Initial import

1 files changed, 1453 insertions, 0 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
new file mode 100644
index 000000000..733824e38
--- /dev/null
+++ b/drivers/target/target_core_sbc.c
@@ -0,0 +1,1453 @@
+/*
+ * SCSI Block Commands (SBC) parsing and emulation.
+ *
+ * (c) Copyright 2002-2013 Datera, Inc.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/ratelimit.h>
+#include <linux/crc-t10dif.h>
+#include <asm/unaligned.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_tcq.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_backend.h>
+#include <target/target_core_fabric.h>
+
+#include "target_core_internal.h"
+#include "target_core_ua.h"
+#include "target_core_alua.h"
+
+static sense_reason_t
+sbc_check_prot(struct se_device *, struct se_cmd *, unsigned char *, u32, bool);
+
+static sense_reason_t
+sbc_emulate_readcapacity(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	unsigned char *cdb = cmd->t_task_cdb;
+	unsigned long long blocks_long = dev->transport->get_blocks(dev);
+	unsigned char *rbuf;
+	unsigned char buf[8];
+	u32 blocks;
+
+	/*
+	 * SBC-2 says:
+	 *   If the PMI bit is set to zero and the LOGICAL BLOCK
+	 *   ADDRESS field is not set to zero, the device server shall
+	 *   terminate the command with CHECK CONDITION status with
+	 *   the sense key set to ILLEGAL REQUEST and the additional
+	 *   sense code set to INVALID FIELD IN CDB.
+	 *
+	 * In SBC-3, these fields are obsolete, but some SCSI
+	 * compliance tests actually check this, so we might as well
+	 * follow SBC-2.
+	 */
+	if (!(cdb[8] & 1) && !!(cdb[2] | cdb[3] | cdb[4] | cdb[5]))
+		return TCM_INVALID_CDB_FIELD;
+
+	if (blocks_long >= 0x00000000ffffffff)
+		blocks = 0xffffffff;
+	else
+		blocks = (u32)blocks_long;
+
+	buf[0] = (blocks >> 24) & 0xff;
+	buf[1] = (blocks >> 16) & 0xff;
+	buf[2] = (blocks >> 8) & 0xff;
+	buf[3] = blocks & 0xff;
+	buf[4] = (dev->dev_attrib.block_size >> 24) & 0xff;
+	buf[5] = (dev->dev_attrib.block_size >> 16) & 0xff;
+	buf[6] = (dev->dev_attrib.block_size >> 8) & 0xff;
+	buf[7] = dev->dev_attrib.block_size & 0xff;
+
+	rbuf = transport_kmap_data_sg(cmd);
+	if (rbuf) {
+		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
+		transport_kunmap_data_sg(cmd);
+	}
+
+	target_complete_cmd_with_length(cmd, GOOD, 8);
+	return 0;
+}
+
+static sense_reason_t
+sbc_emulate_readcapacity_16(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct se_session *sess = cmd->se_sess;
+	int pi_prot_type = dev->dev_attrib.pi_prot_type;
+
+	unsigned char *rbuf;
+	unsigned char buf[32];
+	unsigned long long blocks = dev->transport->get_blocks(dev);
+
+	memset(buf, 0, sizeof(buf));
+	buf[0] = (blocks >> 56) & 0xff;
+	buf[1] = (blocks >> 48) & 0xff;
+	buf[2] = (blocks >> 40) & 0xff;
+	buf[3] = (blocks >> 32) & 0xff;
+	buf[4] = (blocks >> 24) & 0xff;
+	buf[5] = (blocks >> 16) & 0xff;
+	buf[6] = (blocks >> 8) & 0xff;
+	buf[7] = blocks & 0xff;
+	buf[8] = (dev->dev_attrib.block_size >> 24) & 0xff;
+	buf[9] = (dev->dev_attrib.block_size >> 16) & 0xff;
+	buf[10] = (dev->dev_attrib.block_size >> 8) & 0xff;
+	buf[11] = dev->dev_attrib.block_size & 0xff;
+	/*
+	 * Set P_TYPE and PROT_EN bits for DIF support
+	 */
+	if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
+		/*
+		 * Only override a device's pi_prot_type if no T10-PI is
+		 * available, and sess_prot_type has been explicitly enabled.
+		 */
+		if (!pi_prot_type)
+			pi_prot_type = sess->sess_prot_type;
+
+		if (pi_prot_type)
+			buf[12] = (pi_prot_type - 1) << 1 | 0x1;
+	}
+
+	if (dev->transport->get_lbppbe)
+		buf[13] = dev->transport->get_lbppbe(dev) & 0x0f;
+
+	if (dev->transport->get_alignment_offset_lbas) {
+		u16 lalba = dev->transport->get_alignment_offset_lbas(dev);
+		buf[14] = (lalba >> 8) & 0x3f;
+		buf[15] = lalba & 0xff;
+	}
+
+	/*
+	 * Set Thin Provisioning Enable bit following sbc3r22 in section
+	 * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
+	 */
+	if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws)
+		buf[14] |= 0x80;
+
+	rbuf = transport_kmap_data_sg(cmd);
+	if (rbuf) {
+		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
+		transport_kunmap_data_sg(cmd);
+	}
+
+	target_complete_cmd_with_length(cmd, GOOD, 32);
+	return 0;
+}
+
+sector_t sbc_get_write_same_sectors(struct se_cmd *cmd)
+{
+	u32 num_blocks;
+
+	if (cmd->t_task_cdb[0] == WRITE_SAME)
+		num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
+	else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
+		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
+	else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
+		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
+
+	/*
+	 * Use the explicit range when non zero is supplied, otherwise calculate
+	 * the remaining range based on ->get_blocks() - starting LBA.
