target: Enable READ_STRIP emulation in target_complete_ok_work

This patch enables the use of READ_STRIP software emulation in
target_complete_ok_work() code for I/O READs.

This is useful when the fabric does not support READ_STRIP hardware
offload, but would still like to interact with backend device
that have T10 PI enabled.

v2 changes:
   - Move TARGET_PROT_DIN_STRIP check from target_check_read_strip()
     into target_complete_ok_work() (Sagi)

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Sagi Grimberg <sagig@mellanox.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>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index a7a4ef2d589e..d4b98690a736 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1905,6 +1905,21 @@ static void transport_handle_queue_full(
         schedule_work(&cmd->se_dev->qf_work_queue);
 }
 
+static bool target_check_read_strip(struct se_cmd *cmd)
+{
+        sense_reason_t rc;
+
+        if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
+                rc = sbc_dif_read_strip(cmd);
+                if (rc) {
+                        cmd->pi_err = rc;
+                        return true;
+                }
+        }
+
+        return false;
+}
+
 static void target_complete_ok_work(struct work_struct *work)
 {
         struct se_cmd *cmd = container_of(work, struct se_cmd, work);
@@ -1969,6 +1984,22 @@ static void target_complete_ok_work(struct work_struct *work)
                                         cmd->data_length;
                 }
                 spin_unlock(&cmd->se_lun->lun_sep_lock);
+                /*
+                 * Perform READ_STRIP of PI using software emulation when
+                 * backend had PI enabled, if the transport will not be
+                 * performing hardware READ_STRIP offload.
+                 */
+                if (cmd->prot_op == TARGET_PROT_DIN_STRIP &&
+                    target_check_read_strip(cmd)) {
+                        ret = transport_send_check_condition_and_sense(cmd,
+                                                cmd->pi_err, 0);
+                        if (ret == -EAGAIN || ret == -ENOMEM)
+                                goto queue_full;
+
+                        transport_lun_remove_cmd(cmd);
+                        transport_cmd_check_stop_to_fabric(cmd);
+                        return;
+                }
 
                 trace_target_cmd_complete(cmd);
                 ret = cmd->se_tfo->queue_data_in(cmd);