scsi: lpfc: Ignore ndlp rport mismatch in dev_loss_tmo callbk

JIRA: https://issues.redhat.com/browse/RHEL-82167

commit 23ed628
Author: Justin Tee <justin.tee@broadcom.com>
Date:   Thu Jan 30 16:05:21 2025 -0800

    scsi: lpfc: Ignore ndlp rport mismatch in dev_loss_tmo callbk

    With repeated port swaps between separate fabrics, there can be multiple
    registrations for fabric well known address 0xfffffe.  This can cause ndlp
    reference confusion due to the usage of a single ndlp ptr that stores the
    rport object in fc_rport struct private storage during transport
    registration.  Subsequent registrations update the ndlp->rport field with
    the newer rport, so when transport layer triggers dev_loss_tmo for the
    earlier registered rport the ndlp->rport private storage is referencing the
    newer rport instead of the older rport in dev_loss_tmo callbk.

    Because the older ndlp->rport object is already cleaned up elsewhere in
    driver code during the time of fabric swap, check that the rport provided
    in dev_loss_tmo callbk actually matches the rport stored in the LLDD's
    ndlp->rport field.  Otherwise, skip dev_loss_tmo work on a stale rport.

    Signed-off-by: Justin Tee <justin.tee@broadcom.com>
    Link: https://lore.kernel.org/r/20250131000524.163662-4-justintee8345@gmail.com
    Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: Dick Kennedy <dkennedy@redhat.com>

Author: Dick Kennedy

drivers/scsi/lpfc/lpfc_hbadisc.c

@@ -228,10 +228,16 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport)
 	if (ndlp->nlp_state == NLP_STE_MAPPED_NODE)
 		return;
 
-	/* check for recovered fabric node */
-	if (ndlp->nlp_state == NLP_STE_UNMAPPED_NODE &&
-	    ndlp->nlp_DID == Fabric_DID)
+	/* Ignore callback for a mismatched (stale) rport */
+	if (ndlp->rport != rport) {
+		lpfc_vlog_msg(vport, KERN_WARNING, LOG_NODE,
+			      "6788 fc rport mismatch: d_id x%06x ndlp x%px "
+			      "fc rport x%px node rport x%px state x%x "
+			      "refcnt %u\n",
+			      ndlp->nlp_DID, ndlp, rport, ndlp->rport,
+			      ndlp->nlp_state, kref_read(&ndlp->kref));
 		return;
+	}
 
 	if (rport->port_name != wwn_to_u64(ndlp->nlp_portname.u.wwn))
 		lpfc_printf_vlog(vport, KERN_ERR, LOG_TRACE_EVENT,