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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 BA0C2C4321D for ; Thu, 16 Aug 2018 10:18:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3254E2146E for ; Thu, 16 Aug 2018 10:18:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3254E2146E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390984AbeHPNQT (ORCPT ); Thu, 16 Aug 2018 09:16:19 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:11120 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729663AbeHPNQT (ORCPT ); Thu, 16 Aug 2018 09:16:19 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id B83C2A62DED6E; Thu, 16 Aug 2018 18:18:44 +0800 (CST) Received: from [127.0.0.1] (10.177.29.68) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.399.0; Thu, 16 Aug 2018 18:18:45 +0800 Message-ID: <5B754F84.3070502@huawei.com> Date: Thu, 16 Aug 2018 18:18:44 +0800 From: zhong jiang User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Claudiu Beznea CC: Alexandre Belloni , , , Subject: Re: [PATCH] arm/mach-at91/pm: Do not double put the device node References: <1534211696-4221-1-git-send-email-zhongjiang@huawei.com> <20180814125954.GM943@piout.net> <59e252e6-6027-9f52-9ee8-8d0bd32659d2@microchip.com> In-Reply-To: <59e252e6-6027-9f52-9ee8-8d0bd32659d2@microchip.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.29.68] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/8/16 17:32, Claudiu Beznea wrote: > Hi Alexandre, > > On 14.08.2018 15:59, Alexandre Belloni wrote: >> On 14/08/2018 09:54:56+0800, zhong jiang wrote: >>> Device node iterators put the previous value of the index variable, >>> so an explicit put causes a double put. >>> >> While for_each_matching_node_and_match will get and put the node >> properly, there is also a call to of_find_device_by_node that will get a >> reference to the node. >> > Looking through of_find_device_by_node() it seems that a put_device() on the > struct device member of the returned struct platform_device has to be called > instead of of_node_put(). > > of_find_device_by_node() calls bus_find_device(): > > dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match); > > the match function, of_dev_node_match(), is just as follows: > > static int of_dev_node_match(struct device *dev, void *data) > { > return dev->of_node == data; > } > > but bus_find_device() takes a reference to the struct device returned in case it > founds a match, via get_device(): > > struct device *bus_find_device(struct bus_type *bus, > struct device *start, void *data, > int (*match)(struct device *dev, > void*data)) > { > struct klist_iter i; > struct device *dev; > > if (!bus || !bus->p) > return NULL; > > klist_iter_init_node(&bus->p->klist_devices, &i, > (start ? &start->p->knode_bus : NULL)); > while ((dev = next_device(&i))) > if (match(dev, data) && get_device(dev)) > break; > klist_iter_exit(&i); > return dev; > } > > So, I think a put_device(&pdev->dev) has to be called in at91_pm_config_ws() > instead of of_node_put(np). My bad! Yes, you're right. Thanks, Claudiu. I will repost in v2. Sincerely, zhong jiang > Thank you, > Claudiu Beznea > >>> I detect the issue with the help of Coccinelle. >>> >>> Signed-off-by: zhong jiang >>> --- >>> arch/arm/mach-at91/pm.c | 5 +---- >>> 1 file changed, 1 insertion(+), 4 deletions(-) >>> >>> diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c >>> index 32fae4d..a5ec35f 100644 >>> --- a/arch/arm/mach-at91/pm.c >>> +++ b/arch/arm/mach-at91/pm.c >>> @@ -143,15 +143,12 @@ static int at91_pm_config_ws(unsigned int pm_mode, bool set) >>> >>> /* Check if enabled on SHDWC. */ >>> if (wsi->shdwc_mr_bit && !(val & wsi->shdwc_mr_bit)) >>> - goto put_node; >>> + continue; >>> >>> mode |= wsi->pmc_fsmr_bit; >>> if (wsi->set_polarity) >>> polarity |= wsi->pmc_fsmr_bit; >>> } >>> - >>> -put_node: >>> - of_node_put(np); >>> } >>> >>> if (mode) { >>> -- >>> 1.7.12.4 >>> > . >