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Date: Sat, 25 Dec 2010 17:55:22 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
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To: Tejun Heo <tj@kernel.org>
cc: "H. Peter Anvin" <hpa@zytor.com>, akpm@linux-foundation.org,
        Pekka Enberg <penberg@cs.helsinki.fi>, linux-kernel@vger.kernel.org,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [cpuops cmpxchg double V1 1/4] Generic support for
 this_cpu_cmpxchg_double
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On Sat, 25 Dec 2010, Tejun Heo wrote:

> ABI.  But that said, it might still be problematic on other
> architectures when we try to apply it to different architectures.  Is
> everyone against just taking a scalar for the first variable instead
> of taking a pointer?  I'd be happier with that than the current one.

How about replacing that with two scalars? Macro will check that the
scalaers are properly aligned and that the second follows the first. Then
there is also better symmetry in the parameters.

bool this_cpu_cmpxchg_double(
          percpu_1, percpu_2
          old_1, old_2
          new_1, new_2
)