+	 */
+	if (num_blocks)
+		return num_blocks;
+
+	return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
+		cmd->t_task_lba + 1;
+}
+EXPORT_SYMBOL(sbc_get_write_same_sectors);
+
+static sense_reason_t
+sbc_emulate_noop(struct se_cmd *cmd)
+{
+	target_complete_cmd(cmd, GOOD);
+	return 0;
+}
+
+static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
+{
+	return cmd->se_dev->dev_attrib.block_size * sectors;
+}
+
+static inline u32 transport_get_sectors_6(unsigned char *cdb)
+{
+	/*
+	 * Use 8-bit sector value.  SBC-3 says:
+	 *
+	 *   A TRANSFER LENGTH field set to zero specifies that 256
+	 *   logical blocks shall be written.  Any other value
+	 *   specifies the number of logical blocks that shall be
+	 *   written.
+	 */
+	return cdb[4] ? : 256;
+}
+
+static inline u32 transport_get_sectors_10(unsigned char *cdb)
+{
+	return (u32)(cdb[7] << 8) + cdb[8];
+}
+
+static inline u32 transport_get_sectors_12(unsigned char *cdb)
+{
+	return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
+}
+
+static inline u32 transport_get_sectors_16(unsigned char *cdb)
+{
+	return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
+		    (cdb[12] << 8) + cdb[13];
+}
+
+/*
+ * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
+ */
+static inline u32 transport_get_sectors_32(unsigned char *cdb)
+{
+	return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
+		    (cdb[30] << 8) + cdb[31];
+
+}
+
+static inline u32 transport_lba_21(unsigned char *cdb)
+{
+	return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
+}
+
+static inline u32 transport_lba_32(unsigned char *cdb)
+{
+	return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
+}
+
+static inline unsigned long long transport_lba_64(unsigned char *cdb)
+{
+	unsigned int __v1, __v2;
+
+	__v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
+	__v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
+
+	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+/*
+ * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
+ */
+static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
+{
+	unsigned int __v1, __v2;
+
+	__v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
+	__v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
+
+	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+static sense_reason_t
+sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *ops)
+{
+	struct se_device *dev = cmd->se_dev;
+	sector_t end_lba = dev->transport->get_blocks(dev) + 1;
+	unsigned int sectors = sbc_get_write_same_sectors(cmd);
+	sense_reason_t ret;
+
+	if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
+		pr_err("WRITE_SAME PBDATA and LBDATA"
+			" bits not supported for Block Discard"
+			" Emulation\n");
+		return TCM_UNSUPPORTED_SCSI_OPCODE;
+	}
+	if (sectors > cmd->se_dev->dev_attrib.max_write_same_len) {
+		pr_warn("WRITE_SAME sectors: %u exceeds max_write_same_len: %u\n",
+			sectors, cmd->se_dev->dev_attrib.max_write_same_len);
+		return TCM_INVALID_CDB_FIELD;
+	}
+	/*
+	 * Sanity check for LBA wrap and request past end of device.
+	 */
+	if (((cmd->t_task_lba + sectors) < cmd->t_task_lba) ||
+	    ((cmd->t_task_lba + sectors) > end_lba)) {
+		pr_err("WRITE_SAME exceeds last lba %llu (lba %llu, sectors %u)\n",
+		       (unsigned long long)end_lba, cmd->t_task_lba, sectors);
+		return TCM_ADDRESS_OUT_OF_RANGE;
+	}
+
+	/* We always have ANC_SUP == 0 so setting ANCHOR is always an error */
+	if (flags[0] & 0x10) {
+		pr_warn("WRITE SAME with ANCHOR not supported\n");
+		return TCM_INVALID_CDB_FIELD;
+	}
+	/*
+	 * Special case for WRITE_SAME w/ UNMAP=1 that ends up getting
+	 * translated into block discard requests within backend code.
+	 */
+	if (flags[0] & 0x08) {
+		if (!ops->execute_write_same_unmap)
+			return TCM_UNSUPPORTED_SCSI_OPCODE;
+
+		if (!dev->dev_attrib.emulate_tpws) {
+			pr_err("Got WRITE_SAME w/ UNMAP=1, but backend device"
+			       " has emulate_tpws disabled\n");
+			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		}
+		cmd->execute_cmd = ops->execute_write_same_unmap;
+		return 0;
+	}
+	if (!ops->execute_write_same)
+		return TCM_UNSUPPORTED_SCSI_OPCODE;
+
+	ret = sbc_check_prot(dev, cmd, &cmd->t_task_cdb[0], sectors, true);
+	if (ret)
+		return ret;
+
+	cmd->execute_cmd = ops->execute_write_same;
+	return 0;
+}
+
+static sense_reason_t xdreadwrite_callback(struct se_cmd *cmd, bool success)
+{
+	unsigned char *buf, *addr;
+	struct scatterlist *sg;
+	unsigned int offset;
+	sense_reason_t ret = TCM_NO_SENSE;
+	int i, count;
+	/*
+	 * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
+	 *
+	 * 1) read the specified logical block(s);
+	 * 2) transfer logical blocks from the data-out buffer;
+	 * 3) XOR the logical blocks transferred from the data-out buffer with
+	 *    the logical blocks read, storing the resulting XOR data in a buffer;
+	 * 4) if the DISABLE WRITE bit is set to zero, then write the logical
+	 *    blocks transferred from the data-out buffer; and
+	 * 5) transfer the resulting XOR data to the data-in buffer.
