net: push code from net notifier reg/unreg into helpers

Push the code which is done under rtnl lock in net notifier register and
unregister function into separate helpers.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -1784,6 +1784,42 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_netdevice_notifier);
 
+static int __register_netdevice_notifier_net(struct net *net,
+					     struct notifier_block *nb,
+					     bool ignore_call_fail)
+{
+	int err;
+
+	err = raw_notifier_chain_register(&net->netdev_chain, nb);
+	if (err)
+		return err;
+	if (dev_boot_phase)
+		return 0;
+
+	err = call_netdevice_register_net_notifiers(nb, net);
+	if (err && !ignore_call_fail)
+		goto chain_unregister;
+
+	return 0;
+
+chain_unregister:
+	raw_notifier_chain_unregister(&net->netdev_chain, nb);
+	return err;
+}
+
+static int __unregister_netdevice_notifier_net(struct net *net,
+					       struct notifier_block *nb)
+{
+	int err;
+
+	err = raw_notifier_chain_unregister(&net->netdev_chain, nb);
+	if (err)
+		return err;
+
+	call_netdevice_unregister_net_notifiers(nb, net);
+	return 0;
+}
+
 /**
  * register_netdevice_notifier_net - register a per-netns network notifier block
  * @net: network namespace
@@ -1804,23 +1840,9 @@ int register_netdevice_notifier_net(struct net *net, struct notifier_block *nb)
 	int err;
 
 	rtnl_lock();
-	err = raw_notifier_chain_register(&net->netdev_chain, nb);
-	if (err)
-		goto unlock;
-	if (dev_boot_phase)
-		goto unlock;
-
-	err = call_netdevice_register_net_notifiers(nb, net);
-	if (err)
-		goto chain_unregister;
-
-unlock:
+	err = __register_netdevice_notifier_net(net, nb, false);
 	rtnl_unlock();
 	return err;
-
-chain_unregister:
-	raw_notifier_chain_unregister(&netdev_chain, nb);
-	goto unlock;
 }
 EXPORT_SYMBOL(register_netdevice_notifier_net);
 
@@ -1846,13 +1868,7 @@ int unregister_netdevice_notifier_net(struct net *net,
 	int err;
 
 	rtnl_lock();
-	err = raw_notifier_chain_unregister(&net->netdev_chain, nb);
-	if (err)
-		goto unlock;
-
-	call_netdevice_unregister_net_notifiers(nb, net);
-
-unlock:
+	err = __unregister_netdevice_notifier_net(net, nb);
 	rtnl_unlock();
 	return err;
 }