Subject: [PATCH ipsec-next v2 0/6] xfrm: remove xfrm replay indirections

From: Florian Westphal <[email-masked]>
Date: Wed, 24 Jun 2020 10:07:58 +0200

v2: fix unitialized variable buf reported by kbuild robot.

The xfrm replay logic is implemented via indirect calls.

xfrm_state struct holds a pointer to a
'struct xfrm_replay', which is one of several replay protection
backends.

XFRM then invokes the backend via state->repl->callback().
Due to retpoline all indirect calls have become a lot more
expensive.  Fortunately, there are no 'replay modules', all are available
for direct calls.

This series removes the 'struct xfrm_replay' and adds replay
functions that can be called instead of the redirection.

Example:
  -  err = x->repl->overflow(x, skb);
  +  err = xfrm_replay_overflow(x, skb);

Instead of a pointer to a struct with function pointers, xfrm_state
now holds an enum that tells the replay core what kind of replay
test is to be done.

Florian Westphal (6):
      xfrm: replay: avoid xfrm replay notify indirection
      xfrm: replay: get rid of duplicated notification code
      xfrm: replay: remove advance indirection
      xfrm: replay: remove recheck indirection
      xfrm: replay: avoid replay indirection
      xfrm: replay: remove last replay indirection

 include/net/xfrm.h     |  29 ++++----
 net/xfrm/xfrm_input.c  |   6 +-
 net/xfrm/xfrm_output.c |   2 +-
 net/xfrm/xfrm_replay.c | 189 +++++++++++++++++++++++++++----------------------
 net/xfrm/xfrm_state.c  |   2 +-
 5 files changed, 125 insertions(+), 103 deletions(-)