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    SubjectRe: mapping user space buffer to kernel address space
    On Tue, Oct 17, 2000 at 12:27:30PM -0700, David S. Miller wrote:
    > Hint: smp_flush_tlb_page()
    > Current kiobufs never need to do that, under any circumstances.
    > This is not by accident.

    I don't understand. flush_tlb_page() done in the context of a thread won't care
    about the state of the physical page. I don't see how it's related to kiobufs.

    > I don't see what the big deal is in requiring that user applications
    > do their own locking to protect page contents being modified in one
    > thread while a direct I/O from it is happening in another thread. I

    We never talked about this issue in the previous emails. That is required
    regardless of how we solve the MM corruption.

    > also don't see why any bug with kiobufs can't be fixed without the
    > expensive and complex pinning.

    IMHO pinning the page in the pte is less expensive and less complex than making
    rawio and the VM aware of those issues. (remap_page_range is so clean
    implementation exactly because it pins the page into the pte)

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