2013/1/31 Vlad Yasevich [off-list ref]:

Adds an optional infrustructure component to bridge that would allow
native vlan filtering in the bridge.  Each bridge port (as well
as the bridge device) now get a VLAN bitmap.  Each bit in the bitmap
is associated with a vlan id.  This way if the bit corresponding to
the vid is set in the bitmap that the packet with vid is allowed to
enter and exit the port.

Write access the bitmap is protected by RTNL and read access
protected by RCU.

[...]

+static int __vlan_del(struct net_port_vlans *v, u16 vid)
+{
+       unsigned long first_bit;
+       unsigned long last_bit;
+
+       if (!test_bit(vid, v->vlan_bitmap))
+               return -EINVAL;
+
+       /* Check to see if any other vlans are in this table.  If this
+        * is the last vlan, delete the whole structure.  If this is not the
+        * last vlan, just clear the bit.
+        */
+       first_bit = find_first_bit(v->vlan_bitmap, BR_VLAN_BITMAP_LEN);
+       last_bit = find_last_bit(v->vlan_bitmap, BR_VLAN_BITMAP_LEN);
+
+       if (v->port_idx && vid) {
+               struct net_device *dev = vlans_to_port(v)->dev;
+
+               if (dev->features & NETIF_F_HW_VLAN_FILTER)
+                       dev->netdev_ops->ndo_vlan_rx_kill_vid(dev, vid);
+       }
+
+       clear_bit(vid, v->vlan_bitmap);
+       if (first_bit == last_bit) {

if (bitmap_empty(v->vlan_bitmap, BR_VLAN_BITMAP_LEN))

+               if (v->port_idx) {
+                       struct net_bridge_port *p = vlans_to_port(v);
+                       rcu_assign_pointer(p->vlan_info, NULL);
+               } else {
+                       struct net_bridge *br = vlans_to_bridge(v);
+                       rcu_assign_pointer(br->vlan_info, NULL);
+               }

You seem to use vlans_to_port/vlans_to_bridge only to get at
vlan_info. Maybe that could be abstracted to a single interface, or
even change v->parent to be a 'net_port_vlans **'?

Best Regards,
Michał Mirosław