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    SubjectRe: upcalls from kernel code to user space daemons
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    On Mon, 2004-06-14 at 23:57, Chris Friesen wrote:
    > Oliver Neukum wrote:
    >
    > > > userspace daemon loops on ioctl()
    > > > kernel portion of ioctl call goes to sleep until something to do
    > > > when needed, fill in data and return to userspace
    > > > userspace does stuff, then passes data back down via ioctl()
    > > > ioctl() puts userspace back to sleep and continues on with other work
    > >
    > > You could just as well implement an ordinary read()
    >
    > Not quite. The userspace is passing data down as well. I don't know how you'd
    > do that with read().

    For this you use write().

    Bernd
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