Re: [PATCH] mutex: make mutex_lock_nested an inline function

From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>,
	akpm@linux-foundation.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] mutex: make mutex_lock_nested an inline function
Date: Wed, 14 Oct 2015 11:00:20 +0200	[thread overview]
Message-ID: <11240940.NHO2vFoJOz@wuerfel> (raw)
In-Reply-To: <20151014083707.GR11639@twins.programming.kicks-ass.net>

On Wednesday 14 October 2015 10:37:07 Peter Zijlstra wrote:
> On Wed, Oct 14, 2015 at 10:20:50AM +0200, Peter Zijlstra wrote:
> > > > On Tue, Oct 13, 2015 at 10:30:08PM +0200, Arnd Bergmann wrote:
> > > > > The second argument of the mutex_lock_nested() helper is only
> > > > > evaluated if CONFIG_DEBUG_LOCK_ALLOC is set. Otherwise we
> > > > > get this build warning for the new regulator_lock_supply
> > > > > function:
> > > > > 
> > > > > drivers/regulator/core.c: In function 'regulator_lock_supply':
> > > > > drivers/regulator/core.c:142:6: warning: unused variable 'i' [-Wunused-variable]
> > > > > 
> > > > > To avoid the warning, this patch changes the definition of
> > > > > mutex_lock_nested() to be static inline function rather than
> > > > > a macro, which tells gcc that the variable is potentially
> > > > > used.
> > 
> > Uuh, I just looked at next and saw this regulator_lock_supply()
> > function. How is that limited? subclass must be <8 otherwise bad things
> > happen.
> 
> Also, the function appears unused, just delete it 

That was my first suggestion as well when I ran into 

drivers/regulator/core.c:139:13: warning: 'regulator_lock_supply' defined but not used

but apparently this is work-in-progress and the plan is to use it
in 4.4 when the rest of the currently-under-review patches are merged.

	Arnd