scsi: lpfc: Skip reg_vpi when link is down for SLI3 in ADISC cmpl path

During RSCN storms, some instances of LIP on SLI-3 adapters lead to a
situation where FLOGIs keep failing with firmware indicating an illegal
command error code.  This situation was preceded by an ADISC completion
that was processed while the link was down. This path on SLI-3 performs a
CLEAR_LA and attempts to activate a VPI with REG_VPI.  Later, as the FLOGI
completes, it's no longer in sync with the VPI state.  In SLI-3 it is
illegal to have an active VPI during FLOGI.

Resolve by circumventing the SLI-3 path that performs the CLEAR_LA and
REG_VPI. The path will be taken after the FLOGI after the next Link Up.

Link: https://lore.kernel.org/r/20210707184351.67872-18-jsmart2021@gmail.comCo-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_els.c

@@ -2610,6 +2610,14 @@ lpfc_adisc_done(struct lpfc_vport *vport)
 	if ((phba->sli3_options & LPFC_SLI3_NPIV_ENABLED) &&
 	    !(vport->fc_flag & FC_RSCN_MODE) &&
 	    (phba->sli_rev < LPFC_SLI_REV4)) {
+
+		/*
+		 * If link is down, clear_la and reg_vpi will be done after
+		 * flogi following a link up event
+		 */
+		if (!lpfc_is_link_up(phba))
+			return;
+
 		/* The ADISCs are complete.  Doesn't matter if they
 		 * succeeded or failed because the ADISC completion
 		 * routine guarantees to call the state machine and