int ret;
struct klist_iter i; struct device_driver * drv; int error = 0;
int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,		     void * data, int (*fn)(struct device_driver *, void *)){	int ret;	down_read(&bus->subsys.rwsem);	ret = __bus_for_each_drv(bus, start, data, fn);	up_read(&bus->subsys.rwsem);	return ret;}