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Date: Mon, 19 Sep 2005 09:22:25 +1000
From: Paul Mackerras <paulus@samba.org>
To: Jon Loeliger <jdl@freescale.com>
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Cc: "linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>,
	linuxppc64-dev <linuxppc64-dev@ozlabs.org>
Subject: Re: Merge Question on asm-ppc*/rwsem.h
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Jon Loeliger writes:

> Which begs the question, what is the "else smp_wmb();" clause
> really doing for us in the ppc32 case, and can we either
> get rid of it, or is it safe to add to the ppc64 case?

I think the difference is that the atomic ops that return a value also
have include a barrier on ppc64, but don't on ppc32 (although they
probably should).  IOW I think the merged case should follow ppc64
here.

Paul.