From mboxrd@z Thu Jan 1 00:00:00 1970 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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 28017C43461 for ; Wed, 5 May 2021 12:22:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB6A1613BA for ; Wed, 5 May 2021 12:22:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233172AbhEEMXB (ORCPT ); Wed, 5 May 2021 08:23:01 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3018 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232896AbhEEMW4 (ORCPT ); Wed, 5 May 2021 08:22:56 -0400 Received: from fraeml736-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4FZwfc1vhcz6yhqR; Wed, 5 May 2021 20:16:08 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml736-chm.china.huawei.com (10.206.15.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 5 May 2021 14:21:56 +0200 Received: from localhost (10.52.120.138) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 5 May 2021 13:21:55 +0100 Date: Wed, 5 May 2021 13:20:16 +0100 From: Jonathan Cameron To: Mauro Carvalho Chehab CC: , , Krzysztof Kozlowski , Mauro Carvalho Chehab , Sylwester Nawrocki , , , , Subject: Re: [PATCH 23/25] media: exynos4-is: fix pm_runtime_get_sync() usage count Message-ID: <20210505132016.000078b5@Huawei.com> In-Reply-To: References: Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.52.120.138] X-ClientProxiedBy: lhreml725-chm.china.huawei.com (10.201.108.76) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 May 2021 11:42:13 +0200 Mauro Carvalho Chehab wrote: > The pm_runtime_get_sync() internally increments the > dev->power.usage_count without decrementing it, even on errors. > > On some places, this is ok, but on others the usage count > ended being unbalanced on failures. > > Replace it by the new pm_runtime_resume_and_get(), introduced by: > commit dd8088d5a896 ("PM: runtime: Add pm_runtime_resume_and_get to deal with usage counter") > in order to properly decrement the usage counter, avoiding > a potential PM usage counter leak. > > As a bonus, such function always return zero on success. So, > some code can be simplified. > > Reviewed-by: Sylwester Nawrocki > Signed-off-by: Mauro Carvalho Chehab Might be nice to call out the two odd cases below. > diff --git a/drivers/media/platform/exynos4-is/mipi-csis.c b/drivers/media/platform/exynos4-is/mipi-csis.c > index 1aac167abb17..ebf39c856894 100644 > --- a/drivers/media/platform/exynos4-is/mipi-csis.c > +++ b/drivers/media/platform/exynos4-is/mipi-csis.c > @@ -494,7 +494,7 @@ static int s5pcsis_s_power(struct v4l2_subdev *sd, int on) > struct device *dev = &state->pdev->dev; > > if (on) > - return pm_runtime_get_sync(dev); > + return pm_runtime_resume_and_get(dev); > > return pm_runtime_put_sync(dev); > } > @@ -509,11 +509,9 @@ static int s5pcsis_s_stream(struct v4l2_subdev *sd, int enable) > > if (enable) { > s5pcsis_clear_counters(state); > - ret = pm_runtime_get_sync(&state->pdev->dev); > - if (ret && ret != 1) { Perhaps add something to the description on this less common case? > - pm_runtime_put_noidle(&state->pdev->dev); > + ret = pm_runtime_resume_and_get(&state->pdev->dev); > + if (ret < 0) > return ret; > - } > } > > mutex_lock(&state->lock); > @@ -535,7 +533,7 @@ static int s5pcsis_s_stream(struct v4l2_subdev *sd, int enable) > if (!enable) > pm_runtime_put(&state->pdev->dev); > > - return ret == 1 ? 0 : ret; > + return ret; > } > > static int s5pcsis_enum_mbus_code(struct v4l2_subdev *sd,