Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures

[Chris Snook <csnook@redhat.com>]

Herbert Xu wrote:
> On Thu, Aug 16, 2007 at 03:48:54PM -0400, Chris Snook wrote:
> > > Can you find an actual atomic_read code snippet there that is
> > > broken without the volatile modifier?
> > A whole bunch of atomic_read uses will be broken without the volatile 
> > modifier once we start removing barriers that aren't needed if volatile 
> > behavior is guaranteed.
>
> Could you please cite the file/function names so we can
> see whether removing the barrier makes sense?
>
> Thanks,

At a glance, several architectures' implementations of smp_call_function() have 
one or more legitimate atomic_read() busy-waits that shouldn't be using 
CPU-relax.  Some of them do work in the loop.

I'm sure there are plenty more examples that various maintainers could find in 
their own code.

	-- Chris
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