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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 345E2C433E6 for ; Tue, 1 Sep 2020 14:08:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 067B72078B for ; Tue, 1 Sep 2020 14:08:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728150AbgIAN42 (ORCPT ); Tue, 1 Sep 2020 09:56:28 -0400 Received: from elvis.franken.de ([193.175.24.41]:45709 "EHLO elvis.franken.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728294AbgIANzc (ORCPT ); Tue, 1 Sep 2020 09:55:32 -0400 Received: from uucp (helo=alpha) by elvis.franken.de with local-bsmtp (Exim 3.36 #1) id 1kD6kf-0001nf-02; Tue, 01 Sep 2020 15:55:09 +0200 Received: by alpha.franken.de (Postfix, from userid 1000) id 62CB0C0E4C; Tue, 1 Sep 2020 15:53:04 +0200 (CEST) Date: Tue, 1 Sep 2020 15:53:04 +0200 From: Thomas Bogendoerfer To: Christoph Hellwig Cc: Mauro Carvalho Chehab , "James E.J. Bottomley" , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Ben Skeggs , Pawel Osciak , Marek Szyprowski , Matt Porter , iommu@lists.linux-foundation.org, Tom Lendacky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-samsung-soc@vger.kernel.org, nouveau@lists.freedesktop.org, netdev@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-mm@kvack.org, alsa-devel@alsa-project.org Subject: Re: [PATCH 08/28] MIPS: make dma_sync_*_for_cpu a little less overzealous Message-ID: <20200901135304.GC11944@alpha.franken.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-9-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200819065555.1802761-9-hch@lst.de> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Wed, Aug 19, 2020 at 08:55:35AM +0200, Christoph Hellwig wrote: > When transferring DMA ownership back to the CPU there should never > be any writeback from the cache, as the buffer was owned by the > device until now. Instead it should just be invalidated for the > mapping directions where the device could have written data. > Note that the changes rely on the fact that kmap_atomic is stubbed > out for the !HIGHMEM case to simplify the code a bit. > > Signed-off-by: Christoph Hellwig > --- > arch/mips/mm/dma-noncoherent.c | 44 +++++++++++++++++++++------------- > 1 file changed, 28 insertions(+), 16 deletions(-) Acked-by: Thomas Bogendoerfer -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]