scsi: lpfc: Defer issuing new PLOGI if received RSCN before completing REG_LOGIN

When mapped to a target with multiple virtual ports, a link bounce
sometimes results in unsuccessful rediscovery of all of the target's
virtual ports.  This is because a succession of repeat RSCNs for the
virtual target ports leaves ndlps in the REG_LOGIN state with the
NLP_REG_LOGIN_SEND flag set.  With NLP_REG_LOGIN_SEND set, during the next
PLOGI, the driver will UNREG_RPI.  When UNREG_RPI is processed, the driver
can be in the middle of PRLI_ISSUE or MAPPED state resulting in an illegal
state transition by the discovery engine and stalling.

Fix by calling the discovery state machine with DEVICE_RECOVERY event
during RSCN processing.  This will set the NLP_IGNR_REG_CMPL bit and
prevent the old REG_LOGIN state from advancing.  Then for the new PLOGI
issue, add the check for the NLP_IGNR_REG_CMPL bit to delay issuing the new
PLOGI until the queued REG_LOGIN and UNREG_LOGIN have been processed.
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Link: https://lore.kernel.org/r/20230301231626.9621-6-justintee8345@gmail.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_els.c

@@ -2208,14 +2208,15 @@ lpfc_issue_els_plogi(struct lpfc_vport *vport, uint32_t did, uint8_t retry)
 	 * outstanding UNREG_RPI mbox command completes, unless we
 	 * are going offline. This logic does not apply for Fabric DIDs
 	 */
-	if ((ndlp->nlp_flag & NLP_UNREG_INP) &&
+	if ((ndlp->nlp_flag & (NLP_IGNR_REG_CMPL | NLP_UNREG_INP)) &&
 	    ((ndlp->nlp_DID & Fabric_DID_MASK) != Fabric_DID_MASK) &&
 	    !(vport->fc_flag & FC_OFFLINE_MODE)) {
 		lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY,
 				 "4110 Issue PLOGI x%x deferred "
-				 "on NPort x%x rpi x%x Data: x%px\n",
+				 "on NPort x%x rpi x%x flg x%x Data:"
+				 " x%px\n",
 				 ndlp->nlp_defer_did, ndlp->nlp_DID,
-				 ndlp->nlp_rpi, ndlp);
+				 ndlp->nlp_rpi, ndlp->nlp_flag, ndlp);
 
 		/* We can only defer 1st PLOGI */
 		if (ndlp->nlp_defer_did == NLP_EVT_NOTHING_PENDING)

drivers/scsi/lpfc/lpfc_hbadisc.c

@@ -5755,8 +5755,8 @@ lpfc_setup_disc_node(struct lpfc_vport *vport, uint32_t did)
 			     (NLP_FCP_TARGET | NLP_NVME_TARGET)))
 				return NULL;
 
-			ndlp->nlp_prev_state = ndlp->nlp_state;
-			lpfc_nlp_set_state(vport, ndlp, NLP_STE_NPR_NODE);
+			lpfc_disc_state_machine(vport, ndlp, NULL,
+						NLP_EVT_DEVICE_RECOVERY);
 
 			spin_lock_irq(&ndlp->lock);
 			ndlp->nlp_flag |= NLP_NPR_2B_DISC;