spin_is_locked() broken for uniprocessor?

[Benjamin Herrenschmidt]

On Wed, 2009-08-19 at 11:41 +0200, Peter Zijlstra wrote:
> > > > which implies to me that spin_is_locked() will always return
> false.  Is this
> > > > expected behavior.
> > > 
> > > That's wrong. spin_is_locked should always return true on UP.
> > 
> > Surely it's not that simple?  Maybe spin_is_lock() should be
> undefined on UP.
> 
> #define spin_is_locked(l) panic()
> 
> should sort things out quickly ;-)

Not defining it would sort things out even faster and avoid nasty case
of system panic'ing when a module is loaded :-)

Cheers,
Ben.