Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation

[Steven Rostedt]

On Fri, 2005-12-16 at 14:19 -0800, Linus Torvalds wrote:
> 
> On Fri, 16 Dec 2005, Thomas Gleixner wrote:
> > 
> > Well, in case of a semaphore it is a semantically correct use case. In
> > case of of a mutex it is not.
> 
> I disagree.
> 
> Think of "initialization" as a user. The system starts out initializing 
> stuff, and as such the mutex should start out being held. It's that 
> simple. It _is_ mutual exclusion, with one user being the early bootup 
> state.

That's stretching it quite a bit.  So you are saying that the owner is
the first swapper task, from the booting CPU?  Well, you better have
that same process unlock that mutex, since a mutex has a owner and the
owner _must_ be the one to unlock it.  And in lots of these cases, it's
some other thread that releases the lock.

With mutexs, the owner is not a state, but a task.

-- Steve


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