int device_offline(struct device *dev)
{
	int ret;

	if (dev->offline_disabled)
		return -EPERM;

	ret = device_for_each_child(dev, NULL, device_check_offline);
	if (ret)
		return ret;

	device_lock(dev);
	if (device_supports_offline(dev)) {
		if (dev->offline) {
			ret = 1;
		} else {
			ret = dev->bus->offline(dev);
			if (!ret) {
				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
				dev->offline = true;
			}
		}
	}
	device_unlock(dev);

	return ret;
}
int device_offline(struct device *dev)
{
	int ret;

	if (dev->offline_disabled)
		return -EPERM;

	ret = device_for_each_child(dev, NULL, device_check_offline);
	if (ret)
		return ret;

	device_lock(dev);
	if (device_supports_offline(dev)) {
		if (dev->offline) {
			ret = 1;
		} else {
			ret = dev->bus->offline(dev);
			if (!ret) {
				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
				dev->offline = true;
			}
		}
	}
	device_unlock(dev);

	return ret;
}