[PATCH mm-unstable v1 16/20] mm/frame-vector: remove FOLL_FORCE usage
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- To: linux-kernel@xxxxxxxxxxxxxxx
- Subject: [PATCH mm-unstable v1 16/20] mm/frame-vector: remove FOLL_FORCE usage
- From: David Hildenbrand <david@xxxxxxxxxx>
- Date: Wed, 16 Nov 2022 11:26:55 +0100
- Cc: x86@xxxxxxxxxx, linux-alpha@xxxxxxxxxxxxxxx, linux-arm-kernel@xxxxxxxxxxxxxxxxxxx, linux-ia64@xxxxxxxxxxxxxxx, linux-mips@xxxxxxxxxxxxxxx, linuxppc-dev@xxxxxxxxxxxxxxxx, sparclinux@xxxxxxxxxxxxxxx, linux-um@xxxxxxxxxxxxxxxxxxx, etnaviv@xxxxxxxxxxxxxxxxxxxxx, dri-devel@xxxxxxxxxxxxxxxxxxxxx, linux-samsung-soc@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx, linux-media@xxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx, linux-mm@xxxxxxxxx, linux-perf-users@xxxxxxxxxxxxxxx, linux-security-module@xxxxxxxxxxxxxxx, linux-kselftest@xxxxxxxxxxxxxxx, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Jason Gunthorpe <jgg@xxxxxxxx>, John Hubbard <jhubbard@xxxxxxxxxx>, Peter Xu <peterx@xxxxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Andrea Arcangeli <aarcange@xxxxxxxxxx>, Hugh Dickins <hughd@xxxxxxxxxx>, Nadav Amit <namit@xxxxxxxxxx>, Vlastimil Babka <vbabka@xxxxxxx>, Matthew Wilcox <willy@xxxxxxxxxxxxx>, Mike Kravetz <mike.kravetz@xxxxxxxxxx>, Muchun Song <songmuchun@xxxxxxxxxxxxx>, Shuah Khan <shuah@xxxxxxxxxx>, Lucas Stach <l.stach@xxxxxxxxxxxxxx>, David Airlie <airlied@xxxxxxxxx>, Oded Gabbay <ogabbay@xxxxxxxxxx>, Arnd Bergmann <arnd@xxxxxxxx>, Christoph Hellwig <hch@xxxxxxxxxxxxx>, Alex Williamson <alex.williamson@xxxxxxxxxx>, David Hildenbrand <david@xxxxxxxxxx>, Hans Verkuil <hverkuil@xxxxxxxxx>, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>, Tomasz Figa <tfiga@xxxxxxxxxxxx>, Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
- In-reply-to: <20221116102659.70287-1-david@redhat.com>
- References: <20221116102659.70287-1-david@redhat.com>
FOLL_FORCE is really only for ptrace access. According to commit
707947247e95 ("media: videobuf2-vmalloc: get_userptr: buffers are always
writable"), get_vaddr_frames() currently pins all pages writable as a
workaround for issues with read-only buffers.
FOLL_FORCE, however, seems to be a legacy leftover as it predates
commit 707947247e95 ("media: videobuf2-vmalloc: get_userptr: buffers are
always writable"). Let's just remove it.
Once the read-only buffer issue has been resolved, FOLL_WRITE could
again be set depending on the DMA direction.
Cc: Hans Verkuil <hverkuil@xxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Tomasz Figa <tfiga@xxxxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
drivers/media/common/videobuf2/frame_vector.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/common/videobuf2/frame_vector.c b/drivers/media/common/videobuf2/frame_vector.c
index 542dde9d2609..062e98148c53 100644
--- a/drivers/media/common/videobuf2/frame_vector.c
+++ b/drivers/media/common/videobuf2/frame_vector.c
@@ -50,7 +50,7 @@ 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,
+ FOLL_WRITE | FOLL_LONGTERM,
(struct page **)(vec->ptrs));
if (ret > 0) {
vec->got_ref = true;
--
2.38.1
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