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    SubjectRe: [PATCH] 2.5.17 IDE 65


    On Tue, 21 May 2002, Martin Dalecki wrote:

    > - Make the synchronization token active resident on the same level as the
    > spin lock. They interact with each other until the generic queue handling
    > gets sanitized to not attach hardware properties like the hard sector size
    > to the queue entities. This is a design mistake in ll_rw_blk biting everybody
    > out there.

    This does not parse. It is _not_ a design mistake in ll_rw_blk - if it
    bites you, you're doing something wrong.

    The queue should be a per-device thing. If you have multiple devices with
    different hard-sector-sizes (or other queue attributes) on the same queue,
    that's _your_ problem, not the problem of ll_rw_block.

    Sure, ll_rw_block _allows_ you to use the same queue for multiple devices,
    but if you do that you only have yourself to blame, and you get:

    - shared values (like the hardsector-size above)
    - worse elevator performance (longer queues to traverse)
    - worse elevator schedules (mixing devices will caused mixed queue
    contents, which makes it basically impossible to do a good ordering)

    I thought the IDE layer already did the "one queue per device" thing, is
    there somewhere where this isn't true?

    In short, I think whatever synchronization token problem there is is
    completely an internal IDE problem, and no blame should be laid at anybody
    else.

    Linus

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