From: Sam Ravnborg <sam@ravnborg.org>
To: Fabio Estevam <fabio.estevam@freescale.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
paul.gortmaker@windriver.com, linux@arm.linux.org.uk
Subject: Re: [PATCH] kernel.h: Include <linux/bug.h> to avoid build breakage with ARRAY_SIZE()
Date: Tue, 28 Feb 2012 16:51:24 +0100 [thread overview]
Message-ID: <20120228155124.GA2827@merkur.ravnborg.org> (raw)
In-Reply-To: <1330436499-17190-1-git-send-email-fabio.estevam@freescale.com>
On Tue, Feb 28, 2012 at 10:41:39AM -0300, Fabio Estevam wrote:
> Building imx_v6_v7_defconfig generated the following build error:
>
> arch/arm/mach-imx/cpu_op-mx51.c: In function 'mx51_get_cpu_op':
> arch/arm/mach-imx/cpu_op-mx51.c:27: error: implicit declaration of function 'BUILD_BUG_ON_ZERO'
>
> commit 6f863554 (kernel.h: doesn't explicitly use bug.h, so don't include it.)
> has removed asm/debug.h from linux/kernel.h.
>
> Quoting Russell King (http://www.spinics.net/lists/arm-kernel/msg161916.html)
>
> "linux/kernel.h _does_ use bug stuff - in ARRAY_SIZE().
>
> ARRAY_SIZE() uses __must_be_array(), which is defined in linux/compiler-gcc.h,
> which is obtained via linux/compiler.h and linux/linkage.h.
>
> linux/compiler-gcc.h defines __must_be_array() to be:
> #define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
In which case linux/compiler-gcc.h uses bug.h - so this is where you
should add the include.
Not in kernel.h that just happens to use __must_be_array()
We do not want to add "#include bug.h" to all header files
that happens to use __must_be_array.
Sam
next prev parent reply other threads:[~2012-02-28 15:51 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-28 13:41 [PATCH] kernel.h: Include <linux/bug.h> to avoid build breakage with ARRAY_SIZE() Fabio Estevam
2012-02-28 15:51 ` Sam Ravnborg [this message]
2012-02-28 16:43 ` Paul Gortmaker
2012-02-28 20:06 ` Sam Ravnborg
2012-03-02 1:15 ` [PATCH v2] compiler.h: " Fabio Estevam
2012-03-02 2:49 ` Paul Gortmaker
2012-03-02 3:13 ` Fabio Estevam
2012-03-02 14:22 ` Paul Gortmaker
2012-04-04 14:29 ` Uwe Kleine-König
2012-04-05 18:35 ` Paul Gortmaker
2012-04-05 18:52 ` Uwe Kleine-König
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