target/sbc: Add sbc_dif_read_strip software emulation

Split up __sbc_dif_verify_read() so that VERIFY READ emulation can
perform target-core specific READ_STRIP, seperate from the existing
FILEIO/RAMDISK backend emulation code.

Also add sbc_dif_read_strip() in order to determine number of sectors
using cmd->prot_length, and skip the extra sbc_dif_copy_prot().

Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 28 insertions, 4 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index cc8c0ba53930..e0229592ec55 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -1271,9 +1271,9 @@ sbc_dif_verify_write(struct se_cmd *cmd, sector_t start, unsigned int sectors,
 }
 EXPORT_SYMBOL(sbc_dif_verify_write);
 
-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)
+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;
@@ -1326,8 +1326,31 @@ sbc_dif_verify_read(struct se_cmd *cmd, sector_t start, unsigned int sectors,
                 kunmap_atomic(paddr);
                 kunmap_atomic(daddr);
         }
-        sbc_dif_copy_prot(cmd, sectors, true, sg, sg_off);
 
         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);
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 0a36c6cb93b2..3a1c1eea1fff 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -78,6 +78,7 @@ sense_reason_t	sbc_dif_verify_write(struct se_cmd *, sector_t, unsigned int,
                                      unsigned int, struct scatterlist *, int);
 sense_reason_t  sbc_dif_verify_read(struct se_cmd *, sector_t, unsigned int,
                                     unsigned int, struct scatterlist *, int);
+sense_reason_t  sbc_dif_read_strip(struct se_cmd *);
 
 void    transport_set_vpd_proto_id(struct t10_vpd *, unsigned char *);
 int     transport_set_vpd_assoc(struct t10_vpd *, unsigned char *);