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    SubjectRe: [PATCH] Define wc_wmb, a write barrier for PCI write combining
    Bryan O'Sullivan wrote:
    > On Tue, 2006-02-28 at 05:01 -0500, Jes Sorensen wrote:
    >>Could you explain why the current mmiowb() API won't suffice for this?
    >>It seems that this is basically trying to achieve the same thing.
    > It's a no-op on every arch I care about:
    > #define mmiowb()
    > Which makes it useless. Also, based on the comments in the qla driver,
    > mmiowb() seems to have inter-CPU ordering semantics that I don't want.
    > I'm thus hesitant to appropriate it for my needs.

    The fact that it's a no-op may simply be because nobody on a specific
    arch got to the point where it made sense to define it yet.

    Anyway, based on Jesse and Jeremy's comments, then maybe the semantics
    here are different. However I do think the name wc_wmb() isn't quite
    defining it. If it's only to be used on mmio space, something like
    mmio_wc_wmb() would probably be more descriptive.

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