mlxsw: spectrum: Don't assume upper device's type

When an upper device is configured on top of a vPort we make sure it's a
bridge master during PRECHANGEUPPER and fail otherwise. Therefore, when
CHANGEUPPER is later received we don't bother checking the upper's type.

Make the code more extendable in preparation for VRF uppers, by checking
the upper's type.
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -4818,6 +4818,8 @@ static int mlxsw_sp_netdevice_vport_event(struct net_device *dev,
 	int err = 0;
 
 	mlxsw_sp_vport = mlxsw_sp_port_vport_find(mlxsw_sp_port, vid);
+	if (!mlxsw_sp_vport)
+		return 0;
 
 	switch (event) {
 	case NETDEV_PRECHANGEUPPER:
@@ -4835,16 +4837,17 @@ static int mlxsw_sp_netdevice_vport_event(struct net_device *dev,
 		break;
 	case NETDEV_CHANGEUPPER:
 		upper_dev = info->upper_dev;
-		if (info->linking) {
-			if (WARN_ON(!mlxsw_sp_vport))
-				return -EINVAL;
-			err = mlxsw_sp_vport_bridge_join(mlxsw_sp_vport,
-							 upper_dev);
+		if (netif_is_bridge_master(upper_dev)) {
+			if (info->linking)
+				err = mlxsw_sp_vport_bridge_join(mlxsw_sp_vport,
+								 upper_dev);
+			else
+				mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport);
 		} else {
-			if (!mlxsw_sp_vport)
-				return 0;
-			mlxsw_sp_vport_bridge_leave(mlxsw_sp_vport);
+			err = -EINVAL;
+			WARN_ON(1);
 		}
+		break;
 	}
 
 	return err;