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SubjectRe: [thisops uV2 04/10] x86: Support for this_cpu_add,sub,dec,inc_return
* Christoph Lameter (cl@linux.com) wrote:
> On Sat, 27 Nov 2010, Mathieu Desnoyers wrote:
>
> > > +/*
> > > + * Add return operation
> > > + */
> > > +#define percpu_add_return_op(var, val) \
> > > +({ \
> > > + typedef typeof(var) pao_T__; \
> > > + typeof(var) pfo_ret__ = val; \
> > > + if (0) { \
> > > + pao_T__ pao_tmp__; \
> > > + pao_tmp__ = (val); \
> > > + (void)pao_tmp__; \
> > > + } \
> >
> > OK, I'm dumb: why is the above needed ?
>
> Ensure that the compiler agrees that *var and val are compatible. Taken
> over from percpu_add_op().

Isn't that the purpose of __builtin_types_compatible_p(t1, t2) ?

Mathieu

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com


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