[PATCH v2 03/20] scsi: ibmvfc: complete NVMe FCP requests on H_CLOSED send failure

[Tyrel Datwyler]

When ibmvfc_send_event() returns H_CLOSED the event is freed without
notifying the NVMe-FC transport. The caller ibmvfc_nvme_fcp_io() returns
SCSI_MLQUEUE_HOST_BUSY back to the transport, which is a SCSI midlayer
concept the NVMe-FC transport does not interpret. The result is that the
NVMe-FC transport is left waiting on a request that was silently dropped,
causing the I/O to hang permanently.

Fix this by calling fcp_req->done() with a -EBUSY status before freeing
the event in the H_CLOSED path, consistent with how other FC-NVMe LLDDs
(e.g. lpfc) signal a retryable transport-level failure to the NVMe-FC
transport.

Fixes: 73c13e30c56f ("scsi: ibmvfc: implement nvme-fc IO command submission callback")
Signed-off-by: Tyrel Datwyler <tyreld@xxxxxxxxxxxxx>
---
 drivers/scsi/ibmvscsi/ibmvfc-nvme.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc-nvme.c b/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
index 9ed6522c2e9e..08dd897b8e64 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
@@ -367,8 +367,12 @@ static int ibmvfc_nvme_fcp_io(struct nvme_fc_local_port *lport,
 
 	vfc_cmd->correlation = cpu_to_be64((u64)evt);
 
-	if (likely(!(rc = ibmvfc_nvme_map_sg_data(fcp_req, evt, vfc_cmd))))
-		return ibmvfc_send_event(evt, vhost, 0);
+	if (likely(!(rc = ibmvfc_nvme_map_sg_data(fcp_req, evt, vfc_cmd)))) {
+		rc = ibmvfc_send_event(evt, vhost, 0);
+		if (rc)
+			return -EBUSY;
+		return 0;
+	}
 
 	ibmvfc_free_event(evt);
 
-- 
2.55.0