Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F478C433F5 for ; Mon, 15 Nov 2021 23:12:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5837761414 for ; Mon, 15 Nov 2021 23:12:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344069AbhKOXPn (ORCPT ); Mon, 15 Nov 2021 18:15:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237334AbhKOTLX (ORCPT ); Mon, 15 Nov 2021 14:11:23 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0AB1C0431A8; Mon, 15 Nov 2021 09:59:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=OTCtPaHwniBROQ1KohHRpPYNoRP5VsY2XqJDv3P4Ku8=; b=p44p58onIF9Z6LsfhgifLQmpAQ 5rbfZ5rZCcIfYI1EN82K2qOPc31bzqeDPDxORr1CCmk6ghtzXIUolrh7rKherFqFYbEe7QAEUEHT+ C1ki1M6pI0QGkAvwgKH4ZYOKgZStlL9i3ZZKRfRq/TZO4kweYM5mhxufLO5fx+mCI9ryljqRdjiTP avUby45C7olHbESiRE2qoMu8fLD1e727JeYNko6BxgWGbL6jeaTMH/A/XyLIMZamG6KaLbM11fL3J T/SjN1AktjqOicD1baasIqVAuRpN8/TIMGtuz296vRO+qKCYMK2YvgFbzdIZ3PnPqlMUvmEtWYMhS AWmJaU4Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mmgGk-00GcKy-2q; Mon, 15 Nov 2021 17:59:50 +0000 Date: Mon, 15 Nov 2021 09:59:50 -0800 From: Christoph Hellwig To: Ilias Apalodimas Cc: Yunsheng Lin , Guillaume Tucker , davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linuxarm@openeuler.org, hawk@kernel.org, akpm@linux-foundation.org, peterz@infradead.org, will@kernel.org, jhubbard@nvidia.com, yuzhao@google.com, mcroce@microsoft.com, fenghua.yu@intel.com, feng.tang@intel.com, jgg@ziepe.ca, aarcange@redhat.com, guro@fb.com, "kernelci@groups.io" Subject: Re: [PATCH net-next v6] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA Message-ID: References: <20211013091920.1106-1-linyunsheng@huawei.com> <1090744a-3de6-1dc2-5efe-b7caae45223a@huawei.com> <644e10ca-87b8-b553-db96-984c0b2c6da1@collabora.com> <93173400-1d37-09ed-57ef-931550b5a582@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is just popping out of nowhere on lkml, but yes ARM LPAE uses a 64-bit dma_addr_t, as a 64-bit phys_addr_t implies that. Same for x86-32 PAE and similar cases on MIPS and probably a few other architectures. But what is the actual problem with a 32-bit virtual and 64-bit pysical/dma address? That is a pretty common setup and absolutely needs to be deal with in drivers and inrastructure.