+	 */
+	buf = kmalloc(cmd->data_length, GFP_KERNEL);
+	if (!buf) {
+		pr_err("Unable to allocate xor_callback buf\n");
+		return TCM_OUT_OF_RESOURCES;
+	}
+	/*
+	 * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
+	 * into the locally allocated *buf
+	 */
+	sg_copy_to_buffer(cmd->t_data_sg,
+			  cmd->t_data_nents,
+			  buf,
+			  cmd->data_length);
+
+	/*
+	 * Now perform the XOR against the BIDI read memory located at
+	 * cmd->t_mem_bidi_list
+	 */
+
+	offset = 0;
+	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
+		addr = kmap_atomic(sg_page(sg));
+		if (!addr) {
+			ret = TCM_OUT_OF_RESOURCES;
+			goto out;
+		}
+
+		for (i = 0; i < sg->length; i++)
+			*(addr + sg->offset + i) ^= *(buf + offset + i);
+
+		offset += sg->length;
+		kunmap_atomic(addr);
+	}
+
+out:
+	kfree(buf);
+	return ret;
+}
+
+static sense_reason_t
+sbc_execute_rw(struct se_cmd *cmd)
+{
+	return cmd->execute_rw(cmd, cmd->t_data_sg, cmd->t_data_nents,
+			       cmd->data_direction);
+}
+
+static sense_reason_t compare_and_write_post(struct se_cmd *cmd, bool success)
+{
+	struct se_device *dev = cmd->se_dev;
+
+	/*
+	 * Only set SCF_COMPARE_AND_WRITE_POST to force a response fall-through
+	 * within target_complete_ok_work() if the command was successfully
+	 * sent to the backend driver.
+	 */
+	spin_lock_irq(&cmd->t_state_lock);
+	if ((cmd->transport_state & CMD_T_SENT) && !cmd->scsi_status)
+		cmd->se_cmd_flags |= SCF_COMPARE_AND_WRITE_POST;
+	spin_unlock_irq(&cmd->t_state_lock);
+
+	/*
+	 * Unlock ->caw_sem originally obtained during sbc_compare_and_write()
+	 * before the original READ I/O submission.
+	 */
+	up(&dev->caw_sem);
+
+	return TCM_NO_SENSE;
+}
+
+static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool success)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct scatterlist *write_sg = NULL, *sg;
+	unsigned char *buf = NULL, *addr;
+	struct sg_mapping_iter m;
+	unsigned int offset = 0, len;
+	unsigned int nlbas = cmd->t_task_nolb;
+	unsigned int block_size = dev->dev_attrib.block_size;
+	unsigned int compare_len = (nlbas * block_size);
+	sense_reason_t ret = TCM_NO_SENSE;
+	int rc, i;
+
+	/*
+	 * Handle early failure in transport_generic_request_failure(),
+	 * which will not have taken ->caw_sem yet..
+	 */
+	if (!success && (!cmd->t_data_sg || !cmd->t_bidi_data_sg))
+		return TCM_NO_SENSE;
+	/*
+	 * Handle special case for zero-length COMPARE_AND_WRITE
+	 */
+	if (!cmd->data_length)
+		goto out;
+	/*
+	 * Immediately exit + release dev->caw_sem if command has already
+	 * been failed with a non-zero SCSI status.
+	 */
+	if (cmd->scsi_status) {
+		pr_err("compare_and_write_callback: non zero scsi_status:"
+			" 0x%02x\n", cmd->scsi_status);
+		goto out;
+	}
+
+	buf = kzalloc(cmd->data_length, GFP_KERNEL);
+	if (!buf) {
+		pr_err("Unable to allocate compare_and_write buf\n");
+		ret = TCM_OUT_OF_RESOURCES;
+		goto out;
+	}
+
+	write_sg = kmalloc(sizeof(struct scatterlist) * cmd->t_data_nents,
+			   GFP_KERNEL);
+	if (!write_sg) {
+		pr_err("Unable to allocate compare_and_write sg\n");
+		ret = TCM_OUT_OF_RESOURCES;
+		goto out;
+	}
+	sg_init_table(write_sg, cmd->t_data_nents);
+	/*
+	 * Setup verify and write data payloads from total NumberLBAs.
+	 */
+	rc = sg_copy_to_buffer(cmd->t_data_sg, cmd->t_data_nents, buf,
+			       cmd->data_length);
+	if (!rc) {
+		pr_err("sg_copy_to_buffer() failed for compare_and_write\n");
+		ret = TCM_OUT_OF_RESOURCES;
+		goto out;
+	}
+	/*
+	 * Compare against SCSI READ payload against verify payload
+	 */
+	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, i) {
+		addr = (unsigned char *)kmap_atomic(sg_page(sg));
+		if (!addr) {
+			ret = TCM_OUT_OF_RESOURCES;
+			goto out;
+		}
+
+		len = min(sg->length, compare_len);
+
+		if (memcmp(addr, buf + offset, len)) {
+			pr_warn("Detected MISCOMPARE for addr: %p buf: %p\n",
+				addr, buf + offset);
+			kunmap_atomic(addr);
+			goto miscompare;
+		}
+		kunmap_atomic(addr);
+
+		offset += len;
+		compare_len -= len;
+		if (!compare_len)
+			break;
+	}
+
+	i = 0;
+	len = cmd->t_task_nolb * block_size;
+	sg_miter_start(&m, cmd->t_data_sg, cmd->t_data_nents, SG_MITER_TO_SG);
+	/*
+	 * Currently assumes NoLB=1 and SGLs are PAGE_SIZE..
+	 */
+	while (len) {
+		sg_miter_next(&m);
+
+		if (block_size < PAGE_SIZE) {
+			sg_set_page(&write_sg[i], m.page, block_size,
+				    block_size);
+		} else {
+			sg_miter_next(&m);
+			sg_set_page(&write_sg[i], m.page, block_size,
+				    0);
+		}
+		len -= block_size;
+		i++;
+	}
+	sg_miter_stop(&m);
+	/*
+	 * Save the original SGL + nents values before updating to new
+	 * assignments, to be released in transport_free_pages() ->
+	 * transport_reset_sgl_orig()
+	 */
+	cmd->t_data_sg_orig = cmd->t_data_sg;
+	cmd->t_data_sg = write_sg;
+	cmd->t_data_nents_orig = cmd->t_data_nents;
+	cmd->t_data_nents = 1;
+
+	cmd->sam_task_attr = TCM_HEAD_TAG;
+	cmd->transport_complete_callback = compare_and_write_post;
+	/*
+	 * Now reset ->execute_cmd() to the normal sbc_execute_rw() handler
+	 * for submitting the adjusted SGL to write instance user-data.
