From patchwork Thu Feb 21 15:37:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 10824295 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 31658139A for ; Thu, 21 Feb 2019 16:03:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1EF4431822 for ; Thu, 21 Feb 2019 16:03:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 10AFB31870; Thu, 21 Feb 2019 16:03:08 +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,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 A548531822 for ; Thu, 21 Feb 2019 16:03:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726525AbfBUQDH (ORCPT ); Thu, 21 Feb 2019 11:03:07 -0500 Received: from gateway30.websitewelcome.com ([192.185.150.24]:15883 "EHLO gateway30.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725870AbfBUQDG (ORCPT ); Thu, 21 Feb 2019 11:03:06 -0500 X-Greylist: delayed 1485 seconds by postgrey-1.27 at vger.kernel.org; Thu, 21 Feb 2019 11:03:06 EST Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway30.websitewelcome.com (Postfix) with ESMTP id F1816E76C for ; Thu, 21 Feb 2019 09:38:20 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id wqQWgK3S6YTGMwqQWgc440; Thu, 21 Feb 2019 09:38:20 -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-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: 12 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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;