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    SubjectRe: [patch 13/13] signalfd/timerfd/asyncfd v5 - KAIO asyncfd support (example/maybe-broken) ...
    On Wed, 14 Mar 2007, Linus Torvalds wrote:

    > On Wed, 14 Mar 2007, Davide Libenzi wrote:
    > > >
    > > > That won't work. aio_complete() is supposed to be irq safe.
    > >
    > > Can you point me to a kernel path that ends up calling aio_complete() in a
    > > do-not-sleep mode?
    >
    > All of them.
    >
    > It's called from dio_bio_end_aio(), which is the bi_end_io function for an
    > AIO action. Which in turn is called at IO completion time.
    >
    > Which is basically _always_ interrupt context.
    >
    > So you cannot sleep. It's not about holding spinlocks (which it might well
    > do as well). It's about a much more fundamental issue: you can only sleep
    > in process context, not from interrupts.

    Ack! Gotcha. Sigh! :)



    - Davide


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