dri-devel Archive on lore.kernel.org
 help / color / Atom feed
From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>
Cc: "Jan Kara" <jack@suse.cz>,
	kvm@vger.kernel.org, "Daniel Vetter" <daniel.vetter@ffwll.ch>,
	linux-mm@kvack.org, "Daniel Vetter" <daniel.vetter@intel.com>,
	"Michel Lespinasse" <walken@google.com>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	linux-samsung-soc@vger.kernel.org,
	"Daniel Jordan" <daniel.m.jordan@oracle.com>,
	"Jason Gunthorpe" <jgg@ziepe.ca>,
	linux-arm-kernel@lists.infradead.org,
	linux-media@vger.kernel.org, "Kees Cook" <keescook@chromium.org>,
	"Pawel Osciak" <pawel@osciak.com>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Laurent Dufour" <ldufour@linux.ibm.com>,
	"Vlastimil Babka" <vbabka@suse.cz>,
	"Tomasz Figa" <tfiga@chromium.org>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"Andrew Morton" <akpm@linux-foundation.org>
Subject: [PATCH v7 14/17] media/videobuf1|2: Mark follow_pfn usage as unsafe
Date: Fri, 27 Nov 2020 17:41:28 +0100
Message-ID: <20201127164131.2244124-15-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20201127164131.2244124-1-daniel.vetter@ffwll.ch>

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 <tfiga@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
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 <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
--
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;
 
-- 
2.29.2

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  parent reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27 16:41 [PATCH v7 00/17] follow_pfn and other iomap races Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 01/17] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 02/17] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 03/17] misc/habana: Stop using frame_vector helpers Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 04/17] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 05/17] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 06/17] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 07/17] mm: Close race in generic_access_phys Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 08/17] PCI: Obey iomem restrictions for procfs mmap Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 09/17] /dev/mem: Only set filp->f_mapping Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 10/17] resource: Move devmem revoke code to resource framework Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 11/17] sysfs: Support zapping of binary attr mmaps Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 12/17] PCI: Revoke mappings like devmem Daniel Vetter
2021-01-19  8:17   ` Daniel Vetter
2021-01-19 14:32     ` Greg Kroah-Hartman
2021-01-19 14:34       ` Daniel Vetter
2021-01-19 15:20         ` Greg Kroah-Hartman
2021-01-19 16:03           ` Daniel Vetter
2021-02-03 16:14             ` Daniel Vetter
2021-02-04 10:23               ` Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 13/17] mm: Add unsafe_follow_pfn Daniel Vetter
2020-11-27 16:41 ` Daniel Vetter [this message]
2021-01-19 12:24   ` [PATCH v7 14/17] media/videobuf1|2: Mark follow_pfn usage as unsafe Hans Verkuil
2020-11-27 16:41 ` [PATCH v7 15/17] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 16/17] kvm: pass kvm argument to follow_pfn callsites Daniel Vetter
2020-11-27 16:41 ` [PATCH v7 17/17] mm: add mmu_notifier argument to follow_pfn Daniel Vetter
2020-11-27 19:10   ` kernel test robot
2020-11-30 14:28     ` Daniel Vetter
2020-11-30 18:03       ` Nick Desaulniers
2021-01-12 13:24 ` [PATCH v7 00/17] follow_pfn and other iomap races Daniel Vetter
2021-01-12 13:28   ` Daniel Vetter
2021-01-12 20:57   ` Stephen Rothwell

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201127164131.2244124-15-daniel.vetter@ffwll.ch \
    --to=daniel.vetter@ffwll.ch \
    --cc=akpm@linux-foundation.org \
    --cc=dan.j.williams@intel.com \
    --cc=daniel.m.jordan@oracle.com \
    --cc=daniel.vetter@intel.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jack@suse.cz \
    --cc=jgg@ziepe.ca \
    --cc=jglisse@redhat.com \
    --cc=jhubbard@nvidia.com \
    --cc=keescook@chromium.org \
    --cc=kvm@vger.kernel.org \
    --cc=kyungmin.park@samsung.com \
    --cc=ldufour@linux.ibm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=m.szyprowski@samsung.com \
    --cc=pawel@osciak.com \
    --cc=tfiga@chromium.org \
    --cc=vbabka@suse.cz \
    --cc=walken@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

dri-devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/dri-devel/0 dri-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dri-devel dri-devel/ https://lore.kernel.org/dri-devel \
		dri-devel@lists.freedesktop.org
	public-inbox-index dri-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.freedesktop.lists.dri-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git