Merge branch 'faster-soreuseport'

Craig Gallek says:

====================
Faster SO_REUSEPORT

This series contains two optimizations for the SO_REUSEPORT feature:
Faster lookup when selecting a socket for an incoming packet and
the ability to select the socket from the group using a BPF program.

This series only includes the UDP path.  I plan to submit a follow-up
including the TCP path if the implementation in this series is
acceptable.

Changes in v4:
- pskb_may_pull is unnecessary with pskb_pull (per Alexei Starovoitov)

Changes in v3:
- skb_pull_inline -> pskb_pull (per Alexei Starovoitov)
- reuseport_attach* -> sk_reuseport_attach* and simple return statement
  syntax change (per Daniel Borkmann)

Changes in v2:
- Fix ARM build; remove unnecessary include.
- Handle case where protocol header is not in linear section (per
  Alexei Starovoitov).
====================

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