static bool update_mapping(struct int_map *map,
			   struct bucket *neighborhood,
			   u64 key,
			   void *new_value,
			   bool update,
			   void **old_value_ptr)
static bool update_mapping(struct int_map *map, struct bucket *neighborhood,
			   u64 key, void *new_value, bool update, void **old_value_ptr)