hrtimer_expires_remaining
} while (hrtimer_expires_remaining(timer) > 0);
remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer));
rem = hrtimer_expires_remaining(timer);
ktime_t rem = hrtimer_expires_remaining(&t->timer);
remaining = ktime_to_ns(hrtimer_expires_remaining(&t.timer));