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=-13.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 34D00C34022 for ; Mon, 17 Feb 2020 20:34:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 085BC2067D for ; Mon, 17 Feb 2020 20:34:10 +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="Sy87GQ6f" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729484AbgBQUeJ (ORCPT ); Mon, 17 Feb 2020 15:34:09 -0500 Received: from gateway21.websitewelcome.com ([192.185.45.133]:37011 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726704AbgBQUeJ (ORCPT ); Mon, 17 Feb 2020 15:34:09 -0500 X-Greylist: delayed 1459 seconds by postgrey-1.27 at vger.kernel.org; Mon, 17 Feb 2020 15:34:08 EST Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway21.websitewelcome.com (Postfix) with ESMTP id A04FF400C863E for ; Mon, 17 Feb 2020 14:09:49 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 3miDjuGNWAGTX3miDj5Q7u; Mon, 17 Feb 2020 14:09:49 -0600 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=vHceqN2sfu9/dun1wAVisIIuaP0oWbPTBe15FV0Ep7k=; b=Sy87GQ6f+8H2i0L06NBJWgrn++ rUw2BwxRHTrbMJC/ri+w3KZGetwhbP+bqzS8J3KZuync1nQ9jUNxWzlbN5j28m4B9HRzwHJwbaKhw 443xGyx6HnAGZiLt66hahset5y/AfSUPxiE4ELEvMlDUdSbU5MLZPV6klhQ4wsCL+Ygf2fB4qTv1J I4oq+mlOgjCNw8HjEOdZ836EIaMyGJ1KgllIZ9SpLBR17b2zjo+u9nzbQ64qRZd7RXpp8Fgqxx3wH R2ZQ9kUibgw3qxmOSz3jHp4jT+LhK5nCjoVUE/PItMBHjhIRQFOM4eXyltvVNtCTae5HYgB3FvICn wdzlEClQ==; Received: from [200.68.140.26] (port=7630 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j3miC-000TtM-3r; Mon, 17 Feb 2020 14:09:48 -0600 Date: Mon, 17 Feb 2020 14:12:29 -0600 From: "Gustavo A. R. Silva" To: Wolfgang Grandegger , Marc Kleine-Budde , "David S. Miller" Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] can: peak_canfd: replace zero-length array with flexible-array member Message-ID: <20200217201229.GA9608@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: 200.68.140.26 X-Source-L: No X-Exim-ID: 1j3miC-000TtM-3r X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [200.68.140.26]:7630 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 18 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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/net/can/peak_canfd/peak_pciefd_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/can/peak_canfd/peak_pciefd_main.c b/drivers/net/can/peak_canfd/peak_pciefd_main.c index d08a3d559114..6ad83a881039 100644 --- a/drivers/net/can/peak_canfd/peak_pciefd_main.c +++ b/drivers/net/can/peak_canfd/peak_pciefd_main.c @@ -146,7 +146,7 @@ struct pciefd_rx_dma { __le32 irq_status; __le32 sys_time_low; __le32 sys_time_high; - struct pucan_rx_msg msg[0]; + struct pucan_rx_msg msg[]; } __packed __aligned(4); /* Tx Link record */ @@ -194,7 +194,7 @@ struct pciefd_board { struct pci_dev *pci_dev; int can_count; spinlock_t cmd_lock; /* 64-bits cmds must be atomic */ - struct pciefd_can *can[0]; /* array of network devices */ + struct pciefd_can *can[]; /* array of network devices */ }; /* supported device ids. */ -- 2.25.0