From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:52855 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751230AbaLSK6l (ORCPT ); Fri, 19 Dec 2014 05:58:41 -0500 Message-ID: <549404DE.3060905@iki.fi> Date: Fri, 19 Dec 2014 12:58:38 +0200 From: Antti Palosaari MIME-Version: 1.0 To: Lars-Peter Clausen CC: linux-media@vger.kernel.org, Mark Brown Subject: Re: [PATCH 1/2] regmap: pass map name to lockdep References: <1418936717-2806-1-git-send-email-crope@iki.fi> <5493485E.7020803@metafoo.de> In-Reply-To: <5493485E.7020803@metafoo.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 12/18/2014 11:34 PM, Lars-Peter Clausen wrote: > On 12/18/2014 10:05 PM, Antti Palosaari wrote: >> lockdep complains recursive locking and deadlock when two different >> regmap instances are called in a nested order. That happen easily >> for example when both I2C client and muxed/repeater I2C adapter are >> using regmap. As a solution, pass regmap name for lockdep in order >> to force lockdep validate regmap mutex per driver - not as all regmap >> instances grouped together. > > That's not how it works. Locks are grouped by lock class, the name is > just for pretty printing. The only reason you do not get a warning > anymore is because you have now different lock classes one for configs > with a name and one for configs without a name. > > You really need a way to specify a custom lock class per regmap instance > in order to solve this problem. I looked example for that solution from v4l controls. So it is also wrong? https://patchwork.linuxtv.org/patch/17262/ Do you think I should change to mutex_lock_nested() as documented in Documentation/locking/lockdep-design.txt ? Should these macros used at all: include/linux/lockdep.h There is not much documentation, especially how these recursive lock warnings should be silenced. regards Antti -- http://palosaari.fi/