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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 5D27BC31E5E for ; Wed, 19 Jun 2019 19:42:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 431C2214AF for ; Wed, 19 Jun 2019 19:42:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730312AbfFSTmd (ORCPT ); Wed, 19 Jun 2019 15:42:33 -0400 Received: from gateway21.websitewelcome.com ([192.185.45.159]:20485 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbfFSTmd (ORCPT ); Wed, 19 Jun 2019 15:42:33 -0400 Received: from cm13.websitewelcome.com (cm13.websitewelcome.com [100.42.49.6]) by gateway21.websitewelcome.com (Postfix) with ESMTP id 80C85400CFFAD for ; Wed, 19 Jun 2019 14:42:32 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id dgTYh0XG6YTGMdgTYhw6Zq; Wed, 19 Jun 2019 14:42:32 -0500 X-Authority-Reason: nr=8 Received: from cablelink-187-160-61-213.pcs.intercable.net ([187.160.61.213]:12106 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1hdgTX-000jo6-Cw; Wed, 19 Jun 2019 14:42:31 -0500 Date: Wed, 19 Jun 2019 14:41:26 -0500 From: "Gustavo A. R. Silva" To: Willem Riede , "James E.J. Bottomley" , "Martin K. Petersen" Cc: osst-users@lists.sourceforge.net, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] scsi: osst: Use struct_size() in kzalloc() Message-ID: <20190619194126.GA3069@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: 187.160.61.213 X-Source-L: No X-Exim-ID: 1hdgTX-000jo6-Cw X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-187-160-61-213.pcs.intercable.net (embeddedor) [187.160.61.213]:12106 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 15 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 osst_buffer { ... struct scatterlist sg[1]; /* MUST BE last item */ } ; i = sizeof(struct osst_buffer) + (osst_max_sg_segs - 1) * sizeof(struct scatterlist); instance = kzalloc(i, 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, sg, count), GFP_KERNEL); Notice that, in this case, variable i is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- drivers/scsi/osst.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/scsi/osst.c b/drivers/scsi/osst.c index 815bb4097c1b..a11455a7e6bf 100644 --- a/drivers/scsi/osst.c +++ b/drivers/scsi/osst.c @@ -5307,7 +5307,6 @@ static long osst_compat_ioctl(struct file * file, unsigned int cmd_in, unsigned /* Try to allocate a new tape buffer skeleton. Caller must not hold os_scsi_tapes_lock */ static struct osst_buffer * new_tape_buffer( int from_initialization, int need_dma, int max_sg ) { - int i; gfp_t priority; struct osst_buffer *tb; @@ -5316,8 +5315,7 @@ static struct osst_buffer * new_tape_buffer( int from_initialization, int need_d else priority = GFP_KERNEL; - i = sizeof(struct osst_buffer) + (osst_max_sg_segs - 1) * sizeof(struct scatterlist); - tb = kzalloc(i, priority); + tb = kzalloc(struct_size(tb, sg, osst_max_sg_segs - 1), priority); if (!tb) { printk(KERN_NOTICE "osst :I: Can't allocate new tape buffer.\n"); return NULL; -- 2.21.0