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From:   John Hubbard <jhubbard@nvidia.com>
To:     Andrew Morton <akpm@linux-foundation.org>
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Subject: [PATCH 15/19] media/v4l2-core: pin_user_pages (FOLL_PIN) and put_user_page() conversion
Date:   Sun, 24 Nov 2019 20:20:07 -0800
Message-ID: <20191125042011.3002372-16-jhubbard@nvidia.com>
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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().

Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 drivers/media/v4l2-core/videobuf-dma-sg.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2=
-core/videobuf-dma-sg.c
index 28262190c3ab..162a2633b1e3 100644
--- 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 video=
buf_dmabuf *dma,
 	dprintk(1, "init user [0x%lx+0x%lx =3D> %d pages]\n",
 		data, size, dma->nr_pages);
=20
-	err =3D get_user_pages(data & PAGE_MASK, dma->nr_pages,
+	err =3D pin_user_pages(data & PAGE_MASK, dma->nr_pages,
 			     flags | FOLL_LONGTERM, dma->pages, NULL);
=20
 	if (err !=3D dma->nr_pages) {
 		dma->nr_pages =3D (err >=3D 0) ? err : 0;
-		dprintk(1, "get_user_pages: err=3D%d [%d]\n", err,
+		dprintk(1, "pin_user_pages: err=3D%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);
=20
 	if (dma->pages) {
-		for (i =3D 0; i < dma->nr_pages; i++) {
-			if (dma->direction =3D=3D 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 =3D=3D DMA_FROM_DEVICE);
 		kfree(dma->pages);
 		dma->pages =3D NULL;
 	}
--=20
2.24.0