isci: Add decode for SMP request retry error condition

There are situations with slow expanders in which a first attempt
to execute an SMP request will fail with a timeout.  Immediate
subsequent retries will generally succeed.  This change makes sure
SMP I/O failures are immediately failed to libsas so that retries
happen with no discovery process timeout delay.

Signed-off-by: Jeff Skirvin <jeffrey.d.skirvin@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 52 insertions, 10 deletions

diff --git a/drivers/scsi/isci/request.c b/drivers/scsi/isci/request.c
index 8bd1f7dbad37..3a891d32c331 100644
--- a/drivers/scsi/isci/request.c
+++ b/drivers/scsi/isci/request.c
@@ -2508,9 +2508,16 @@ static void isci_request_handle_controller_specific_errors(
                 /* Task in the target is not done. */
                 *response_ptr = SAS_TASK_UNDELIVERED;
                 *status_ptr = SAM_STAT_TASK_ABORTED;
-                request->complete_in_target = false;
 
-                *complete_to_host_ptr = isci_perform_error_io_completion;
+                if (task->task_proto == SAS_PROTOCOL_SMP) {
+                        request->complete_in_target = true;
+
+                        *complete_to_host_ptr = isci_perform_normal_io_completion;
+                } else {
+                        request->complete_in_target = false;
+
+                        *complete_to_host_ptr = isci_perform_error_io_completion;
+                }
                 break;
         }
 }
@@ -2882,6 +2889,21 @@ static void isci_request_io_request_complete(struct isci_host *isci_host,
                         request->complete_in_target = false;
                         break;
 
+                case SCI_FAILURE_RETRY_REQUIRED:
+
+                        /* Fail the I/O so it can be retried. */
+                        response = SAS_TASK_UNDELIVERED;
+                        if ((isci_device->status == isci_stopping) ||
+                            (isci_device->status == isci_stopped))
+                                status = SAS_DEVICE_UNKNOWN;
+                        else
+                                status = SAS_ABORTED_TASK;
+
+                        complete_to_host = isci_perform_normal_io_completion;
+                        request->complete_in_target = true;
+                        break;
+
+
                 default:
                         /* Catch any otherwise unhandled error codes here. */
                         dev_warn(&isci_host->pdev->dev,
@@ -2901,8 +2923,13 @@ static void isci_request_io_request_complete(struct isci_host *isci_host,
                         else
                                 status = SAS_ABORTED_TASK;
 
-                        complete_to_host = isci_perform_error_io_completion;
-                        request->complete_in_target = false;
+                        if (SAS_PROTOCOL_SMP == task->task_proto) {
+                                request->complete_in_target = true;
+                                complete_to_host = isci_perform_normal_io_completion;
+                        } else {
+                                request->complete_in_target = false;
+                                complete_to_host = isci_perform_error_io_completion;
+                        }
                         break;
                 }
                 break;
diff --git a/drivers/scsi/isci/task.h b/drivers/scsi/isci/task.h
index 432b81aecd47..c8dd075d2be2 100644
--- a/drivers/scsi/isci/task.h
+++ b/drivers/scsi/isci/task.h
@@ -301,6 +301,27 @@ isci_task_set_completion_status(
         task->task_status.stat = status;
 
         switch (task_notification_selection) {
+
+        case isci_perform_error_io_completion:
+
+                if (task->task_proto == SAS_PROTOCOL_SMP) {
+                        /* There is no error escalation in the SMP case.
+                         * Convert to a normal completion to avoid the
+                         * timeout in the discovery path and to let the
+                         * next action take place quickly.
+                         */
+                        task_notification_selection
+                                = isci_perform_normal_io_completion;
+
+                        /* Fall through to the normal case... */
+                } else {
+                        /* Use sas_task_abort */
+                        /* Leave SAS_TASK_STATE_DONE clear
+                         * Leave SAS_TASK_AT_INITIATOR set.
+                         */
+                        break;
+                }
+
         case isci_perform_aborted_io_completion:
                 /* This path can occur with task-managed requests as well as
                  * requests terminated because of LUN or device resets.
@@ -313,12 +334,6 @@ isci_task_set_completion_status(
         default:
                 WARN_ONCE(1, "unknown task_notification_selection: %d\n",
                          task_notification_selection);
-                /* Fall through to the error case... */
-        case isci_perform_error_io_completion:
-                /* Use sas_task_abort */
-                /* Leave SAS_TASK_STATE_DONE clear
-                 * Leave SAS_TASK_AT_INITIATOR set.
-                 */
                 break;
         }