From patchwork Thu Nov 19 06:06:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 11916497 X-Patchwork-Delegate: viresh.linux@gmail.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B41BC2D0E4 for ; Thu, 19 Nov 2020 06:06:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B375124655 for ; Thu, 19 Nov 2020 06:06:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="s0/jCYgw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726189AbgKSGGX (ORCPT ); Thu, 19 Nov 2020 01:06:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726172AbgKSGGW (ORCPT ); Thu, 19 Nov 2020 01:06:22 -0500 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFAC1C0617A7 for ; Wed, 18 Nov 2020 22:06:20 -0800 (PST) Received: by mail-pf1-x444.google.com with SMTP id t8so3419491pfg.8 for ; Wed, 18 Nov 2020 22:06:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=IomRGRIUUKoHDndCyhGBwVfU4P/jhWiv1ig1BoI3gF8=; b=s0/jCYgwS/sLeOVNCKtlEwbgmIWthbEbn7dsveVESIfChJXh/XH1X4bVE6ZNPgk+4D 8guC92UHS/p5N6IeEPk5noIWDovt0ShmBpLvkom+qZW3r7HCjFeMGTKWMtJ99oIU4TZi 6q24UBIQPIFbJP2YSMvwv/b1quVaH/Yz32kq4B+oPbnoAa3wJyCCkLnO8Jizov8DerJf 6DAVhB0jyF7QCVOsgmyrI2pGqpxPmct/6uUw6yz4fFWam+UEmAnN4NcYB/z5LmWq0s9v HY5YlBEGFfLjfu454o9UEt52qCCNfASF59GEvTLAt97oBsM4NgLNn56v67L/9RDj6WDj yAbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=IomRGRIUUKoHDndCyhGBwVfU4P/jhWiv1ig1BoI3gF8=; b=WHcDwiyLoluhCBwIKE2yWC6tmiAYhsVENyUcY7wG352+h6glacZD2qO2SzeWlbHX4Q 1r3xi6dRoN0ZTfOHUjXqx2XHJqW6pDeAw/H0xRAIk1GKW5AeChDFz5gp05rB5jJxAvPP Q1dSPHsMjqlVb7FuUvUw83PpIQ3IC6k7dHgYdBwnI9T2NC6kGhpFnnA/9La4X+gwDjll cMr/Zar0qr8ez0jeLIBy9/bD8r3miqhXr3uVbIi5zjPxzvImeKcqZkDmNvCN6oT2AbOC auPEDR6onPu2oECRKFiLbYXtlBx8SlePUMxXv/Inbc8kExJ/8IPesJdJFEr4dTHBorBo LOKg== X-Gm-Message-State: AOAM533sviuAyALcbgJdSM15YHg6NEBAPU2eOD7PfF+HNYZHFV2MHvo8 prak7SwJrU/9lKJxRhjgxMfnxT2zJAr8Fw== X-Google-Smtp-Source: ABdhPJx8lGHoI+b43W1nPNovzf7uF6MtzFXk5g3Cr/FR1KU1SQuPHGFgBpHN+rWP7wffBhlYnR4WjA== X-Received: by 2002:a63:5758:: with SMTP id h24mr11882286pgm.109.1605765980389; Wed, 18 Nov 2020 22:06:20 -0800 (PST) Received: from localhost ([122.172.12.172]) by smtp.gmail.com with ESMTPSA id u6sm906769pgp.57.2020.11.18.22.06.19 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Nov 2020 22:06:19 -0800 (PST) From: Viresh Kumar To: Rafael Wysocki , Viresh Kumar , Nishanth Menon , Stephen Boyd Cc: Viresh Kumar , linux-pm@vger.kernel.org, Vincent Guittot , Rob Clark , linux-kernel@vger.kernel.org Subject: [PATCH] opp: Reduce the size of critical section in _opp_kref_release() Date: Thu, 19 Nov 2020 11:36:16 +0530 Message-Id: X-Mailer: git-send-email 2.25.0.rc1.19.g042ed3e048af MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org There is a lot of stuff here which can be done outside of the opp_table->lock, do that. This helps avoiding a circular dependency lockdeps around debugfs. Reported-by: Rob Clark Signed-off-by: Viresh Kumar --- drivers/opp/core.c | 94 +++++++++++++++++++++++----------------------- 1 file changed, 47 insertions(+), 47 deletions(-) diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 9d145bb99a59..4268eb359915 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -1251,9 +1251,14 @@ void _opp_free(struct dev_pm_opp *opp) kfree(opp); } -static void _opp_kref_release(struct dev_pm_opp *opp, - struct opp_table *opp_table) +static void _opp_kref_release(struct kref *kref) { + struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref); + struct opp_table *opp_table = opp->opp_table; + + list_del(&opp->node); + mutex_unlock(&opp_table->lock); + /* * Notify