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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 86B3EC4363A for ; Tue, 27 Oct 2020 08:36:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34CE82070E for ; Tue, 27 Oct 2020 08:36:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2894989AbgJ0Igv (ORCPT ); Tue, 27 Oct 2020 04:36:51 -0400 Received: from verein.lst.de ([213.95.11.211]:37883 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2395068AbgJ0Igu (ORCPT ); Tue, 27 Oct 2020 04:36:50 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id B264A67373; Tue, 27 Oct 2020 09:36:47 +0100 (CET) Date: Tue, 27 Oct 2020 09:36:47 +0100 From: Christoph Hellwig To: Alexey Kardashevskiy Cc: linuxppc-dev@lists.ozlabs.org, Christoph Hellwig , Michael Ellerman , linux-kernel@vger.kernel.org Subject: Re: [PATCH kernel 0/2] powerpc/dma: Fallback to dma_ops when persistent memory present Message-ID: <20201027083647.GA24318@lst.de> References: <20201021032026.45030-1-aik@ozlabs.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201021032026.45030-1-aik@ozlabs.ru> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 21, 2020 at 02:20:24PM +1100, Alexey Kardashevskiy wrote: > This allows mixing direct DMA (to/from RAM) and > IOMMU (to/from apersistent memory) on the PPC64/pseries > platform. This was supposed to be a single patch but > unexpected move of direct DMA functions happened. > > This is based on sha1 > 7cf726a59435 Linus Torvalds "Merge tag 'linux-kselftest-kunit-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest". > > Please comment. Thanks. I really don't like your revert. I'm almost ready to kill of dma-direct.h, and I really want it private in kernel/dma/, as people keep adding abuses to drivers. We have two options here: (1) duplicate the code in arch/powerpc/ (2) add a hook to kernel/dma/ I've not been a fan of (2) in the past, but now that the code is out of line, and we could make it dependent on a config option only set by powerpc, I see it as the lesser evil now.