From patchwork Mon Jun 10 15:04:12 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: 10985067 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 36D5613AF for ; Mon, 10 Jun 2019 15:25:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 21E4F28786 for ; Mon, 10 Jun 2019 15:25:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 12440287CE; Mon, 10 Jun 2019 15:25:09 +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 9574C28786 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-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 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 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 Reviewed-by: Kees Cook --- 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);