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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 0DDC3C5519F for ; Fri, 20 Nov 2020 08:07:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6566C22227 for ; Fri, 20 Nov 2020 08:07:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=xs4all.nl header.i=@xs4all.nl header.b="sCz/nqjJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727039AbgKTIHL (ORCPT ); Fri, 20 Nov 2020 03:07:11 -0500 Received: from lb2-smtp-cloud7.xs4all.net ([194.109.24.28]:39201 "EHLO lb2-smtp-cloud7.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726558AbgKTIHL (ORCPT ); Fri, 20 Nov 2020 03:07:11 -0500 Received: from cust-b5b5937f ([IPv6:fc0c:c16d:66b8:757f:c639:739b:9d66:799d]) by smtp-cloud7.xs4all.net with ESMTPA id g1RVk0X9Olmd2g1RYkPQEf; Fri, 20 Nov 2020 09:07:07 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=xs4all.nl; s=s2; t=1605859628; bh=5ef7lI42EJC0jhODZv8aRbqRC0kxVqZ7bUU3H8kTkJ0=; h=Subject:To:From:Message-ID:Date:MIME-Version:Content-Type:From: Subject; b=sCz/nqjJKBqA3Iy+hXRhoPwJZL4RSnoEtFxis6hkV75LW75H+8Mmf4xAFrJVrm+pe 8hj9fY43X0dqeh5hcaBFUdzWOJyUGVN+kLdzF+HYD2GMKZ191HzrbBTSABtTsVzA60 CvFYS7ezfnr1FTaFjba06AEAIGK1cPKBvJnU0bV//E1AUEPH/j9aY3U67vZ93V4hF3 6I2h2Od2vKJaEqVVhdF9KG8FIUuOZ8CG53hsXtNKL1Ch1fABIwEX5ve+bjxpFXGSyB aulCIunjrg9nl2+Y0ytv3CWHuxLF8HC5EnBBERF6rxbWpTScSnwiEMYNWkAwQXYMxf cBr7jUjdLWeiw== Subject: Re: [PATCH v6 09/17] media/videbuf1|2: Mark follow_pfn usage as unsafe To: Daniel Vetter , DRI Development , LKML Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, Tomasz Figa , Daniel Vetter , Jason Gunthorpe , Kees Cook , Dan Williams , Andrew Morton , John Hubbard , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jan Kara , Pawel Osciak , Marek Szyprowski , Kyungmin Park , Laurent Dufour , Vlastimil Babka , Daniel Jordan , Michel Lespinasse References: <20201119144146.1045202-1-daniel.vetter@ffwll.ch> <20201119144146.1045202-10-daniel.vetter@ffwll.ch> From: Hans Verkuil Message-ID: Date: Fri, 20 Nov 2020 09:06:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201119144146.1045202-10-daniel.vetter@ffwll.ch> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-CMAE-Envelope: MS4xfFkC2JJwDijdDHxk6QLdzYl86sxkzUvUR2rXQtLzS7Z3VCur8Sec0yc9/yj+teseucfM5Id3FSotdLzmsmr0WrYFYFXWblZvd586PxVzp7yalD+lMMTn /GP83mNKzjc5heCNLfvA46owaFZXBn0xPi+CrgcCTXCH+zCXDT/AugYk6WH31S/1fbilR/Bbn3VeP/VhTIjFK4ZkC7eOo9LJEqJWAP4kRBAdILmunjJmxXCT T9pw+MuwA6aQValWt8fR+2+Lohjgd26Kp3nsob/wGjkR2luEcNWBtmlzFVNrH+o+PP5aQAr4PDD+Z3dwOYMFNf76JTi6TFmlFZu78KxaX22EGz/bSPQghfFt yr7PTAmX010Y9mMvI/xJ8+OsZxM4+7H5b5EdPvoogEg/pCMQmvIqXLrivqredG5EOF57yPgwvUWyST9kqoBQZ0Y5vkkhX1LEjhptReds6BhrXH1RbB7N/mgZ ZNy1MjlvK64zXtOJ8uXaMBuHmzQtKNk3YzD5aJoakoowrkbNlF3olnS6jqrDz84rGP635GzH4xQ2JVz/bYDGw6/RyYu6BwKwqJsYho1oIn5pWJtwG6eL4Sys WJAb+ARL9Ka4wQ5SjbYr73z0jlMszhtNG0g91E+gV/ngoX+TfzOw3D4uv9zhis07qCCrZd9mZ+HYWRB2t95Ix5qwHZnN7P6GbcP06CUCv3W3u8KpUPI+dEI0 