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=ham 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 05209C4332E for ; Thu, 19 Mar 2020 23:09:43 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CE16820714 for ; Thu, 19 Mar 2020 23:09:42 +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="ayDLz5wY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE16820714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 3918D10FC36E3; Thu, 19 Mar 2020 16:10:33 -0700 (PDT) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=192.185.47.144; helo=gateway22.websitewelcome.com; envelope-from=gustavo@embeddedor.com; receiver= Received: from gateway22.websitewelcome.com (gateway22.websitewelcome.com [192.185.47.144]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 57E3810FC36DF for ; Thu, 19 Mar 2020 16:10:30 -0700 (PDT) Received: from cm16.websitewelcome.com (cm16.websitewelcome.com [100.42.49.19]) by gateway22.websitewelcome.com (Postfix) with ESMTP id EA80650 for ; Thu, 19 Mar 2020 18:09:38 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id F4IEjZyQh8vkBF4IEjQzqM; Thu, 19 Mar 2020 18:09:38 -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=sQw+xjq5+WUJP7rhAnVh9p35OyAlvz4DhIGg/W9Bo1E=; b=ayDLz5wYvqjcoLy7zs/4VkaZlH Hd/BG0qT9NFzyMG5Ae+DNwyxzCjExZ5N0EZNw2RXcJdJDXu3OxqV2PNb1CT1Y+R6IqeNKOkaSEP13 9PbapJaxcJq/0KPUVIp4W+XCx05fY3vN8+/9ENVO9l8PwuSkBBdGLKK5nkL11khGCsG6IFRg8CzzP bpw9bd3JfHFr5GxL3opfwYwOxpRO/ZzcrxSfr2E5H+dnlyxwvYJMIgkAsDEw7pxlo9RkbtFW4azjJ yJb9BDRaPt2/yJ9yUW32/nXW+VxAM3stl/9P4WTDiMObnNtnx7m4m68OFaqA+3uGkUVsxhSZ3gS9C qS91LuwQ==; Received: from cablelink-189-218-116-241.hosts.intercable.net ([189.218.116.241]:54046 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.92) (envelope-from ) id 1jF4ID-002QMW-CK; Thu, 19 Mar 2020 18:09:37 -0500 Date: Thu, 19 Mar 2020 18:09:37 -0500 From: "Gustavo A. R. Silva" To: Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny Subject: [PATCH][next] nvdimm: nd.h: Replace zero-length array with flexible-array member Message-ID: <20200319230937.GA16648@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 - lists.01.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: 1jF4ID-002QMW-CK X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-189-218-116-241.hosts.intercable.net (embeddedor) [189.218.116.241]:54046 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 21 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Message-ID-Hash: G5ULPMLTMSX256NOU625R3VQ2AUXVQXG X-Message-ID-Hash: G5ULPMLTMSX256NOU625R3VQ2AUXVQXG X-MailFrom: gustavo@embeddedor.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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/nvdimm/nd.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h index c4d69c1cce55..85dbb2a322b9 100644 --- a/drivers/nvdimm/nd.h +++ b/drivers/nvdimm/nd.h @@ -39,7 +39,7 @@ struct nd_region_data { int ns_count; int ns_active; unsigned int hints_shift; - void __iomem *flush_wpq[0]; + void __iomem *flush_wpq[]; }; static inline void __iomem *ndrd_get_flush_wpq(struct nd_region_data *ndrd, @@ -157,7 +157,7 @@ struct nd_region { struct nd_interleave_set *nd_set; struct nd_percpu_lane __percpu *lane; int (*flush)(struct nd_region *nd_region, struct bio *bio); - struct nd_mapping mapping[0]; + struct nd_mapping mapping[]; }; struct nd_blk_region { -- 2.23.0 _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org