nvme-fc: use lock accessing port_state and rport state

nvme_fc_unregister_remote removes the remote port on a lport object at
any point in time when there is no active association. This races with
with the reconnect logic, because nvme_fc_create_association is not
taking a lock to check the port_state and atomically increase the
active count on the rport.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Closes: https://lore.kernel.org/all/u4ttvhnn7lark5w3sgrbuy2rxupcvosp4qmvj46nwzgeo5ausc@uyrkdls2muwx
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: igaw

drivers/nvme/host/fc.c

@@ -3032,11 +3032,17 @@ nvme_fc_create_association(struct nvme_fc_ctrl *ctrl)
 
 	++ctrl->ctrl.nr_reconnects;
 
-	if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE)
+	spin_lock_irqsave(&ctrl->rport->lock, flags);
+	if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE) {
+		spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 		return -ENODEV;
+	}
 
-	if (nvme_fc_ctlr_active_on_rport(ctrl))
+	if (nvme_fc_ctlr_active_on_rport(ctrl)) {
+		spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 		return -ENOTUNIQ;
+	}
+	spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 
 	dev_info(ctrl->ctrl.device,
 		"NVME-FC{%d}: create association : host wwpn 0x%016llx "