From patchwork Wed Jun 19 19:41:26 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: 11005179 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 91AB514B6 for ; Wed, 19 Jun 2019 20:05:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7E4AB284C9 for ; Wed, 19 Jun 2019 20:05:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7230E284ED; Wed, 19 Jun 2019 20:05:53 +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 19A3F284C9 for ; Wed, 19 Jun 2019 20:05:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726251AbfFSUFw (ORCPT ); Wed, 19 Jun 2019 16:05:52 -0400 Received: from gateway34.websitewelcome.com ([192.185.148.222]:49042 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726244AbfFSUFw (ORCPT ); Wed, 19 Jun 2019 16:05:52 -0400 X-Greylist: delayed 1400 seconds by postgrey-1.27 at vger.kernel.org; Wed, 19 Jun 2019 16:05:52 EDT Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 803B33E72 for ; Wed, 19 Jun 2019 14:42:32 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id dgTYhkiCv90ondgTYhjqeR; 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-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: 14 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@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 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;