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Date: Fri, 11 Jul 2008 16:02:13 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu
Subject: Re: [patch 13/17] Use WARN() in drivers/base/
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On Fri, 11 Jul 2008 15:51:05 -0700 Arjan van de Ven <arjan@infradead.org> wrote:

> On Fri, 11 Jul 2008 15:11:10 -0700
> Andrew Morton <akpm@linux-foundation.org> wrote:
> 
> > 
> > I don't suppose there's any way of tricking the preprocessor into
> > supporting
> > 
> > 	WARN_ON(foo == 42);
> > 
> > as well as
> > 
> > 	WARN_ON(foo == 42, "bite me!");
> > 
> 
> after reading preprocessor docs from gcc and trying some things:
> We can do this. It comes at a price: the price is a blank line in the
> WARN trace for the "no printk comments" case, and we lose the ability
> to override the printk level. (which you can argue is a feature by just
> setting it to KERN_WARNING).
> 
> (and some interesting but otherwise non-harmful preprocessor stuff in
> headers)

the blank line: might be avoidable by doing some extra work at runtime
to recognise its presence?

overriding facility level: doesn't sound very useful, as WARN()'s
stack-trace's facility level is not controllable.

> Is this is price worth paying to not have a second macro?

Dunno, how ugly is the patch?

It would be rather nice to not go and fatten the interface.  Would
there be additional text or data size costs?