Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs

[Linus Torvalds]

On Wed, May 4, 2011 at 1:04 PM, Christoph Lameter <cl@xxxxxxxxx> wrote:
>
> Maybe I should have pushed the cmpxchg_double() before the
> this_cpu_cmpxchg to avoid these misunderstandings

Christoph, the only mis-understanding is yours.

I understand perfectly that the percpu cmpxchg isn't SMP-atomic. We
all know that.

The problem is that cmpxchg *IS*NOT*AN*CMPXCHG*AT*ALL*. Not even on UP.

It's something totally different.

                   Linus
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