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    SubjectRe: [PATCH 1/4] scatterlist: new helper functions

    >
    > I don't think so.
    >
    > Splitting (or merging) a request and playing with sg lists
    > inside a
    > driver is a bad idea. Such should be done in the block
    > layer.
    >
    > I still don't see why the block layer can't do that for the
    > driver.
    >
    > I believe that the helper functions for such should not be
    > added.
    >


    In a particular case of flash-like devices, letting the block layer
    split requests into memory sequential blocks too often results in
    unnecessary fragmentation of writes/erases.

    If only one sg entry is requested from the block layer, it will be (more
    often than not) only 1 or 2 pages in length, even if total size of
    prospective write request spans multiple erase blocks.

    So there are really only two options for legacy memorystick driver:
    1. Play with scatterlists explicitly.
    2. Make it an MTD backend, rather then stand-alone block device.

    The second option makes more sense, but it is not necessarily the optimal
    approach for implementation of this particular media format.






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