Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs
From: Valdis . Kletnieks
Date: Wed May 04 2011 - 16:24:38 EST
On Wed, 04 May 2011 15:04:39 CDT, Christoph Lameter said:
> On Wed, 4 May 2011, Linus Torvalds wrote:
> > But cmpxchg DOES NOT MAKE SENSE without atomicity guarantees.
>
> This is not a real cmpxchg after all. Its not atomic in the sense of
> other functions. Its only "percpu atomic" if you want it that way. This is
> *not* a full cmpxchg_double().
Calling it a cmpxchg when it doesn't have the primary distinguishing property
of a hardware cmpxchg is just loading a bullet in the chamber and inviting
kernel hackers to point it at their feet...
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