[RFC v2 11/11] vb2: dma-contig: Add WARN_ON_ONCE() to check for potential bugs

Laurent Pinchart
2016-12-16T01:24:06Z

From: Sakari Ailus <sakari.ailus@linux.intel.com>

The scatterlist should always be present when the cache would need to be
flushed. Each buffer type has its own means to provide that. Add
WARN_ON_ONCE() to check the scatterist exists.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
drivers/media/v4l2-core/videobuf2-dma-contig.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index a0e88ad93f07..9409f458cf89 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -122,6 +122,9 @@ static void vb2_dc_prepare(void *buf_priv)
if (!(buf->attrs & DMA_ATTR_NON_CONSISTENT))
return;

+ if (WARN_ON_ONCE(!sgt))
+ return;
+
dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir);
}
@@ -138,6 +141,9 @@ static void vb2_dc_finish(void *buf_priv)
if (!(buf->attrs & DMA_ATTR_NON_CONSISTENT))
return;

+ if (WARN_ON_ONCE(!sgt))
+ return;
+
dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
}