Re: [PATCH] sparc32: Implement xchg and atomic_xchg using ATOMIC_HASH locks

From: David Miller
Date: Fri Nov 07 2014 - 15:52:36 EST


From: Andreas Larsson <andreas@xxxxxxxxxxx>
Date: Wed, 5 Nov 2014 15:52:08 +0100

> Atomicity between xchg and cmpxchg cannot be guaranteed when xchg is
> implemented with a swap and cmpxchg is implemented with locks.
> Without this, e.g. mcs_spin_lock and mcs_spin_unlock are broken.
>
> Signed-off-by: Andreas Larsson <andreas@xxxxxxxxxxx>

Unfortunate, but obviously necessary.

Applied and queued up for -stable, thanks!
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