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=-11.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 E3002C10F27 for ; Tue, 10 Mar 2020 18:36:40 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 903C320873 for ; Tue, 10 Mar 2020 18:36:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="TY7gC281" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 903C320873 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=/Dy+Bv9/SnxGh3PjqPE98+ksdLPL6lI0FdignON7MOg=; b=TY7gC281UOCHIs DDd3AzcgDJl443C0t+nPVD7sKWE9CivbIpBxk3b8kVcUhFePX0JVIVhil32QHdZ390nPuV2vWqSk6 iSvJY8lpViYyTNmaxsgTIfi3FcXSor9z0xPOGxKtFgwotMkvSQeAojmY2if+ZW5Gr4u0COHXNU1Qw xPPzT1Nig3xgx1KvPBdgmec32DI4cuI6GFMZ7Ys76X0MKakUMyeGSQ0rd18x6Hu8o7BjvvEvug+Cf GIYNdwgEs71gble5CwAKFLJZgzm3ev33oXja9E6vGbkG0vQZhGYhwJLFW7O40LkCmVUFe5fpwdOk6 sPVlVOppWvl3OeksJMVA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jBjjz-0001xN-Mc; Tue, 10 Mar 2020 18:36:31 +0000 Received: from relay1-d.mail.gandi.net ([217.70.183.193]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jBjew-0004DL-18; Tue, 10 Mar 2020 18:31:19 +0000 X-Originating-IP: 91.224.148.103 Received: from localhost.localdomain (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id C1BB4240008; Tue, 10 Mar 2020 18:31:13 +0000 (UTC) From: Miquel Raynal To: "Gustavo A. R. Silva" , Masahiro Yamada , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Liang Yang , Kevin Hilman , Xiaolei Li , Matthias Brugger , Maxime Ripard , Chen-Yu Tsai Subject: Re: [PATCH] mtd: rawnand: Replace zero-length array with flexible-array member Date: Tue, 10 Mar 2020 19:31:12 +0100 Message-Id: <20200310183112.18567-1-miquel.raynal@bootlin.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200226222722.GA18020@embeddedor> References: MIME-Version: 1.0 X-linux-mtd-patch-notification: thanks X-linux-mtd-patch-commit: 76d2f79cf5ae53bc5781903af98a1cb51ef12915 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200310_113118_234034_CD1EB0F4 X-CRM114-Status: GOOD ( 10.93 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mtd@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Wed, 2020-02-26 at 22:27:22 UTC, "Gustavo A. R. Silva" wrote: > 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 > Acked-by: Masahiro Yamada Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks. Miquel ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/