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 0B573C10F01 for ; Mon, 18 Feb 2019 19:06:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6014217D9 for ; Mon, 18 Feb 2019 19:06:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728342AbfBRTGp (ORCPT ); Mon, 18 Feb 2019 14:06:45 -0500 Received: from gateway31.websitewelcome.com ([192.185.143.51]:24488 "EHLO gateway31.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726380AbfBRTGn (ORCPT ); Mon, 18 Feb 2019 14:06:43 -0500 Received: from cm14.websitewelcome.com (cm14.websitewelcome.com [100.42.49.7]) by gateway31.websitewelcome.com (Postfix) with ESMTP id 58B701C20E for ; Mon, 18 Feb 2019 13:06:42 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id voFWg9hl42qH7voFWggfj0; Mon, 18 Feb 2019 13:06:42 -0600 X-Authority-Reason: nr=8 Received: from [189.250.119.20] (port=44716 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1gvoFV-000cwg-KH; Mon, 18 Feb 2019 13:06:41 -0600 Date: Mon, 18 Feb 2019 13:06:41 -0600 From: "Gustavo A. R. Silva" To: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] usb: core: config: Use struct_size() in kzalloc() Message-ID: <20190218190641.GA18000@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: 1gvoFV-000cwg-KH X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.119.20]:44716 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 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 len is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- drivers/usb/core/config.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 7bb6b1bd06c8..20ff036b4c22 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -552,7 +552,7 @@ static int usb_parse_configuration(struct usb_device *dev, int cfgidx, unsigned char *buffer2; int size2; struct usb_descriptor_header *header; - int len, retval; + int retval; u8 inums[USB_MAXINTERFACES], nalts[USB_MAXINTERFACES]; unsigned iad_num = 0; @@ -707,8 +707,8 @@ static int usb_parse_configuration(struct usb_device *dev, int cfgidx, nalts[i] = j = USB_MAXALTSETTING; } - len = sizeof(*intfc) + sizeof(struct usb_host_interface) * j; - config->intf_cache[i] = intfc = kzalloc(len, GFP_KERNEL); + intfc = kzalloc(struct_size(intfc, altsetting, j), GFP_KERNEL); + config->intf_cache[i] = intfc; if (!intfc) return -ENOMEM; kref_init(&intfc->ref); -- 2.20.1