Optimize bridge forwarding table for the fastpath of updating
an existing entry. Use RCU to find the entry and change it's time.
Fallback to normal locking for insert. This gives about a 1/3
improvement in packets forwarding per second on SMP.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>