scsi: lpfc: Fix driver not recovering NVME rports during target link faults

During target-side port faults, the driver would not recover all target
port logins. This resulted in a loss of nvme device discovery.

The driver is coded to wait for all GID_FT requests to complete before
restarting discovery. A fault is seen where the outstanding GIT_FT
counts are not properly decremented, thus discovery would never
start. Another fault was found in the clearing of the gidft_inp counter
that would be skipped in this condition. And a third fault found with
lpfc_nvme_register_port that would remove a reverence on the ndlp which
then allows a node swap on a port address change to prematurely remove
the reference and release the ndlp.

The following changes are made:

 - Correct the decrementing of the outstanding GID_FT counters.

 - In RSCN handling, no longer zero the counter before calling to issue
   another GID_FT.

 - No longer remove the reference on the dlp when the ndlp->nrport value
   is not yet null.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/scsi/lpfc/lpfc_nvme.c b/drivers/scsi/lpfc/lpfc_nvme.c
index 1cb2c634e9f7..22962b08c275 100644
--- a/drivers/scsi/lpfc/lpfc_nvme.c
+++ b/drivers/scsi/lpfc/lpfc_nvme.c
@@ -2721,8 +2721,16 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 			spin_unlock_irq(&vport->phba->hbalock);
 			rport->ndlp = NULL;
 			rport->remoteport = NULL;
-			if (prev_ndlp)
-				lpfc_nlp_put(ndlp);
+
+			/* Reference only removed if previous NDLP is no longer
+			 * active. It might be just a swap and removing the
+			 * reference would cause a premature cleanup.
+			 */
+			if (prev_ndlp && prev_ndlp != ndlp) {
+				if ((!NLP_CHK_NODE_ACT(prev_ndlp)) ||
+				    (!prev_ndlp->nrport))
+					lpfc_nlp_put(prev_ndlp);
+			}
 		}
 
 		/* Clean bind the rport to the ndlp. */