net: NETDEV_UNREGISTER_PERNET -> NETDEV_UNREGISTER_BATCH

The motivation for an additional notifier in batched netdevice
notification (rt_do_flush) only needs to be called once per batch not
once per namespace.

For further batching improvements I need a guarantee that the
netdevices are unregistered in order allowing me to unregister an all
of the network devices in a network namespace at the same time with
the guarantee that the loopback device is really and truly
unregistered last.

Additionally it appears that we moved the route cache flush after
the final synchronize_net, which seems wrong and there was no
explanation.  So I have restored the original location of the final
synchronize_net.

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

1 files changed, 3 insertions, 1 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 6c1e56aef1f4..3b373a8b0473 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -959,9 +959,11 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
                 break;
         case NETDEV_CHANGEMTU:
         case NETDEV_CHANGE:
-        case NETDEV_UNREGISTER_PERNET:
                 rt_cache_flush(dev_net(dev), 0);
                 break;
+        case NETDEV_UNREGISTER_BATCH:
+                rt_cache_flush_batch();
+                break;
         }
         return NOTIFY_DONE;
 }