Re: [uclinux-dist-devel] [GIT PULL] Blackfin updates for 3.11

[Linus Torvalds]

On Mon, Jul 15, 2013 at 10:28 AM, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> wrote:
>
> but the first one is non-trivial: using xchg() on atomic_t is a bit gross...

It's also broken. There's no guarantee that an "atomic_t" is just a
value. Now, the old sparc32 stuff (which hid lock bits in atomic_t)
may be gone, but it's still the case that atomic_t may not actually
work with xchg.

(In *practice* it works on normal architectures, so I'm not saying
that we don't have it, but it's a bug if we do).

There are "atomic_xchg()" and "atomic_xchg64()" functions that are supported.

             Linus
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