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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 B94C6C43387 for ; Sun, 6 Jan 2019 20:34:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 844432070C for ; Sun, 6 Jan 2019 20:34:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726116AbfAFUeA (ORCPT ); Sun, 6 Jan 2019 15:34:00 -0500 Received: from gateway23.websitewelcome.com ([192.185.50.104]:15012 "EHLO gateway23.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726060AbfAFUeA (ORCPT ); Sun, 6 Jan 2019 15:34:00 -0500 Received: from cm10.websitewelcome.com (cm10.websitewelcome.com [100.42.49.4]) by gateway23.websitewelcome.com (Postfix) with ESMTP id 34E8C2FD7 for ; Sun, 6 Jan 2019 14:33:59 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id gF7PgJfRq2PzOgF7PgyqtO; Sun, 06 Jan 2019 14:33:59 -0600 X-Authority-Reason: nr=8 Received: from [189.250.130.205] (port=58960 helo=[192.168.1.76]) by gator4166.hostgator.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.91) (envelope-from ) id 1ggF7O-002pd3-R8; Sun, 06 Jan 2019 14:33:58 -0600 Subject: Re: [PATCH] dmaengine: fsl-edma: use struct_size() in kzalloc() To: Angelo Dureghello Cc: Dan Williams , Vinod Koul , dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190104212545.GA16927@embeddedor> <20190106194059.GA2120@jerusalem> From: "Gustavo A. R. Silva" Message-ID: Date: Sun, 6 Jan 2019 14:33:57 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190106194059.GA2120@jerusalem> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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: 189.250.130.205 X-Source-L: No X-Exim-ID: 1ggF7O-002pd3-R8 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.1.76]) [189.250.130.205]:58960 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 5 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 On 1/6/19 1:40 PM, Angelo Dureghello wrote: > On Fri, Jan 04, 2019 at 03:25:45PM -0600, Gustavo A. R. Silva wrote: >> 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; >> void *entry[]; >> }; >> >> instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, 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); >> >> This code was detected with the help of Coccinelle. >> >> Signed-off-by: Gustavo A. R. Silva >> --- >> drivers/dma/fsl-edma-common.c | 4 +--- >> 1 file changed, 1 insertion(+), 3 deletions(-) >> >> diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c >> index 8876c4c1bb2c..fe529100674f 100644 >> --- a/drivers/dma/fsl-edma-common.c >> +++ b/drivers/dma/fsl-edma-common.c >> @@ -339,9 +339,7 @@ static struct fsl_edma_desc *fsl_edma_alloc_desc(struct fsl_edma_chan *fsl_chan, >> struct fsl_edma_desc *fsl_desc; >> int i; >> >> - fsl_desc = kzalloc(sizeof(*fsl_desc) + >> - sizeof(struct fsl_edma_sw_tcd) * >> - sg_len, GFP_NOWAIT); >> + fsl_desc = kzalloc(struct_size(fsl_desc, tcd, sg_len), GFP_NOWAIT); >> if (!fsl_desc) >> return NULL; >> > > Tested-by: Angelo Dureghello > Thanks, Angelo. -- Gustavo