From patchwork Mon Feb 18 19:06:41 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: 10818709 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 069391390 for ; Mon, 18 Feb 2019 19:36:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E223A2B27F for ; Mon, 18 Feb 2019 19:36:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D5F012B34C; Mon, 18 Feb 2019 19:36:20 +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 C92262B27F for ; Mon, 18 Feb 2019 19:36:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727272AbfBRTgT (ORCPT ); Mon, 18 Feb 2019 14:36:19 -0500 Received: from gateway34.websitewelcome.com ([192.185.150.114]:44173 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726941AbfBRTgT (ORCPT ); Mon, 18 Feb 2019 14:36:19 -0500 X-Greylist: delayed 1490 seconds by postgrey-1.27 at vger.kernel.org; Mon, 18 Feb 2019 14:36:18 EST Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 5E8D317AC83 for ; Mon, 18 Feb 2019 13:06:42 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id voFWgO4VsYTGMvoFWggdOj; 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-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: 2 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@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 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);