Received: by 2002:a9a:4c47:0:b029:116:c383:538 with SMTP id u7csp1164145lko; Tue, 13 Jul 2021 18:32:05 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzz0ICk70Y1s4QPfGDGxq8Z4rhWgePFoU5SfryeowXKBgGU+unTTkVx1qAhH6rpAt4AOj0B X-Received: by 2002:a02:8184:: with SMTP id n4mr6530192jag.17.1626226325282; Tue, 13 Jul 2021 18:32:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1626226325; cv=none; d=google.com; s=arc-20160816; b=ZFEh2qd0Gz1WXdsAl29V/c7XMY4JfWDotSXXXcoTTpXJ0lCsbPZfST83xmLcpsuKCu u8122CqQpVeCau09tVc7E7ruGvK1sSruZTQsN/G+BcdIlMkKtG5DyhWljAD4/7PD7Oyl AC9QUi2FA6wtErDsDH1Jp2lytKcLKwHnXOqFWr8lyFpgdWLuUj+UBT2oHW2k5Iys46i+ biMIZvibRi2tI3r334u84oNmutZaQqo8yqqkBVuN+8A4kNg0WbXQh6Ai92d70v734HuU OcF5AAgjiIg0/CC3ZJ8ozCR7T/lQ7IkDoeuFOsDfAYKcGXNB8L394h5ZUabWeUkkvphf mkxQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date :dkim-signature; bh=Oo84eGmcOIX9IjzkXm44BYU8oS26G88L8Unbj2ykR8Y=; b=iNwDJF0MhT3o5t4YMB4CBGiaYZffsp0r/wUgQj0o9BcclF1xl0/aWaUdgZOX5oaf+c 8sArZ9HzgeU5u5Os79sRJwydwo482KUkPctBjjWHSF4nPV8k1PbRMvpvc4Blp6w5DuCX KEBNu0stj0X3/BXDmaQZZlGidLxFYMtMCPQ407nVvGZrybzs+5MrpDjmzX/ua8BVDtiR o0H969v1Lb7JoIiSQcr0XG9pcSNfQb5brzUp/B8jNXAI8I3LOYg9e6in5ukuvamHL70U QwwjZyJ+Uw8ERsB1gZ482/3cVFxOvWbTFFTlXyo/vDhUeSU81GoJgXDKwb5jOzcwA/1o 67Ow== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linux-foundation.org header.s=korg header.b=1jfYwAwW; 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 r6si909318iov.48.2021.07.13.18.31.53; Tue, 13 Jul 2021 18:32:05 -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=@linux-foundation.org header.s=korg header.b=1jfYwAwW; 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 S237335AbhGNBeP (ORCPT + 99 others); Tue, 13 Jul 2021 21:34:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:38680 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237286AbhGNBeP (ORCPT ); Tue, 13 Jul 2021 21:34:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C4EB56128B; Wed, 14 Jul 2021 01:31:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1626226284; bh=GhhAgrzg6+D3QZxWK/qCyoqLLb801ORLrL4xD0yZs7c=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=1jfYwAwWnlof215iZQWp18105XkOaH44dMKb/2tpkwfIWo/PnFEQpMjYpij0Rcy1K /jmfPGqEx8TD+03EXZXQU1gSvpqoI0/HYNuI7z8OVFuK9H0ExwEDHXjd11ccXidEm0 DrCK/UbiAz4LXhaAhbAFnzRf5N4JK4FKSj9aS4Po= Date: Tue, 13 Jul 2021 18:31:23 -0700 From: Andrew Morton To: Christoph Hellwig Cc: Ira Weiny , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] mm: call flush_dcache_page in memcpy_to_page and memzero_page Message-Id: <20210713183123.699769a1b0ee95d69606c35d@linux-foundation.org> In-Reply-To: <20210713055231.137602-2-hch@lst.de> References: <20210713055231.137602-1-hch@lst.de> <20210713055231.137602-2-hch@lst.de> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Jul 2021 07:52:30 +0200 Christoph Hellwig wrote: > memcpy_to_page and memzero_page can write to arbitrary pages, which could > be in the page cache or in high memory, so call flush_kernel_dcache_pages > to flush the dcache. I assume this presently is not known to cause any problems, but that some problems might be discovered in the future? In which case, should we cc:stable?