backward_mask 2230 kernel/locking/lockdep.c unsigned long usage_mask = 0, forward_mask, backward_mask; backward_mask 2276 kernel/locking/lockdep.c backward_mask = original_mask(target_entry1->class->usage_mask); backward_mask 2278 kernel/locking/lockdep.c ret = find_usage_backwards(&this, backward_mask, &target_entry);