net: make vlan ndo_vlan_rx_[add/kill]_vid return error value

Let caller know the result of adding/removing vlan id to/from vlan
filter.

In some drivers I make those functions to just return 0. But in those
where there is able to see if hw setup went correctly, return value is
set appropriately.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5a96172..609c51f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -855,7 +855,7 @@
 	kfree(buf);
 }
 
-static void virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
+static int virtnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct scatterlist sg;
@@ -865,9 +865,10 @@
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
 		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
+	return 0;
 }
 
-static void virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
+static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct scatterlist sg;
@@ -877,6 +878,7 @@
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
 		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
+	return 0;
 }
 
 static void virtnet_get_ringparam(struct net_device *dev,