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.

Signed-off-by: Daniel Vetter <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Pawel Osciak <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Kyungmin Park <[email protected]>
Cc: Tomasz Figa <[email protected]>
Cc: Laurent Dufour <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Daniel Jordan <[email protected]>
Cc: Michel Lespinasse <[email protected]>
---
 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 2b0b97761d15..a1b85fe9e7c1 100644
--- a/drivers/media/common/videobuf2/frame_vector.c
+++ b/drivers/media/common/videobuf2/frame_vector.c
@@ -69,7 +69,7 @@ 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;
 
-- 
2.28.0

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