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

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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