linux-kernel - Re: [PATCH 2/4] pwm: Reduce time the pwm_lock mutex is held in pwmchip

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Message-ID: <Y3ZUT3SNmfInzEv9@smile.fi.intel.com>
Date:   Thu, 17 Nov 2022 17:33:35 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
Cc:     linux-pwm@...r.kernel.org,
        Thierry Reding <thierry.reding@...il.com>,
        linux-kernel@...r.kernel.org, kernel@...gutronix.de
Subject: Re: [PATCH 2/4] pwm: Reduce time the pwm_lock mutex is held in
 pwmchip_add()

On Thu, Nov 17, 2022 at 03:00:24PM +0100, Uwe Kleine-König wrote:
> On Wed, Nov 16, 2022 at 10:11:32AM +0200, Andy Shevchenko wrote:
> > On Tue, Nov 15, 2022 at 10:15:13PM +0100, Uwe Kleine-König wrote:
> > > This simplifies error handling as the need for goto error handling goes
> > > away and at the end of the function the code can be simplified as this
> > > code isn't used in the error case any more.

...

> > > +	mutex_unlock(&pwm_lock);
> > >  
> > >  	if (IS_ENABLED(CONFIG_OF))
> > >  		of_pwmchip_add(chip);
> > 
> > Why calling this without a lock is not a problem? Commit message doesn't share
> > a bit about this change.
> 
> Maybe add another paragraph at the end reading:
> 
> Now memory allocation and the call to of_pwmchip_add() are done without
> holding the lock. Both don't access the data structures protected by
> &pwm_lock.

Good to me, with that added
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

-- 
With Best Regards,
Andy Shevchenko