queue-5.15/nfsd-streamline-the-rare-found-case.patch

   1 From 987c4add1f01341650277784069a49897517ba1e Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Tue, 28 Sep 2021 11:40:59 -0400
   4 Subject: NFSD: Streamline the rare "found" case
   5
   6 From: Chuck Lever <chuck.lever@oracle.com>
   7
   8 [ Upstream commit add1511c38166cf1036765f8c4aa939f0275a799 ]
   9
  10 Move a rarely called function call site out of the hot path.
  11
  12 This is an exceptionally small improvement because the compiler
  13 inlines most of the functions that nfsd_cache_lookup() calls.
  14
  15 Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
  16 ---
  17  fs/nfsd/nfscache.c | 7 +++----
  18  1 file changed, 3 insertions(+), 4 deletions(-)
  19
  20 diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
  21 index 1523d2e3dae97..7da88bdc0d6c3 100644
  22 --- a/fs/nfsd/nfscache.c
  23 +++ b/fs/nfsd/nfscache.c
  24 @@ -448,11 +448,8 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
  25         b = nfsd_cache_bucket_find(rqstp->rq_xid, nn);
  26         spin_lock(&b->cache_lock);
  27         found = nfsd_cache_insert(b, rp, nn);
  28 -       if (found != rp) {
  29 -               nfsd_reply_cache_free_locked(NULL, rp, nn);
  30 -               rp = found;
  31 +       if (found != rp)
  32                 goto found_entry;
  33 -       }
  34
  35         nfsd_stats_rc_misses_inc();
  36         rqstp->rq_cacherep = rp;
  37 @@ -470,8 +467,10 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
  38
  39  found_entry:
  40         /* We found a matching entry which is either in progress or done. */
  41 +       nfsd_reply_cache_free_locked(NULL, rp, nn);
  42         nfsd_stats_rc_hits_inc();
  43         rtn = RC_DROPIT;
  44 +       rp = found;
  45
  46         /* Request being processed */
  47         if (rp->c_state == RC_INPROG)
  48 --
  49 2.43.0
  50