+	 */
+	cmd->execute_cmd = sbc_execute_rw;
+
+	spin_lock_irq(&cmd->t_state_lock);
+	cmd->t_state = TRANSPORT_PROCESSING;
+	cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
+	spin_unlock_irq(&cmd->t_state_lock);
+
+	__target_execute_cmd(cmd);
+
+	kfree(buf);
+	return ret;
+
+miscompare:
+	pr_warn("Target/%s: Send MISCOMPARE check condition and sense\n",
+		dev->transport->name);
+	ret = TCM_MISCOMPARE_VERIFY;
+out:
+	/*
+	 * In the MISCOMPARE or failure case, unlock ->caw_sem obtained in
+	 * sbc_compare_and_write() before the original READ I/O submission.
+	 */
+	up(&dev->caw_sem);
+	kfree(write_sg);
+	kfree(buf);
+	return ret;
+}
+
+static sense_reason_t
+sbc_compare_and_write(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	sense_reason_t ret;
+	int rc;
+	/*
+	 * Submit the READ first for COMPARE_AND_WRITE to perform the
+	 * comparision using SGLs at cmd->t_bidi_data_sg..
+	 */
+	rc = down_interruptible(&dev->caw_sem);
+	if (rc != 0) {
+		cmd->transport_complete_callback = NULL;
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+	}
+	/*
+	 * Reset cmd->data_length to individual block_size in order to not
+	 * confuse backend drivers that depend on this value matching the
+	 * size of the I/O being submitted.
+	 */
+	cmd->data_length = cmd->t_task_nolb * dev->dev_attrib.block_size;
+
+	ret = cmd->execute_rw(cmd, cmd->t_bidi_data_sg, cmd->t_bidi_data_nents,
+			      DMA_FROM_DEVICE);
+	if (ret) {
+		cmd->transport_complete_callback = NULL;
+		up(&dev->caw_sem);
+		return ret;
+	}
+	/*
+	 * Unlock of dev->caw_sem to occur in compare_and_write_callback()
+	 * upon MISCOMPARE, or in compare_and_write_done() upon completion
+	 * of WRITE instance user-data.
+	 */
+	return TCM_NO_SENSE;
+}
+
+static int
+sbc_set_prot_op_checks(u8 protect, bool fabric_prot, enum target_prot_type prot_type,
+		       bool is_write, struct se_cmd *cmd)
+{
+	if (is_write) {
+		cmd->prot_op = fabric_prot ? TARGET_PROT_DOUT_STRIP :
+			       protect ? TARGET_PROT_DOUT_PASS :
+			       TARGET_PROT_DOUT_INSERT;
+		switch (protect) {
+		case 0x0:
+		case 0x3:
+			cmd->prot_checks = 0;
+			break;
+		case 0x1:
+		case 0x5:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x2:
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x4:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			break;
+		default:
+			pr_err("Unsupported protect field %d\n", protect);
+			return -EINVAL;
+		}
+	} else {
+		cmd->prot_op = fabric_prot ? TARGET_PROT_DIN_INSERT :
+			       protect ? TARGET_PROT_DIN_PASS :
+			       TARGET_PROT_DIN_STRIP;
+		switch (protect) {
+		case 0x0:
+		case 0x1:
+		case 0x5:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks |= TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x2:
+			if (prot_type == TARGET_DIF_TYPE1_PROT)
+				cmd->prot_checks = TARGET_DIF_CHECK_REFTAG;
+			break;
+		case 0x3:
+			cmd->prot_checks = 0;
+			break;
+		case 0x4:
+			cmd->prot_checks = TARGET_DIF_CHECK_GUARD;
+			break;
+		default:
+			pr_err("Unsupported protect field %d\n", protect);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static sense_reason_t
+sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
+	       u32 sectors, bool is_write)
+{
+	u8 protect = cdb[1] >> 5;
+	int sp_ops = cmd->se_sess->sup_prot_ops;
+	int pi_prot_type = dev->dev_attrib.pi_prot_type;
+	bool fabric_prot = false;
+
+	if (!cmd->t_prot_sg || !cmd->t_prot_nents) {
+		if (unlikely(protect &&
+		    !dev->dev_attrib.pi_prot_type && !cmd->se_sess->sess_prot_type)) {
+			pr_err("CDB contains protect bit, but device + fabric does"
+			       " not advertise PROTECT=1 feature bit\n");
+			return TCM_INVALID_CDB_FIELD;
+		}
+		if (cmd->prot_pto)
+			return TCM_NO_SENSE;
+	}
+
+	switch (dev->dev_attrib.pi_prot_type) {
+	case TARGET_DIF_TYPE3_PROT:
+		cmd->reftag_seed = 0xffffffff;
+		break;
+	case TARGET_DIF_TYPE2_PROT:
+		if (protect)
+			return TCM_INVALID_CDB_FIELD;
+
+		cmd->reftag_seed = cmd->t_task_lba;
+		break;
+	case TARGET_DIF_TYPE1_PROT:
+		cmd->reftag_seed = cmd->t_task_lba;
+		break;
+	case TARGET_DIF_TYPE0_PROT:
+		/*
+		 * See if the fabric supports T10-PI, and the session has been
+		 * configured to allow export PROTECT=1 feature bit with backend
+		 * devices that don't support T10-PI.
+		 */
+		fabric_prot = is_write ?
