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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 A64A8C3F2CE for ; Wed, 4 Mar 2020 17:55:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7CDF221775 for ; Wed, 4 Mar 2020 17:55:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583344514; bh=GbkfQSF4gx69Uq29jGSUD3eH6p008JMGE1/+vzwNYdM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=aRVhmBlroAoVpUV/8KjGfOJekQ/QoCjDraXaUyGIsxKFmqH2fhVRg20nrHCLUJ356 KVz2C0zbWIrHvnuo7DdpgHy0cuL/eGLiUpDyovBqyaq9XbJpbcyNZrZg6rUp0blq2b qBgwa5kPcMRCwlbRRzMYrknWmQbdV7UGn5j8UKcY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729471AbgCDRzO (ORCPT ); Wed, 4 Mar 2020 12:55:14 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:40109 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728926AbgCDRzO (ORCPT ); Wed, 4 Mar 2020 12:55:14 -0500 Received: by mail-wm1-f65.google.com with SMTP id e26so2807046wme.5; Wed, 04 Mar 2020 09:55:12 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=IXbD/GgJVPZ9WOOjQZpIDfTuKHqUvdwDS5tyVn1vzKs=; b=dZW/rNEE4siDef5TElhDwRimjVffVGL/eOVlNvygHaKe9GqFlWeXkbCIMvCK3PCaQr +RmoAAoMydHmWeDXg35PHKU5FbUnpljLq1iE0S6P3N+yWp0lnYrWw9mM+SnXNNRe6gfl FCISM22tFhE/KC2LjQT1WI5MOSuS/dm54S55YvmE6jjfqLTzfQkQj4HU3RqC89TQ0er3 vHYmm64WT8Cjzc3sObAijW4zuScMmaN0Un+Xf4bDjhVTrTrQZxw0gShFf7AOdFTbSzIh oQh3CDKvJCCHSdDEDAUQy+O1WfhJkcVL4oKUE5zZH9jfj5pnWVxthweTDqrqiVXx9gCf R/Nw== X-Gm-Message-State: ANhLgQ1DQXr77lGXKu7uGgOwWlInL18ONrS+2rC6uNFh/sD90rRrTFXN GSrpkcotjqAyyhjW1LcUqugC1Bqu X-Google-Smtp-Source: ADFU+vs9Ns5cKiBuxZvEKxGfUWqB4Wx333NSJ3TdOFT09JNhgx8N5gGqFg8moiDT+XIM3+5kO/phPg== X-Received: by 2002:a7b:c019:: with SMTP id c25mr4825181wmb.126.1583344512200; Wed, 04 Mar 2020 09:55:12 -0800 (PST) Received: from debian (41.142.6.51.dyn.plus.net. [51.6.142.41]) by smtp.gmail.com with ESMTPSA id o8sm5015597wmh.15.2020.03.04.09.55.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Mar 2020 09:55:11 -0800 (PST) Date: Wed, 4 Mar 2020 17:55:09 +0000 From: Wei Liu To: Dexuan Cui , Lorenzo Pieralisi Cc: "Gustavo A. R. Silva" , KY Srinivasan , Haiyang Zhang , Stephen Hemminger , Sasha Levin , Lorenzo Pieralisi , Andrew Murray , Bjorn Helgaas , "linux-hyperv@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Wei Liu Subject: Re: [PATCH] PCI: hv: Replace zero-length array with flexible-array member Message-ID: <20200304175509.dwhn63omfzewaukv@debian> References: <20200213005048.GA9662@embeddedor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716 Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Thu, Feb 13, 2020 at 03:43:40AM +0000, Dexuan Cui wrote: > > From: linux-hyperv-owner@vger.kernel.org > > On Behalf Of Gustavo A. R. Silva > > Sent: Wednesday, February 12, 2020 4:51 PM > > ... > > 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. > > Looks good to me. Thanks, Gustavo! > > Reviewed-by: Dexuan Cui > Lorenzo, will you be picking up this patch? It seems to me you've been handling patches to pci-hyperv.c. This patch is not yet in pci/hv branch in your repository. Let me know what you think. Wei.