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    SubjectRe: linux-next: Tree for July 16 (crash on quad core AMD)
    On Sat, 19 Jul 2008 09:59:11 +0900
    Tejun Heo <htejun@gmail.com> wrote:

    > Pierre Ossman wrote:
    > > I just have one objection to your version, and that is that it cannot
    > > be used to nibble away at the sg list. The _next() call jumps an entire
    > > page, whereas you sometimes need to consume that page in two different
    > > sweeps. This could be handled by some external buffer that keeps the
    > > remainder of the page, but the point of these functions was to keep
    > > things simple for the callers.
    >
    > Well, I don't know how often such usages would be necessary. If it's a
    > very common ops, you can add a param to the next function but frankly I
    > think it's better to build a inside control structure for that. There's
    > no need for external buffer, just an inner loop is sufficient.
    >

    I'm not sure how this can be solved by an inner loop. My primary use
    case is:

    1. Wait for interrupt
    2. Write n bytes
    3. goto 1

    n has no guarantee of being aligned to any page boundaries, so state
    needs to be kept between each invokation of writing a chunk of data. I
    doubt I'm alone in this use pattern (in fact, most device drivers using
    PIO should do something similar).

    --
    -- Pierre Ossman

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