[PATCH 4.2.y-ckt 051/211] [media] media: vb2 dma-contig: Fully cache synchronise buffers in prepare and finish

[Kamal Mostafa]

4.2.8-ckt1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tiffany Lin <tiffany.lin@xxxxxxxxxxxx>

commit d9a985883fa32453d099d6293188c11d75cef1fa upstream.

In videobuf2 dma-contig memory type the prepare and finish ops, instead of
passing the number of entries in the original scatterlist as the "nents"
parameter to dma_sync_sg_for_device() and dma_sync_sg_for_cpu(), the value
returned by dma_map_sg() was used. Albeit this has been suggested in
comments of some implementations (which have since been corrected), this
is wrong.

Fixes: 199d101efdba ("v4l: vb2-dma-contig: add prepare/finish to dma-contig allocator")

Signed-off-by: Tiffany Lin <tiffany.lin@xxxxxxxxxxxx>
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 94c1e64..f8afbd0 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -120,7 +120,8 @@ static void vb2_dc_prepare(void *buf_priv)
 	if (!sgt || buf->db_attach)
 		return;
 
-	dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
+	dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
+			       buf->dma_dir);
 }
 
 static void vb2_dc_finish(void *buf_priv)
@@ -132,7 +133,7 @@ static void vb2_dc_finish(void *buf_priv)
 	if (!sgt || buf->db_attach)
 		return;
 
-	dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
+	dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
 }
 
 /*********************************************/
-- 
1.9.1

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