Merge branch 'net-core-rcuify-rtnl-af_ops'

Florian Westphal says:

====================
net: core: rcuify rtnl af_ops

None of the rtnl af_ops callbacks sleep, so they can be called while
holding rcu read lock.

Switch handling of af_ops to rcu.

This would allow to later call af_ops functions without holding
the rtnl mutex anymore.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>