Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in get_acl. x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx> Cc: Christian Brauner <brauner@xxxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> --- fs/posix_acl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index d7bc81fc0840..420c689e1bec 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -174,7 +174,7 @@ static struct posix_acl *__get_acl(struct user_namespace *mnt_userns, * Cache the result, but only if our sentinel is still in place. */ posix_acl_dup(acl); - if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) + if (unlikely(!try_cmpxchg(p, &sentinel, acl))) posix_acl_release(acl); return acl; } -- 2.38.1
