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

[Linus Torvalds]

On Thu, 15 Dec 2005, Thomas Gleixner wrote:
> 
> Well, depends on the POV. A counting sempahore is a different beast than
> a mutex. At least as far as my limited knowledge of concurrency controls
> goes.

A real semaphore is counting. 

Dammit, unless the pure mutex has a _huge_ performance advantage on major 
architectures, we're not changing it. There's absolutely zero point. A 
counting semaphore is a perfectly fine mutex - the fact that it can _also_ 
be used to allow more than 1 user into a critical region and generally do 
other things is totally immaterial.

It's _extra_ stupid to re-use the names "down()" and "up()" on a 
non-counting mutex, since then the names make zero sense at all. Use 
"lock_mutex()" and "unlock_mutex()" or something, and don't break existing 
code for no measurable gain.

			Linus
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