media/v4l2-core: pin_user_pages (FOLL_PIN) and put_user_page() conversion

1. Change v4l2 from get_user_pages() to pin_user_pages().

2. Because all FOLL_PIN-acquired pages must be released via
   put_user_page(), also convert the put_page() call over to
   put_user_pages_dirty_lock().

Link: http://lkml.kernel.org/r/20200107224558.2362728-19-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
index 28262190c3ab4969ccecda6d4365203b5d344f0b..162a2633b1e317cc28d850f00d1a5c4ac69175d5 100644 (file)
--- a/drivers/media/v4l2-core/videobuf-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -183,12 +183,12 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
        dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
                data, size, dma->nr_pages);
 
-       err = get_user_pages(data & PAGE_MASK, dma->nr_pages,
+       err = pin_user_pages(data & PAGE_MASK, dma->nr_pages,
                             flags | FOLL_LONGTERM, dma->pages, NULL);
 
        if (err != dma->nr_pages) {
                dma->nr_pages = (err >= 0) ? err : 0;
-               dprintk(1, "get_user_pages: err=%d [%d]\n", err,
+               dprintk(1, "pin_user_pages: err=%d [%d]\n", err,
                        dma->nr_pages);
                return err < 0 ? err : -EINVAL;
        }
@@ -349,11 +349,8 @@ int videobuf_dma_free(struct videobuf_dmabuf *dma)
        BUG_ON(dma->sglen);
 
        if (dma->pages) {
-               for (i = 0; i < dma->nr_pages; i++) {
-                       if (dma->direction == DMA_FROM_DEVICE)
-                               set_page_dirty_lock(dma->pages[i]);
-                       put_page(dma->pages[i]);
-               }
+               put_user_pages_dirty_lock(dma->pages, dma->nr_pages,
+                                         dma->direction == DMA_FROM_DEVICE);
                kfree(dma->pages);
                dma->pages = NULL;
        }