[PATCH 04/14] lpfc: Fix NVME rport deregister and registration during ADISC

From: James Smart <jsmart2021@gmail.com>
To: linux-scsi@vger.kernel.org
Cc: James Smart <jsmart2021@gmail.com>,
	Dick Kennedy <dick.kennedy@broadcom.com>
Subject: [PATCH 04/14] lpfc: Fix NVME rport deregister and registration during ADISC
Date: Tue, 30 Jun 2020 14:49:51 -0700	[thread overview]
Message-ID: <20200630215001.70793-5-jsmart2021@gmail.com> (raw)
In-Reply-To: <20200630215001.70793-1-jsmart2021@gmail.com>

During driver unload/reload testing, the nvme initiator would
not re-establish connectivity to nvme controllers on reload.

The failing nvme array supports concurrent FCP and NVME operation
via different nport_id's. The array was repeatedly sending an ADISC
every 2 seconds after PLOGI completed and while nvme subsytems were
executing discovery. The target would continue this state for
roughly 45 seconds.

The driver's current behavior on ADISC receipt is to validate a
the ADISC vs the device and issue a RESUME_RPI to restore
transmission. The receipt of the ADISC effectively caused a driver to
take actions similar to a logout and login for the remote port, causing
the deregistration of the nvme rport and a subsequent re-registration.
This caused a constant reset and re-connect of the nvme controller while
this 45s window occurred. There was no need for the state changes as
ADISC does not change login state.

This patch corrects this behavior by validating if the remoteport is
already logged in (MAPPED) and when true, avoids the call to set the ndlp
state to MAPPED, which triggers the unreg/re-reg. Thus ADISC does not
change the login state of the node.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
---
 drivers/scsi/lpfc/lpfc_nportdisc.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_nportdisc.c b/drivers/scsi/lpfc/lpfc_nportdisc.c
index 2871c9b0cbfa..057af32f498d 100644
--- a/drivers/scsi/lpfc/lpfc_nportdisc.c
+++ b/drivers/scsi/lpfc/lpfc_nportdisc.c
@@ -797,11 +797,17 @@ lpfc_rcv_padisc(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 				ndlp, NULL);
 		}
 out:
-		/* If we are authenticated, move to the proper state */
-		if (ndlp->nlp_type & (NLP_FCP_TARGET | NLP_NVME_TARGET))
-			lpfc_nlp_set_state(vport, ndlp, NLP_STE_MAPPED_NODE);
-		else
-			lpfc_nlp_set_state(vport, ndlp, NLP_STE_UNMAPPED_NODE);
+		/* If we are authenticated, move to the proper state.
+		 * It is possible an ADISC arrived and the remote nport
+		 * is already in MAPPED or UNMAPPED state.  Catch this
+		 * condition and don't set the nlp_state again because
+		 * it causes an unnecessary transport unregister/register.
+		 */
+		if (ndlp->nlp_type & (NLP_FCP_TARGET | NLP_NVME_TARGET)) {
+			if (ndlp->nlp_state != NLP_STE_MAPPED_NODE)
+				lpfc_nlp_set_state(vport, ndlp,
+						   NLP_STE_MAPPED_NODE);
+		}
 
 		return 1;
 	}
-- 
2.25.0

