Merge branch 'sock-lockdep-tightening'

Hannes Frederic Sowa says:

====================
sock: lockdep tightening

First patch is from Eric Dumazet and improves lockdep accuracy for
socket locks. After that, second patch introduces lockdep_sock_is_held
and uses it. Final patch reverts and reworks the lockdep fix from Daniel
in the filter code, as we now have tighter lockdep support.
====================

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