Re: [PATCH 3/3] media: stk1160: use dma_alloc_noncontiguous API

[Sergey Senozhatsky <senozhatsky@chromium.org>]

On (22/01/11 09:59), Christoph Hellwig wrote:
[..]
> >>> You mean you would call "invalidate_kernel_vmap_range" before "dma_sync_sgtable_for_cpu" ?
> >>
> >> Yes.
> >
> > Could you explain why?
> 
> the vmap range is the one actually use for cpu access and thus most
> prone for speculation, so I'd invalidate it first.  It probably does
> not matter to much, but that order looks more sensible.

Shall we do the same in videobuf2?

----

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index 7c4096e62173..0e3f264122af 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -132,12 +132,12 @@ static void vb2_dc_prepare(void *buf_priv)
 	if (!buf->non_coherent_mem)
 		return;
 
-	/* For both USERPTR and non-coherent MMAP */
-	dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
-
 	/* Non-coherent MMAP only */
 	if (buf->vaddr)
 		flush_kernel_vmap_range(buf->vaddr, buf->size);
+
+	/* For both USERPTR and non-coherent MMAP */
+	dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
 }
 
 static void vb2_dc_finish(void *buf_priv)
@@ -152,12 +152,12 @@ static void vb2_dc_finish(void *buf_priv)
 	if (!buf->non_coherent_mem)
 		return;
 
-	/* For both USERPTR and non-coherent MMAP */
-	dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
-
 	/* Non-coherent MMAP only */
 	if (buf->vaddr)
 		invalidate_kernel_vmap_range(buf->vaddr, buf->size);
+
+	/* For both USERPTR and non-coherent MMAP */
+	dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 }
 
 /*********************************************/