From patchwork Tue Nov 19 05:17:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 179656 Delivered-To: patch@linaro.org Received: by 2002:a92:38d5:0:0:0:0:0 with SMTP id g82csp157502ilf; Mon, 18 Nov 2019 21:36:21 -0800 (PST) X-Google-Smtp-Source: APXvYqzjOzLREWdUt1FSP6xiRYTE5UGme+s1/DSPAg1dD2nNBZ90ecmpax+BuPskkFqN7YfYxLtL X-Received: by 2002:a17:906:1c4d:: with SMTP id l13mr31888003ejg.308.1574141781125; Mon, 18 Nov 2019 21:36:21 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1574141781; cv=none; d=google.com; s=arc-20160816; b=a/Ohj7UJQ0MVz0dgVyWfSxlKhMjFgsfgUpFfcJ6Bzsn92uenXJIjs4Ii+SPNFP0HZi l43wn4T/xur/Wa0I61ShBLJpV+WWex7UL1d6lnV+IGJDXzd/l1f6u/6qzSlebc4dsxXX e4qvDftCLoWKlQfPOT/lBR+Ji8UnkOfCxeSytHHPiYiBaZYJxR1kF/8B4NzFiSitSOjI bPJXNl3TKDFwLH5WWGuuTslnMx6qxxtmblxWjU8dLmV4POFA2jtAGpyxA7L1JOZ/WnHh HbFdOV0hKaktTydPlUpRQh8cqLQNXIx0KbMWFSC8x4OVwyFRAMEl+yu0rX8P+XTy4Ryi PePw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=T/f5swdpHA27rdZfs/XRev1PYC1hkoBx1lwqcXYTddM=; b=ZcxibHTuL6TRjX7KsMUzHd2K57TxIBz+2UC7u65LcZZvYD2UARU1+X5CMkF76rThIc LFHaSdb55FJk0AqOBcaIefovvlxbC+Q6WKFIcJyY7t4vjzyQpNrRk4hs4q6mmCn5Vzj4 Yk1TGzZDAu1Macyq8Z6Mk2spkgxdQJZeSRe8JObWwNJinhZSuQWRiPQ3qfbSmwFwc+DC c1Xox7ViS9z7V9ggaxcJgqmIsmhj9yn9PGls6FPWpDyl8t/Z5B75/WV7KwHh36lhSvdu k3GvCU6WO8abCIsdC5/2IL7MhA58mBqLzQsry4vgKWYEsgiwFSDzgQjhn47vQh7pXuM5 6KNQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="kYDdGyr/"; 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 Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id j21si12647248ejd.265.2019.11.18.21.36.20; Mon, 18 Nov 2019 21:36:21 -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; dkim=pass header.i=@kernel.org header.s=default header.b="kYDdGyr/"; 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 S1729932AbfKSFgP (ORCPT + 26 others); Tue, 19 Nov 2019 00:36:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:57362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728721AbfKSFgN (ORCPT ); Tue, 19 Nov 2019 00:36:13 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F28B120672; Tue, 19 Nov 2019 05:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574141771; bh=VHiTryP+MU+PLdWreCOV2vP2vxJ3anEvXl6BhTjOKbg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kYDdGyr/+NZ+3R8azNnnZS6Sgq8T7Ne4J4Jqyqre0ZzdvCAfPMwY01AccgLOn4/K1 IrJsSv75YXnfbY5UBhORVmk3+8oSRjtWo0y1feM7Dkp+Sd1a9ryKelIXERzPqhUw2Y 03nsUkKMmDmRuu5XEj06H/8/4VlBCoUhYQ6q0LeM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Niklas Cassel , Viresh Kumar , Sasha Levin Subject: [PATCH 4.19 268/422] OPP: Protect dev_list with opp_table lock Date: Tue, 19 Nov 2019 06:17:45 +0100 Message-Id: <20191119051416.355082371@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191119051400.261610025@linuxfoundation.org> References: <20191119051400.261610025@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Viresh Kumar [ Upstream commit 3d2556992a878a2210d3be498416aee39e0c32aa ] The dev_list needs to be protected with a lock, else we may have simultaneous access (addition/removal) to it and that would be racy. Extend scope of the opp_table lock to protect dev_list as well. Tested-by: Niklas Cassel Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin --- drivers/opp/core.c | 21 +++++++++++++++++++-- drivers/opp/cpu.c | 2 ++ drivers/opp/opp.h | 2 +- 3 files changed, 22 insertions(+), 3 deletions(-) -- 2.20.1 diff --git a/drivers/opp/core.c b/drivers/opp/core.c index f3433bf47b100..14d4ef5943741 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -48,9 +48,14 @@ static struct opp_device *_find_opp_dev(const struct device *dev, static struct opp_table *_find_opp_table_unlocked(struct device *dev) { struct opp_table *opp_table; + bool found; list_for_each_entry(opp_table, &opp_tables, node) { - if (_find_opp_dev(dev, opp_table)) { + mutex_lock(&opp_table->lock); + found = !!