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=-5.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 1740EC433E0 for ; Fri, 15 Jan 2021 09:25:21 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 BA56F233CF for ; Fri, 15 Jan 2021 09:25:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BA56F233CF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=YrNnETP//WIrCJW0e4dKt8Z7ztEgOQqeov9YglYwOdM=; b=uMY46yuVBQL+d8YSMBOwMPGdh UO93zX/iMTkGCPjcqrbShWh8vijHkx4ojinDTXc1XnTNorTrzouWqBXCLa8JJtS2UtQJf1AdnReyW 1Y0q5gVXheaA6TJFFb9JEMi0DMipXKx5AVs8ENIdvYqePX7ScY29yHNxCBQq+bQ9zL5hkWoX8qx0/ BrKtEihBKR3GZ1M/lfAUiaHkkhemCIYiJvCrnoLzIxbAXz2JDsf9xkHuTINyHs/ihD9QuEuNhsbaK 2qhrdqMFtikpgGLYIWl9r2+0iffVzp9lnShx0HbwrLsF5WIOOei7B7e15l+oqP9FDuKHjOOrE7zTZ Gl72+3OKg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l0LKD-0001nj-U4; Fri, 15 Jan 2021 09:23:21 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l0LKB-0001nL-Lb for linux-arm-kernel@lists.infradead.org; Fri, 15 Jan 2021 09:23:20 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id A6C1523128; Fri, 15 Jan 2021 09:23:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610702598; bh=YUOoXIAq/McVqyyFlnSUnFFrxg1lB2e+xTyNR3jGHyA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hEqu4l3j282rJAOphaS8MwVUBWSv9TQZdio0FDP+NxklrAhEgedE4wiyjcXV27oVH cuRO6fZEXjx26Egc7ICn3VrW/EJGj3OvXedjlLywgwx/oHVdHl61qAuRjUXn++6lOr ORCUtywMXqtaG7loHLP3FqxSqXJGCql/v5zeqIky2zzgwlfFuAsZ4TABILEO1J40R9 mXIIbYoTR9aZ4Toj523mBY7xcOZ+WnEC8dYgRfCY1ohe0IqfK9b6zoAH99EvOeXvR/ XkqP2hf5I+p22GOeQxk6SmGIYtT/KROrCiTqoZVEHMWNnfuFpgT3BWg+lI2QBYjjVX /+JV6lQm7iHPQ== Date: Fri, 15 Jan 2021 09:23:13 +0000 From: Will Deacon To: Linus Torvalds Subject: Re: [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault' Message-ID: <20210115092313.GA13700@willie-the-truck> References: <20210114175934.13070-1-will@kernel.org> <20210114175934.13070-5-will@kernel.org> <20210114190021.GB13135@willie-the-truck> <20210114194129.GA13314@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210115_042319_809398_71B68868 X-CRM114-Status: GOOD ( 18.15 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jan Kara , Minchan Kim , Catalin Marinas , Nick Desaulniers , Linux Kernel Mailing List , Linux-MM , Vinayak Menon , Hugh Dickins , "Kirill A . Shutemov" , Andrew Morton , Android Kernel Team , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jan 14, 2021 at 01:11:12PM -0800, Linus Torvalds wrote: > On Thu, Jan 14, 2021 at 11:41 AM Will Deacon wrote: > > > > Sure enough, an arm64 defconfig builds perfectly alright with that change, > > but it really shouldn't. I'm using clang 11.0.5, so I had another go with > > GCC 9.2.1 and bang: > > Ok, looks like a clang bug, but a reasonably benign one. > > As long as we have sufficient coverage with gcc, we'll get error > reporting in a timely manner for any new incorrect assignments, so I > think we can do that constant anonymous struct even if it does mean > that clang might let some bad cases through (I personally use gcc for > build testing, and then clang for building my boot kernels, so I'd > catch anything x86-64 allmodconfig in my build tests). > > And keeping it unnamed it would avoid a lot of noisy churn.. Hmm. The feedback on the clang bug suggests that GCC is the one in the wrong here (although the argument is based on C11 and I haven't trawled through the standards to see how this has evolved): https://bugs.llvm.org/show_bug.cgi?id=48755#c1 There is at least some sympathy to generating a warning, so that might be good enough. Otherwise, I suppose we can explicitly mark the fields as 'const' but I won't jump to that immediately. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel