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

[Sam Ravnborg <sam@ravnborg.org>]

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.

	Sam