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=-5.2 required=3.0 tests=BAYES_00, 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 DA34BC433E1 for ; Thu, 20 Aug 2020 04:52:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 95E2A20786 for ; Thu, 20 Aug 2020 04:52:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95E2A20786 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2EB3A6B0098; Thu, 20 Aug 2020 00:52:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 29B3A6B0099; Thu, 20 Aug 2020 00:52:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 164A26B009B; Thu, 20 Aug 2020 00:52:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0081.hostedemail.com [216.40.44.81]) by kanga.kvack.org (Postfix) with ESMTP id F40996B0098 for ; Thu, 20 Aug 2020 00:52:05 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AEBA12494 for ; Thu, 20 Aug 2020 04:52:05 +0000 (UTC) X-FDA: 77169725010.24.love91_0c00cd82702d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 8899A1A4A0 for ; Thu, 20 Aug 2020 04:52:05 +0000 (UTC) X-HE-Tag: love91_0c00cd82702d X-Filterd-Recvd-Size: 3384 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Thu, 20 Aug 2020 04:52:05 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 690FB68BEB; Thu, 20 Aug 2020 06:52:01 +0200 (CEST) Date: Thu, 20 Aug 2020 06:52:01 +0200 From: Christoph Hellwig To: Tomasz Figa Cc: Robin Murphy , Christoph Hellwig , alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, Linux Doc Mailing List , nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, Linux Kernel Mailing List , "James E.J. Bottomley" , linux-mm@kvack.org, Marek Szyprowski , linux-samsung-soc , Joonyoung Shim , linux-scsi@vger.kernel.org, Kyungmin Park , Ben Skeggs , Matt Porter , Linux Media Mailing List , Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , "list@263.net:IOMMU DRIVERS" , Joerg Roedel , "list@263.net:IOMMU DRIVERS , Joerg Roedel ," , Thomas Bogendoerfer , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-mips@vger.kernel.org Subject: Re: [PATCH 05/28] media/v4l2: remove V4L2-FLAG-MEMORY-NON-CONSISTENT Message-ID: <20200820045201.GB4570@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-6-hch@lst.de> <62e4f4fc-c8a5-3ee8-c576-fe7178cb4356@arm.com> <2b32f1d8-16f7-3352-40a5-420993d52fb5@arm.com> 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) X-Rspamd-Queue-Id: 8899A1A4A0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Aug 19, 2020 at 04:22:29PM +0200, Tomasz Figa wrote: > > > FWIW, I asked back in time what the plan is for non-coherent > > > allocations and it seemed like DMA_ATTR_NON_CONSISTENT and > > > dma_sync_*() was supposed to be the right thing to go with. [2] The > > > same thread also explains why dma_alloc_pages() isn't suitable for the > > > users of dma_alloc_attrs() and DMA_ATTR_NON_CONSISTENT. > > > > AFAICS even back then Christoph was implying getting rid of > > NON_CONSISTENT and *replacing* it with something streaming-API-based - > > That's not how I read his reply from the thread I pointed to, but that > might of course be my misunderstanding. Yes. Without changes like in this series just calling dma_sync_single_* will break in various cases, e.g. because dma_alloc_attrs returns memory remapped in the vmalloc space, and the dma_sync_single_* implementation implementation can't cope with vmalloc addresses.