net: dsa: Don't add vlans when vlan filtering is disabled

The software bridge can be build with vlan filtering support
included. However, by default it is turned off. In its turned off
state, it still passes VLANs via switchev, even though they are not to
be used. Don't pass these VLANs to the hardware. Only do so when vlan
filtering is enabled.

This fixes at least one corner case. There are still issues in other
corners, such as when vlan_filtering is later enabled.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/port.c

@@ -252,7 +252,10 @@ int dsa_port_vlan_add(struct dsa_port *dp,
 		.vlan = vlan,
 	};
 
-	return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info);
+	if (br_vlan_enabled(dp->bridge_dev))
+		return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info);
+
+	return 0;
 }
 
 int dsa_port_vlan_del(struct dsa_port *dp,
@@ -264,7 +267,10 @@ int dsa_port_vlan_del(struct dsa_port *dp,
 		.vlan = vlan,
 	};
 
-	return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_DEL, &info);
+	if (br_vlan_enabled(dp->bridge_dev))
+		return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_DEL, &info);
+
+	return 0;
 }
 
 int dsa_port_fixed_link_register_of(struct dsa_port *dp)