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From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it.
Date: Tue, 28 May 2013 19:20:37 +0200	[thread overview]
Message-ID: <201305281920.37452.arnd@arndb.de> (raw)
In-Reply-To: <51A4D618.3080208@zytor.com>

On Tuesday 28 May 2013, H. Peter Anvin wrote:
> On 05/28/2013 08:43 AM, Arnd Bergmann wrote:
> > 
> > Right, that is what the patch I just posted does.
> > 
> > On a related note, I found that WARN_ON() can no longer be compiled
> > out since there is already code that relies on the side-effects of
> > the condition. I assume that was an intentional change I missed,
> > since it used to be defined so that you could remove it completely.
> > 
> 
> It is possible to define WARN_ON() as:
> 
> #define WARN_ON(x) ((void)(x))
> 
> ... which preserves side effects.

Yes, actually the return value has to be maintained as well.
The current (!CONFIG_BUG) default implementation is

#define WARN_ON(condition) ({                                           \
        int __ret_warn_on = !!(condition);                              \
        unlikely(__ret_warn_on);                                        \
})

which seems fine.

#define WARN_ON(condition) unlikely(!!(condition))

is probably just as good.

	Arnd

  reply	other threads:[~2013-05-28 17:20 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-23  7:57 [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it Chen Gang
2013-05-23  8:40 ` Geert Uytterhoeven
2013-05-23  8:54   ` Arnd Bergmann
2013-05-23  9:05   ` Russell King - ARM Linux
2013-05-23  9:12     ` Geert Uytterhoeven
2013-05-23  9:39       ` Arnd Bergmann
2013-05-23 10:04         ` Russell King - ARM Linux
2013-05-23 10:41           ` Chen Gang
2013-05-23 10:59           ` Arnd Bergmann
2013-05-23 11:19             ` Chen Gang
2013-05-23 11:24             ` Russell King - ARM Linux
2013-05-23 12:09               ` Arnd Bergmann
2013-05-23 12:50                 ` Russell King - ARM Linux
2013-05-23 14:10                   ` Geert Uytterhoeven
2013-05-24  2:13                     ` Chen Gang
2013-05-24  4:17                       ` Chen Gang
2013-05-26  4:43                         ` [PATCH v2] arch: configuration issue, random return value when disable 'CONFIG_BUG' Chen Gang
2013-05-28  8:19           ` [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it Ingo Molnar
2013-05-28 10:25             ` Chen Gang
2013-05-28 14:49             ` Arnd Bergmann
2013-05-28 14:55             ` H. Peter Anvin
2013-05-28 15:43               ` Arnd Bergmann
2013-05-28 16:06                 ` H. Peter Anvin
2013-05-28 17:20                   ` Arnd Bergmann [this message]
2013-05-23 10:09         ` Eric W. Biederman
2013-05-23 10:29           ` Russell King - ARM Linux
2013-05-23 10:05       ` Chen Gang
2013-05-24  5:59 ` Eric W. Biederman

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