From patchwork Mon Jan 11 17:35:58 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juri Lelli X-Patchwork-Id: 59560 Delivered-To: patch@linaro.org Received: by 10.112.130.2 with SMTP id oa2csp2252424lbb; Mon, 11 Jan 2016 09:38:50 -0800 (PST) X-Received: by 10.66.234.226 with SMTP id uh2mr16821417pac.20.1452533930116; Mon, 11 Jan 2016 09:38:50 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id v83si12013291pfi.105.2016.01.11.09.38.49; Mon, 11 Jan 2016 09:38:50 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934084AbcAKRio (ORCPT + 29 others); Mon, 11 Jan 2016 12:38:44 -0500 Received: from foss.arm.com ([217.140.101.70]:57300 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761295AbcAKRhr (ORCPT ); Mon, 11 Jan 2016 12:37:47 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4FB3B600; Mon, 11 Jan 2016 09:37:12 -0800 (PST) Received: from e106622-lin.cambridge.arm.com (e106622-lin.cambridge.arm.com [10.1.208.152]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 457533F24D; Mon, 11 Jan 2016 09:37:45 -0800 (PST) From: Juri Lelli To: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org, peterz@infradead.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, mturquette@baylibre.com, steve.muckle@linaro.org, vincent.guittot@linaro.org, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, juri.lelli@arm.com Subject: [RFC PATCH 17/19] cpufreq: stop checking for cpufreq_driver being present in cpufreq_cpu_get Date: Mon, 11 Jan 2016 17:35:58 +0000 Message-Id: <1452533760-13787-18-git-send-email-juri.lelli@arm.com> X-Mailer: git-send-email 2.2.2 In-Reply-To: <1452533760-13787-1-git-send-email-juri.lelli@arm.com> References: <1452533760-13787-1-git-send-email-juri.lelli@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After cpufreq_driver_lock() is acquired in cpufreq_cpu_get() we are sure we can't race with cpufreq_policy_free() (which is in the path that ends up removing cpufreq_driver). We can thus safely remove check for cpufreq_driver being present (which is a leftover from commit 6eed9404ab3c ("cpufreq: Use rwsem for protecting critical sections")). Cc: "Rafael J. Wysocki" Cc: Viresh Kumar Signed-off-by: Juri Lelli --- drivers/cpufreq/cpufreq.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) -- 2.2.2 diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 797bfae..6c9bef7 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -282,15 +282,15 @@ struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu) if (WARN_ON(cpu >= nr_cpu_ids)) return NULL; - /* get the cpufreq driver */ read_lock_irqsave(&cpufreq_driver_lock, flags); - if (cpufreq_driver) { - /* get the CPU */ - policy = cpufreq_cpu_get_raw(cpu); - if (policy) - kobject_get(&policy->kobj); - } + /* + * If we get a policy, cpufreq_policy_free() didn't + * yet run. + */ + policy = cpufreq_cpu_get_raw(cpu); + if (policy) + kobject_get(&policy->kobj); read_unlock_irqrestore(&cpufreq_driver_lock, flags);