V4L2 devices usually grab additional references to user pages for a very long period of time, what causes permanent migration failures if the given page has been allocated from CMA pageblock. By setting FOLL_DURABLE flag, videobuf2 will instruct __get_user_pages() to migrate user pages out of CMA pageblocks before blocking them with an additional reference.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Signed-off-by: Kyungmin Park kyungmin.park@samsung.com --- drivers/media/v4l2-core/videobuf2-dma-contig.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 10beaee..70649ab 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -443,9 +443,13 @@ static int vb2_dc_get_user_pages(unsigned long start, struct page **pages, } } else { int n; + int flags = FOLL_TOUCH | FOLL_GET | FOLL_FORCE | FOLL_DURABLE;
- n = get_user_pages(current, current->mm, start & PAGE_MASK, - n_pages, write, 1, pages, NULL); + if (write) + flags |= FOLL_WRITE; + + n = __get_user_pages(current, current->mm, start & PAGE_MASK, + n_pages, flags, pages, NULL, NULL); /* negative error means that no page was pinned */ n = max(n, 0); if (n != n_pages) {