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    SubjectRe: Linux Buffer Cache Does Not Support Mirroring
    Jeff,

    BTW, the RAID code is also using the async b_end_io callback, to
    get a success/failure report on each I/O transaction. Cross
    reference raid5_end_request() in raid5.c and raid1_end_request()
    in raid1.c, which are installed as b_end_io callbacks in the
    buffers which go to the real block drivers. In the RAID-5 case,
    the callback function (called at the interrupt context) then wakes
    up a kernel thread for further processing.

    Gadi

    On Tue, 2 Nov 1999, Jeff V. Merkey wrote:

    >
    > Alan,
    >
    > I'll try this.
    >
    > Jeff
    >
    > Alan Cox wrote:
    > >
    > > > I looked at the brw_page code. While everyone calls this an "async"
    > > > interface, in fact, it uses the same semantic as a sync interface and
    > > > does not allow support for callbacks.
    > >
    > > Its a function pointer. What else do you need other than passing a parameter
    > > void * or similar to get more flexibility.
    > >
    > > You can use the callback to wake a thread, you can schedule a task after
    > > IRQ completion, you can do stuff directly on the IRQ callback if you are
    > > careful about deadlocks.
    > >
    > > -
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    > > Please read the FAQ at http://www.tux.org/lkml/
    >
    > -
    > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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    >


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