From: Arnd Bergmann <arnd@arndb•de>
To: "H. Peter Anvin" <hpa@zytor•com>
Cc: Catalin Marinas <Catalin.Marinas@arm•com>,
Linux-sh list <linux-sh@vger•kernel.org>,
Chen Gang <gang.chen@asianux•com>,
Heiko Carstens <heiko.carstens@de•ibm.com>,
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Russell King - ARM Linux <linux@arm•linux.org.uk>,
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David Miller <davem@davemloft•net>
Subject: Re: [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
next prev parent reply other threads:[~2013-05-28 17:23 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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