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    SubjectRe: PATCH: (as177) Add class_device_unregister_wait() and platform_device_unregister_wait() to the driver model core
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    * Valdis Kletnieks <Valdis.Kletnieks@vt.edu> writes:

    > On Mon, 26 Jan 2004 15:06:48 +1000, Steve Youngs <sryoungs@bigpond.net.au> said:
    >> > A boolean is just a one-bit reference count. If the maximum number of
    >> > simultaneous 'users' for a given module is one, then a boolean will work.
    >> > If there is potential for more than one simultaneous user then you need
    >> > more bits.
    >>
    >> Why? A module is either being used or it isn't, the number of uses
    >> shouldn't even come into it.

    > OK. There's 2 users of the module. The first one exits. How does
    > it (or anything else) know that it's NOT safe to just clear the
    > in-use bit and clean it up?

    Because the 2nd user is still using the module so its in-use bit
    should still be set. Remember that when the module was first loaded
    it registered a function with the kernel for testing whether the
    module is in use.

    I must be overlooking something because I see the answer so clearly.
    Maybe if someone could give me a real world example of a situation
    where it'd be hard/impossible/unsafe to unload a module and I'll see
    if my ideas can be applied.



    --
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    | Ashes to ashes, dust to dust. |
    | The proof of the pudding, is under the crust. |
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