Re: [bisected] kernel panic 2.6.22 -> 2.6.26-rc9+

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 13 Jul 2008 23:51:06 +0200 Krzysztof Halasa <khc@pm.waw.pl> wrote:

> Andrew Morton <akpm@linux-foundation.org> writes:
> 
> > --- a/include/asm-arm/bitops.h~a
> > +++ a/include/asm-arm/bitops.h
> > @@ -277,9 +277,16 @@ static inline int constant_fls(int x)
> >   * the clz instruction for much better code efficiency.
> >   */
> >  
> > -#define fls(x) \
> > +#define __fls(x) \
> >  	( __builtin_constant_p(x) ? constant_fls(x) : \
> >  	  ({ int __r; asm("clz\t%0, %1" : "=r"(__r) : "r"(x) : "cc"); 32-__r; }) )
> > +
> > +/* Implement fls() in C so that 64-bit args are suitably truncated */
> > +static inline int fls(int x)
> > +{
> > +	return __fls(x);
> > +}
> > +
> 
> Well, I like it more as it fixes all possible places instead of only
> fls64().
> 
> But... can't we just move the #define body into the inline fls(x)?
> Will there be other users of __fls(x)? It seems the
> __builtin_constant_p(x) works for inline functions.

Could.  That was a minimal&safe thing.

> The above patch fixes the kernel panic, too.

OK, thanks.