On 28 April 2015 at 19:04, Arnd Bergmann <[email protected]> wrote:

> On Tuesday 28 April 2015 18:50:25 Baolin Wang wrote:
> > On 28 April 2015 at 17:49, Arnd Bergmann <[email protected]> wrote:
>
> > > > +void
> > > > +jiffies_to_timespec(const unsigned long jiffies, struct timespec
> *value)
> > > > +{
> > > > +     struct timespec64 *ts;
> > > > +
> > > > +     *ts = timespec_to_timespec64(*value);
> > > > +     jiffies_to_timespec64(jiffies, ts);
> > > > +}
> > > >  EXPORT_SYMBOL(jiffies_to_timespec);
> > > >
> > >
> > > I would probably again put timespec_to_jiffies and jiffies_to_timespec
> > > into the header file as static inline functions, which implies that you
> > > then have to declare and export __timespec_to_jiffies.
> > >
> > >         Arnd
> > >
> >
> > But according to Thomas's suggestion, he would not like to add too much
> > "EXPORT_SYMBOL".
> > I also think here the "EXPORT_SYMBOL" is essential.
> >
>
> I think you just misunderstood his comments:
>
> On Monday 20 April 2015 23:09:17 Thomas Gleixner wrote:
> > 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.
>
> The main takeaway here is that you should use specifically the
> exports that are required, no more or less.
>
> If a kernel-internal API has an 'extern' declaration in a header
> file, it usually needs to be exported. What Thomas was suggesting
> here was to reduce the number of exports that are required by
> moving the two functions timespec_to_jiffies() and
> timespec64_to_jiffies() into the header file as 'static inline'
> functions that do not require the export.
>
> If you get a review comment asking you to change something in your
> patches, always make sure that you understand why that change is
> a good idea. If you don't understand it, it's better to ask for
> clarification than to blindly follow the advice and risk doing it
> wrong again.
>
>         Arnd
>

Thanks for your explanation, and i'll do that follow your suggestion.

-- 
Baolin.wang
Best Regards
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