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SubjectRe: [PATCH] Define wc_wmb, a write barrier for PCI write combining
On Wed, Mar 01, 2006 at 12:05:07PM -0800, Bryan O'Sullivan wrote:
> This section also makes it clear yet again that wmb() is absolutely not
> sufficient to get program store order semantics in the presence of WC;
> you *have* to use an explicit synchronising instruction of some kind.

The semantics your code seems to care about are not those of a memory
barrier (which deals with ordering), but of a flush of the write combining
buffers. That's an important high level distinction as they are implemented
differently across architectures. Please rename the macro something like
flush_wc() and document it as such, at which point I remove my objection.

-ben
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