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    SubjectRe: virt_to_page/pci_map_page vs. pci_map_single
    >>>>> "James" == James Bottomley <> writes:

    James> On Tue, 2003-11-04 at 03:48, Jes Sorensen wrote:
    >> The question is whether that should be allowed in the first
    >> place. Some IOMMU's will have to map it page-by-page
    >> anyway. However if it is to remain a valid use then I don't see why
    >> pci_map_page() shouldn't be able to handle it under the same
    >> conditions by passing it a size > PAGE_SIZE.

    James> I really don't see what's to be gained by doing this. map_page
    James> is for mapping one page or a fragment of it. It's designed for
    James> small zero copy stuff, like networking. To get it to map more
    James> than one page, really we should pass in an array of struct
    James> pages.

    I am totally in favor of that. I think it's a really bad idea on
    relying on the pci_map infrstructure to do the page chopping for
    multi-page mappings since the IOMMUs will normally have to chop it up
    anyway. The driver authors needs to be aware of this.

    The above was more meant as an example of how pci_map_page() can be
    hacked to do the same thing as pci_map_single if we really wanted to
    rely on that behavior.

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