Re: [PATCH ipsec-next v2 0/5] xfrm: remove xfrm replay indirections

On Fri, Jun 18, 2021 at 03:51:55PM +0200, Florian Westphal wrote:

This is v2 of an older patchset that got stuck in backlog hell. Changes:

 - drop bogus "get rid of duplicated notification code" patch. As noted
   by Sabrina it does change behavior.
 - fix a compiler warning in patch 2.

ipsec.c selftest passes.

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 (5):
  xfrm: replay: avoid xfrm replay notify indirection
  xfrm: replay: remove advance indirection
  xfrm: replay: remove recheck indirection
  xfrm: replay: avoid replay indirection
  xfrm: replay: remove last replay indirection

All applied, thanks a lot Florian!