vxlan: break dependency with netdev drivers

Currently all drivers depend and autoload the vxlan module because how
vxlan_get_rx_port is linked into them. Remove this dependency:

By using a new event type in the netdevice notifier call chain we proxy
the request from the drivers to flush and resetup the vxlan ports not
directly via function call but by the already existing netdevice
notifier call chain.

I added a separate new event type, NETDEV_OFFLOAD_PUSH_VXLAN, to do so.
We don't need to save those ids, as the event type field is an unsigned
long and using specialized event types for this purpose seemed to be a
more elegant way. This also comes in beneficial if in future we want to
add offloading knobs for vxlan.

Cc: Jesse Gross <jesse@kernel.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 4 deletions

diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index d442eb3129cd..673e9f9e6da7 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -390,13 +390,11 @@ static inline __be32 vxlan_compute_rco(unsigned int start, unsigned int offset)
 	return vni_field;
 }
 
-#if IS_ENABLED(CONFIG_VXLAN)
-void vxlan_get_rx_port(struct net_device *netdev);
-#else
 static inline void vxlan_get_rx_port(struct net_device *netdev)
 {
+	ASSERT_RTNL();
+	call_netdevice_notifiers(NETDEV_OFFLOAD_PUSH_VXLAN, netdev);
 }
-#endif
 
 static inline unsigned short vxlan_get_sk_family(struct vxlan_sock *vs)
 {