This is a straightforward patch, using hlist_nulls infrastructure.

RCUification already done on UDP two weeks ago.

Using hlist_nulls permits us to avoid some memory barriers, both
at lookup time and delete time.

Patch is large because it adds new macros to include/net/sock.h.
These macros will be used by TCP & DCCP in next patch.


Signed-off-by: Eric Dumazet <redacted>
---
 include/linux/rculist.h |   17 -----------
 include/net/sock.h      |   57 ++++++++++++++++++++++++++++++--------
 include/net/udp.h       |    2 -
 net/ipv4/udp.c          |   47 ++++++++++++++-----------------
 net/ipv6/udp.c          |   26 +++++++++--------
 5 files changed, 83 insertions(+), 66 deletions(-)