From patchwork Fri Apr 26 07:38:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chengguang Xu X-Patchwork-Id: 10918723 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8AFB414C0 for ; Fri, 26 Apr 2019 07:39:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 698CB20500 for ; Fri, 26 Apr 2019 07:39:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 42C2828DA4; Fri, 26 Apr 2019 07:39:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FROM,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C28D620500 for ; Fri, 26 Apr 2019 07:39:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725965AbfDZHjI (ORCPT ); Fri, 26 Apr 2019 03:39:08 -0400 Received: from mout.gmx.net ([212.227.17.22]:44451 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725912AbfDZHjI (ORCPT ); Fri, 26 Apr 2019 03:39:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1556264336; bh=eXVuQ4GxcSyfn1xn0uo5tTdWse+H/ZssVULo+dS1BoU=; h=X-UI-Sender-Class:From:To:Cc:Subject:Date; b=lcL9mS3LSWTYbsmDr75NK0+owYv4AKZjIIcYOa8UGx5JB/gjP2Z9MyzVcJTieCEbT A02tQAMCB6AymIs1RLbNwZacgyUh9zDSZTzDbVJkrVVMFTxqrn7bPlFlcDtCvGt9Kg J/IhaJIhQLQSxUld3zwqIEWdrquTN9YeXN2tIf8o= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from localhost.localdomain ([218.18.229.179]) by mail.gmx.com (mrgmx102 [212.227.17.174]) with ESMTPSA (Nemesis) id 0LwXCt-1gjEo41SRD-018I5Y; Fri, 26 Apr 2019 09:38:56 +0200 From: Chengguang Xu To: gregkh@linuxfoundation.org Cc: dan.carpenter@oracle.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Chengguang Xu Subject: [RESEND PATCH] chardev: set variable ret to -EBUSY before checking minor range overlap Date: Fri, 26 Apr 2019 15:38:37 +0800 Message-Id: <20190426073837.23086-1-cgxu519@gmx.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Provags-ID: V03:K1:jnnTDKRqPbZvDx0A1eDgWqsaN67fPTgX38a3r2ZqdcyNAxNwdVI MZvaX+ciStiXcxrhZjAvRhm8j5wOD0RZl1Qi75+aQoY8IDD5kwGlF+mvEvZazW6Lqb8JG1K 0yG8G4I1bvxj5IqhR8BDtZfKuw5a/TnrDvUmoIYVgf5TdxXnhwRnzvbPuv8s9RRuZuHrauU 2sN2rLYhlpK0E8L1w/t2Q== X-UI-Out-Filterresults: notjunk:1;V03:K0:oNbZKfoyKYA=:Z8ApCNUhkpE/xtVgxngKFw 89Rlw4JFrb+XiV29Cbb5uPeu8llW8gbgJhHRuU6PV+jt5zE5UDyB3HPnxIRNGaU1qy0rSepGb Symvh75azF1L5hfukz7nSMJVCsS89ZDx9irMdhnbTQ/1hHnwf0UDrJHGT1YVftZUi9rEL8hnK Pou/R++bvpRDm1wFSzdXHKqQkv2ZawB+LcIal40xXYehI4lAuGS6xindXqqugT/I1nsUwIPqj EbJoZvNzoHUSTeTOcckZSncULF4t0PPJmqIwDrajN3HCUXTcPmT9trxk4wY7QpT2ZsZ5KMs8A 5jpnpiucAEyvqzUiFOAY8HQUWPOxiG2dKKTYccVB9se4KsR0+ireh6tOoh6G64G8zFIw/MQ/3 aDr11gV/dTuvhWr00Fjb1zGWhHoV5Amu42ACokIpeuUbW/CwGTHWLskxXy3tIvDZZKMEI/2pB HLvHtmdT6sjxZoqioGx+gmyc8qzxET3BSGHrsmvCf/0At3Nq9rlWnWWdzlFuy595FHFJ55fU/ MiaX0DY6g2j9WDn4yCHwSVel0+c7gt8TgFZhJpgD/kp/ASnEeQeHxuG+tqxn6m7906iBeewXH WBfsUDstrYa1nO1XqGNih8+C+UZ6Rfhb2znZ9WmwuLhkTm6Y1uBG2J+UyB0Ct4oCP435/pf28 KKSacRwGI4AOXuyWDrQj/zPAhMlDd7LpIJ6+S/N+za18/FhMMU1M6tiry4n4e9muFlNkQxo0H Txfmh+WDRYUaLcIUrMfoZc+M6zZqMFSQhosUoRG0ycVIOEbh1k6sS/AUlp8PTdHvddzjxUMnG OHwdaUwNxmBBl6tmLp/DV5KluW5PY4rFyyVTswWOnbH3QgA49emIxgQJ6HemGiZaDBydMV92K EoK+GbjAMTe5LDDVrzrbKnSJsJDmK2g1b4S8yDfzz+8/7iY0aMYKGi2TQNuLLn Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When allocating dynamic major, the minor range overlap check in __register_chrdev_region() will not fail, so actually there is no real case to passing non negative error code to caller. However, set variable ret to -EBUSY before chekcking minor range overlap will avoid false-positive warning from code analyzing tool(like Smatch) and also make the code more easy to understand. Suggested-by: Dan Carpenter Signed-off-by: Chengguang Xu --- fs/char_dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.20.1 diff --git a/fs/char_dev.c b/fs/char_dev.c index d18cad28c1c3..00dfe17871ac 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -98,7 +98,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, int minorct, const char *name) { struct char_device_struct *cd, *curr, *prev = NULL; - int ret = -EBUSY; + int ret; int i; if (major >= CHRDEV_MAJOR_MAX) { @@ -129,6 +129,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor, major = ret; } + ret = -EBUSY; i = major_to_index(major); for (curr = chrdevs[i]; curr; prev = curr, curr = curr->next) { if (curr->major < major)