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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 AAA22C38A2A for ; Fri, 8 May 2020 15:09:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 913F4206B8 for ; Fri, 8 May 2020 15:09:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727891AbgEHPJK (ORCPT ); Fri, 8 May 2020 11:09:10 -0400 Received: from cmccmta3.chinamobile.com ([221.176.66.81]:10924 "EHLO cmccmta3.chinamobile.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726627AbgEHPJK (ORCPT ); Fri, 8 May 2020 11:09:10 -0400 Received: from spf.mail.chinamobile.com (unknown[172.16.121.13]) by rmmx-syy-dmz-app09-12009 (RichMail) with SMTP id 2ee95eb5748fa8f-5ad2c; Fri, 08 May 2020 23:02:41 +0800 (CST) X-RM-TRANSID: 2ee95eb5748fa8f-5ad2c X-RM-TagInfo: emlType=0 X-RM-SPAM-FLAG: 00000000 Received: from [192.168.43.52] (unknown[223.104.148.118]) by rmsmtp-syy-appsvr07-12007 (RichMail) with SMTP id 2ee75eb574902e0-a19d8; Fri, 08 May 2020 23:02:41 +0800 (CST) X-RM-TRANSID: 2ee75eb574902e0-a19d8 Subject: Re: [PATCH] USB: host: ehci: Add error handlinginehci_mxc_drv_probe() To: Greg KH Cc: stern@rowland.harvard.edu, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Zhang Shengju References: <20200508114453.15436-1-tangbin@cmss.chinamobile.com> <20200508114858.GA4085349@kroah.com> <20200508143110.GA447591@kroah.com> From: Tang Bin Message-ID: <107353c0-09f2-858d-2a87-498e2d8584c6@cmss.chinamobile.com> Date: Fri, 8 May 2020 23:03:27 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200508143110.GA447591@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/5/8 22:31, Greg KH wrote: > On Fri, May 08, 2020 at 09:55:53PM +0800, Tang Bin wrote: >> Hi, Greg: >> >> On 2020/5/8 19:48, Greg KH wrote: >>> On Fri, May 08, 2020 at 07:44:53PM +0800, Tang Bin wrote: >>>> The function ehci_mxc_drv_probe() does not perform sufficient error >>>> checking after executing platform_get_irq(), thus fix it. >>>> >>>> Fixes: 7e8d5cd93fa ("USB: Add EHCI support for MX27 and MX31 based boards") >>>> Signed-off-by: Zhang Shengju >>>> Signed-off-by: Tang Bin >>>> --- >>>> drivers/usb/host/ehci-mxc.c | 2 ++ >>>> 1 file changed, 2 insertions(+) >>>> >>>> diff --git a/drivers/usb/host/ehci-mxc.c b/drivers/usb/host/ehci-mxc.c >>>> index a1eb5ee77..a0b42ba59 100644 >>>> --- a/drivers/usb/host/ehci-mxc.c >>>> +++ b/drivers/usb/host/ehci-mxc.c >>>> @@ -50,6 +50,8 @@ static int ehci_mxc_drv_probe(struct platform_device *pdev) >>>> } >>>> irq = platform_get_irq(pdev, 0); >>>> + if (irq < 0) >>>> + return irq; >>> <= ? >> In the file 'drivers/base/platform.c'， the function platform_get_irq() is >> explained and used as follows: >> >>      * Gets an IRQ for a platform device and prints an error message if >> finding the >>      * IRQ fails. Device drivers should check the return value for errors so >> as to >>      * not pass a negative integer value to the request_irq() APIs. >>      * >>      * Example: >>      *        int irq = platform_get_irq(pdev, 0); >>      *        if (irq < 0) >>      *            return irq; >>      * >>      * Return: IRQ number on success, negative error number on failure. >> >> And in my hardware experiment, even if I set the irq failed deliberately in >> the DTS, the returned value is negative instead of zero. > Please read the thread at > https://lore.kernel.org/r/20200501224042.141366-1-helgaas%40kernel.org > for more details about this. > Great, It looks beautiful, finally someone took a knife to the file 'platform.c'. I have been studied this place for a long time, and don't know what platform can return 0, which made me curious. So the example should be:      *        int irq = platform_get_irq(pdev, 0);      *        if (irq <= 0)      *            return irq; Thanks, Tang Bin