From patchwork Thu Mar 19 22:25:33 2020 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: 11448167 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BFA4114B4 for ; Thu, 19 Mar 2020 22:49:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CDE72076C for ; Thu, 19 Mar 2020 22:49:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="alNFm6x1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727500AbgCSWtI (ORCPT ); Thu, 19 Mar 2020 18:49:08 -0400 Received: from gateway32.websitewelcome.com ([192.185.145.115]:26107 "EHLO gateway32.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726663AbgCSWtI (ORCPT ); Thu, 19 Mar 2020 18:49:08 -0400 X-Greylist: delayed 1412 seconds by postgrey-1.27 at vger.kernel.org; Thu, 19 Mar 2020 18:49:07 EDT Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway32.websitewelcome.com (Postfix) with ESMTP id 8FB6C17F1E3 for ; Thu, 19 Mar 2020 17:25:35 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id F3bbjZEMS8vkBF3bbjQG6Y; Thu, 19 Mar 2020 17:25:35 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Type:MIME-Version:Message-ID:Subject: Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=TL6TVrB3e/45SD3ES0SlXrCS9Eof0rSqhEbtuxxX0x8=; b=alNFm6x1iNM37ziy9M+QKtKG7v uLOAGBZq2cjGF2t9Bq0aV0HHx5vOnX/eamgh1v+JKST0U+F6zxQAYEt0S/p6uVtCt7rFPmuGT0guC 5zGYp/EaHyrT1FcNCRDgGs2geqaMmJIoG4Yqa6s1I2LZ+ZN0EuxPIxj7meKVKdnkVrFtV36VU7nqW JzDqaju2felTxZPBWkZntMVDOaFoxTPUijloYULUTi6+1T16stQ3+YOFyNx5LK+fqsywCkwrQ/35U ICQwfGd3V36Qs9eFOyMMdmhz8oTqtj6+6fo9m4xXpo9woCOtco4JjyI1m8pfVab1TFbzqaMKyqdJ4 1vzluDzg==; Received: from cablelink-189-218-116-241.hosts.intercable.net ([189.218.116.241]:53902 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1jF3ba-002549-1L; Thu, 19 Mar 2020 17:25:34 -0500 Date: Thu, 19 Mar 2020 17:25:33 -0500 From: "Gustavo A. R. Silva" To: Sathya Prakash , Chaitra P B , Suganath Prabu Subramani Cc: MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] message: fusion: mptsas.h: Replace zero-length array with flexible-array member Message-ID: <20200319222533.GA20577@embeddedor.com> 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: 189.218.116.241 X-Source-L: No X-Exim-ID: 1jF3ba-002549-1L X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-189-218-116-241.hosts.intercable.net (embeddedor) [189.218.116.241]:53902 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 23 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 The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- drivers/message/fusion/mptsas.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/message/fusion/mptsas.h b/drivers/message/fusion/mptsas.h index c396483d3624..e35b13891fe4 100644 --- a/drivers/message/fusion/mptsas.h +++ b/drivers/message/fusion/mptsas.h @@ -110,7 +110,7 @@ struct fw_event_work { MPT_ADAPTER *ioc; u32 event; u8 retries; - char event_data[0] __aligned(4); + char event_data[] __aligned(4); }; struct mptsas_discovery_event {