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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 3A924C433FF for ; Thu, 15 Aug 2019 06:53:05 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 82F0B2084D for ; Thu, 15 Aug 2019 06:53:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82F0B2084D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 468HG63C5DzDr3M for ; Thu, 15 Aug 2019 16:53:02 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 468HDH140bzDqJh for ; Thu, 15 Aug 2019 16:51:25 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id CCA2068B02; Thu, 15 Aug 2019 08:51:17 +0200 (CEST) Date: Thu, 15 Aug 2019 08:51:17 +0200 From: Christoph Hellwig To: Rob Clark Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc Message-ID: <20190815065117.GA23761@lst.de> References: <20190814220011.26934-1-robdclark@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190814220011.26934-1-robdclark@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kate Stewart , Masayoshi Mizuma , "Maciej W. Rozycki" , Eric Biggers , Catalin Marinas , Imre Deak , dri-devel@lists.freedesktop.org, Chris Wilson , Masahiro Yamada , Benjamin Gaignard , Mauro Carvalho Chehab , Will Deacon , Christoph Hellwig , Emil Velikov , Rob Clark , Mike Rapoport , Geert Uytterhoeven , "moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)" , Daniel Vetter , "open list:MIPS" , Linus Walleij , Robin Murphy , "open list:DRM DRIVER FOR MSM ADRENO GPU" , Deepak Sharma , Joerg Roedel , Arnd Bergmann , Anshuman Khandual , Hauke Mehrtens , Jesper Dangaard Brouer , "Wolfram Sang \(Renesas\)" , "open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)" , Alexios Zavras , Russell King , Doug Anderson , Thomas Gleixner , Sean Paul , Allison Randal , Enrico Weigelt , Ard Biesheuvel , Greg Kroah-Hartman , open list , Paul Burton , Souptick Joarder , Andrew Morton , "open list:DRM DRIVER FOR MSM ADRENO GPU" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" As said before I don't think these low-level helpers are the right API to export, but even if they did you'd just cover a tiny subset of the architectures. Also to distil the previous thread - if you remap memory to uncached the helper to use is arch_dma_prep_coherent, which does a writeback+ invalidate everywhere, and there is no need to clean up after a long-term uncached mapping. We might still get speculations into that area, if we don't remap the direct mapping, but it isn't like invalidting that just before freeing the memory is going to help anyone. Also it seems like patches 5 and 6 are missing in my inbox.