Re: [PATCH] futex: cmpxchg_futex_value_locked API change

From: Chris Metcalf
Date: Mon Mar 07 2011 - 09:25:41 EST


On 3/6/2011 9:11 PM, Michel Lespinasse wrote:
> The cmpxchg_futex_value_locked API was funny in that it returned either
> the original, user-exposed futex value OR an error code such as -EFAULT.
> This was confusing at best, and could be a source of livelocks in places
> that retry the cmpxchg_futex_value_locked after trying to fix the issue
> by running fault_in_user_writeable().
>
> This change makes the cmpxchg_futex_value_locked API more similar to the
> get_futex_value_locked one, returning an error code and updating the
> original value through a reference argument.
> [...]
> diff --git a/arch/tile/include/asm/futex.h b/arch/tile/include/asm/futex.h

Makes sense to me; that API is a little crazy.

For the tile changes:

Acked-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>

--
Chris Metcalf, Tilera Corp.
http://www.tilera.com

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