From patchwork Thu Mar 5 11:12:16 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: 11421571 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 04737174A 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 D820720848 for ; Thu, 5 Mar 2020 11:31:19 +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="ji17C/Va" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727052AbgCELbT (ORCPT ); Thu, 5 Mar 2020 06:31:19 -0500 Received: from gateway34.websitewelcome.com ([192.185.148.140]:26083 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725897AbgCELbS (ORCPT ); Thu, 5 Mar 2020 06:31:18 -0500 X-Greylist: delayed 1326 seconds by postgrey-1.27 at vger.kernel.org; Thu, 05 Mar 2020 06:31:18 EST Received: from cm11.websitewelcome.com (cm11.websitewelcome.com [100.42.49.5]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 7FFD627486 for ; Thu, 5 Mar 2020 05:09:12 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 9oNMjQEfgSl8q9oNMj2hNe; Thu, 05 Mar 2020 05:09:12 -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=P2Op+mBXz77ucWJILHHJw8eByoBg+MewO1F656lbx2E=; b=ji17C/Vaif3YLuwY5Eupaw96C3 UkR/HtBh0rxG6oqJeCoxCqvqpi8ybYvNhPQZc4u4PspBum9K9otRdwHGpp+z6kQ1uO9p92AV+U9o7 cw9NCmRgwQgYR6IKYvyO4Pn0kx2NMJLQKHNufslluDwqCrWy57oC1/EufE58QHrSsbRocu4B48Kql vv2w6FXCFADmLqKzJGTHjOyf5h6EC1YVaRTCLN7T8DrqS+2XhYCUtytm54y3AwCZv0MZ78p/tN7i3 OdDZH28+0ahQ1sIeoZbD9r6KcdhTMUJXEzFN69oODHqCrukUWxVQX3K/N+6C4WecmGUZzLpD+tbP8 M6etCAWw==; Received: from [201.166.169.220] (port=30902 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1j9oNK-003q3G-0k; Thu, 05 Mar 2020 05:09:10 -0600 Date: Thu, 5 Mar 2020 05:12:16 -0600 From: "Gustavo A. R. Silva" To: Daniel Drake , Ulrich Kunitz , 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] zd1211rw/zd_usb.h: Replace zero-length array with flexible-array member Message-ID: <20200305111216.GA24982@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: 1j9oNK-003q3G-0k X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [201.166.169.220]:30902 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 9 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/zydas/zd1211rw/zd_usb.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/zydas/zd1211rw/zd_usb.h b/drivers/net/wireless/zydas/zd1211rw/zd_usb.h index a52ee323a142..8f03b09a602c 100644 --- a/drivers/net/wireless/zydas/zd1211rw/zd_usb.h +++ b/drivers/net/wireless/zydas/zd1211rw/zd_usb.h @@ -69,7 +69,7 @@ enum control_requests { struct usb_req_read_regs { __le16 id; - __le16 addr[0]; + __le16 addr[]; } __packed; struct reg_data { @@ -79,7 +79,7 @@ struct reg_data { struct usb_req_write_regs { __le16 id; - struct reg_data reg_writes[0]; + struct reg_data reg_writes[]; } __packed; enum { @@ -95,7 +95,7 @@ struct usb_req_rfwrite { /* 2: other (default) */ __le16 bits; /* RF2595: 24 */ - __le16 bit_values[0]; + __le16 bit_values[]; /* (ZD_CR203 & ~(RF_IF_LE | RF_CLK | RF_DATA)) | (bit ? RF_DATA : 0) */ } __packed; @@ -118,7 +118,7 @@ struct usb_int_header { struct usb_int_regs { struct usb_int_header hdr; - struct reg_data regs[0]; + struct reg_data regs[]; } __packed; struct usb_int_retry_fail {