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=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 17BE7C43218 for ; Mon, 10 Jun 2019 21:22:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC1452082E for ; Mon, 10 Jun 2019 21:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390032AbfFJVWX (ORCPT ); Mon, 10 Jun 2019 17:22:23 -0400 Received: from gateway24.websitewelcome.com ([192.185.51.202]:36069 "EHLO gateway24.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389736AbfFJVWW (ORCPT ); Mon, 10 Jun 2019 17:22:22 -0400 Received: from cm12.websitewelcome.com (cm12.websitewelcome.com [100.42.49.8]) by gateway24.websitewelcome.com (Postfix) with ESMTP id E47A97C7C for ; Mon, 10 Jun 2019 16:22:21 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id aRkDhsBuwiQeraRkDhQPXS; Mon, 10 Jun 2019 16:22:21 -0500 X-Authority-Reason: nr=8 Received: from [189.250.75.107] (port=49560 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1haRkD-003lwk-0k; Mon, 10 Jun 2019 16:22:21 -0500 Date: Mon, 10 Jun 2019 16:22:19 -0500 From: "Gustavo A. R. Silva" To: Andrew Morton Cc: linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] tracepoint: Use struct_size() in kmalloc() Message-ID: <20190610212219.GA27692@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: 1haRkD-003lwk-0k X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.75.107]:49560 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 9 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 tp_probes { ... struct tracepoint_func probes[0]; }; instance = kmalloc(sizeof(sizeof(struct tp_probes) + sizeof(struct tracepoint_func) * 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, probes, count) GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- kernel/tracepoint.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index df3ade14ccbd..73956eaff8a9 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -55,8 +55,8 @@ struct tp_probes { static inline void *allocate_probes(int count) { - struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func) - + sizeof(struct tp_probes), GFP_KERNEL); + struct tp_probes *p = kmalloc(struct_size(p, probes, count), + GFP_KERNEL); return p == NULL ? NULL : p->probes; } -- 2.21.0