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path: root/drivers/target/target_core_sbc.c
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Diffstat (limited to 'drivers/target/target_core_sbc.c')
-rw-r--r--drivers/target/target_core_sbc.c463
1 files changed, 419 insertions, 44 deletions
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 52ae54e6010..bd78d9235ac 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -23,6 +23,7 @@
#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>
@@ -33,7 +34,7 @@
#include "target_core_internal.h"
#include "target_core_ua.h"
-
+#include "target_core_alua.h"
static sense_reason_t
sbc_emulate_readcapacity(struct se_cmd *cmd)
@@ -80,7 +81,7 @@ sbc_emulate_readcapacity(struct se_cmd *cmd)
transport_kunmap_data_sg(cmd);
}
- target_complete_cmd(cmd, GOOD);
+ target_complete_cmd_with_length(cmd, GOOD, 8);
return 0;
}
@@ -88,6 +89,7 @@ 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;
unsigned char *rbuf;
unsigned char buf[32];
unsigned long long blocks = dev->transport->get_blocks(dev);
@@ -105,6 +107,13 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
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)) {
+ if (dev->dev_attrib.pi_prot_type)
+ buf[12] = (dev->dev_attrib.pi_prot_type - 1) << 1 | 0x1;
+ }
if (dev->transport->get_lbppbe)
buf[13] = dev->transport->get_lbppbe(dev) & 0x0f;
@@ -128,7 +137,7 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
transport_kunmap_data_sg(cmd);
}
- target_complete_cmd(cmd, GOOD);
+ target_complete_cmd_with_length(cmd, GOOD, 32);
return 0;
}
@@ -167,24 +176,6 @@ static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
return cmd->se_dev->dev_attrib.block_size * sectors;
}
-static int sbc_check_valid_sectors(struct se_cmd *cmd)
-{
- struct se_device *dev = cmd->se_dev;
- unsigned long long end_lba;
- u32 sectors;
-
- sectors = cmd->data_length / dev->dev_attrib.block_size;
- end_lba = dev->transport->get_blocks(dev) + 1;
-
- if (cmd->t_task_lba + sectors > end_lba) {
- pr_err("target: lba %llu, sectors %u exceeds end lba %llu\n",
- cmd->t_task_lba, sectors, end_lba);
- return -EINVAL;
- }
-
- return 0;
-}
-
static inline u32 transport_get_sectors_6(unsigned char *cdb)
{
/*
@@ -419,13 +410,14 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd)
goto out;
}
- write_sg = kzalloc(sizeof(struct scatterlist) * cmd->t_data_nents,
+ 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.
*/
@@ -563,6 +555,116 @@ sbc_compare_and_write(struct se_cmd *cmd)
return TCM_NO_SENSE;
}
+static int
+sbc_set_prot_op_checks(u8 protect, enum target_prot_type prot_type,
+ bool is_write, struct se_cmd *cmd)
+{
+ if (is_write) {
+ cmd->prot_op = 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 = 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 bool
+sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
+ u32 sectors, bool is_write)
+{
+ u8 protect = cdb[1] >> 5;
+
+ if ((!cmd->t_prot_sg || !cmd->t_prot_nents) && cmd->prot_pto)
+ return true;
+
+ 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 false;
+
+ 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:
+ default:
+ return true;
+ }
+
+ if (sbc_set_prot_op_checks(protect, dev->dev_attrib.pi_prot_type,
+ is_write, cmd))
+ return false;
+
+ cmd->prot_type = dev->dev_attrib.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 true;
+}
+
sense_reason_t
sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
{
@@ -583,6 +685,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case READ_10:
sectors = transport_get_sectors_10(cdb);
cmd->t_task_lba = transport_lba_32(cdb);
+
+ if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
@@ -590,6 +696,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case READ_12:
sectors = transport_get_sectors_12(cdb);
cmd->t_task_lba = transport_lba_32(cdb);
+
+ if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
@@ -597,6 +707,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case READ_16:
sectors = transport_get_sectors_16(cdb);
cmd->t_task_lba = transport_lba_64(cdb);
+
+ if (!sbc_check_prot(dev, cmd, cdb, sectors, false))
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
cmd->execute_rw = ops->execute_rw;
cmd->execute_cmd = sbc_execute_rw;
@@ -612,6 +726,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case WRITE_VERIFY:
sectors = transport_get_sectors_10(cdb);
cmd->t_task_lba = transport_lba_32(cdb);
+
+ if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+
if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
@@ -621,6 +739,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case WRITE_12:
sectors = transport_get_sectors_12(cdb);
cmd->t_task_lba = transport_lba_32(cdb);
+
+ if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+
if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
@@ -630,6 +752,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
case WRITE_16:
sectors = transport_get_sectors_16(cdb);
cmd->t_task_lba = transport_lba_64(cdb);
+
+ if (!sbc_check_prot(dev, cmd, cdb, sectors, true))
+ return TCM_UNSUPPORTED_SCSI_OPCODE;
+
if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
@@ -731,6 +857,9 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
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);
@@ -741,15 +870,6 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
break;
case SYNCHRONIZE_CACHE:
case SYNCHRONIZE_CACHE_16:
- if (!ops->execute_sync_cache) {
- size = 0;
- cmd->execute_cmd = sbc_emulate_noop;
- break;
- }
-
- /*
- * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
- */
if (cdb[0] == SYNCHRONIZE_CACHE) {
sectors = transport_get_sectors_10(cdb);
cmd->t_task_lba = transport_lba_32(cdb);
@@ -757,18 +877,12 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
sectors = transport_get_sectors_16(cdb);
cmd->t_task_lba = transport_lba_64(cdb);
}
-
- size = sbc_get_size(cmd, sectors);
-
- /*
- * Check to ensure that LBA + Range does not exceed past end of
- * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
- */
- if (cmd->t_task_lba || sectors) {
- if (sbc_check_valid_sectors(cmd) < 0)
- return TCM_ADDRESS_OUT_OF_RANGE;
+ if (ops->execute_sync_cache) {
+ cmd->execute_cmd = ops->execute_sync_cache;
+ goto check_lba;
}
- cmd->execute_cmd = ops->execute_sync_cache;
+ size = 0;
+ cmd->execute_cmd = sbc_emulate_noop;
break;
case UNMAP:
if (!ops->execute_unmap)
@@ -811,8 +925,10 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
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;
- break;
+ goto check_lba;
case REZERO_UNIT:
case SEEK_6:
case SEEK_10:
@@ -852,7 +968,7 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
dev->dev_attrib.hw_max_sectors);
return TCM_INVALID_CDB_FIELD;
}
-
+check_lba:
end_lba = dev->transport->get_blocks(dev) + 1;
if (cmd->t_task_lba + sectors > end_lba) {
pr_err("cmd exceeds last lba %llu "
@@ -959,3 +1075,262 @@ err:
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 (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT)
+ sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
+ sdt->app_tag = 0;
+
+ pr_debug("DIF WRITE INSERT 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));
+
+ sector++;
+ offset += sizeof(struct se_dif_v1_tuple);
+ }
+
+ kunmap_atomic(paddr);
+ kunmap_atomic(daddr);
+ }
+}
+
+static sense_reason_t
+sbc_dif_v1_verify(struct se_device *dev, struct se_dif_v1_tuple *sdt,
+ const void *p, sector_t sector, unsigned int ei_lba)
+{
+ int block_size = dev->dev_attrib.block_size;
+ __be16 csum;
+
+ 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;
+ }
+
+ if (dev->dev_attrib.pi_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 (dev->dev_attrib.pi_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;
+
+ 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(dev, 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);
+ }
+ 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(dev, 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);