On Tue, Oct 02, 2007 at 03:22:10PM +0100, Thiemo Seufer wrote:
> > +#define __cmpxchg(ptr,old,new,barrier) \
> > +({ \
> > + __typeof__(ptr) __ptr = (ptr); \
> > + __typeof__(*(ptr)) __old = (old); \
> > + __typeof__(*(ptr)) __new = (new); \
> > + __typeof__(*(ptr)) __res = 0; \
>
> Maybe we need an acquire barrier here for some systems.
Release you meant. The acquire lock would be at the end. Documentation
and actual implmeentations of cmpxchg seem to differ. It's a relativly
rarely used primitve so I think I err on the side of paranoia for now
and throw in the additional SYNC you suggest.
Ralf
