[PATCH] Document Linux's memory barriers

[Bryan O'Sullivan]

On Tue, 2006-03-07 at 18:30 +0000, David Howells wrote:

> True, I suppose. I should make it clear that these accessor functions imply
> memory barriers, if indeed they do,

They don't, but according to Documentation/DocBook/deviceiobook.tmpl
they are performed by the compiler in the order specified.

They also convert between PCI byte order and CPU byte order.  If you
want to avoid that, you need the __raw_* versions, which are not
guaranteed to be provided by all arches.

	<b