Re: [PATCH 09/11] cputime:Introduce the cputime_to_timespec64/timespec64_to_cputime function

Thomas Gleixner
2015-04-20T21:09:17Z

On Mon, 20 Apr 2015, Baolin Wang wrote:

> This patch introduces some functions for converting cputime to timespec64 and back,
> that repalce the timespec type with timespec64 type, as well as for arch/s390 and
> arch/powerpc architecture.

No. We want a patch which adds the functions and then a patch which
uses them. This stuff is tricky and hard to review. So please split
the patches into smaller chunks.

> +unsigned long
> +timespec64_to_jiffies(const struct timespec64 *value)
> +{
> + return __timespec_to_jiffies(value->tv_sec, value->tv_nsec);
> +}
> +EXPORT_SYMBOL(timespec64_to_jiffies);

So we have now two exports which are doing exactly the same
thing. Copy and paste is wonderful, right?

What about exporting __timespec_to_jiffies() and providing inlines for
timespec_to_jiffies() and timespec64_to_jiffies() ?

EXPORT_SYMBOL is not just a stupid annotation. Its impact on the
resulting kernel size is larger than the actual function
implementation.

> +void
> +jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
> +{
> + /*
> + * Convert jiffies to nanoseconds and separate with
> + * one divide.
> + */
> + u32 rem;
> + value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
> + NSEC_PER_SEC, &rem);
> + value->tv_nsec = rem;
> +}
> +EXPORT_SYMBOL(jiffies_to_timespec64);

Sigh.

Thanks,

tglx