scsi: qla2xxx: Fix loss of NVMe namespaces after driver reload test

Driver registration of localport can race when it happens at the remote
port discovery time. Fix this by calling the registration under a mutex.

Link: https://lore.kernel.org/r/20220310092604.22950-4-njavali@marvell.com
Fixes: e84067d ("scsi: qla2xxx: Add FC-NVMe F/W initialization and transport registration")
Cc: stable@vger.kernel.org
Reported-by: Marco Patalano <mpatalan@redhat.com>
Tested-by: Marco Patalano <mpatalan@redhat.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_nvme.c

@@ -782,8 +782,6 @@ int qla_nvme_register_hba(struct scsi_qla_host *vha)
 	ha = vha->hw;
 	tmpl = &qla_nvme_fc_transport;
 
-	WARN_ON(vha->nvme_local_port);
-
 	if (ql2xnvme_queues < MIN_NVME_HW_QUEUES || ql2xnvme_queues > MAX_NVME_HW_QUEUES) {
 		ql_log(ql_log_warn, vha, 0xfffd,
 		    "ql2xnvme_queues=%d is out of range(MIN:%d - MAX:%d). Resetting ql2xnvme_queues to:%d\n",
@@ -797,21 +795,33 @@ int qla_nvme_register_hba(struct scsi_qla_host *vha)
 		(uint8_t)(ha->max_qpairs ? ha->max_qpairs : 1));
 
 	ql_log(ql_log_info, vha, 0xfffb,
-	    "Number of NVME queues used for this port: %d\n",
+	       "Number of NVME queues used for this port: %d\n",
 	    qla_nvme_fc_transport.max_hw_queues);
 
 	pinfo.node_name = wwn_to_u64(vha->node_name);
 	pinfo.port_name = wwn_to_u64(vha->port_name);
 	pinfo.port_role = FC_PORT_ROLE_NVME_INITIATOR;
 	pinfo.port_id = vha->d_id.b24;
 
-	ql_log(ql_log_info, vha, 0xffff,
-	    "register_localport: host-traddr=nn-0x%llx:pn-0x%llx on portID:%x\n",
-	    pinfo.node_name, pinfo.port_name, pinfo.port_id);
-	qla_nvme_fc_transport.dma_boundary = vha->host->dma_boundary;
-
-	ret = nvme_fc_register_localport(&pinfo, tmpl,
-	    get_device(&ha->pdev->dev), &vha->nvme_local_port);
+	mutex_lock(&ha->vport_lock);
+	/*
+	 * Check again for nvme_local_port to see if any other thread raced
+	 * with this one and finished registration.
+	 */
+	if (!vha->nvme_local_port) {
+		ql_log(ql_log_info, vha, 0xffff,
+		    "register_localport: host-traddr=nn-0x%llx:pn-0x%llx on portID:%x\n",
+		    pinfo.node_name, pinfo.port_name, pinfo.port_id);
+		qla_nvme_fc_transport.dma_boundary = vha->host->dma_boundary;
+
+		ret = nvme_fc_register_localport(&pinfo, tmpl,
+						 get_device(&ha->pdev->dev),
+						 &vha->nvme_local_port);
+		mutex_unlock(&ha->vport_lock);
+	} else {
+		mutex_unlock(&ha->vport_lock);
+		return 0;
+	}
 	if (ret) {
 		ql_log(ql_log_warn, vha, 0xffff,
 		    "register_localport failed: ret=%x\n", ret);