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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 4CDB2C04EB8 for ; Fri, 7 Dec 2018 01:21:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7E7D20850 for ; Fri, 7 Dec 2018 01:21:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D7E7D20850 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726034AbeLGBVn (ORCPT ); Thu, 6 Dec 2018 20:21:43 -0500 Received: from verein.lst.de ([213.95.11.211]:60695 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725967AbeLGBVn (ORCPT ); Thu, 6 Dec 2018 20:21:43 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id 1B6EB68AA6; Fri, 7 Dec 2018 02:21:42 +0100 (CET) Date: Fri, 7 Dec 2018 02:21:42 +0100 From: Christoph Hellwig To: Robin Murphy Cc: Christoph Hellwig , Linus Torvalds , iommu@lists.linux-foundation.org, brouer@redhat.com, tariqt@mellanox.com, ilias.apalodimas@linaro.org, toke@toke.dk, Linux List Kernel Mailing Subject: Re: [RFC] avoid indirect calls for DMA direct mappings Message-ID: <20181207012141.GA4256@lst.de> References: <20181206153720.10702-1-hch@lst.de> <20181206184330.GB30039@lst.de> <173bfba7-033d-93c4-6ef1-48c9e39c9efc@arm.com> <20181206200006.GA31548@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 06, 2018 at 08:24:38PM +0000, Robin Murphy wrote: > On 06/12/2018 20:00, Christoph Hellwig wrote: >> On Thu, Dec 06, 2018 at 06:54:17PM +0000, Robin Murphy wrote: >>> I'm pretty sure we used to assign dummy_dma_ops explicitly to devices at >>> the point we detected the ACPI properties are wrong - that shouldn't be too >>> much of a headache to go back to. >> >> Ok. I've cooked up a patch to use NULL as the go direct marker. >> This cleans up a few things nicely, but also means we now need to >> do the bypass scheme for all ops, not just the fast path. But we >> probably should just move the slow path ops out of line anyway, >> so I'm not worried about it. This has survived some very basic >> testing on x86, and really needs to be cleaned up and split into >> multiple patches.. > > I've also just finished hacking something up to keep the arm64 status quo - > I'll need to actually test it tomorrow, but the overall diff looks like the > below. Nice. I created a branch that picked up your bits and also the ideas from Linus, and the result looks reall nice. I'll still need a signoff for your bits, though. Jesper, can you give this a spin if it changes the number even further? git://git.infradead.org/users/hch/misc.git dma-direct-calls.2 http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-direct-calls.2