_find_opp_dev(dev, opp_table); + mutex_unlock(&opp_table->lock); + + if (found) { _get_opp_table_kref(opp_table); return opp_table; @@ -766,6 +771,8 @@ struct opp_device *_add_opp_dev(const struct device *dev, /* Initialize opp-dev */ opp_dev->dev = dev; + + mutex_lock(&opp_table->lock); list_add(&opp_dev->node, &opp_table->dev_list); /* Create debugfs entries for the opp_table */ @@ -773,6 +780,7 @@ struct opp_device *_add_opp_dev(const struct device *dev, if (ret) dev_err(dev, "%s: Failed to register opp debugfs (%d)\n", __func__, ret); + mutex_unlock(&opp_table->lock); return opp_dev; } @@ -791,6 +799,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev) if (!opp_table) return NULL; + mutex_init(&opp_table->lock); INIT_LIST_HEAD(&opp_table->dev_list); opp_dev = _add_opp_dev(dev, opp_table); @@ -812,7 +821,6 @@ static struct opp_table *_allocate_opp_table(struct device *dev) BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head); INIT_LIST_HEAD(&opp_table->opp_list); - mutex_init(&opp_table->lock); kref_init(&opp_table->kref); /* Secure the device table modification */ @@ -854,6 +862,10 @@ static void _opp_table_kref_release(struct kref *kref) if (!IS_ERR(opp_table->clk)) clk_put(opp_table->clk); + /* + * No need to take opp_table->lock here as we are guaranteed that no + * references to the OPP table are taken at this point. + */ opp_dev = list_first_entry(&opp_table->dev_list, struct opp_device, node); @@ -1719,6 +1731,9 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, { struct dev_pm_opp *opp, *tmp; + /* Protect dev_list */ + mutex_lock(&opp_table->lock); + /* Find if opp_table manages a single device */ if (list_is_singular(&opp_table->dev_list)) { /* Free static OPPs */ @@ -1736,6 +1751,8 @@ void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, } else { _remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table); } + + mutex_unlock(&opp_table->lock); } void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all) diff --git a/drivers/opp/cpu.c b/drivers/opp/cpu.c index 0c09107094350..2868a022a0407 100644 --- a/drivers/opp/cpu.c +++ b/drivers/opp/cpu.c @@ -222,8 +222,10 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) cpumask_clear(cpumask); if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) { + mutex_lock(&opp_table->lock); list_for_each_entry(opp_dev, &opp_table->dev_list, node) cpumask_set_cpu(opp_dev->dev->id, cpumask); + mutex_unlock(&opp_table->lock); } else { cpumask_set_cpu(cpu_dev->id, cpumask); } diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h index 7c540fd063b2d..e0866b1c1f1b2 100644 --- a/drivers/opp/opp.h +++ b/drivers/opp/opp.h @@ -126,7 +126,7 @@ enum opp_table_access { * @dev_list: list of devices that share these OPPs * @opp_list: table of opps * @kref: for reference count of the table. - * @lock: mutex protecting the opp_list. + * @lock: mutex protecting the opp_list and dev_list. * @np: struct device_node pointer for opp's DT node. * @clock_latency_ns_max: Max clock latency in nanoseconds. * @shared_opp: OPP is shared between multiple devices.