diff options
| author | Hans Verkuil <hverkuil-cisco@xs4all.nl> | 2022-11-28 08:23:56 +0000 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2022-12-06 07:14:31 +0000 |
| commit | e2fc6edd37ba487c64f4dd09f7118b3e45b12d88 (patch) | |
| tree | 26266931ca718aa0229833e39b3132bb00607c38 /drivers/media/common/videobuf2/frame_vector.c | |
| parent | 1aba7930c63ea57b4918dc61dcc315f451cec21e (diff) | |
media: videobuf2: revert "get_userptr: buffers are always writable"
Commit 707947247e95 ("media: videobuf2-vmalloc: get_userptr: buffers are
always writable") caused problems in a corner case (passing read-only
shmem memory as a userptr). So revert this patch.
The original problem for which that commit was originally made is
something that I could not reproduce after reverting it. So just go
back to the way it was for many years, and if problems arise in
the future, then another approach should be taken to resolve it.
This patch is based on a patch from Hirokazu.
Fixes: 707947247e95 ("media: videobuf2-vmalloc: get_userptr: buffers are always writable")
Signed-off-by: Hirokazu Honda <hiroh@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'drivers/media/common/videobuf2/frame_vector.c')
| -rw-r--r-- | drivers/media/common/videobuf2/frame_vector.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c index 542dde9d2609..aad72640f055 100644 --- a/drivers/media/common/videobuf2/frame_vector.c +++ b/drivers/media/common/videobuf2/frame_vector.c @@ -14,6 +14,7 @@ * get_vaddr_frames() - map virtual addresses to pfns * @start: starting user address * @nr_frames: number of pages / pfns from start to map + * @write: the mapped address has write permission * @vec: structure which receives pages / pfns of the addresses mapped. * It should have space for at least nr_frames entries. * @@ -32,7 +33,7 @@ * * This function takes care of grabbing mmap_lock as necessary. */ -int get_vaddr_frames(unsigned long start, unsigned int nr_frames, +int get_vaddr_frames(unsigned long start, unsigned int nr_frames, bool write, struct frame_vector *vec) { struct mm_struct *mm = current->mm; @@ -40,6 +41,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, int ret_pin_user_pages_fast = 0; int ret = 0; int err; + unsigned int gup_flags = FOLL_FORCE | FOLL_LONGTERM; if (nr_frames == 0) return 0; @@ -49,8 +51,10 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, start = untagged_addr(start); - ret = pin_user_pages_fast(start, nr_frames, - FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM, + if (write) + gup_flags |= FOLL_WRITE; + + ret = pin_user_pages_fast(start, nr_frames, gup_flags, (struct page **)(vec->ptrs)); if (ret > 0) { vec->got_ref = true; |