[PATCH v2 1/2] nvme_fc: correct io termination handling

[jsmart2021@gmail.com (James Smart)]

The io completion handling for i/o's that are failing due to
to a transport error or association termination had issues, causing
io failures (DNR set so retries didn't kick in) or long stalls.

Change the io completion handler for the following items:

When an io has been completed due to a transport abort (based on an
exchange error) or when marked as aborted as part of an association
termination (FCOP_FLAGS_TERMIO), set the NVME completion status to
NVME_SC_ABORTED. By default, do not set DNR on the status so that a
retry can be attempted after association recreate.

In cases where an io is failed (non-successful nvme status including
aborted), if the controller is being deleted (blk_queue_dying) or
the io was part of the ios used for association creation (ctrl state
is NEW or RECONNECTING), then additionally set the DNR bit so the io
will not be retried. If the failed io was part of association creation,
the failure will tear down the partially completioned association and
typically restart a new reconnect attempt (another create association
later).

Rearranged code flow to remove a largely unneeded local variable.

Signed-off-by: James Smart <james.smart at broadcom.com>
---
 drivers/nvme/host/fc.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 18e036c6833b..ce8617188d3a 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1387,7 +1387,7 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
 	struct nvme_command *sqe = &op->cmd_iu.sqe;
 	__le16 status = cpu_to_le16(NVME_SC_SUCCESS << 1);
 	union nvme_result result;
-	bool complete_rq, terminate_assoc = true;
+	bool terminate_assoc = true;
 
 	/*
 	 * WARNING:
@@ -1429,8 +1429,9 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
 	fc_dma_sync_single_for_cpu(ctrl->lport->dev, op->fcp_req.rspdma,
 				sizeof(op->rsp_iu), DMA_FROM_DEVICE);
 
-	if (atomic_read(&op->state) == FCPOP_STATE_ABORTED)
-		status = cpu_to_le16((NVME_SC_ABORT_REQ | NVME_SC_DNR) << 1);
+	if (atomic_read(&op->state) == FCPOP_STATE_ABORTED ||
+			op->flags & FCOP_FLAGS_TERMIO)
+		status = cpu_to_le16(NVME_SC_ABORT_REQ << 1);
 	else if (freq->status)
 		status = cpu_to_le16(NVME_SC_INTERNAL << 1);
 
@@ -1494,23 +1495,27 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req *req)
 done:
 	if (op->flags & FCOP_FLAGS_AEN) {
 		nvme_complete_async_event(&queue->ctrl->ctrl, status, &result);
-		complete_rq = __nvme_fc_fcpop_chk_teardowns(ctrl, op);
+		__nvme_fc_fcpop_chk_teardowns(ctrl, op);
 		atomic_set(&op->state, FCPOP_STATE_IDLE);
 		op->flags = FCOP_FLAGS_AEN;	/* clear other flags */
 		nvme_fc_ctrl_put(ctrl);
 		goto check_error;
 	}
 
-	complete_rq = __nvme_fc_fcpop_chk_teardowns(ctrl, op);
-	if (!complete_rq) {
-		if (unlikely(op->flags & FCOP_FLAGS_TERMIO)) {
-			status = cpu_to_le16(NVME_SC_ABORT_REQ << 1);
-			if (blk_queue_dying(rq->q))
-				status |= cpu_to_le16(NVME_SC_DNR << 1);
-		}
-		nvme_end_request(rq, status, result);
-	} else
+	/*
+	 * Force failures of commands if we're killing the controller
+	 * or have an error on a command used to create an new association
+	 */
+	if (status &&
+	    (blk_queue_dying(rq->q) ||
+	     ctrl->ctrl.state == NVME_CTRL_NEW ||
+	     ctrl->ctrl.state == NVME_CTRL_RECONNECTING))
+		status |= cpu_to_le16(NVME_SC_DNR << 1);
+
+	if (__nvme_fc_fcpop_chk_teardowns(ctrl, op))
 		__nvme_fc_final_op_cleanup(rq);
+	else
+		nvme_end_request(rq, status, result);
 
 check_error:
 	if (terminate_assoc)
-- 
2.13.1