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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 550EDC31E4D for ; Fri, 14 Jun 2019 15:35:00 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 35F2E2175B for ; Fri, 14 Jun 2019 15:35:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35F2E2175B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 04CB61175; Fri, 14 Jun 2019 15:35:00 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 357451175 for ; Fri, 14 Jun 2019 15:34:59 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id C4718174 for ; Fri, 14 Jun 2019 15:34:58 +0000 (UTC) Received: by newverein.lst.de (Postfix, from userid 2407) id DF91968AFE; Fri, 14 Jun 2019 17:34:28 +0200 (CEST) Date: Fri, 14 Jun 2019 17:34:28 +0200 From: Christoph Hellwig To: Greg KH Subject: Re: [PATCH 12/16] staging/comedi: mark as broken Message-ID: <20190614153428.GA10008@lst.de> References: <20190614134726.3827-1-hch@lst.de> <20190614134726.3827-13-hch@lst.de> <20190614140239.GA7234@kroah.com> <20190614144857.GA9088@lst.de> <20190614153032.GD18049@kroah.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190614153032.GD18049@kroah.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Maxime Ripard , Joonas Lahtinen , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Christoph Hellwig , devel@driverdev.osuosl.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, David Airlie , linux-media@vger.kernel.org, Intel Linux Wireless , intel-gfx@lists.freedesktop.org, Maarten Lankhorst , Jani Nikula , Ian Abbott , Rodrigo Vivi , Sean Paul , "moderated list:ARM PORT" , netdev@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, H Hartley Sweeten , iommu@lists.linux-foundation.org, Daniel Vetter X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Fri, Jun 14, 2019 at 05:30:32PM +0200, Greg KH wrote: > On Fri, Jun 14, 2019 at 04:48:57PM +0200, Christoph Hellwig wrote: > > On Fri, Jun 14, 2019 at 04:02:39PM +0200, Greg KH wrote: > > > Perhaps a hint as to how we can fix this up? This is the first time > > > I've heard of the comedi code not handling dma properly. > > > > It can be fixed by: > > > > a) never calling virt_to_page (or vmalloc_to_page for that matter) > > on dma allocation > > b) never remapping dma allocation with conflicting cache modes > > (no remapping should be doable after a) anyway). > > Ok, fair enough, have any pointers of drivers/core code that does this > correctly? I can put it on my todo list, but might take a week or so... Just about everyone else. They just need to remove the vmap and either do one large allocation, or live with the fact that they need helpers to access multiple array elements instead of one net vmap, which most of the users already seem to do anyway, with just a few using the vmap (which might explain why we didn't see blowups yet). _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu