net: In unregister_netdevice_notifier unregister the netdevices.

We already synthesize events in register_netdevice_notifier and synthesizing
events in unregister_netdevice_notifier allows to us remove the need for
special case cleanup code.

This change should be safe as it adds no new cases for existing callers
of unregiser_netdevice_notifier to handle.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index c25d453b2803..9bb8f87c4cda 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1409,14 +1409,34 @@ EXPORT_SYMBOL(register_netdevice_notifier);
  *      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.
  */
 
 int unregister_netdevice_notifier(struct notifier_block *nb)
 {
+        struct net_device *dev;
+        struct net *net;
         int err;
 
         rtnl_lock();
         err = raw_notifier_chain_unregister(&netdev_chain, nb);
+        if (err)
+                goto unlock;
+
+        for_each_net(net) {
+                for_each_netdev(net, dev) {
+                        if (dev->flags & IFF_UP) {
+                                nb->notifier_call(nb, NETDEV_GOING_DOWN, dev);
+                                nb->notifier_call(nb, NETDEV_DOWN, dev);
+                        }
+                        nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
+                        nb->notifier_call(nb, NETDEV_UNREGISTER_BATCH, dev);
+                }
+        }
+unlock:
         rtnl_unlock();
         return err;
 }