+			      !!(sp_ops & (TARGET_PROT_DOUT_PASS | TARGET_PROT_DOUT_STRIP)) :
+			      !!(sp_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DIN_INSERT));
+
+		if (fabric_prot && cmd->se_sess->sess_prot_type) {
+			pi_prot_type = cmd->se_sess->sess_prot_type;
+			break;
+		}
+		if (!protect)
+			return TCM_NO_SENSE;
+		/* Fallthrough */
+	default:
+		pr_err("Unable to determine pi_prot_type for CDB: 0x%02x "
+		       "PROTECT: 0x%02x\n", cdb[0], protect);
+		return TCM_INVALID_CDB_FIELD;
+	}
+
+	if (sbc_set_prot_op_checks(protect, fabric_prot, pi_prot_type, is_write, cmd))
+		return TCM_INVALID_CDB_FIELD;
+
+	cmd->prot_type = pi_prot_type;
+	cmd->prot_length = dev->prot_length * sectors;
+
+	/**
+	 * In case protection information exists over the wire
+	 * we modify command data length to describe pure data.
+	 * The actual transfer length is data length + protection
+	 * length
+	 **/
+	if (protect)
+		cmd->data_length = sectors * dev->dev_attrib.block_size;
+
+	pr_debug("%s: prot_type=%d, data_length=%d, prot_length=%d "
+		 "prot_op=%d prot_checks=%d\n",
+		 __func__, cmd->prot_type, cmd->data_length, cmd->prot_length,
+		 cmd->prot_op, cmd->prot_checks);
+
+	return TCM_NO_SENSE;
+}
+
+static int
+sbc_check_dpofua(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb)
+{
+	if (cdb[1] & 0x10) {
+		if (!dev->dev_attrib.emulate_dpo) {
+			pr_err("Got CDB: 0x%02x with DPO bit set, but device"
+			       " does not advertise support for DPO\n", cdb[0]);
+			return -EINVAL;
+		}
+	}
+	if (cdb[1] & 0x8) {
+		if (!dev->dev_attrib.emulate_fua_write || !se_dev_check_wce(dev)) {
+			pr_err("Got CDB: 0x%02x with FUA bit set, but device"
+			       " does not advertise support for FUA write\n",
+			       cdb[0]);
+			return -EINVAL;
+		}
+		cmd->se_cmd_flags |= SCF_FUA;
+	}
+	return 0;
+}
+
+sense_reason_t
+sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
+{
+	struct se_device *dev = cmd->se_dev;
+	unsigned char *cdb = cmd->t_task_cdb;
+	unsigned int size;
+	u32 sectors = 0;
+	sense_reason_t ret;
+
+	switch (cdb[0]) {
+	case READ_6:
+		sectors = transport_get_sectors_6(cdb);
+		cmd->t_task_lba = transport_lba_21(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case READ_10:
+		sectors = transport_get_sectors_10(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
+		if (ret)
+			return ret;
+
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case READ_12:
+		sectors = transport_get_sectors_12(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
+		if (ret)
+			return ret;
+
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case READ_16:
+		sectors = transport_get_sectors_16(cdb);
+		cmd->t_task_lba = transport_lba_64(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, false);
+		if (ret)
+			return ret;
+
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case WRITE_6:
+		sectors = transport_get_sectors_6(cdb);
+		cmd->t_task_lba = transport_lba_21(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case WRITE_10:
+	case WRITE_VERIFY:
+		sectors = transport_get_sectors_10(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, true);
+		if (ret)
+			return ret;
+
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case WRITE_12:
+		sectors = transport_get_sectors_12(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, true);
+		if (ret)
+			return ret;
+
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case WRITE_16:
+		sectors = transport_get_sectors_16(cdb);
+		cmd->t_task_lba = transport_lba_64(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		ret = sbc_check_prot(dev, cmd, cdb, sectors, true);
+		if (ret)
+			return ret;
+
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		break;
+	case XDWRITEREAD_10:
+		if (cmd->data_direction != DMA_TO_DEVICE ||
+		    !(cmd->se_cmd_flags & SCF_BIDI))
+			return TCM_INVALID_CDB_FIELD;
+		sectors = transport_get_sectors_10(cdb);
+
+		if (sbc_check_dpofua(dev, cmd, cdb))
+			return TCM_INVALID_CDB_FIELD;
+
+		cmd->t_task_lba = transport_lba_32(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+
+		/*
+		 * Setup BIDI XOR callback to be run after I/O completion.
+		 */
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_execute_rw;
+		cmd->transport_complete_callback = &xdreadwrite_callback;
+		break;
+	case VARIABLE_LENGTH_CMD:
+	{
+		u16 service_action = get_unaligned_be16(&cdb[8]);
+		switch (service_action) {
+		case XDWRITEREAD_32:
+			sectors = transport_get_sectors_32(cdb);
+
+			if (sbc_check_dpofua(dev, cmd, cdb))
+				return TCM_INVALID_CDB_FIELD;
+			/*
+			 * Use WRITE_32 and READ_32 opcodes for the emulated
+			 * XDWRITE_READ_32 logic.
+			 */
+			cmd->t_task_lba = transport_lba_64_ext(cdb);
+			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+
+			/*
+			 * Setup BIDI XOR callback to be run during after I/O
+			 * completion.
+			 */
+			cmd->execute_rw = ops->execute_rw;
+			cmd->execute_cmd = sbc_execute_rw;
+			cmd->transport_complete_callback = &xdreadwrite_callback;
+			break;
+		case WRITE_SAME_32:
+			sectors = transport_get_sectors_32(cdb);
+			if (!sectors) {
+				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
+				       " supported\n");
+				return TCM_INVALID_CDB_FIELD;
+			}
+
+			size = sbc_get_size(cmd, 1);
+			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
+
+			ret = sbc_setup_write_same(cmd, &cdb[10], ops);
+			if (ret)
+				return ret;
+			break;
+		default:
+			pr_err("VARIABLE_LENGTH_CMD service action"
+				" 0x%04x not supported\n", service_action);
+			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		}
+		break;
+	}
+	case COMPARE_AND_WRITE:
+		sectors = cdb[13];
+		/*
+		 * Currently enforce COMPARE_AND_WRITE for a single sector
+		 */
+		if (sectors > 1) {
+			pr_err("COMPARE_AND_WRITE contains NoLB: %u greater"
+			       " than 1\n", sectors);
+			return TCM_INVALID_CDB_FIELD;
+		}
+		/*
+		 * Double size because we have two buffers, note that
+		 * zero is not an error..
