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Message-Id: <20070720132138.63d8f931.akpm@linux-foundation.org>
Date: Fri, 20 Jul 2007 13:21:38 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>,
Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>,
linux-ia64@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [IA64] Add mapping table between irq and vector
On Fri, 20 Jul 2007 13:17:28 -0700
Andrew Morton <akpm@...ux-foundation.org> wrote:
> On Fri, 20 Jul 2007 19:59:17 GMT
> Linux Kernel Mailing List <linux-kernel@...r.kernel.org> wrote:
>
> > + BUG_ON(bind_irq_vector(irq, vector));
>
> It's not good practice to do assert(expression-with-side-effects). Because
> if someone wants to create a build which has all the assertions disabled,
> the resulting binary will not work.
>
> In the present implementation our BUG_ON(expression) will evaluate
> `expression' even if CONFIG_BUG=n. But that's totally lame and we are just
> leaving optimisation opportunities on the floor.
>
> Our objective _should_ be to make BUG_ON(expr) generate no code at all if
> CONFIG_BUG=n.
>
> So please, prefer to do
>
> if (bind_irq_vector(irq, vector))
> BUG();
>
hm, now I think about it, our present implementation seems OK. If you
have CONFIG_BUG=n then this:
BUG_ON(foo < bar);
will generate no code and this:
BUG_ON(some_function());
will still call some_function().
So I guess we're OK.
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