From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [PATCH] gpiolib: irqchip: use different lockdep class for each gpio irqchip Date: Fri, 14 Aug 2015 16:05:52 +0300 Message-ID: <55CDE7B0.5040108@ti.com> References: <1439477919-24356-1-git-send-email-grygorii.strashko@ti.com> <55CDE1BB.1060708@metafoo.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55CDE1BB.1060708@metafoo.de> Sender: linux-kernel-owner@vger.kernel.org To: Lars-Peter Clausen , Linus Walleij Cc: Alexandre Courbot , Linux-OMAP , "linux-gpio@vger.kernel.org" , Sekhar Nori , "linux-kernel@vger.kernel.org" , Geert Uytterhoeven , Roger Quadros List-Id: linux-gpio@vger.kernel.org On 08/14/2015 03:40 PM, Lars-Peter Clausen wrote: > On 08/14/2015 02:34 PM, Linus Walleij wrote: > [...] >> Every chip will get their own lock class on the heap. >> >> But I think it is a bit kludgy. >> >> Is it not possible to have the lock key in struct gpio_chip >> be a real member instead of a pointer and get a per-chip >> lock that way? >> >> (...) >> struct lock_class_key lock_key; >> >> instead of: >> >> struct lock_class_key *lock_key; >> >> -> problem solved, without kludgy header defines? > > > Lock keys need to be in persistent memory since they have a unlimited life > time. Once registered it is expected to exist until the system is reset. > > We recently fixed the same issue of nested locks in regmap. For reference > the discussion with had a look at different ways to solve this can be found > here[1] and the final patch series that went in here[2]. > > - Lars > > [1] https://lkml.org/lkml/2015/6/25/144 > [2] https://lkml.org/lkml/2015/7/8/43 I've actually followed [2], but without deep digging in Lock keys anatomy :) (as mentioned in commit message) -- regards, -grygorii