+		 */
+		size = 2 * sbc_get_size(cmd, sectors);
+		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
+		cmd->t_task_nolb = sectors;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB | SCF_COMPARE_AND_WRITE;
+		cmd->execute_rw = ops->execute_rw;
+		cmd->execute_cmd = sbc_compare_and_write;
+		cmd->transport_complete_callback = compare_and_write_callback;
+		break;
+	case READ_CAPACITY:
+		size = READ_CAP_LEN;
+		cmd->execute_cmd = sbc_emulate_readcapacity;
+		break;
+	case SERVICE_ACTION_IN_16:
+		switch (cmd->t_task_cdb[1] & 0x1f) {
+		case SAI_READ_CAPACITY_16:
+			cmd->execute_cmd = sbc_emulate_readcapacity_16;
+			break;
+		case SAI_REPORT_REFERRALS:
+			cmd->execute_cmd = target_emulate_report_referrals;
+			break;
+		default:
+			pr_err("Unsupported SA: 0x%02x\n",
+				cmd->t_task_cdb[1] & 0x1f);
+			return TCM_INVALID_CDB_FIELD;
+		}
+		size = (cdb[10] << 24) | (cdb[11] << 16) |
+		       (cdb[12] << 8) | cdb[13];
+		break;
+	case SYNCHRONIZE_CACHE:
+	case SYNCHRONIZE_CACHE_16:
+		if (cdb[0] == SYNCHRONIZE_CACHE) {
+			sectors = transport_get_sectors_10(cdb);
+			cmd->t_task_lba = transport_lba_32(cdb);
+		} else {
+			sectors = transport_get_sectors_16(cdb);
+			cmd->t_task_lba = transport_lba_64(cdb);
+		}
+		if (ops->execute_sync_cache) {
+			cmd->execute_cmd = ops->execute_sync_cache;
+			goto check_lba;
+		}
+		size = 0;
+		cmd->execute_cmd = sbc_emulate_noop;
+		break;
+	case UNMAP:
+		if (!ops->execute_unmap)
+			return TCM_UNSUPPORTED_SCSI_OPCODE;
+
+		if (!dev->dev_attrib.emulate_tpu) {
+			pr_err("Got UNMAP, but backend device has"
+			       " emulate_tpu disabled\n");
+			return TCM_UNSUPPORTED_SCSI_OPCODE;
+		}
+		size = get_unaligned_be16(&cdb[7]);
+		cmd->execute_cmd = ops->execute_unmap;
+		break;
+	case WRITE_SAME_16:
+		sectors = transport_get_sectors_16(cdb);
+		if (!sectors) {
+			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
+			return TCM_INVALID_CDB_FIELD;
+		}
+
+		size = sbc_get_size(cmd, 1);
+		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
+
+		ret = sbc_setup_write_same(cmd, &cdb[1], ops);
+		if (ret)
+			return ret;
+		break;
+	case WRITE_SAME:
+		sectors = transport_get_sectors_10(cdb);
+		if (!sectors) {
+			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
+			return TCM_INVALID_CDB_FIELD;
+		}
+
+		size = sbc_get_size(cmd, 1);
+		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
+
+		/*
+		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
+		 * of byte 1 bit 3 UNMAP instead of original reserved field
+		 */
+		ret = sbc_setup_write_same(cmd, &cdb[1], ops);
+		if (ret)
+			return ret;
+		break;
+	case VERIFY:
+		size = 0;
+		sectors = transport_get_sectors_10(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+		cmd->execute_cmd = sbc_emulate_noop;
+		goto check_lba;
+	case REZERO_UNIT:
+	case SEEK_6:
+	case SEEK_10:
+		/*
+		 * There are still clients out there which use these old SCSI-2
+		 * commands. This mainly happens when running VMs with legacy
+		 * guest systems, connected via SCSI command pass-through to
+		 * iSCSI targets. Make them happy and return status GOOD.
