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    SubjectRe: [patch] cache flush bug in mm/filemap.c (all kernels >= 2.5.30(at least))
    I don't think the flush_dcache_page thing is done almost anywhere in the 
    block/driver level right now. And we shouldn't be doing io reads to
    pagecache pages with user mappings anyway normally. direct-io is a
    different thing.

    --Mika


    David S. Miller wrote:

    >On Fri, 2003-05-23 at 11:34, Russell King wrote:
    >
    >
    >>So no, I don't think it is a device driver issue at all.
    >>
    >>DaveM?
    >>
    >>
    >
    >Oh yes, this part is. If you don't ensure this, everything
    >breaks.
    >
    >At the end of an I/O operation, say to a page cache page, that
    >data ought to be visible equally to a userspace vs. a kernel
    >space mapping to that page.
    >
    >For example, this is why we use language about "cpu visibility" in the
    >DMA api documentation and not "kernel cpu visibility" :-) And because
    >PIO transfers are basically pseudo-DMA they need to make the same exact
    >guarentees.
    >
    >If you've been living in a world where you didn't think this is
    >necessary, I certainly feel bad for you :-)
    >
    >
    >


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