From: James Smart <jsmart2021@gmail.com>
Date: Wed, 14 Aug 2019 16:56:45 -0700
Subject: scsi: lpfc: Fix null ptr oops updating lpfc_devloss_tmo via sysfs
 attribute
Patch-mainline: v5.4-rc1
Git-commit: 07f50997d66c3273121dd6b8a7d433cdfb5395c1
References: jsc#SLE-8284 jsc#SLE-8654

If an admin updates lpfc's devloss_tmo sysfs attribute, the kernel will
oops.

Coding of a loop allowed a new value (rport) to be set/checked for null
followed by an older value (remoteport) checked for null to allow progress
where the new value, even though null, will be referenced.

Rework the logic to validate and prevent any reference to the null ptr.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/scsi/lpfc/lpfc_attr.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -3682,8 +3682,8 @@ lpfc_update_rport_devloss_tmo(struct lpf
 		if (rport)
 			remoteport = rport->remoteport;
 		spin_unlock(&vport->phba->hbalock);
-		if (remoteport)
-			nvme_fc_set_remoteport_devloss(rport->remoteport,
+		if (rport && remoteport)
+			nvme_fc_set_remoteport_devloss(remoteport,
 						       vport->cfg_devloss_tmo);
 #endif
 	}