Date: Thu, 19 Aug 2010 15:39:22 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Andi Kleen <andi@firstfloor.org>, Namhyung Kim <namhyung@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] introduce ptr_diff()
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On Thu, Aug 19, 2010 at 03:05:13PM +0200, Bernd Petrovitsch wrote:
> On Don, 2010-08-19 at 14:59 +0200, Andi Kleen wrote:
> > > If so, the warning seems valid as sizeof(struct page) is probably not
> > > (always) a power of 2. On a native build on x86_64 it is 56 bytes
> > > hereover.
> > > Hmm ....
> > 
> > gcc just generats a mull with inverted value. mull is cheap on any
> > reasonable CPU.  Please fix sparse.
> 
> Not that I really know the code of sparse but what would be an
> acceptable condition (except plain simply disabling/removing the warning
> as such)?

I think acceptable would be to warn if the type is variable sized
(although I think gcc likely would error out in this case anyways)

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.
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