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    SubjectRe: USB mass storage and ARM cache coherency
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    On Wed, 2010-02-24 at 11:19 -0500, Alan Stern wrote:
    > > It is but I'm not confident the responsibility for doing that
    > cleanup
    > > is at the HCD level. That would impact a lot of HCD activities that
    > > don't need such flushing since the use of the page is purely
    > in-kernel.
    >
    > That's right. The HCD merely puts data wherever it's told to. It
    > doesn't know whether the destination is in the page cache, in
    > userspace, or anywhere else. The same is true for usb-storage.

    I'm surprised that usb-storage has an issue here. It shouldn't afaik,
    since it's just a SCSI driver (or not anymore ?) and the BIO or
    filesystems handle things there no ? I haven't seen a single call to
    flush_dcache_page() in any of drivers/scsi, drivers/ata or drivers/ide
    when I looked...

    Cheers,
    Ben.




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