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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 2775CC433DF for ; Fri, 29 May 2020 02:04:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F0FE2075F for ; Fri, 29 May 2020 02:04:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404525AbgE2CD7 (ORCPT ); Thu, 28 May 2020 22:03:59 -0400 Received: from mail.loongson.cn ([114.242.206.163]:60268 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390805AbgE2CD6 (ORCPT ); Thu, 28 May 2020 22:03:58 -0400 Received: from [10.130.0.52] (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxP2iKbdBeCYM6AA--.1603S3; Fri, 29 May 2020 10:03:55 +0800 (CST) Subject: Re: [PATCH v4 1/2] clk: hisilicon: Use correct return value about hisi_reset_init() To: Stephen Boyd , Michael Turquette References: <1590590362-11570-1-git-send-email-yangtiezhu@loongson.cn> <159060638492.88029.3855641102752089121@swboyd.mtv.corp.google.com> <51c21311-a301-1a55-3eb1-a11583e7df43@loongson.cn> <159070775347.69627.5841986835404441281@swboyd.mtv.corp.google.com> Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, Xuefeng Li From: Tiezhu Yang Message-ID: Date: Fri, 29 May 2020 10:03:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <159070775347.69627.5841986835404441281@swboyd.mtv.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-CM-TRANSID: AQAAf9DxP2iKbdBeCYM6AA--.1603S3 X-Coremail-Antispam: 1UD129KBjvJXoWxAw48WFy5Aw18ArWUtr47urg_yoW5GFyUpr 1xGayakr4F9r17X3y7AF45Aa43ZF1fKw4UJr1rXws3Aw15GrWkAr4rKa48urZ5urW7Gay5 tr4SkF4rZayqyaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvE14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AKxV W8Jr0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xf McIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7 v_Jr0_Gr1lF7xvr2IY64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7Mxk0xIA0c2IEe2xF o4CEbIxvr21lc2xSY4AK67AK6r4UMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r 1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CE b7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0x vE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Wr1j6rW3Jr1l IxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVWUJVW8JbIYCTnIWI evJa73UjIFyTuYvjfU0GYLUUUUU X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On 05/29/2020 07:15 AM, Stephen Boyd wrote: > Quoting Tiezhu Yang (2020-05-27 19:27:42) >> On 05/28/2020 03:06 AM, Stephen Boyd wrote: >>> Quoting Tiezhu Yang (2020-05-27 07:39:21) >>>> The return value about hisi_reset_init() is not correct, fix it. >>>> >>>> Fixes: e9a2310fb689 ("reset: hisilicon: fix potential NULL pointer dereference") >>> hisi_reset_init() returns NULL on error in that commit. This patch >>> doesn't make sense. >> Hi Stephen, >> >> The initial aim of this patch is to use correct return value about >> hisi_reset_init(), maybe NULL is OK, but the return value in this >> patch is more accurate. > The implementation of hisi_reset_init() that I see is this: > > > struct hisi_reset_controller *rstc; > > rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL); > if (!rstc) > return NULL; > > rstc->membase = devm_platform_ioremap_resource(pdev, 0); > if (IS_ERR(rstc->membase)) > return NULL; > > spin_lock_init(&rstc->lock); > rstc->rcdev.owner = THIS_MODULE; > rstc->rcdev.ops = &hisi_reset_ops; > rstc->rcdev.of_node = pdev->dev.of_node; > rstc->rcdev.of_reset_n_cells = 2; > rstc->rcdev.of_xlate = hisi_reset_of_xlate; > reset_controller_register(&rstc->rcdev); > > return rstc; > > And that returns NULL on an error and a valid pointer on success. > Changing the code to check the return value of hisi_reset_init() for an > error pointer is simply wrong without updating hisi_reset_init() to > return an error pointer on error. Where is the patch that changes > hisi_reset_init() to return an error pointer? Hi Stephen, Do you mean the following changes? diff --git a/drivers/clk/hisilicon/reset.c b/drivers/clk/hisilicon/reset.c index 93cee17..c733e2e 100644 --- a/drivers/clk/hisilicon/reset.c +++ b/drivers/clk/hisilicon/reset.c @@ -93,11 +93,11 @@ struct hisi_reset_controller *hisi_reset_init(struct platform_device *pdev) rstc = devm_kmalloc(&pdev->dev, sizeof(*rstc), GFP_KERNEL); if (!rstc) - return NULL; + return ERR_PTR(-ENOMEM); rstc->membase = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(rstc->membase)) - return NULL; + return ERR_CAST(rstc->membase); spin_lock_init(&rstc->lock); rstc->rcdev.owner = THIS_MODULE; devm_platform_ioremap_resource() devm_ioremap_resource() __devm_ioremap_resource() By the way, we can see the comment of devm_ioremap_resource(): Usage example: res = platform_get_resource(pdev, IORESOURCE_MEM, 0); base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(base)) return PTR_ERR(base);