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 <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/if_vlan.h

···
 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)
···
 }
 
 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

net/8021q/vlan_core.c

···
 	}
 }
 EXPORT_SYMBOL(vlan_vid_del);
+
+int vlan_vids_add_by_dev(struct net_device *dev,
+			 const struct net_device *by_dev)
+{
+	struct vlan_vid_info *vid_info;
+	int err;
+
+	ASSERT_RTNL();
+
+	if (!by_dev->vlan_info)
+		return 0;
+
+	list_for_each_entry(vid_info, &by_dev->vlan_info->vid_list, list) {
+		err = vlan_vid_add(dev, vid_info->vid);
+		if (err)
+			goto unwind;
+	}
+	return 0;
+
+unwind:
+	list_for_each_entry_continue_reverse(vid_info,
+					     &by_dev->vlan_info->vid_list,
+					     list) {
+		vlan_vid_del(dev, vid_info->vid);
+	}
+
+	return err;
+}
+EXPORT_SYMBOL(vlan_vids_add_by_dev);
+
+void vlan_vids_del_by_dev(struct net_device *dev,
+			  const struct net_device *by_dev)
+{
+	struct vlan_vid_info *vid_info;
+
+	ASSERT_RTNL();
+
+	if (!by_dev->vlan_info)
+		return;
+
+	list_for_each_entry(vid_info, &by_dev->vlan_info->vid_list, list)
+		vlan_vid_del(dev, vid_info->vid);
+}
+EXPORT_SYMBOL(vlan_vids_del_by_dev);