linux-kernel - Re: [PATCH] pwm: remove set but not set variable 'pwm'

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Message-ID: <20200120114832.uqa4dthodltu6xdv@pengutronix.de>
Date:   Mon, 20 Jan 2020 12:48:32 +0100
From:   Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
To:     "yukuai (C)" <yukuai3@...wei.com>
Cc:     thierry.reding@...il.com, linux-pwm@...r.kernel.org,
        linux-kernel@...r.kernel.org, zhengbin13@...wei.com,
        yi.zhang@...wei.com
Subject: Re: [PATCH] pwm: remove set but not set variable 'pwm'

On Mon, Jan 20, 2020 at 07:40:37PM +0800, yukuai (C) wrote:
> On 2020/1/20 15:34, Uwe Kleine-König wrote:
> > Fixes: e926b12c611c ("pwm: Clear chip_data in pwm_put()")
> 
> Thank you for your advise! I'll add 'Fixes' in a V2 patch.
> 
> > Did you check that dropping the locking is save? (I didn't)
> > 
> > I'd assume that no harm is introduced, but mentioning that in the commit
> > log would be good.
> 
> I think dropping the lock is safe since there is nothing to be done
> inside the lock. However, I didn't run a full test. By the way, I'll
> mentioning it in a V2 patch.

There are (rare) situations where taking and dropping a lock might make
sense. For example if you have a another context and want to make sure
that a shared resource isn't about to be used.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |