Date: Thu, 26 Nov 2015 14:52:34 +0000
From: Chris Wilson <chris@chris-wilson.co.uk>
To: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: mingo@kernel.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        Patrick Plagwitz <patrick.plagwitz@fau.de>,
        Andreas Ziegler <ziegler@cs.fau.de>, Daniel Lohmann <dl@cs.fau.de>
Subject: Re: kernel: stop_machine: report (un)dead code (and feedback request)
Message-ID: <20151126145234.GL23362@nuc-i3427.alporthouse.com>
References: <20151126144559.GA19758@debian-vm>
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On Thu, Nov 26, 2015 at 03:45:59PM +0100, Valentin Rothberg wrote:
> Hi Chris,
> 
> your commit 4c477de14237 ("kernel: remove stop_machine() Kconfig
> dependency") has shown up in today's linux-next tree (20151126).
> The commit changes the #ifdef condition in kernel/stop_machine.c
> from/to:
> 
>     -#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
>     +#if defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
> 
> Although this change fixes certain configs on X86, the condition now is
> a tautology since CONFIG_SMP is already required to compile the file:
> 
>     kernel/Makefile:65:obj-$(CONFIG_SMP) += stop_machine.o
> 
> AFAIU, we can safely remove this #ifdef?

That seems logical. The argument in favour of it would be to keep the
ifdeffery around the function defintion the same as the function
declaration in stop_machine.h.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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