MFC: r317982

- Also outside of the KOBJOPLOOKUP macro - which in turn is used by
  the code auto-generated for *.m - kobj_lookup_method(9) is useful;
  for example in back-ends or base class device drivers in order to
  determine whether a default method has been overridden. Thus, allow
  for the kobj_method_t pointer argument - used by KOBJOPLOOKUP in
  order to update the cache entry - of kobj_lookup_method(9), to be
  NULL. Actually, that pointer is redundant as it's just set to the
  same kobj_method_t that the kobj_lookup_method(9) function returns
  in the first place, but probably it serves to reduce the number of
  instructions generated for KOBJOPLOOKUP.
- For the same reason, move updating kobj_lookup_{hits,misses} (if
  KOBJ_STATS is defined) from kobj_lookup_method(9) to KOBJOPLOOKUP.
  As a side-effect, this gets rid of the convoluted approach of always
  incrementing kobj_lookup_hits in KOBJOPLOOKUP and then in case of
  a cache miss, decrementing it in kobj_lookup_method(9) again.

1 files changed, 2 insertions, 10 deletions

diff --git a/sys/kern/subr_kobj.c b/sys/kern/subr_kobj.c
index 5be746a..15a7b8a 100644
--- a/sys/kern/subr_kobj.c
+++ b/sys/kern/subr_kobj.c
@@ -213,19 +213,11 @@ kobj_lookup_method(kobj_class_t cls,
 {
 	kobj_method_t *ce;
 
-#ifdef KOBJ_STATS
-	/*
-	 * Correct for the 'hit' assumption in KOBJOPLOOKUP and record
-	 * a 'miss'.
-	 */
-	kobj_lookup_hits--;
-	kobj_lookup_misses++;
-#endif
-
 	ce = kobj_lookup_method_mi(cls, desc);
 	if (!ce)
 		ce = &desc->deflt;
-	*cep = ce;
+	if (cep)
+		*cep = ce;
 	return ce;
 }