Re: [PATCH 1/9] kernel: export sound/core/pcm_timer.c gcd implementation

[Florian Fainelli]

Le Tuesday 02 June 2009 06:50:34 Andrew Morton, vous avez écrit :
> On Mon, 1 Jun 2009 13:57:09 +0200 Florian Fainelli <florian@xxxxxxxxxxx> 
wrote:
> > This patch exports the gcd implementation from
> > sound/core/pcm_timer.c into include/linux/kernel.h.
> > AR7 uses it in its clock routines.
> >
> > ...
> >
> > diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> > index 883cd44..878a27a 100644
> > --- a/include/linux/kernel.h
> > +++ b/include/linux/kernel.h
> > @@ -147,6 +147,22 @@ extern int _cond_resched(void);
> >  		(__x < 0) ? -__x : __x;		\
> >  	})
> >
> > +/* Greatest common divisor */
> > +static inline unsigned long gcd(unsigned long a, unsigned long b)
> > +{
> > +        unsigned long r;
> > +        if (a < b) {
> > +                r = a;
> > +                a = b;
> > +                b = r;
> > +        }
> > +        while ((r = a % b) != 0) {
> > +                a = b;
> > +                b = r;
> > +        }
> > +        return b;
> > +}
>
> a) the name's a bit sucky.   Is there some convention for this name?

We might want something better like greatest_common_divisor which is a bit 
more self-explanatory ?

>
> b) It looks too large to be inlined.  lib/gdc.c?

And its users select it in order not to increase the size of kernel.h, sounds 
good.

>
> b) there's an implementation of gcd() in
>    net/netfilter/ipvs/ip_vs_wrr.c.  I expect that this patch broke the
>    build.

I did forget about this. That gcd implementation only treats the a > b case.

What do you prefer, each user keeps its gcd implementation locally or we make 
a lib/gcd.c for it ?

Thanks
-- 
Best regards, Florian Fainelli
Email : florian@xxxxxxxxxxx
http://openwrt.org
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