videobuf-dma-contig: zero copy USERPTR V3 comments
Commit Message
From: Magnus Damm <damm@igel.co.jp>
This patch adds function descriptions to V3 of the V4L2
videobuf-dma-contig USERPTR zero copy patch.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
---
drivers/media/video/videobuf-dma-contig.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
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@@ -110,6 +110,12 @@ static struct vm_operations_struct video
.close = videobuf_vm_close,
};
+/**
+ * videobuf_dma_contig_user_put() - reset pointer to user space buffer
+ * @mem: per-buffer private videobuf-dma-contig data
+ *
+ * This function resets the user space pointer
+ */
static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
{
mem->is_userptr = 0;
@@ -117,6 +123,16 @@ static void videobuf_dma_contig_user_put
mem->size = 0;
}
+/**
+ * videobuf_dma_contig_user_get() - setup user space memory pointer
+ * @mem: per-buffer private videobuf-dma-contig data
+ * @vb: video buffer to map
+ *
+ * This function validates and sets up a pointer to user space memory.
+ * Only physically contiguous pfn-mapped memory is accepted.
+ *
+ * Returns 0 if successful.
+ */
static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
struct videobuf_buffer *vb)
{