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    SubjectRe: VM_RESERVED [was Re: mapping user space buffer to kernel address space]
    Andrea Arcangeli wrote:
    > > As to your rvmalloc()/rvfree() changes, I don't think they are safe as-is:
    > > I think it's the right thing to do, but I don't trust the drivers to
    > > maintain the right page counts. The code used to mark the pages as
    > > reserved, which probably means that it hides bad drivers that do not do
    > > proper reference counting - and I'm not willing to make that kind of
    > > change at this point.
    > The page count of the mapped pages should be ok, it seems those mapped pages
    > have a reference count of 1 just from the vmalloc allocation and they use
    > PG_reserved just to skip swap_out, but I feel safer too if the bttv maintainers
    > will check it and send it to you themself after checking it's correct. (I only
    > verified that it was compiling correctly)

    In any case, we shouldn't modify videodev.c to call vma_reserve()...
    Let the driver's mmap operation do that or not do that, as it chooses.


    Jeff Garzik | The difference between laziness and
    Building 1024 | prioritization is the end result.
    MandrakeSoft |
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