epoch: Prefer additional return point to nesting.

src/ck_epoch.c

@@ -143,12 +143,15 @@ void
 _ck_epoch_delref(struct ck_epoch_record *record,
     struct ck_epoch_section *section)
 {
-	struct ck_epoch_ref *current;
+	struct ck_epoch_ref *current, *other;
 	unsigned int i = section->bucket;
 
 	current = &record->local.bucket[i];
 	current->count--;
 
+	if (current->count > 0)
+		return;
+
 	/*
 	 * If the current bucket no longer has any references, then
 	 * determine whether we have already transitioned into a newer
@@ -158,9 +161,6 @@ _ck_epoch_delref(struct ck_epoch_record *record,
 	 * If no other active bucket exists, then the record will go
 	 * inactive in order to allow for forward progress.
 	 */
-	if (current->count == 0) {
-		struct ck_epoch_ref *other;
-
 	other = &record->local.bucket[(i + 1) &
 	    CK_EPOCH_SENSE_MASK];
 	if (other->count > 0 &&
@@ -171,7 +171,6 @@ _ck_epoch_delref(struct ck_epoch_record *record,
 		 */
 		ck_pr_store_uint(&record->epoch, other->epoch);
 	}
-	}
 
 	return;
 }