b7vGOZDkWvFsE1dmLjD9sCa6x/ZGIgVOw626FWzt8bTHFsqPP2Z98RzxcN50nCJkPPI4P7rtQrMlsZmhmzigHBYPfh6cR7KNLyviHXr0Ek3rvsLoxjZOhR9P ZAaqSLxwNMHu8kbI+D4pvREzqEx2gbSD1KX/g26bCR0cSsz8hqf0mItBK2Ua6ADVuO/ZaLWD+DrKIUrbYZn3vfZdKI8Mrv3xJUieHzHB/b6gDHFWvMdfKJii mpsBubC9N+hw7++PiHs0zH7FLmEY2rO4oZf0kE/dqwF7EyrF Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/11/2020 15:41, Daniel Vetter wrote: > The media model assumes that buffers are all preallocated, so that > when a media pipeline is running we never miss a deadline because the > buffers aren't allocated or available. > > This means we cannot fix the v4l follow_pfn usage through > mmu_notifier, without breaking how this all works. The only real fix > is to deprecate userptr support for VM_IO | VM_PFNMAP mappings and > tell everyone to cut over to dma-buf memory sharing for zerocopy. > > userptr for normal memory will keep working as-is, this only affects > the zerocopy userptr usage enabled in 50ac952d2263 ("[media] > videobuf2-dma-sg: Support io userptr operations on io memory"). > > Acked-by: Tomasz Figa Acked-by: Hans Verkuil Thanks! Hans > Signed-off-by: Daniel Vetter > Cc: Jason Gunthorpe > Cc: Kees Cook > Cc: Dan Williams > Cc: Andrew Morton > Cc: John Hubbard > Cc: Jérôme Glisse > Cc: Jan Kara > Cc: Dan Williams > Cc: linux-mm@kvack.org > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-samsung-soc@vger.kernel.org > Cc: linux-media@vger.kernel.org > Cc: Pawel Osciak > Cc: Marek Szyprowski > Cc: Kyungmin Park > Cc: Tomasz Figa > Cc: Laurent Dufour > Cc: Vlastimil Babka > Cc: Daniel Jordan > Cc: Michel Lespinasse > Signed-off-by: Daniel Vetter > -- > v3: > - Reference the commit that enabled the zerocopy userptr use case to > make it abundandtly clear that this patch only affects that, and not > normal memory userptr. The old commit message already explained that > normal memory userptr is unaffected, but I guess that was not clear > enough. > --- > drivers/media/common/videobuf2/frame_vector.c | 2 +- > drivers/media/v4l2-core/videobuf-dma-contig.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c > index a0e65481a201..1a82ec13ea00 100644 > --- a/drivers/media/common/videobuf2/frame_vector.c > +++ b/drivers/media/common/videobuf2/frame_vector.c > @@ -70,7 +70,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, > break; > > while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) { > - err = follow_pfn(vma, start, &nums[ret]); > + err = unsafe_follow_pfn(vma, start, &nums[ret]); > if (err) { > if (ret == 0) > ret = err; > diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c > index 52312ce2ba05..821c4a76ab96 100644 > --- a/drivers/media/v4l2-core/videobuf-dma-contig.c > +++ b/drivers/media/v4l2-core/videobuf-dma-contig.c > @@ -183,7 +183,7 @@ static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem, > user_address = untagged_baddr; > > while (pages_done < (mem->size >> PAGE_SHIFT)) { > - ret = follow_pfn(vma, user_address, &this_pfn); > + ret = unsafe_follow_pfn(vma, user_address, &this_pfn); > if (ret) > break; > >