From patchwork Sat Sep 19 00:52:07 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Boyd X-Patchwork-Id: 7221451 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 3A0699F6CD for ; Sat, 19 Sep 2015 00:53:56 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5548A209A9 for ; Sat, 19 Sep 2015 00:53:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 683A1209AB for ; Sat, 19 Sep 2015 00:53:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754841AbbISAw7 (ORCPT ); Fri, 18 Sep 2015 20:52:59 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:36564 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754538AbbISAwO (ORCPT ); Fri, 18 Sep 2015 20:52:14 -0400 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 7303F13FB4A; Sat, 19 Sep 2015 00:52:13 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id 4158513FB77; Sat, 19 Sep 2015 00:52:13 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from sboyd-linux.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) (using TLSv1.1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: sboyd@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id EE0DB13FB4A; Sat, 19 Sep 2015 00:52:11 +0000 (UTC) From: Stephen Boyd To: linux-arm-msm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Nishanth Menon , Viresh Kumar , Srinivas Kandagatla , Andy Gross , linux-pm@vger.kernel.org, Mark Brown , David Collins , Krzysztof Kozlowski Subject: [PATCH v2 3/5] OPP: Allow notifiers to call dev_pm_opp_get_{voltage, freq} RCU-free Date: Fri, 18 Sep 2015 17:52:07 -0700 Message-Id: <1442623929-4507-4-git-send-email-sboyd@codeaurora.org> X-Mailer: git-send-email 2.6.0.rc2.11.g3da0120 In-Reply-To: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org> References: <1442623929-4507-1-git-send-email-sboyd@codeaurora.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We pass the dev_pm_opp structure to OPP notifiers but the users of the notifier need to surround calls to dev_pm_opp_get_*() with RCU read locks to avoid lockdep warnings. The notifier is already called with the dev_opp's srcu lock held, so it should be safe to assume the devm_pm_opp structure is already protected inside the notifier. Update the lockdep check for this. Cc: Krzysztof Kozlowski Signed-off-by: Stephen Boyd Acked-by: Viresh Kumar --- drivers/base/power/opp.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index 35b66c46dcb7..1d8c45e53245 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -146,9 +146,10 @@ static LIST_HEAD(dev_opp_list); /* Lock to allow exclusive modification to the device and opp lists */ static DEFINE_MUTEX(dev_opp_list_lock); -#define opp_rcu_lockdep_assert() \ +#define opp_rcu_lockdep_assert(s) \ do { \ RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \ + !(s && srcu_read_lock_held(s)) && \ !lockdep_is_held(&dev_opp_list_lock), \ "Missing rcu_read_lock() or " \ "dev_opp_list_lock protection"); \ @@ -236,9 +237,10 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp) struct dev_pm_opp *tmp_opp; unsigned long v = 0; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu); - tmp_opp = rcu_dereference(opp); + tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu, + rcu_read_lock_held()); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) pr_err("%s: Invalid parameters\n", __func__); else @@ -268,9 +270,10 @@ unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp) struct dev_pm_opp *tmp_opp; unsigned long f = 0; - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(&opp->dev_opp->srcu_head.srcu); - tmp_opp = rcu_dereference(opp); + tmp_opp = srcu_dereference_check(opp, &opp->dev_opp->srcu_head.srcu, + rcu_read_lock_held()); if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) pr_err("%s: Invalid parameters\n", __func__); else @@ -437,7 +440,7 @@ 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); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); dev_opp = _find_device_opp(dev); if (IS_ERR(dev_opp)) { @@ -485,7 +488,7 @@ 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); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq); @@ -535,7 +538,7 @@ 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); - opp_rcu_lockdep_assert(); + opp_rcu_lockdep_assert(NULL); if (!dev || !freq) { dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);