Re: Fix unlock_buffer() to work the same way as bit_unlock()

[Nick Piggin]

Zoltan Menyhart wrote:

> However, I do not think your implementation would be efficient due to
> selecting the ordering mode at run time:
>
> > +    switch (mode) {
> > +    case MODE_NONE :
> > +    case MODE_ACQUIRE :
> > +        return cmpxchg_acq(m, old, new);
> > +    case MODE_FENCE :
> > +        smp_mb();
> > +        /* Fall through */
> > +    case MODE_RELEASE :
> > +        return cmpxchg_rel(m, old, new);

BTW. Isn't MODE_FENCE wrong? Seems like a read or write could be moved
above cmpxchg_rel?

I think you need rel+acq rather than acq+rel (if I'm right, then the
same goes for your earlier bitops patches, btw).

--
SUSE Labs, Novell Inc.
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