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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 98F61C43381 for ; Thu, 21 Feb 2019 15:38:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6AD562075A for ; Thu, 21 Feb 2019 15:38:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728265AbfBUPiX (ORCPT ); Thu, 21 Feb 2019 10:38:23 -0500 Received: from gateway24.websitewelcome.com ([192.185.51.253]:26942 "EHLO gateway24.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725858AbfBUPiW (ORCPT ); Thu, 21 Feb 2019 10:38:22 -0500 Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway24.websitewelcome.com (Postfix) with ESMTP id AA630147BC for ; Thu, 21 Feb 2019 09:38:21 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id wqQWg5h3T2qH7wqQXgc6pe; Thu, 21 Feb 2019 09:38:21 -0600 X-Authority-Reason: nr=8 Received: from [189.250.119.20] (port=37002 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1gwqPr-000VkX-16; Thu, 21 Feb 2019 09:38:19 -0600 Date: Thu, 21 Feb 2019 09:37:38 -0600 From: "Gustavo A. R. Silva" To: Dmitry Torokhov Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] Input: evdev - use struct_size() in kzalloc() and vzalloc() Message-ID: <20190221153738.GA17825@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.250.119.20 X-Source-L: No X-Exim-ID: 1gwqPr-000VkX-16 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.119.20]:37002 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 13 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; struct boo entry[]; }; size = sizeof(struct foo) + count * sizeof(struct boo); instance = kzalloc(size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); Notice that, in this case, variable size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- drivers/input/evdev.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index f48369d6f3a0..ee8dd8b1b09e 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -503,14 +503,13 @@ static int evdev_open(struct inode *inode, struct file *file) { struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev); unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev); - unsigned int size = sizeof(struct evdev_client) + - bufsize * sizeof(struct input_event); struct evdev_client *client; int error; - client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); + client = kzalloc(struct_size(client, buffer, bufsize), + GFP_KERNEL | __GFP_NOWARN); if (!client) - client = vzalloc(size); + client = vzalloc(struct_size(client, buffer, bufsize)); if (!client) return -ENOMEM; -- 2.20.1