the changes in the availability of the operable * frequency/voltage list. @@ -1261,27 +1266,9 @@ static void _opp_kref_release(struct dev_pm_opp *opp, blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_REMOVE, opp); _of_opp_free_required_opps(opp_table, opp); opp_debug_remove_one(opp); - list_del(&opp->node); kfree(opp); } -static void _opp_kref_release_unlocked(struct kref *kref) -{ - struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref); - struct opp_table *opp_table = opp->opp_table; - - _opp_kref_release(opp, opp_table); -} - -static void _opp_kref_release_locked(struct kref *kref) -{ - struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref); - struct opp_table *opp_table = opp->opp_table; - - _opp_kref_release(opp, opp_table); - mutex_unlock(&opp_table->lock); -} - void dev_pm_opp_get(struct dev_pm_opp *opp) { kref_get(&opp->kref); @@ -1289,16 +1276,10 @@ void dev_pm_opp_get(struct dev_pm_opp *opp) void dev_pm_opp_put(struct dev_pm_opp *opp) { - kref_put_mutex(&opp->kref, _opp_kref_release_locked, - &opp->opp_table->lock); + kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock); } EXPORT_SYMBOL_GPL(dev_pm_opp_put); -static void dev_pm_opp_put_unlocked(struct dev_pm_opp *opp) -{ - kref_put(&opp->kref, _opp_kref_release_unlocked); -} - /** * dev_pm_opp_remove() - Remove an OPP from OPP table * @dev: device for which we do this operation @@ -1342,30 +1323,49 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) } EXPORT_SYMBOL_GPL(dev_pm_opp_remove); +static struct dev_pm_opp *_opp_get_next(struct opp_table *opp_table, + bool dynamic) +{ + struct dev_pm_opp *opp = NULL, *temp; + + mutex_lock(&opp_table->lock); + list_for_each_entry(temp, &opp_table->opp_list, node) { + if (dynamic == temp->dynamic) { + opp = temp; + break; + } + } + + mutex_unlock(&opp_table->lock); + return opp; +} + bool _opp_remove_all_static(struct opp_table *opp_table) { - struct dev_pm_opp *opp, *tmp; - bool ret = true; + struct dev_pm_opp *opp; mutex_lock(&opp_table->lock); if (!opp_table->parsed_static_opps) { - ret = false; - goto unlock; + mutex_unlock(&opp_table->lock); + return false; } - if (--opp_table->parsed_static_opps) - goto unlock; - - list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) { - if (!opp->dynamic) - dev_pm_opp_put_unlocked(opp); + if (--opp_table->parsed_static_opps) { + mutex_unlock(&opp_table->lock); + return true; } -unlock: mutex_unlock(&opp_table->lock); - return ret; + /* + * Can't remove the OPP from under the lock, debugfs removal needs to + * happen lock less to avoid circular dependency issues. + */ + while ((opp = _opp_get_next(opp_table, false))) + dev_pm_opp_put(opp); + + return true; } /** @@ -1377,21 +1377,21 @@ bool _opp_remove_all_static(struct opp_table *opp_table) void dev_pm_opp_remove_all_dynamic(struct device *dev) { struct opp_table *opp_table; - struct dev_pm_opp *opp, *temp; + struct dev_pm_opp *opp; int count = 0; opp_table = _find_opp_table(dev); if (IS_ERR(opp_table)) return; - mutex_lock(&opp_table->lock); - list_for_each_entry_safe(opp, temp, &opp_table->opp_list, node) { - if (opp->dynamic) { - dev_pm_opp_put_unlocked(opp); - count++; - } + /* + * Can't remove the OPP from under the lock, debugfs removal needs to + * happen lock less to avoid circular dependency issues. + */ + while ((opp = _opp_get_next(opp_table, true))) { + dev_pm_opp_put(opp); + count++; } - mutex_unlock(&opp_table->lock); /* Drop the references taken by dev_pm_opp_add() */ while (count--)