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Subject: Re: [PATCH] Real-Time Preemption V0.7.52-07: rt_init_MUTEX_LOCKED
	declaration
From: Sven-Thorsten Dietrich <sdietrich@mvista.com>
To: Luca Falavigna <dktrkranz@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, mingo@elte.hu
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Date: Mon, 01 Aug 2005 12:13:41 -0700
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On Mon, 2005-08-01 at 19:05 +0000, Luca Falavigna wrote:
> > The patch you wanted to send was:
> > 
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > 
> > Index: linux_realtime_ernie/drivers/char/watchdog/cpu5wdt.c
> > ===================================================================
> > --- linux_realtime_ernie/drivers/char/watchdog/cpu5wdt.c        (revision 265)
> > +++ linux_realtime_ernie/drivers/char/watchdog/cpu5wdt.c        (working copy)
> > @@ -56,7 +56,7 @@
> >  /* some device data */
> > 
> >  static struct {
> > -       struct semaphore stop;
> > +       struct compat_semaphore stop;
> >         volatile int running;
> >         struct timer_list timer;
> >         volatile int queue;
> 
> Another solution could be this (as shown in drivers/cpufreq/cpufreq.c):
> -	init_MUTEX_LOCKED(&policy->lock);
> +	init_MUTEX(&policy->lock);
> +	down(&policy->lock);
> -

If the semaphore is being used as a mutex, 
then it could be converted to an RT-mutex.

That would nicely side-step the problem.

Note this won't work if you are counting with the sema.

Sven