[4.2.y-ckt stable] Patch "[media] media: vb2 dma-sg: Fully cache synchronise buffers in prepare and finish" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    [media] media: vb2 dma-sg: Fully cache synchronise buffers in prepare and finish

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt1.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From a919d0dee0c31b8b0c7af71360ff998788865644 Mon Sep 17 00:00:00 2001
From: Tiffany Lin <tiffany.lin at mediatek.com>
Date: Thu, 24 Sep 2015 06:02:36 -0300
Subject: [media] media: vb2 dma-sg: Fully cache synchronise buffers in prepare
 and finish

commit 418dae2276065680bde7ae27d2c075e612a54de6 upstream.

In videobuf2 dma-sg memory types 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: d790b7eda953 ("vb2-dma-sg: move dma_(un)map_sg here")

Signed-off-by: Tiffany Lin <tiffany.lin at mediatek.com>
Signed-off-by: Sakari Ailus <sakari.ailus at linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab at osg.samsung.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/media/v4l2-core/videobuf2-dma-sg.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index 7289b81..a0a4a62 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -210,7 +210,8 @@ static void vb2_dma_sg_prepare(void *buf_priv)
 	if (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_dma_sg_finish(void *buf_priv)
@@ -222,7 +223,7 @@ static void vb2_dma_sg_finish(void *buf_priv)
 	if (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);
 }

 static inline int vma_is_io(struct vm_area_struct *vma)
--
1.9.1