Received: by 2002:a05:6a10:5bc5:0:0:0:0 with SMTP id os5csp1978463pxb; Thu, 4 Nov 2021 11:49:04 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzvxGXSxuPLwYLlAYLvj8eVKHBeMZ/zyTPuYArLZeD9WOi4B6yIuac6QTKJc9J1fxWmKBqS X-Received: by 2002:a17:907:72d4:: with SMTP id du20mr67281653ejc.324.1636051744388; Thu, 04 Nov 2021 11:49:04 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1636051744; cv=none; d=google.com; s=arc-20160816; b=Dne0M6MnMKyuPAEU3osF0WACkPBXoSPePG2AkLBGM4210LJg2Aa6BZPmedxWxLsG6B REY+7M8r4UYhSAjYExl8RyEmm+Xsy3/MJL9HtPOZlJFbPCmthWBTCEgGUyKdJTvsMhWx XKOLRSc5DbN8ihVDqrzClz5gIK56yxU87V3p2zGuVD2WErSDZi3YGR6I7GDsARvQTwLS MzgSOiLpxCM+YRPrM+kWZdmXq4RzybLVCfa7j0oF+77s4+YaET6CmG5tvzj7Aul9XRJv c3qfjRjW0K19ynzVHnKdMlvZCYJvzfY7xmCufi+7XaSqdgsqJBp9CXA+oJb+6nq0GRCZ IKCw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:in-reply-to:content-disposition:mime-version :references:message-id:subject:cc:to:from:date:dkim-signature; bh=i3yErMeEVElHCsw4wyrp8I0BlcKHj/KRuLthwWRSHBU=; b=L7LYEIVRl3dElSRcfoaoyaJXACMWbQ/kRxBmHGSXtgOWMnUmFB4l2aENwK3L0iRuzQ bplPFp2cUHhHig9xkiwozKfjlNnOpLSAK0zjA2pbcEvITN8XvU9yhwO1eUPWDnhrUznn eUFC8MFtFfSh8LqUfbjUrkAcro/ZCj3CwC99lnGXexHGEWNmpfP2WJFjy3467ZXeTR0A kC/D6bvspzmZ4Jn41eN8+MpOURMcAJzNO2345Wy+lV5vafXCLJwaaul4eWGPv9Us7KzK bB9htOqId2S+g6vA0MbmdpteZbbaNtVUeUSrUIys42L2BnhmhNFBa7Den+Xnh87fwBuQ oPCw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=LqXwIstX; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id b12si11649550edz.460.2021.11.04.11.48.39; Thu, 04 Nov 2021 11:49:04 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=LqXwIstX; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234103AbhKDSmx (ORCPT + 99 others); Thu, 4 Nov 2021 14:42:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234074AbhKDSmq (ORCPT ); Thu, 4 Nov 2021 14:42:46 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48354C061714; Thu, 4 Nov 2021 11:40:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=i3yErMeEVElHCsw4wyrp8I0BlcKHj/KRuLthwWRSHBU=; b=LqXwIstX8b4GBZbTO3TLFRk7Zw +7LCIu5/EiQjRqH7LDBDT49duNQNThLmg1ar4gFTf5tXeOSO/ryiX8qIzSJOYApBvLr+yM2zdQswJ Kud9+J2T30jhHTcQJRNUwNqZWEe9PQAg43ltudbNtP0O0VTDgv139rbjfE8YExWpcwaBI+k4uCfWi KyqUl6MsqHz11LQJPWjvBpaD+Q2WDeFVa2X0ZF8t0YbhruveDrA1TP/0JS+LAkgdqQVJO/VGIfB4q 09qmEPqkdWXmWQQN6nuXSW+MZ8n5IIoH/2FOFkWK0pwj4B1K3ho95YzrdZXueCbQel7CE0U3PUSAu F+OpblNw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mihdY-00641C-Dg; Thu, 04 Nov 2021 18:39:10 +0000 Date: Thu, 4 Nov 2021 18:38:56 +0000 From: Matthew Wilcox To: Linus Torvalds Cc: Christoph Hellwig , linux-arch , Ira Weiny , Andrew Morton , Linux Kernel Mailing List , Thomas Gleixner Subject: Re: flush_dcache_page vs kunmap_local Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 04, 2021 at 08:30:55AM -0700, Linus Torvalds wrote: > Why did this come up? Do you actually have some hardware or situation > that cares? Oh, we're doing review of the XFS/iomap folio patches, which led to looking at zero_user_segments(), and I realised that memzero_page() was now functionally identical to zero_user(). And you'd been quite specific about not having flush_dcache_page() in there, so ... I wondered if you'd had a change of mind.