From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH V2 2/3] cpufreq: Initialize policy before making it available for others to use Date: Tue, 4 Mar 2014 11:44:00 +0800 Message-ID: <99ab97f08241ac295eae898b48587fedda13f340.1393904428.git.viresh.kumar@linaro.org> References: <98b7ae22d936456bf830aa749556a115969cfa47.1393904428.git.viresh.kumar@linaro.org> Return-path: Received: from mail-pd0-f172.google.com ([209.85.192.172]:41779 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756160AbaCDDo2 (ORCPT ); Mon, 3 Mar 2014 22:44:28 -0500 Received: by mail-pd0-f172.google.com with SMTP id p10so4555867pdj.17 for ; Mon, 03 Mar 2014 19:44:28 -0800 (PST) In-Reply-To: <98b7ae22d936456bf830aa749556a115969cfa47.1393904428.git.viresh.kumar@linaro.org> In-Reply-To: <98b7ae22d936456bf830aa749556a115969cfa47.1393904428.git.viresh.kumar@linaro.org> References: <98b7ae22d936456bf830aa749556a115969cfa47.1393904428.git.viresh.kumar@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: rjw@rjwysocki.net, skannan@codeaurora.org Cc: linaro-kernel@lists.linaro.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, srivatsa.bhat@linux.vnet.ibm.com, Viresh Kumar Policy must be fully initialized before it is being made available for use by others. Otherwise cpufreq_cpu_get() would be able to grab a half initialized policy structure that might not have affected_cpus (for example) filled. And so anybody accessing those fields will get the wrong value and hence the results would be unpredictable. So, in order to fix this lets do all the necessary initialization before we make policy structure available via cpufreq_cpu_get(). With this we can guarantee that any code accessing fields of policy would be stable enough, as policy would be completely initialized by now. Signed-off-by: Viresh Kumar --- V1->V2: - Improved commit logs drivers/cpufreq/cpufreq.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index fff2968..3c6f9a5 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1114,6 +1114,20 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, goto err_set_policy_cpu; } + /* related cpus should atleast have policy->cpus */ + cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); + + /* + * affected cpus must always be the one, which are online. We aren't + * managing offline cpus here. + */ + cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); + + if (!frozen) { + policy->user_policy.min = policy->min; + policy->user_policy.max = policy->max; + } + write_lock_irqsave(&cpufreq_driver_lock, flags); for_each_cpu(j, policy->cpus) per_cpu(cpufreq_cpu_data, j) = policy; @@ -1167,20 +1181,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif, } } - /* related cpus should atleast have policy->cpus */ - cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus); - - /* - * affected cpus must always be the one, which are online. We aren't - * managing offline cpus here. - */ - cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); - - if (!frozen) { - policy->user_policy.min = policy->min; - policy->user_policy.max = policy->max; - } - blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_START, policy); -- 1.7.12.rc2.18.g61b472e