Subject: Re: [RFC][PATCH] introduce ptr_diff()
From: Bernd Petrovitsch <bernd@sysprog.at>
To: Namhyung Kim <namhyung@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>, Arnd Bergmann <arnd@arndb.de>,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <1282233186.1713.10.camel@leonhard>
References: <1282217856-8625-1-git-send-email-namhyung@gmail.com>
	 <87aaoiu6z6.fsf@basil.nowhere.org>  <1282233186.1713.10.camel@leonhard>
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Date: Thu, 19 Aug 2010 18:04:49 +0200
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On Fre, 2010-08-20 at 00:53 +0900, Namhyung Kim wrote:
> 2010-08-19 (목), 14:23 +0200, Andi Kleen:
> > IMHO it would be better to simply disable the warning in sparse instead
> > of uglying the code just to work around sparse bogosity. It doesnt' seem
> > to make much sense. A subtraction followed by a shift is not expensive.
[...]
> I'm curious who turns on that switch. -Wptr-subtraction-blows is turned
> off by default, I didn't use CF variable at build time and I could not
> find any reference of it in the source tree. Hmm..

sparse also gets gcc's parameters which include (usually) "-Wall". And
this activates it.
Adding -Wno-ptr-subtraction-blows to CHECKFLAGS should do the trick.

	Bernd
-- 
mobile: +43 664 4416156              http://www.sysprog.at/
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