[patch 1/2] powerpc: rmb fix
Segher Boessenkool
segher at kernel.crashing.org
Wed Aug 22 13:33:16 EST 2007
>> The I/O accessor functions enforce the necessary ordering
>> already I believe.
>
> Hmm, I never followed those discussions last year about IO ordering,
> and
> I can't see where (if) it was documented anywhere :(
The comments in system.h weren't updated with the last fix, I think.
> It appears that legacy code is handled by defining the old IO
> accessors to
> be completely ordered, and introducing new __raw_ variants that are not
> (OTOH, it seems like other architectures are implementing __raw prefix
> as
> inorder unless there is a _relaxed postfix).
__raw_XX() is for platform code only, which can do the needed
barriers without having to use the heavy hammer like everything
else unfortunately does.
> Drivers are definitely using these __raw_ accessors, and from a quick
> look, they do appear to be hoping that *mb() is going to order access
> for
> them.
Which drivers?
Segher
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