/* Request a notification when the current cpu returns to userspace. Must be called in atomic context. The notifier will also be called in atomic context.  */
void user_return_notifier_register(struct user_return_notifier *urn)
/* Request a notification when the current cpu returns to userspace. Must be called in atomic context. The notifier will also be called in atomic context.  */
void user_return_notifier_register(struct user_return_notifier *urn)
{
	set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
	hlist_add_head(&urn->link, &__get_cpu_var(return_notifier_list));
}