From patchwork Mon Mar 2 12:10:51 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: 1247596 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=embeddedor.com header.i=@embeddedor.com header.a=rsa-sha256 header.s=default header.b=c5+T4h6f; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48WJqj0v79z9sPR for ; Mon, 2 Mar 2020 23:10:09 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727517AbgCBMKI (ORCPT ); Mon, 2 Mar 2020 07:10:08 -0500 Received: from gateway31.websitewelcome.com ([192.185.143.234]:12368 "EHLO gateway31.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726773AbgCBMKH (ORCPT ); Mon, 2 Mar 2020 07:10:07 -0500 Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway31.websitewelcome.com (Postfix) with ESMTP id 754CA23CBEC for ; Mon, 2 Mar 2020 06:10:06 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 8jtejXn3DAGTX8jtejgDUG; Mon, 02 Mar 2020 06:10:06 -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=SI9L7t5+PJPUj9nJSrkM4IY5Y4jla0GxFqwLN6bviuM=; b=c5+T4h6ffuTf0aWn7ux1BWA2Yr hXkYlM9AjdbBIi5V8XZ/z7/oJTlLFZD3hICBaLLQxSZsxdNO2l2p9fTi6H/tkYjDOVu27Vb1N3PVG rR/bFcR6cy/wJSWeRqkqD/6hzBKvr6B4R/ri4yqKX6FDWzDi1IeijJ0ZEW3y3RkCU6S6+STp3nxzk oLWU6DHq5LzuRD38CkYfEPOR8XA8iH8FsVTSkU4ThnNUsYHSilhei9giFG+PueTQHtpbXUaISmIf+ 9wJrUdx5mzYFXYPT0RE6/tYIOi5shFMXPYpxwaRf+Nx8ZmJgGHjxNEy78a2JYwmBtaH4acM0wTp0R AzhRR0Ew==; Received: from [201.166.157.38] (port=42262 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j8jrV-003wUT-JF; Mon, 02 Mar 2020 06:07:54 -0600 Date: Mon, 2 Mar 2020 06:10:51 -0600 From: "Gustavo A. R. Silva" To: Rasesh Mody , Sudarsana Kalluru , "GR-Linux-NIC-Dev@marvell.com David S. Miller" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] bna: bnad: Replace zero-length array with flexible-array member Message-ID: <20200302121051.GA28820@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: 201.166.157.38 X-Source-L: No X-Exim-ID: 1j8jrV-003wUT-JF X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.157.38]:42262 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 20 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/ethernet/brocade/bna/bnad.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/brocade/bna/bnad.h b/drivers/net/ethernet/brocade/bna/bnad.h index 492a02d54f14..bfa58b40dc3f 100644 --- a/drivers/net/ethernet/brocade/bna/bnad.h +++ b/drivers/net/ethernet/brocade/bna/bnad.h @@ -253,7 +253,7 @@ struct bnad_rx_unmap_q { int alloc_order; u32 map_size; enum bnad_rxbuf_type type; - struct bnad_rx_unmap unmap[0] ____cacheline_aligned; + struct bnad_rx_unmap unmap[] ____cacheline_aligned; }; #define BNAD_PCI_DEV_IS_CAT2(_bnad) \