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From:   John Hubbard <jhubbard@nvidia.com>
To:     Andrew Morton <akpm@linux-foundation.org>
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Subject: [PATCH 04/19] media/v4l2-core: set pages dirty upon releasing DMA buffers
Date:   Wed, 30 Oct 2019 15:49:15 -0700
Message-ID: <20191030224930.3990755-5-jhubbard@nvidia.com>
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After DMA is complete, and the device and CPU caches are synchronized,
it's still required to mark the CPU pages as dirty, if the data was
coming from the device. However, this driver was just issuing a
bare put_page() call, without any set_page_dirty*() call.

Fix the problem, by calling set_page_dirty_lock() if the CPU pages
were potentially receiving data from the device.

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 drivers/media/v4l2-core/videobuf-dma-sg.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2=
-core/videobuf-dma-sg.c
index 66a6c6c236a7..28262190c3ab 100644
--- a/drivers/media/v4l2-core/videobuf-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -349,8 +349,11 @@ 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++)
+		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]);
+		}
 		kfree(dma->pages);
 		dma->pages =3D NULL;
 	}
--=20
2.23.0