+		 */
+		size = 0;
+		cmd->execute_cmd = sbc_emulate_noop;
+		break;
+	default:
+		ret = spc_parse_cdb(cmd, &size);
+		if (ret)
+			return ret;
+	}
+
+	/* reject any command that we don't have a handler for */
+	if (!cmd->execute_cmd)
+		return TCM_UNSUPPORTED_SCSI_OPCODE;
+
+	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
+		unsigned long long end_lba;
+check_lba:
+		end_lba = dev->transport->get_blocks(dev) + 1;
+		if (((cmd->t_task_lba + sectors) < cmd->t_task_lba) ||
+		    ((cmd->t_task_lba + sectors) > end_lba)) {
+			pr_err("cmd exceeds last lba %llu "
+				"(lba %llu, sectors %u)\n",
+				end_lba, cmd->t_task_lba, sectors);
+			return TCM_ADDRESS_OUT_OF_RANGE;
+		}
+
+		if (!(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE))
+			size = sbc_get_size(cmd, sectors);
+	}
+
+	return target_cmd_size_check(cmd, size);
+}
+EXPORT_SYMBOL(sbc_parse_cdb);
+
+u32 sbc_get_device_type(struct se_device *dev)
+{
+	return TYPE_DISK;
+}
+EXPORT_SYMBOL(sbc_get_device_type);
+
+sense_reason_t
+sbc_execute_unmap(struct se_cmd *cmd,
+	sense_reason_t (*do_unmap_fn)(struct se_cmd *, void *,
+				      sector_t, sector_t),
+	void *priv)
+{
+	struct se_device *dev = cmd->se_dev;
+	unsigned char *buf, *ptr = NULL;
+	sector_t lba;
+	int size;
+	u32 range;
+	sense_reason_t ret = 0;
+	int dl, bd_dl;
+
+	/* We never set ANC_SUP */
+	if (cmd->t_task_cdb[1])
+		return TCM_INVALID_CDB_FIELD;
+
+	if (cmd->data_length == 0) {
+		target_complete_cmd(cmd, SAM_STAT_GOOD);
+		return 0;
+	}
+
+	if (cmd->data_length < 8) {
+		pr_warn("UNMAP parameter list length %u too small\n",
+			cmd->data_length);
+		return TCM_PARAMETER_LIST_LENGTH_ERROR;
+	}
+
+	buf = transport_kmap_data_sg(cmd);
+	if (!buf)
+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+	dl = get_unaligned_be16(&buf[0]);
+	bd_dl = get_unaligned_be16(&buf[2]);
+
+	size = cmd->data_length - 8;
+	if (bd_dl > size)
+		pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
+			cmd->data_length, bd_dl);
+	else
+		size = bd_dl;
+
+	if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
+		ret = TCM_INVALID_PARAMETER_LIST;
+		goto err;
+	}
+
+	/* First UNMAP block descriptor starts at 8 byte offset */
+	ptr = &buf[8];
+	pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
+		" ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
+
+	while (size >= 16) {
+		lba = get_unaligned_be64(&ptr[0]);
+		range = get_unaligned_be32(&ptr[8]);
+		pr_debug("UNMAP: Using lba: %llu and range: %u\n",
+				 (unsigned long long)lba, range);
+
+		if (range > dev->dev_attrib.max_unmap_lba_count) {
+			ret = TCM_INVALID_PARAMETER_LIST;
+			goto err;
+		}
+
+		if (lba + range > dev->transport->get_blocks(dev) + 1) {
+			ret = TCM_ADDRESS_OUT_OF_RANGE;
+			goto err;
+		}
+
+		ret = do_unmap_fn(cmd, priv, lba, range);
+		if (ret)
+			goto err;
+
+		ptr += 16;
+		size -= 16;
+	}
+
+err:
+	transport_kunmap_data_sg(cmd);
+	if (!ret)
+		target_complete_cmd(cmd, GOOD);
+	return ret;
+}
+EXPORT_SYMBOL(sbc_execute_unmap);
+
+void
+sbc_dif_generate(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct se_dif_v1_tuple *sdt;
+	struct scatterlist *dsg, *psg = cmd->t_prot_sg;
+	sector_t sector = cmd->t_task_lba;
+	void *daddr, *paddr;
+	int i, j, offset = 0;
+
+	for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
+		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
+		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+
+		for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
+
+			if (offset >= psg->length) {
+				kunmap_atomic(paddr);
+				psg = sg_next(psg);
+				paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+				offset = 0;
+			}
+
+			sdt = paddr + offset;
+			sdt->guard_tag = cpu_to_be16(crc_t10dif(daddr + j,
+						dev->dev_attrib.block_size));
+			if (cmd->prot_type == TARGET_DIF_TYPE1_PROT)
+				sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
+			sdt->app_tag = 0;
+
+			pr_debug("DIF %s INSERT sector: %llu guard_tag: 0x%04x"
+				 " app_tag: 0x%04x ref_tag: %u\n",
+				 (cmd->data_direction == DMA_TO_DEVICE) ?
+				 "WRITE" : "READ", (unsigned long long)sector,
+				 sdt->guard_tag, sdt->app_tag,
+				 be32_to_cpu(sdt->ref_tag));
+
+			sector++;
+			offset += sizeof(struct se_dif_v1_tuple);
+		}
+
+		kunmap_atomic(paddr);
+		kunmap_atomic(daddr);
+	}
+}
+
+static sense_reason_t
+sbc_dif_v1_verify(struct se_cmd *cmd, struct se_dif_v1_tuple *sdt,
+		  const void *p, sector_t sector, unsigned int ei_lba)
+{
+	struct se_device *dev = cmd->se_dev;
+	int block_size = dev->dev_attrib.block_size;
+	__be16 csum;
+
+	if (!(cmd->prot_checks & TARGET_DIF_CHECK_GUARD))
+		goto check_ref;
+
+	csum = cpu_to_be16(crc_t10dif(p, block_size));
+
+	if (sdt->guard_tag != csum) {
+		pr_err("DIFv1 checksum failed on sector %llu guard tag 0x%04x"
+			" csum 0x%04x\n", (unsigned long long)sector,
+			be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
+		return TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED;
+	}
+
+check_ref:
+	if (!(cmd->prot_checks & TARGET_DIF_CHECK_REFTAG))
+		return 0;
+
+	if (cmd->prot_type == TARGET_DIF_TYPE1_PROT &&
+	    be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
+		pr_err("DIFv1 Type 1 reference failed on sector: %llu tag: 0x%08x"
