struct class_device *tmp;  if (!bus) return NULL;  tmp = class_device_get(&bus->class_dev); if (tmp) return to_usb_bus(tmp); else return NULL;
if (bus) kref_get(&bus->kref); return bus;
struct usb_bus *usb_bus_get (struct usb_bus *bus){	struct class_device *tmp;	if (!bus)		return NULL;	tmp = class_device_get(&bus->class_dev);	if (tmp)        		return to_usb_bus(tmp);	else		return NULL;}