Re: [patch 1/2] powerpc: rmb fix

quoted

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