Re: [patch 03/44] posix-timer: Use a callback for cancel synchronization

[Christoph Hellwig]

> +	if (!WARN_ON_ONCE(kc->timer_wait_running))
> +		kc->timer_wait_running(timer);

This looks weird. The only place calling yor new method only does so
after checking that it is not set and actually warns if it set?