Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751240AbaLPFbO (ORCPT ); Tue, 16 Dec 2014 00:31:14 -0500 Received: from mail-ob0-f180.google.com ([209.85.214.180]:61840 "EHLO mail-ob0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750881AbaLPFbM (ORCPT ); Tue, 16 Dec 2014 00:31:12 -0500 MIME-Version: 1.0 In-Reply-To: <20141216004204.GA30467@dtor-ws> References: <20141216004204.GA30467@dtor-ws> Date: Tue, 16 Dec 2014 11:01:12 +0530 Message-ID: Subject: Re: [PATCH] PM / OPP: add some lockdep annotations From: Viresh Kumar To: Dmitry Torokhov Cc: "Rafael J. Wysocki" , Pavel Machek , Len Brown , Greg Kroah-Hartman , Nishanth Menon , Chander Kashyap , Inderpal Singh , Paul Gortmaker , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16 December 2014 at 06:12, Dmitry Torokhov wrote: > Certain OPP APIs need to be called under RCU lock; let's add a few > rcu_lockdep_assert() calls to warn about potential misuse. Very nice.. > Signed-off-by: Dmitry Torokhov > --- > drivers/base/power/opp.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c > index d24dd614a..852eebf 100644 > --- a/drivers/base/power/opp.c > +++ b/drivers/base/power/opp.c > @@ -218,6 +218,11 @@ int dev_pm_opp_get_opp_count(struct device *dev) > struct dev_pm_opp *temp_opp; > int count = 0; > > + rcu_lockdep_assert(rcu_read_lock_held() || > + lockdep_is_held(&dev_opp_list_lock), > + "dev_pm_opp_get_opp_count() needs rcu_read_lock() " > + "or dev_opp_list_lock protection"); > + > dev_opp = find_device_opp(dev); > if (IS_ERR(dev_opp)) { > int r = PTR_ERR(dev_opp); > @@ -267,6 +272,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, > struct device_opp *dev_opp; > struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); > > + rcu_lockdep_assert(rcu_read_lock_held() || > + lockdep_is_held(&dev_opp_list_lock), > + "dev_pm_opp_find_freq_exact() needs rcu_read_lock() " > + "or dev_opp_list_lock protection"); > + > dev_opp = find_device_opp(dev); > if (IS_ERR(dev_opp)) { > int r = PTR_ERR(dev_opp); > @@ -313,6 +323,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev, > struct device_opp *dev_opp; > struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); > > + rcu_lockdep_assert(rcu_read_lock_held() || > + lockdep_is_held(&dev_opp_list_lock), > + "dev_pm_opp_find_freq_ceil() needs rcu_read_lock() " > + "or dev_opp_list_lock protection"); > + > if (!dev || !freq) { > dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); > return ERR_PTR(-EINVAL); > @@ -361,6 +376,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, > struct device_opp *dev_opp; > struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE); > > + rcu_lockdep_assert(rcu_read_lock_held() || > + lockdep_is_held(&dev_opp_list_lock), > + "dev_pm_opp_find_freq_floor() needs rcu_read_lock() " > + "or dev_opp_list_lock protection"); > + To get rid of the redundancy a bit, what about something like: #define opp_rcu_lockdep_assert() \ rcu_lockdep_assert(rcu_read_lock_held() || \ lockdep_is_held(&dev_opp_list_lock), \ "Missing rcu_read_lock() or dev_opp_list_lock protection"); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/