From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755711Ab3ARTzA (ORCPT ); Fri, 18 Jan 2013 14:55:00 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:44443 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755596Ab3ARTxG (ORCPT ); Fri, 18 Jan 2013 14:53:06 -0500 From: Nishanth Menon To: linux-pm CC: Rafael , Kevin , MyungJoo Ham , lkml , lo , Jack , Alexander , Nishanth Menon Subject: [PATCH 3/4] PM / devfreq: add locking documentation for recommended_opp Date: Fri, 18 Jan 2013 13:52:34 -0600 Message-ID: <1358538755-29109-4-git-send-email-nm@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1358538755-29109-1-git-send-email-nm@ti.com> References: <1358538755-29109-1-git-send-email-nm@ti.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org OPP pointers are protected by RCU locks, the pointer validity is permissible only under the section of rcu_read_lock to rcu_read_unlock Add documentation to the effect. Signed-off-by: Nishanth Menon --- drivers/devfreq/devfreq.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 53766f3..3b36797 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -994,6 +994,11 @@ module_exit(devfreq_exit); * @freq: The frequency given to target function * @flags: Flags handed from devfreq framework. * + * Locking: This function must be called under rcu_read_lock(). opp is a rcu + * protected pointer. The reason for the same is that the opp pointer which is + * returned will remain valid for use with opp_get_{voltage, freq} only while + * under the locked area. The pointer returned must be used prior to unlocking + * with rcu_read_unlock() to maintain the integrity of the pointer. */ struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, u32 flags) -- 1.7.9.5