Re: [RFC] mmiotrace full patch, preview 1

[Pavel Roskin]

Quoting Christoph Hellwig <hch@xxxxxxxxxxxxx>:

> On Mon, Feb 25, 2008 at 02:49:22PM -0800, Andrew Morton wrote:
> > the things which it finds.
> >
> > > +static DECLARE_MUTEX(kmmio_init_mutex);
> >
> > That's not a mutex.
> >
> > > +	down(&kmmio_init_mutex);
> >
> > It's a semaphore.  Please do convert it to a mutex.
> >
> > Andy, I'd say that addition of new semaphores is worth a warning - they're
> > rarely legitimate.
>
> I'm not sure that any semaphore should be a warning, but the initializer
> for semaphore used as binary mutex (DECLARE_MUTEX and init_MUTEX) are
> worth it.

It looks like a mutex, it acts like a mutex, but it isn't a mutex,  
it's a trap for the unwary.  Weird.  I was annoyed by it before; now I  
see a fellow developer actually getting into that trap.

I'd say, rename DECLARE_MUTEX to DECLARE_SEMAPHORE and let external  
code be fixed one way or another (i.e. stick with the "mutex" name or  
stick with the semaphore functionality if it's really needed).

--
Regards,
Pavel Roskin
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