Merge branch 'UDP-sock_wfree-opts'

Pavel Begunkov says:

====================
UDP sock_wfree optimisations

The series is not UDP specific but that the main beneficiary. 2/3 saves one
atomic in sock_wfree() and on top 3/3 removes an extra barrier.
Tested with UDP over dummy netdev, 2038491 -> 2099071 req/s (or around +3%).

note: in regards to 1/3, there is a "Should agree with poll..." comment
that I don't completely get, and there is no git history to explain it.
Though I can't see how it could rely on having the second check without
racing with tasks woken by wake_up*().

The series was split from a larger patchset, see
https://lore.kernel.org/netdev/cover.1648981570.git.asml.silence@gmail.com/


====================

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