unregister_netdevice_notifier — unregister a network notifier block
| int unregister_netdevice_notifier ( | struct notifier_block * nb ); | 
   Unregister a notifier previously registered by
   register_netdevice_notifier. The notifier is unlinked into the
   kernel structures and may then be reused. A negative errno code
   is returned on a failure.
   
After unregistering unregister and down device events are synthesized for all devices on the device list to the removed notifier to remove the need for special case cleanup code.