scsi: qla2xxx: Reduce redundant ADISC command for RSCNs

For each RSCN that triggers a rescan of the fabric, ADISC is used to
revalidate an existing session. If the RSCN is not affecting all
existing sessions, then driver should not send redundant ADISC for all
existing sessions.
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_def.h

@@ -2346,6 +2346,7 @@ typedef struct fc_port {
 	unsigned int login_succ:1;
 	unsigned int query:1;
 	unsigned int id_changed:1;
+	unsigned int rscn_rcvd:1;
 
 	struct work_struct nvme_del_work;
 	struct completion nvme_del_done;

drivers/scsi/qla2xxx/qla_gs.c

@@ -3862,6 +3862,7 @@ void qla24xx_async_gnnft_done(scsi_qla_host_t *vha, srb_t *sp)
 	bool found;
 	struct fab_scan_rp *rp;
 	unsigned long flags;
+	u8 recheck = 0;
 
 	ql_dbg(ql_dbg_disc, vha, 0xffff,
 	    "%s enter\n", __func__);
@@ -3914,6 +3915,7 @@ void qla24xx_async_gnnft_done(scsi_qla_host_t *vha, srb_t *sp)
 		list_for_each_entry(fcport, &vha->vp_fcports, list) {
 			if (memcmp(rp->port_name, fcport->port_name, WWN_SIZE))
 				continue;
+			fcport->rscn_rcvd = 0;
 			fcport->scan_state = QLA_FCPORT_FOUND;
 			found = true;
 			/*
@@ -3942,10 +3944,13 @@ void qla24xx_async_gnnft_done(scsi_qla_host_t *vha, srb_t *sp)
 	 * Logout all previous fabric dev marked lost, except FCP2 devices.
 	 */
 	list_for_each_entry(fcport, &vha->vp_fcports, list) {
-		if ((fcport->flags & FCF_FABRIC_DEVICE) == 0)
+		if ((fcport->flags & FCF_FABRIC_DEVICE) == 0) {
+			fcport->rscn_rcvd = 0;
 			continue;
+		}
 
 		if (fcport->scan_state != QLA_FCPORT_FOUND) {
+			fcport->rscn_rcvd = 0;
 			if ((qla_dual_mode_enabled(vha) ||
 				qla_ini_mode_enabled(vha)) &&
 			    atomic_read(&fcport->state) == FCS_ONLINE) {
@@ -3963,15 +3968,31 @@ void qla24xx_async_gnnft_done(scsi_qla_host_t *vha, srb_t *sp)
 					continue;
 				}
 			}
-		} else
-			qla24xx_fcport_handle_login(vha, fcport);
+		} else {
+			if (fcport->rscn_rcvd ||
+			    fcport->disc_state != DSC_LOGIN_COMPLETE) {
+				fcport->rscn_rcvd = 0;
+				qla24xx_fcport_handle_login(vha, fcport);
+			}
+		}
 	}
 
+	recheck = 1;
 out:
 	qla24xx_sp_unmap(vha, sp);
 	spin_lock_irqsave(&vha->work_lock, flags);
 	vha->scan.scan_flags &= ~SF_SCANNING;
 	spin_unlock_irqrestore(&vha->work_lock, flags);
+
+	if (recheck) {
+		list_for_each_entry(fcport, &vha->vp_fcports, list) {
+			if (fcport->rscn_rcvd) {
+				set_bit(LOCAL_LOOP_UPDATE, &vha->dpc_flags);
+				set_bit(LOOP_RESYNC_NEEDED, &vha->dpc_flags);
+				break;
+			}
+		}
+	}
 }
 
 static void qla2x00_find_free_fcp_nvme_slot(struct scsi_qla_host *vha,

drivers/scsi/qla2xxx/qla_init.c

@@ -1348,6 +1348,7 @@ void qla2x00_fcport_event_handler(scsi_qla_host_t *vha, struct event_arg *ea)
 	fc_port_t *f, *tf;
 	uint32_t id = 0, mask, rid;
 	unsigned long flags;
+	fc_port_t *fcport;
 
 	switch (ea->event) {
 	case FCME_RSCN:
@@ -1375,6 +1376,11 @@ void qla2x00_fcport_event_handler(scsi_qla_host_t *vha, struct event_arg *ea)
 			return;
 		switch (ea->id.b.rsvd_1) {
 		case RSCN_PORT_ADDR:
+			fcport = qla2x00_find_fcport_by_nportid
+				(vha, &ea->id, 1);
+			if (fcport)
+				fcport->rscn_rcvd = 1;
+
 			spin_lock_irqsave(&vha->work_lock, flags);
 			if (vha->scan.scan_flags == 0) {
 				ql_dbg(ql_dbg_disc, vha, 0xffff,