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=-5.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,NICE_REPLY_A,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 2EE46C2B9F4 for ; Fri, 18 Jun 2021 00:12:47 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 359B2613B4 for ; Fri, 18 Jun 2021 00:12:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 359B2613B4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4G5fWd3PWxz3c4y for ; Fri, 18 Jun 2021 10:12:45 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=oSpSYvWF; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=luto@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=oSpSYvWF; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4G5fW80ybHz2ysk for ; Fri, 18 Jun 2021 10:12:19 +1000 (AEST) Received: by mail.kernel.org (Postfix) with ESMTPSA id 2AD2F610CA; Fri, 18 Jun 2021 00:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623975136; bh=NIkBnZc2GHohfpXgF10FM3cZz9pBdstBWE9sKMqAMu8=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=oSpSYvWFKgBFEmjj8o4qaE7vn+cDY9bhzewS9dKRZoiijkKB/+Yqur25dKFc91Vis ZIPJrkANH3XOikALMkUnqGw2NMPt+2syBcTxRTm5Ev0FPDGtcWXmgcUpH0vvkHEkHG eUQLxuoMVV4FDkRNZtCVHL97C/k/qdnN3cp8bPWJY+iKrsdKwIYHjOzT4a9IqX+lyj i1+y1Xo6wBY0AAm1bUVFS8enJ0mzJMsXotkTh2iJ+ORWNNUbZnA4HZP4xG4dZqoay8 o8Bg5Bxd9kWW/TTPnGN7ihP827CtnDc1xghkjSy+TcwjGKxWA/F7/Q+8IdiRR0jt77 rJUiaJF3kPs9g== Subject: Re: [PATCH 8/8] membarrier: Rewrite sync_core_before_usermode() and improve documentation To: Mathieu Desnoyers References: <07a8b963002cb955b7516e61bad19514a3acaa82.1623813516.git.luto@kernel.org> <827549827.10547.1623941277868.JavaMail.zimbra@efficios.com> From: Andy Lutomirski Message-ID: <26196903-4aee-33c4-bed8-8bf8c7b46793@kernel.org> Date: Thu, 17 Jun 2021 17:12:15 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <827549827.10547.1623941277868.JavaMail.zimbra@efficios.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , Will Deacon , linux-mm , Peter Zijlstra , x86 , linux-kernel , Nicholas Piggin , Dave Hansen , Paul Mackerras , stable , Andrew Morton , linuxppc-dev , linux-arm-kernel Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 6/17/21 7:47 AM, Mathieu Desnoyers wrote: > Please change back this #ifndef / #else / #endif within function for > > if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE)) { > ... > } else { > ... > } > > I don't think mixing up preprocessor and code logic makes it more readable. I agree, but I don't know how to make the result work well. membarrier_sync_core_before_usermode() isn't defined in the !IS_ENABLED case, so either I need to fake up a definition or use #ifdef. If I faked up a definition, I would want to assert, at build time, that it isn't called. I don't think we can do: static void membarrier_sync_core_before_usermode() { BUILD_BUG_IF_REACHABLE(); }