net: dsa: Store vlan_filtering as a property of dsa_port

This allows drivers to query the VLAN setting imposed by the bridge
driver directly from DSA, instead of keeping their own state based on
the .port_vlan_filtering callback.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -161,6 +161,7 @@ struct dsa_port {
 	const char		*mac;
 	struct device_node	*dn;
 	unsigned int		ageing_time;
+	bool			vlan_filtering;
 	u8			stp_state;
 	struct net_device	*bridge_dev;
 	struct devlink_port	devlink_port;

net/dsa/port.c

@@ -158,15 +158,19 @@ int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
 			    struct switchdev_trans *trans)
 {
 	struct dsa_switch *ds = dp->ds;
+	int err;
 
 	/* bridge skips -EOPNOTSUPP, so skip the prepare phase */
 	if (switchdev_trans_ph_prepare(trans))
 		return 0;
 
-	if (ds->ops->port_vlan_filtering)
-		return ds->ops->port_vlan_filtering(ds, dp->index,
+	if (ds->ops->port_vlan_filtering) {
+		err = ds->ops->port_vlan_filtering(ds, dp->index,
 						   vlan_filtering);
-
+		if (err)
+			return err;
+		dp->vlan_filtering = vlan_filtering;
+	}
 	return 0;
 }