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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 BC53DC31E40 for ; Mon, 10 Jun 2019 15:25:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 98BB72085A for ; Mon, 10 Jun 2019 15:25:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389322AbfFJPZH (ORCPT ); Mon, 10 Jun 2019 11:25:07 -0400 Received: from gateway34.websitewelcome.com ([192.185.149.62]:23751 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389293AbfFJPZH (ORCPT ); Mon, 10 Jun 2019 11:25:07 -0400 X-Greylist: delayed 1251 seconds by postgrey-1.27 at vger.kernel.org; Mon, 10 Jun 2019 11:25:07 EDT Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway34.websitewelcome.com (Postfix) with ESMTP id EC64FE1528 for ; Mon, 10 Jun 2019 10:04:15 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id aLqJhGFXn90onaLqJhH3l0; Mon, 10 Jun 2019 10:04:15 -0500 X-Authority-Reason: nr=8 Received: from [189.250.75.107] (port=58560 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1haLqI-000U5a-FH; Mon, 10 Jun 2019 10:04:15 -0500 Date: Mon, 10 Jun 2019 10:04:12 -0500 From: "Gustavo A. R. Silva" To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , Kees Cook Subject: [PATCH] block: bio: Use struct_size() in kmalloc() Message-ID: <20190610150412.GA8430@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: 189.250.75.107 X-Source-L: No X-Exim-ID: 1haLqI-000U5a-FH X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.75.107]:58560 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 2 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@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 bio_map_data { ... struct iovec iov[]; }; instance = kmalloc(sizeof(sizeof(struct bio_map_data) + sizeof(struct iovec) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, iov, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- block/bio.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/block/bio.c b/block/bio.c index 683cbb40f051..4bcdcd3f63f4 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1120,8 +1120,7 @@ static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data, if (data->nr_segs > UIO_MAXIOV) return NULL; - bmd = kmalloc(sizeof(struct bio_map_data) + - sizeof(struct iovec) * data->nr_segs, gfp_mask); + bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask); if (!bmd) return NULL; memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs); -- 2.21.0