When pfkey has no km listeners, it still does a lot of work
before finding out there aint nobody out there.
If a tree falls in a forest and no one is around to hear it, does it make
a sound? In this case it makes a lot of noise:
With this short-circuit adding 10s of thousands of SAs using
netlink improves performance by ~10%.
Signed-off-by: NJamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>