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, URIBL_BLOCKED,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 B5DEDC31E49 for ; Wed, 19 Jun 2019 14:27:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92F9D2182B for ; Wed, 19 Jun 2019 14:27:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730613AbfFSO07 (ORCPT ); Wed, 19 Jun 2019 10:26:59 -0400 Received: from gateway30.websitewelcome.com ([192.185.179.30]:35053 "EHLO gateway30.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729423AbfFSO06 (ORCPT ); Wed, 19 Jun 2019 10:26:58 -0400 Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway30.websitewelcome.com (Postfix) with ESMTP id DAF17329E46B for ; Wed, 19 Jun 2019 09:26:57 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id dbY9huOwyYTGMdbY9hq1H0; Wed, 19 Jun 2019 09:26:57 -0500 X-Authority-Reason: nr=8 Received: from cablelink-187-160-61-213.pcs.intercable.net ([187.160.61.213]:37806 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1hdbY8-0025CT-Tf; Wed, 19 Jun 2019 09:26:56 -0500 Date: Wed, 19 Jun 2019 09:26:55 -0500 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: gpio_keys_polled - use struct_size() in devm_kzalloc() Message-ID: <20190619142655.GA20218@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: 187.160.61.213 X-Source-L: No X-Exim-ID: 1hdbY8-0025CT-Tf X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-187-160-61-213.pcs.intercable.net (embeddedor) [187.160.61.213]:37806 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 7 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 gpio_keys_polled_dev { ... struct gpio_keys_button_data data[0]; }; size = sizeof(struct gpio_keys_polled_dev) + count * sizeof(struct gpio_keys_button_data); instance = devm_kzalloc(dev, size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = devm_kzalloc(dev, struct_size(instance, data, 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/keyboard/gpio_keys_polled.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c index edc7262103b9..c4087be0c2e0 100644 --- a/drivers/input/keyboard/gpio_keys_polled.c +++ b/drivers/input/keyboard/gpio_keys_polled.c @@ -235,7 +235,6 @@ static int gpio_keys_polled_probe(struct platform_device *pdev) struct gpio_keys_polled_dev *bdev; struct input_polled_dev *poll_dev; struct input_dev *input; - size_t size; int error; int i; @@ -250,9 +249,8 @@ static int gpio_keys_polled_probe(struct platform_device *pdev) return -EINVAL; } - size = sizeof(struct gpio_keys_polled_dev) + - pdata->nbuttons * sizeof(struct gpio_keys_button_data); - bdev = devm_kzalloc(dev, size, GFP_KERNEL); + bdev = devm_kzalloc(dev, struct_size(bdev, data, pdata->nbuttons), + GFP_KERNEL); if (!bdev) { dev_err(dev, "no memory for private data\n"); return -ENOMEM; -- 2.21.0