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    SubjectRe: [PATCH v3 02/13] dax: require 'struct page' for filesystem dax
    On Fri, Oct 20, 2017 at 08:23:02AM -0700, Dan Williams wrote:
    > Yes, however it seems these drivers / platforms have been living with
    > the lack of struct page for a long time. So they either don't use DAX,
    > or they have a constrained use case that never triggers
    > get_user_pages(). If it is the latter then they could introduce a new
    > configuration option that bypasses the pfn_t_devmap() check in
    > bdev_dax_supported() and fix up the get_user_pages() paths to fail.
    > So, I'd like to understand how these drivers have been using DAX
    > support without struct page to see if we need a workaround or we can
    > go ahead delete this support. If the usage is limited to
    > execute-in-place perhaps we can do a constrained ->direct_access() for
    > just that case.

    For axonram I doubt anyone is using it any more - it was a very for
    the IBM Cell blades, which were produceѕ in a rather limited number.
    And Cell basically seems to be dead as far as I can tell.

    For S/390 Martin might be able to help out what the status of xpram
    in general and DAX support in particular is.

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