alarm_expires_remaining
remain = alarm_expires_remaining(cm_timer);
remaining = alarm_expires_remaining(&ctx->t.alarm);
ktime_t alarm_expires_remaining(const struct alarm *alarm);
EXPORT_SYMBOL_GPL(alarm_expires_remaining);
ktime_t tout = alarm_expires_remaining(&info->timer->alarm);
ktime_t expires_alarm = alarm_expires_remaining(&timer->alarm);