One entry point into the routing code is from the netdev listener block.
Some netdev events require access to internal router structures. For
example, changing the MTU of a netdev requires looking-up the backing
RIF and adjusting its MTU.

In order to serialize access to shared router structures, take the
router lock when processing netdev events that require access to it.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>