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    SubjectRe: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
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    On Fri, 2005-12-16 at 13:41 -0800, Linus Torvalds wrote:
    >
    > > > No one. It's not really a mutex, but a completion.
    > >
    > > Well, then let us use a completion and not some semantically wrong
    > > workaround
    >
    > It is _not_ wrong to have a semaphore start out in locked state.
    >
    > For example, it makes perfect sense if the data structures that the
    > semaphore needs need initialization. The way you _should_ handle that is
    > to make the semaphore come up as locked, and the data structures in some
    > "don't matter" state, and then the thing that initializes stuff can do so
    > properly and then release the semaphore.
    >
    > Yes, in some cases such a locked semaphore is only used once, and ends up
    > being a "completion", but that doesn't invalidate the fact that this is
    > a perfectly fine way to handle a real issue.

    Well, in case of a semaphore it is a semantically correct use case. In
    case of of a mutex it is not.

    Gerd was talking about a mutex. The fact that a mutex is implemented on
    top (or on actually the same) mechanism as a semaphore - for what ever
    reason - does not change the semantical difference between semaphores
    and mutexes.

    tglx


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