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    SubjectRe: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation
    Andrew Morton wrote:

    > This is because there is no file descriptor or anything else associated
    > with the pages which permits the kernel to clean stuff up on unclean
    > application exit. Also there are the obvious issues with permitting
    > pinning of unbounded amounts of memory.

    Then that might explain the "bug" that we're seeing with get_user_pages(). We've been
    assuming that get_user_pages() mappings are permanent.

    Well, I was just about to re-implement get_user_pages() support in our driver to
    demonstrate the bug. I guess I'll hold off on that.

    If you look at the Infiniband code that was recently submitted, I think you'll see it does
    exactly that: after calling mlock(), the driver calls get_user_pages(), and it stores the
    page mappings for future use.

    --
    Timur Tabi
    Staff Software Engineer
    timur.tabi@ammasso.com

    One thing a Southern boy will never say is,
    "I don't think duct tape will fix it."
    -- Ed Smylie, NASA engineer for Apollo 13
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