vlan: introduce functions to do mass addition/deletion of vids by another device

Introduce functions handy to copy vlan ids from one driver's list to
another.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 0c96913..13aff1e 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -97,6 +97,10 @@
 extern int vlan_vid_add(struct net_device *dev, unsigned short vid);
 extern void vlan_vid_del(struct net_device *dev, unsigned short vid);
 
+extern int vlan_vids_add_by_dev(struct net_device *dev,
+				const struct net_device *by_dev);
+extern void vlan_vids_del_by_dev(struct net_device *dev,
+				 const struct net_device *by_dev);
 #else
 static inline struct net_device *
 __vlan_find_dev_deep(struct net_device *real_dev, u16 vlan_id)
@@ -136,6 +140,17 @@
 static inline void vlan_vid_del(struct net_device *dev, unsigned short vid)
 {
 }
+
+static inline int vlan_vids_add_by_dev(struct net_device *dev,
+				       const struct net_device *by_dev)
+{
+	return 0;
+}
+
+static inline void vlan_vids_del_by_dev(struct net_device *dev,
+					const struct net_device *by_dev)
+{
+}
 #endif
 
 /**