From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Lameter <clameter@sgi.com>
Subject: Re: [PATCH 0/24] make atomic_read() behave consistently across all
 architectures
Date: Thu, 16 Aug 2007 13:20:26 -0700 (PDT)
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To: Chris Snook <csnook@redhat.com>
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On Thu, 16 Aug 2007, Chris Snook wrote:

> atomic_dec() already has volatile behavior everywhere, so this is semantically
> okay, but this code (and any like it) should be calling cpu_relax() each
> iteration through the loop, unless there's a compelling reason not to.  I'll
> allow that for some hardware drivers (possibly this one) such a compelling
> reason may exist, but hardware-independent core subsystems probably have no
> excuse.

No it does not have any volatile semantics. atomic_dec() can be reordered 
at will by the compiler within the current basic unit if you do not add a 
barrier.