Re: Missing wait_event_killable_timeout?

From: Peter Hurley
Date: Wed Oct 21 2015 - 10:08:34 EST


Hi Jens,

On 10/21/2015 03:20 AM, Kilian, Jens wrote:
> I'd like to use a version of wait_event_killable() with a timeout, but it seems to be missing? I found a mention of it in a recent LKML message though:
>
> https://lkml.org/lkml/2015/10/14/337
>
> Does this patch look reasonable?

Where is the in-tree user? Without that, someone will notice this
isn't being used and will remove it.

Regards,
Peter Hurley

> diff --git a/include/linux/wait.h b/include/linux/wait.h
> index 1e1bf9f..8419986 100644
> --- a/include/linux/wait.h
> +++ b/include/linux/wait.h
> @@ -738,6 +738,41 @@ do { \
> __ret; \
> })
>
> +#define __wait_event_killable_timeout(wq, condition, timeout) \
> + ___wait_event(wq, ___wait_cond_timeout(condition), \
> + TASK_KILLABLE, 0, timeout, \
> + __ret = schedule_timeout(__ret))
> +
> +/**
> + * wait_event_killable_timeout - sleep until a condition gets true or a timeout elapses
> + * @wq: the waitqueue to wait on
> + * @condition: a C expression for the event to wait for
> + * @timeout: timeout, in jiffies
> + *
> + * The process is put to sleep (TASK_KILLABLE) until the @condition
> + * evaluates to true or a signal is received.
> + * The @condition is checked each time the waitqueue @wq is woken up.
> + *
> + * wake_up() has to be called after changing any variable that could
> + * change the result of the wait condition.
> + *
> + * Returns:
> + * 0 if the @condition evaluated to %false after the @timeout elapsed,
> + * 1 if the @condition evaluated to %true after the @timeout elapsed,
> + * the remaining jiffies (at least 1) if the @condition evaluated
> + * to %true before the @timeout elapsed, or -%ERESTARTSYS if it was
> + * interrupted by a signal.
> + */
> +#define wait_event_killable_timeout(wq, condition, timeout) \
> +({ \
> + long __ret = timeout; \
> + might_sleep(); \
> + if (!___wait_cond_timeout(condition)) \
> + __ret = __wait_event_killable_timeout(wq, \
> + condition, timeout); \
> + __ret; \
> +})
> +
>
> #define __wait_event_lock_irq(wq, condition, lock, cmd) \
> (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
>
>

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