From patchwork Thu Mar 5 11:14:01 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: 11421573 X-Patchwork-Delegate: kvalo@adurom.com 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 8853217E0 for ; Thu, 5 Mar 2020 11:31:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6947120848 for ; Thu, 5 Mar 2020 11:31:20 +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="BEr2mtWC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727279AbgCELbT (ORCPT ); Thu, 5 Mar 2020 06:31:19 -0500 Received: from gateway34.websitewelcome.com ([192.185.148.140]:24201 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725912AbgCELbT (ORCPT ); Thu, 5 Mar 2020 06:31:19 -0500 Received: from cm17.websitewelcome.com (cm17.websitewelcome.com [100.42.49.20]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 606C13C8DD for ; Thu, 5 Mar 2020 05:10:57 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 9oP3juImnAGTX9oP3j2BKu; Thu, 05 Mar 2020 05:10:57 -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=/PmmIcka33M6DCpffXgPTbzuHdS7VrmxxyOXeOtKOCc=; b=BEr2mtWCniGS2h7uzC5+yZXgzV CYD7FwHzciKYdIXJhAIuibexDfR3Fx5/fqoCunXL2mGYlkodttzp3B2D6tqtJvXP8TkiUVb/L4wTF MxRckg1ebX5hOVhLYGS+YM+drBjKAYq/sJFcInsKn8OHwefe3227uKWiL6kXNS9P6f1jBeulfC+7I ebXryUGcRQsBer2ejFkY+MWxbxthshurmq4XB1QS5MucVjILwqnj2Ph3D18C0uhXJOA+svFSPK8d2 J2W/71Ib1TzEJhC96th7OuZeFqXOUuna/FmIMpg8h6+5ufcRFFjiEn/YLKlndsob7K9CND2RGuowq wKJGFleg==; Received: from [201.166.169.220] (port=24188 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j9oP1-003r7m-BW; Thu, 05 Mar 2020 05:10:55 -0600 Date: Thu, 5 Mar 2020 05:14:01 -0600 From: "Gustavo A. R. Silva" To: Solomon Peachy , Kalle Valo , "David S. Miller" Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH][next] cw1200/wsm.h: Replace zero-length array with flexible-array member Message-ID: <20200305111401.GA25126@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: 201.166.169.220 X-Source-L: No X-Exim-ID: 1j9oP1-003r7m-BW X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.169.220]:24188 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 15 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@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/wireless/st/cw1200/wsm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/st/cw1200/wsm.h b/drivers/net/wireless/st/cw1200/wsm.h index ddea57f8c8ab..1ffa47994bb9 100644 --- a/drivers/net/wireless/st/cw1200/wsm.h +++ b/drivers/net/wireless/st/cw1200/wsm.h @@ -1623,7 +1623,7 @@ struct wsm_p2p_device_info { u8 local_devname[D11_MAX_SSID_LEN]; u8 reserved2[3]; u8 num_secdev_supported; - struct wsm_p2p_device_type secdevs[0]; + struct wsm_p2p_device_type secdevs[]; } __packed; /* 4.36 SetWCDMABand - WO */