Re: [PATCH] Make kunmap_atomic() harder to misuse

[Cesar Eduardo Barros]

Em 31-05-2010 07:15, Rusty Russell escreveu:
> On Sun, 30 May 2010 01:12:56 pm Andrew Morton wrote:
> > On Fri, 28 May 2010 07:53:13 -0300 Cesar Eduardo Barros<cesarb@xxxxxxxxxx>  wrote:
> > > +/* Prevent people trying to call kunmap_atomic() as if it were kunmap() */
> > > +struct __kunmap_atomic_dummy {};
> > > +#define kunmap_atomic(addr, idx) do { \
> > > +		BUILD_BUG_ON( \
> > > +			__builtin_types_compatible_p(typeof(addr), struct page *)&&  \
> > > +			!__builtin_types_compatible_p(typeof(addr), struct __kunmap_atomic_dummy *)); \
> > > +		kunmap_atomic_notypecheck((addr), (idx)); \
> > > +	} while (0)
> >
> > We have a little __same_type() helper for this.  __must_be_array()
> > should be using it, too.
>
> Yep... but I think BUILD_BUG_ON(__same_type((addr), struct page *)); is
> sufficient; void * is not compatible in my quick tests here.

That is what I get for only reading the manual instead of testing :(

(I only tested the completed patch, not each step along the way.)

I will try it later today and make a new patch if it works as expected.

--
Cesar Eduardo Barros
cesarb@xxxxxxxxxx
cesar.barros@xxxxxxxxx
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