter->consumed -= miter->length - len;
+	}
+	sg_miter_stop(miter);
+
+	return 0;
+}
+
+static sense_reason_t
+iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
+		  enum dma_data_direction data_direction)
+{
+	struct se_device *dev = cmd->se_dev;
+	sector_t block_lba = target_to_linux_sector(dev, cmd->t_task_lba);
+	struct iblock_req *ibr;
+	struct bio *bio;
+	struct bio_list list;
+	struct scatterlist *sg;
+	u32 sg_num = sgl_nents;
+	blk_opf_t opf;
+	unsigned bio_cnt;
+	int i, rc;
+	struct sg_mapping_iter prot_miter;
+	unsigned int miter_dir;
+
+	if (data_direction == DMA_TO_DEVICE) {
+		struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+		/*
+		 * Force writethrough using REQ_FUA if a volatile write cache
+		 * is not enabled, or if initiator set the Force Unit Access bit.
+		 */
+		opf = REQ_OP_WRITE;
+		miter_dir = SG_MITER_TO_SG;
+		if (bdev_fua(ib_dev->ibd_bd)) {
+			if (cmd->se_cmd_flags & SCF_FUA)
+				opf |= REQ_FUA;
+			else if (!bdev_write_cache(ib_dev->ibd_bd))
+				opf |= REQ_FUA;
+		}
+	} else {
+		opf = REQ_OP_READ;
+		miter_dir = SG_MITER_FROM_SG;
+	}
+
+	ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
+	if (!ibr)
+		goto fail;
+	cmd->priv = ibr;
+
+	if (!sgl_nents) {
+		refcount_set(&ibr->pending, 1);
+		iblock_complete_cmd(cmd);
+		return 0;
+	}
+
+	bio = iblock_get_bio(cmd, block_lba, sgl_nents, opf);
+	if (!bio)
+		goto fail_free_ibr;
+
+	bio_list_init(&list);
+	bio_list_add(&list, bio);
+
+	refcount_set(&ibr->pending, 2);
+	bio_cnt = 1;
+
+	if (cmd->prot_type && dev->dev_attrib.pi_prot_type)
+		sg_miter_start(&prot_miter, cmd->t_prot_sg, cmd->t_prot_nents,
+			       miter_dir);
+
+	for_each_sg(sgl, sg, sgl_nents, i) {
+		/*
+		 * XXX: if the length the device accepts is shorter than the
+		 *	length of the S/G list entry this will cause and
+		 *	endless loop.  Better hope no driver uses huge pages.
+		 */
+		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
+				!= sg->length) {
+			if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
+				rc = iblock_alloc_bip(cmd, bio, &prot_miter);
+				if (rc)
+					goto fail_put_bios;
+			}
+
+			if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
+				iblock_submit_bios(&list);
+				bio_cnt = 0;
+			}
+
+			bio = iblock_get_bio(cmd, block_lba, sg_num, opf);
+			if (!bio)
+				goto fail_put_bios;
+
+			refcount_inc(&ibr->pending);
+			bio_list_add(&list, bio);
+			bio_cnt++;
+		}
+
+		/* Always in 512 byte units for Linux/Block */
+		block_lba += sg->length >> SECTOR_SHIFT;
+		sg_num--;
+	}
+
+	if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
+		rc = iblock_alloc_bip(cmd, bio, &prot_miter);
+		if (rc)
+			goto fail_put_bios;
+	}
+
+	iblock_submit_bios(&list);
+	iblock_complete_cmd(cmd);
+	return 0;
+
+fail_put_bios:
+	while ((bio = bio_list_pop(&list)))
+		bio_put(bio);
+fail_free_ibr:
+	kfree(ibr);
+fail:
+	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+}
+
+static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	struct block_device *bd = ib_dev->ibd_bd;
+	int ret;
+
+	ret = bdev_alignment_offset(bd);
+	if (ret == -1)
+		return 0;
+
+	/* convert offset-bytes to offset-lbas */
+	return ret / bdev_logical_block_size(bd);
+}
+
+static unsigned int iblock_get_lbppbe(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	struct block_device *bd = ib_dev->ibd_bd;
+	unsigned int logs_per_phys =
+		bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
+
+	return ilog2(logs_per_phys);
+}
+
+static unsigned int iblock_get_io_min(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	struct block_device *bd = ib_dev->ibd_bd;
+
+	return bdev_io_min(bd);
+}
+
+static unsigned int iblock_get_io_opt(struct se_device *dev)
+{
+	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
+	struct block_device *bd = ib_dev->ibd_bd;
+
+	return bdev_io_opt(bd);
+}
+
+static struct sbc_ops iblock_sbc_ops = {
+	.execute_rw		= iblock_execute_rw,
+	.execute_sync_cache	= iblock_execute_sync_cache,
+	.execute_write_same	= iblock_execute_write_same,
+	.execute_unmap		= iblock_execute_unmap,
+};
+
+static sense_reason_t
+iblock_parse_cdb(struct se_cmd *cmd)
+{
+	return sbc_parse_cdb(cmd, &iblock_sbc_ops);
+}
+
+static bool iblock_get_write_cache(struct se_device *dev)
+{
+	return bdev_write_cache(IBLOCK_DEV(dev)->ibd_bd);
+}
+
+static const struct target_backend_ops iblock_ops = {
+	.name			= "iblock",
+	.inquiry_prod		= "IBLOCK",
+	.inquiry_rev		= IBLOCK_VERSION,
+	.owner			= THIS_MODULE,
+	.attach_hba		= iblock_attach_hba,
+	.detach_hba		= iblock_detach_hba,
+	.alloc_device		= iblock_alloc_device,
+	.configure_device	= iblock_configure_device,
+	.destroy_device		= iblock_destroy_device,
+	.free_device		= iblock_free_device,
+	.configure_unmap	= iblock_configure_unmap,
+	.plug_device		= iblock_plug_device,
+	.unplug_device		= iblock_unplug_device,
+	.parse_cdb		= iblock_parse_cdb,
+	.set_configfs_dev_params = iblock_set_configfs_dev_params,
+	.show_configfs_dev_params = iblock_show_configfs_dev_params,
+	.get_device_type	= sbc_get_device_type,
+	.get_blocks		= iblock_get_blocks,
+	.get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
+	.get_lbppbe		= iblock_get_lbppbe,
+	.get_io_min		= iblock_get_io_min,
+	.get_io_opt		= iblock_get_io_opt,
+	.get_write_cache	= iblock_get_write_cache,
+	.tb_dev_attrib_attrs	= sbc_attrib_attrs,
+};
+
+static int __init iblock_module_init(void)
+{
+	return transport_backend_register(&iblock_ops);
+}
+
+static void __exit iblock_module_exit(void)
+{
+	target_backend_unregister(&iblock_ops);
+}
+
+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);