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Date: Thu, 24 Apr 2008 15:14:15 -0700 (PDT)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       Alexander van Heukelum <heukelum@mailshack.com>
Subject: Re: [git pull] generic bitops
In-Reply-To: <20080424215739.GA32378@elte.hu>
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References: <20080424215739.GA32378@elte.hu>
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On Thu, 24 Apr 2008, Ingo Molnar wrote:
>
> this started out as improvements/generalizations to x86 bitops, but grew 
> generic impact (and generic optimizations) as well, so it's offered as a 
> separate tree.

Can you do the config thing differently?

> diff --git a/arch/um/Kconfig.i386 b/arch/um/Kconfig.i386
> index e09edfa..49990ea 100644
> --- a/arch/um/Kconfig.i386
> +++ b/arch/um/Kconfig.i386
> @@ -39,6 +39,14 @@ config ARCH_REUSE_HOST_VSYSCALL_AREA
>  	bool
>  	default y
>  
> +config GENERIC_FIND_FIRST_BIT
> +	bool
> +	default y
> +
> +config GENERIC_FIND_NEXT_BIT
> +	bool
> +	default y
> +

.. because instead of having each architecture do these kinds of things, 
we're trying to make the *generic* code (ie lib/Kconfig) do

	config GENERIC_FIND_FIRST_BIT
		bool
		default n

so that you only have one single declaration (close to where the code 
actually exists), and then the architectures would just do

	select GENERIC_FIND_FIRST_BIT
	select GENERIC_FIND_NEXT_BIT

in their architecture settings. That's how we're now doing things like 
HAVE_IDE, HAVE_OPROFILE, etc etc.

Hmm?

		Linus