scsi: lpfc: Skip issuing ADISC when node is in NPR state

When a node moves to NPR state due to a device recovery event, the
nlp_fc4_types in the node are cleared. An ADISC received for a node in the
NPR state triggers an ADISC. Without fc4 types being known, the calls to
register with the transport are no-op'd, thus no additional references are
placed on the node by transport re-registrations. A subsequent RSCN could
trigger another unregister request, which will decrement the reference
counts, leading to the ref count hitting zero and the node being freed
while futher discovery on the node is being attempted by the RSCN event
handling.

Fix by skipping the trigger of an ADISC when in NPR state. The normal ADISC
process will kick off in the regular discovery path after receiving a
response from name server.

Link: https://lore.kernel.org/r/20210707184351.67872-19-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_nportdisc.c

@@ -736,9 +736,13 @@ lpfc_rcv_padisc(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 		 * 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.
+		 *
+		 * Nodes marked for ADISC will move MAPPED or UNMAPPED state
+		 * after issuing ADISC
 		 */
 		if (ndlp->nlp_type & (NLP_FCP_TARGET | NLP_NVME_TARGET)) {
-			if (ndlp->nlp_state != NLP_STE_MAPPED_NODE)
+			if ((ndlp->nlp_state != NLP_STE_MAPPED_NODE) &&
+			    !(ndlp->nlp_flag & NLP_NPR_ADISC))
 				lpfc_nlp_set_state(vport, ndlp,
 						   NLP_STE_MAPPED_NODE);
 		}
@@ -2646,14 +2650,13 @@ lpfc_rcv_prli_npr_node(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 	lpfc_els_rsp_reject(vport, stat.un.lsRjtError, cmdiocb, ndlp, NULL);
 
 	if (!(ndlp->nlp_flag & NLP_DELAY_TMO)) {
-		if (ndlp->nlp_flag & NLP_NPR_ADISC) {
-			spin_lock_irq(&ndlp->lock);
-			ndlp->nlp_flag &= ~NLP_NPR_ADISC;
-			ndlp->nlp_prev_state = NLP_STE_NPR_NODE;
-			spin_unlock_irq(&ndlp->lock);
-			lpfc_nlp_set_state(vport, ndlp, NLP_STE_ADISC_ISSUE);
-			lpfc_issue_els_adisc(vport, ndlp, 0);
-		} else {
+		/*
+		 * ADISC nodes will be handled in regular discovery path after
+		 * receiving response from NS.
+		 *
+		 * For other nodes, Send PLOGI to trigger an implicit LOGO.
+		 */
+		if (!(ndlp->nlp_flag & NLP_NPR_ADISC)) {
 			ndlp->nlp_prev_state = NLP_STE_NPR_NODE;
 			lpfc_nlp_set_state(vport, ndlp, NLP_STE_PLOGI_ISSUE);
 			lpfc_issue_els_plogi(vport, ndlp->nlp_DID, 0);
@@ -2686,12 +2689,13 @@ lpfc_rcv_padisc_npr_node(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 	 */
 	if (!(ndlp->nlp_flag & NLP_DELAY_TMO) &&
 	    !(ndlp->nlp_flag & NLP_NPR_2B_DISC)) {
-		if (ndlp->nlp_flag & NLP_NPR_ADISC) {
-			ndlp->nlp_flag &= ~NLP_NPR_ADISC;
-			ndlp->nlp_prev_state = NLP_STE_NPR_NODE;
-			lpfc_nlp_set_state(vport, ndlp, NLP_STE_ADISC_ISSUE);
-			lpfc_issue_els_adisc(vport, ndlp, 0);
-		} else {
+		/*
+		 * ADISC nodes will be handled in regular discovery path after
+		 * receiving response from NS.
+		 *
+		 * For other nodes, Send PLOGI to trigger an implicit LOGO.
+		 */
+		if (!(ndlp->nlp_flag & NLP_NPR_ADISC)) {
 			ndlp->nlp_prev_state = NLP_STE_NPR_NODE;
 			lpfc_nlp_set_state(vport, ndlp, NLP_STE_PLOGI_ISSUE);
 			lpfc_issue_els_plogi(vport, ndlp->nlp_DID, 0);