From: Liam Girdwood <lrg@slimlogic.co.uk>
To: Mattias Wallin <mattias.wallin@stericsson.com>
Cc: "broonie@opensource.wolfsonmicro.com"
<broonie@opensource.wolfsonmicro.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linus WALLEIJ <linus.walleij@stericsson.com>,
Bengt JONSSON <bengt.g.jonsson@stericsson.com>
Subject: Re: [PATCH] regulator: lock supply in regulator enable
Date: Sat, 06 Nov 2010 11:54:28 +0000 [thread overview]
Message-ID: <1289044468.3318.14.camel@odin> (raw)
In-Reply-To: <4CD29C7D.4050500@stericsson.com>
On Thu, 2010-11-04 at 12:43 +0100, Mattias Wallin wrote:
> > Sorry, got a busy schedule atm. Can you give us your reasoning behind
> > why you think we need a lock here ?
> Yes, when we enter regulator_enable() we take the lock only for that specific regulator rdev->mutex
> and calls the locked function _regulator_enable().
> This locked function then checks if we have a supply and recursively calls the locked _regulator_enable() again but with the supply rdev as argument.
> The supply rdev regulator is however not locked at this stage, only the "original" supplied regulator is locked.
> So if we have two regulators with the same supply regulator trying to enable at approx. the same time they will both
> enter the _regulator_enable without locks and we could get a race condition.
> This would probably result in reference counting error and unbalanced regulator warnings.
>
> In our system we make use the regulator hierarchy quite heavily.
> >
Applied.
Thanks
Liam
--
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
http://www.slimlogic.co.uk
next prev parent reply other threads:[~2010-11-06 11:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-04 10:01 [PATCH] regulator: lock supply in regulator enable Mattias Wallin
2010-11-04 10:18 ` Liam Girdwood
2010-11-04 10:49 ` Mattias Wallin
2010-11-04 11:11 ` Liam Girdwood
2010-11-04 11:43 ` Mattias Wallin
2010-11-06 11:54 ` Liam Girdwood [this message]
2010-11-04 14:05 ` Mark Brown
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