diff mbox

[RFC,v4,11/18] vb2: dma-contig: Add WARN_ON_ONCE() to check for potential bugs

Message ID 1494255810-12672-12-git-send-email-sakari.ailus@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sakari Ailus May 8, 2017, 3:03 p.m. UTC 
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>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
---
 drivers/media/v4l2-core/videobuf2-dma-contig.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff mbox

Patch

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 8b0298a..f572911 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -101,7 +101,7 @@  static void vb2_dc_prepare(void *buf_priv)
 	 * DMABUF exporter will flush the cache for us; only USERPTR
 	 * and MMAP buffers with non-coherent memory will be flushed.
 	 */
-	if (buf->attrs & DMA_ATTR_NON_CONSISTENT)
+	if (buf->attrs & DMA_ATTR_NON_CONSISTENT && !WARN_ON_ONCE(!sgt))
 		dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
 				       buf->dma_dir);
 }
@@ -115,7 +115,7 @@  static void vb2_dc_finish(void *buf_priv)
 	 * DMABUF exporter will flush the cache for us; only USERPTR
 	 * and MMAP buffers with non-coherent memory will be flushed.
 	 */
-	if (buf->attrs & DMA_ATTR_NON_CONSISTENT)
+	if (buf->attrs & DMA_ATTR_NON_CONSISTENT && !WARN_ON_ONCE(!sgt))
 		dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents,
 				    buf->dma_dir);
 }
@@ -363,7 +363,7 @@  static int vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
 	 * DMABUF exporter will flush the cache for us; only USERPTR
 	 * and MMAP buffers with non-coherent memory will be flushed.
 	 */
-	if (buf->attrs & DMA_ATTR_NON_CONSISTENT)
+	if (buf->attrs & DMA_ATTR_NON_CONSISTENT && !WARN_ON_ONCE(!sgt))
 		dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents,
 				    buf->dma_dir);
 
@@ -380,7 +380,7 @@  static int vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
 	 * DMABUF exporter will flush the cache for us; only USERPTR
 	 * and MMAP buffers with non-coherent memory will be flushed.
 	 */
-	if (buf->attrs & DMA_ATTR_NON_CONSISTENT)
+	if (buf->attrs & DMA_ATTR_NON_CONSISTENT && !WARN_ON_ONCE(!sgt))
 		dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents,
 				       buf->dma_dir);