TARGET/sbc,loopback: Adjust command data length in case pi exists on the wire

In various areas of the code, it is assumed that
se_cmd->data_length describes pure data. In case
that protection information exists over the wire
(protect bits is are on) the target core re-calculates
the data length from the CDB and the backed device
block size (instead of each transport peeking in the cdb).

Modify loopback device to include protection information
in the transferred data length (like other scsi transports).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.15+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index c886ad1c39fb357ddb6e72a384474bdc89b01278..1f4c015e90786937423e7c86bd3638c013f6dacd 100644 (file)
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -179,7 +179,7 @@ static void tcm_loop_submission_work(struct work_struct *work)
        struct tcm_loop_hba *tl_hba;
        struct tcm_loop_tpg *tl_tpg;
        struct scatterlist *sgl_bidi = NULL;
-       u32 sgl_bidi_count = 0;
+       u32 sgl_bidi_count = 0, transfer_length;
        int rc;
 
        tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
@@ -213,12 +213,21 @@ static void tcm_loop_submission_work(struct work_struct *work)
 
        }
 
-       if (!scsi_prot_sg_count(sc) && scsi_get_prot_op(sc) != SCSI_PROT_NORMAL)
+       transfer_length = scsi_transfer_length(sc);
+       if (!scsi_prot_sg_count(sc) &&
+           scsi_get_prot_op(sc) != SCSI_PROT_NORMAL) {
                se_cmd->prot_pto = true;
+               /*
+                * loopback transport doesn't support
+                * WRITE_GENERATE, READ_STRIP protection
+                * information operations, go ahead unprotected.
+                */
+               transfer_length = scsi_bufflen(sc);
+       }
 
        rc = target_submit_cmd_map_sgls(se_cmd, tl_nexus->se_sess, sc->cmnd,
                        &tl_cmd->tl_sense_buf[0], tl_cmd->sc->device->lun,
-                       scsi_bufflen(sc), tcm_loop_sam_attr(sc),
+                       transfer_length, tcm_loop_sam_attr(sc),
                        sc->sc_data_direction, 0,
                        scsi_sglist(sc), scsi_sg_count(sc),
                        sgl_bidi, sgl_bidi_count,

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 1d3a626bf24fc71a8c175d7a4164c3dbac7e5528..bd78d9235ac645678aeaacc3a564c1c4c13c5742 100644 (file)
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -647,8 +647,19 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
 
        cmd->prot_type = dev->dev_attrib.pi_prot_type;
        cmd->prot_length = dev->prot_length * sectors;
-       pr_debug("%s: prot_type=%d, prot_length=%d prot_op=%d prot_checks=%d\n",
-                __func__, cmd->prot_type, cmd->prot_length,
+
+       /**
+        * 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;