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From: Andi Kleen <ak@suse.de>
Subject: Re: dealing with excessive includes
Date: Mon, 23 Oct 2006 03:31:16 +0200
References: <20061018091944.GA5343@martell.zuzino.mipt.ru> <200610230242.58647.ak@suse.de> <20061023010812.GE25210@parisc-linux.org>
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To: Matthew Wilcox <matthew@wil.cx>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>, Randy Dunlap <rdunlap@xenotime.net>, Stefan Richter <stefanr@s5r6.in-berlin.de>, Al Viro <viro@ftp.linux.org.uk>, Linus Torvalds <torvalds@osdl.org>, Alexey Dobriyan <adobriyan@gmail.com>, Linux Kernel Development <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org
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On Monday 23 October 2006 03:08, Matthew Wilcox wrote:
> On Mon, Oct 23, 2006 at 02:42:58AM +0200, Andi Kleen wrote:
> > 
> > > /*+
> > >  * Provides: struct sched
> > >  * Provides: total_forks, nr_threads, process_counts, nr_processes()
> > >  * Provides: nr_running(), nr_uninterruptible(), nr_active(), nr_iowait(), weighted_cpuload()
> > >  */
> > 
> > That's ugly.  If it needs that i don't think it's a good idea.
> > We really want standard C, not some Linux dialect.
> 
> Um, that's a comment.  It's standard C.

If you require it to do something it isn't a comment anymore -- it would become
a language extension.

> 
> Here's the problem.  If a file needs canonicalize_irq(), it should
> include <linux/interrupt.h> (which eventually ends up including
> asm/irq,h), and not <asm/irq.h> (where it's defined).
> If a file needs add_wait_queue(), it should include <linux/wait.h>
> (where it's defined) and not <linux/fs.h> (which directly includes
> linux/wait.h>.
> 
> Please define an algorithm which distinguishes the two cases.

Needs are inside {} or in a macro definition
So if the identifier happens after #define or inside {} assume the symbol
is needed from somewhere else, otherwise it is declared here.

That is likely not 100% foolproof, but should be good enough and
the mismatches can be resolved by hand.

-Andi