Re: [GIT PULL -tip] fix 41 'make headers_check' warnings

[Jaswinder Singh Rajput <jaswinder@kernel.org>]

On Sun, 2009-01-18 at 18:29 +0100, Ingo Molnar wrote:
> * Sam Ravnborg <sam@ravnborg.org> wrote:
> 
> > On Sun, Jan 18, 2009 at 01:57:22PM +0100, Sam Ravnborg wrote:
> > > On Sun, Jan 18, 2009 at 12:02:21PM +0100, Ingo Molnar wrote:
> > > > 
> > > > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> > > > 
> > > > > diff --git a/include/linux/acct.h b/include/linux/acct.h
> > > > > index 882dc72..a20c97c 100644
> > > > > --- a/include/linux/acct.h
> > > > > +++ b/include/linux/acct.h
> > > > > @@ -59,9 +59,13 @@ struct acct
> > > > >  	comp_t		ac_majflt;		/* Major Pagefaults */
> > > > >  	comp_t		ac_swaps;		/* Number of Swaps */
> > > > >  /* m68k had no padding here. */
> > > > > -#if !defined(CONFIG_M68K) || !defined(__KERNEL__)
> > > > > +#ifdef __KERNEL__
> > > > > +#ifndef CONFIG_M68K
> > > > >  	__u16		ac_ahz;			/* AHZ */
> > > > > -#endif
> > > > > +#endif /* CONFIG_M68K */
> > > > > +#else /* __KERNEL__ */
> > > > > +	__u16		ac_ahz;			/* AHZ */
> > > > > +#endif /* __KERNEL__ */
> > > > 
> > > > that looks rather ugly.
> > > > 
> > > > Why not just flip it around to:
> > > > 
> > > > 	#if !defined(__KERNEL__) || !defined(CONFIG_M68K)
> > > > 
> > > > ? Does headers_check misinterpret that?
> > > 
> > > The original expression is misinterpreted by headers_check
> > > because we want the ac_ahz to stay if either of __KERNEL__
> > > or CONFIG_M68K is not defined.
> > > And unifdef does not optimize away the !defined(CONFIG_M68K)
> > > part - it has no knowledge that this is kernel internal.
> > > 
> > > So I am happy with Jaswinder's patch.
> > Almost happy.
> > I digged out my original patch and it looks like this:
> > -#if !defined(CONFIG_M68K) || !defined(__KERNEL__)
> > +#ifndef __KERNEL__
> >         __u16           ac_ahz;                 /* AHZ */
> > +#else
> > +  #ifndef CONFIG_M68K
> > +       __u16           ac_ahz;                 /* AHZ */
> > +  #endif
> >  #endif
> > 
> > The indention can be discussed..
> > But the logic is simpler.
> 
> yes - that's the 3-block versus 2-block issue i mentioned to Jaswinder. 
> (the first version duplicated the same thing into 3 places - while the 
> logic only splits it in two)

my 7 lines patch was:
#ifdef __KERNEL__
#ifndef CONFIG_M68K
	__u16		ac_ahz;			/* AHZ */
#endif /* CONFIG_M68K */
#else /* __KERNEL__ */
	__u16		ac_ahz;			/* AHZ */
#endif /* __KERNEL__ */

and Sam's 7 line patch is:
#ifndef __KERNEL__
         __u16           ac_ahz;                 /* AHZ */
#else
  #ifndef CONFIG_M68K
         __u16           ac_ahz;                 /* AHZ */
  #endif
#endif

Ingo, please apply the patch which one you like, I just want to get rid of this warning ;-)

Thanks,
--
JSR