6.5-stable review patch. If anyone has any objections, please let me know.
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From: Hans Verkuil hverkuil-cisco@xs4all.nl
[ Upstream commit 735de5caf79e06cc9fb96b1b4f4974674ae3e917 ]
The WARN_ONCE was issued also in cases that had nothing to do with VM_IO (e.g. if the start address was just a random value and uaccess fails with -EFAULT).
There are no reports of WARN_ONCE being issued for actual VM_IO cases, so just drop it and instead add a note to the comment before the function.
Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Reviewed-by: David Hildenbrand david@redhat.com Reported-by: Yikebaer Aizezi yikebaer61@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/common/videobuf2/frame_vector.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c index 0f430ddc1f670..fd87747be9b17 100644 --- a/drivers/media/common/videobuf2/frame_vector.c +++ b/drivers/media/common/videobuf2/frame_vector.c @@ -31,6 +31,10 @@ * different type underlying the specified range of virtual addresses. * When the function isn't able to map a single page, it returns error. * + * Note that get_vaddr_frames() cannot follow VM_IO mappings. It used + * to be able to do that, but that could (racily) return non-refcounted + * pfns. + * * This function takes care of grabbing mmap_lock as necessary. */ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, bool write, @@ -59,8 +63,6 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, bool write, if (likely(ret > 0)) return ret;
- /* This used to (racily) return non-refcounted pfns. Let people know */ - WARN_ONCE(1, "get_vaddr_frames() cannot follow VM_IO mapping"); vec->nr_frames = 0; return ret ? ret : -EFAULT; }