+		       " sector MSB: 0x%08x\n", (unsigned long long)sector,
+		       be32_to_cpu(sdt->ref_tag), (u32)(sector & 0xffffffff));
+		return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
+	}
+
+	if (cmd->prot_type == TARGET_DIF_TYPE2_PROT &&
+	    be32_to_cpu(sdt->ref_tag) != ei_lba) {
+		pr_err("DIFv1 Type 2 reference failed on sector: %llu tag: 0x%08x"
+		       " ei_lba: 0x%08x\n", (unsigned long long)sector,
+			be32_to_cpu(sdt->ref_tag), ei_lba);
+		return TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
+	}
+
+	return 0;
+}
+
+static void
+sbc_dif_copy_prot(struct se_cmd *cmd, unsigned int sectors, bool read,
+		  struct scatterlist *sg, int sg_off)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct scatterlist *psg;
+	void *paddr, *addr;
+	unsigned int i, len, left;
+	unsigned int offset = sg_off;
+
+	if (!sg)
+		return;
+
+	left = sectors * dev->prot_length;
+
+	for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) {
+		unsigned int psg_len, copied = 0;
+
+		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+		psg_len = min(left, psg->length);
+		while (psg_len) {
+			len = min(psg_len, sg->length - offset);
+			addr = kmap_atomic(sg_page(sg)) + sg->offset + offset;
+
+			if (read)
+				memcpy(paddr + copied, addr, len);
+			else
+				memcpy(addr, paddr + copied, len);
+
+			left -= len;
+			offset += len;
+			copied += len;
+			psg_len -= len;
+
+			if (offset >= sg->length) {
+				sg = sg_next(sg);
+				offset = 0;
+			}
+			kunmap_atomic(addr);
+		}
+		kunmap_atomic(paddr);
+	}
+}
+
+sense_reason_t
+sbc_dif_verify_write(struct se_cmd *cmd, sector_t start, unsigned int sectors,
+		     unsigned int ei_lba, struct scatterlist *sg, int sg_off)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct se_dif_v1_tuple *sdt;
+	struct scatterlist *dsg, *psg = cmd->t_prot_sg;
+	sector_t sector = start;
+	void *daddr, *paddr;
+	int i, j, offset = 0;
+	sense_reason_t rc;
+
+	for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
+		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
+		paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+
+		for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
+
+			if (offset >= psg->length) {
+				kunmap_atomic(paddr);
+				psg = sg_next(psg);
+				paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+				offset = 0;
+			}
+
+			sdt = paddr + offset;
+
+			pr_debug("DIF WRITE sector: %llu guard_tag: 0x%04x"
+				 " app_tag: 0x%04x ref_tag: %u\n",
+				 (unsigned long long)sector, sdt->guard_tag,
+				 sdt->app_tag, be32_to_cpu(sdt->ref_tag));
+
+			rc = sbc_dif_v1_verify(cmd, sdt, daddr + j, sector,
+					       ei_lba);
+			if (rc) {
+				kunmap_atomic(paddr);
+				kunmap_atomic(daddr);
+				cmd->bad_sector = sector;
+				return rc;
+			}
+
+			sector++;
+			ei_lba++;
+			offset += sizeof(struct se_dif_v1_tuple);
+		}
+
+		kunmap_atomic(paddr);
+		kunmap_atomic(daddr);
+	}
+	if (!sg)
+		return 0;
+
+	sbc_dif_copy_prot(cmd, sectors, false, sg, sg_off);
+
+	return 0;
+}
+EXPORT_SYMBOL(sbc_dif_verify_write);
+
+static sense_reason_t
+__sbc_dif_verify_read(struct se_cmd *cmd, sector_t start, unsigned int sectors,
+		      unsigned int ei_lba, struct scatterlist *sg, int sg_off)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct se_dif_v1_tuple *sdt;
+	struct scatterlist *dsg, *psg = sg;
+	sector_t sector = start;
+	void *daddr, *paddr;
+	int i, j, offset = sg_off;
+	sense_reason_t rc;
+
+	for_each_sg(cmd->t_data_sg, dsg, cmd->t_data_nents, i) {
+		daddr = kmap_atomic(sg_page(dsg)) + dsg->offset;
+		paddr = kmap_atomic(sg_page(psg)) + sg->offset;
+
+		for (j = 0; j < dsg->length; j += dev->dev_attrib.block_size) {
+
+			if (offset >= psg->length) {
+				kunmap_atomic(paddr);
+				psg = sg_next(psg);
+				paddr = kmap_atomic(sg_page(psg)) + psg->offset;
+				offset = 0;
+			}
+
+			sdt = paddr + offset;
+
+			pr_debug("DIF READ sector: %llu guard_tag: 0x%04x"
+				 " app_tag: 0x%04x ref_tag: %u\n",
+				 (unsigned long long)sector, sdt->guard_tag,
+				 sdt->app_tag, be32_to_cpu(sdt->ref_tag));
+
+			if (sdt->app_tag == cpu_to_be16(0xffff)) {
+				sector++;
+				offset += sizeof(struct se_dif_v1_tuple);
+				continue;
+			}
+
+			rc = sbc_dif_v1_verify(cmd, sdt, daddr + j, sector,
+					       ei_lba);
+			if (rc) {
+				kunmap_atomic(paddr);
+				kunmap_atomic(daddr);
+				cmd->bad_sector = sector;
+				return rc;
+			}
+
+			sector++;
+			ei_lba++;
+			offset += sizeof(struct se_dif_v1_tuple);
+		}
+
+		kunmap_atomic(paddr);
+		kunmap_atomic(daddr);
+	}
+
+	return 0;
+}
+
+sense_reason_t
+sbc_dif_read_strip(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	u32 sectors = cmd->prot_length / dev->prot_length;
+
+	return __sbc_dif_verify_read(cmd, cmd->t_task_lba, sectors, 0,
+				     cmd->t_prot_sg, 0);
+}
+
+sense_reason_t
+sbc_dif_verify_read(struct se_cmd *cmd, sector_t start, unsigned int sectors,
+		    unsigned int ei_lba, struct scatterlist *sg, int sg_off)
+{
+	sense_reason_t rc;
+
+	rc = __sbc_dif_verify_read(cmd, start, sectors, ei_lba, sg, sg_off);
+	if (rc)
+		return rc;
+
+	sbc_dif_copy_prot(cmd, sectors, true, sg, sg_off);
+	return 0;
+}
+EXPORT_SYMBOL(sbc_dif_verify_read);