[RFC 03/11] vb2: Move cache synchronisation from buffer done to dqbuf handler

[Sakari Ailus <sakari.ailus@linux.intel.com>]

The cache synchronisation may be a time consuming operation and thus not
best performed in an interrupt which is a typical context for
vb2_buffer_done() calls. This may consume up to tens of ms on some
machines, depending on the buffer size.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/videobuf2-core.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 64fce4d..c5c0707a 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1177,7 +1177,6 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 {
 	struct vb2_queue *q = vb->vb2_queue;
 	unsigned long flags;
-	unsigned int plane;
 
 	if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
 		return;
@@ -1197,10 +1196,6 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 	dprintk(4, "done processing on buffer %d, state: %d\n",
 			vb->v4l2_buf.index, state);
 
-	/* sync buffers */
-	for (plane = 0; plane < vb->num_planes; ++plane)
-		call_void_memop(vb, finish, vb->planes[plane].mem_priv);
-
 	/* Add the buffer to the done buffers list */
 	spin_lock_irqsave(&q->done_lock, flags);
 	vb->state = state;
@@ -2086,7 +2081,7 @@ EXPORT_SYMBOL_GPL(vb2_wait_for_all_buffers);
 static void __vb2_dqbuf(struct vb2_buffer *vb)
 {
 	struct vb2_queue *q = vb->vb2_queue;
-	unsigned int i;
+	unsigned int plane;
 
 	/* nothing to do if the buffer is already dequeued */
 	if (vb->state == VB2_BUF_STATE_DEQUEUED)
@@ -2094,13 +2089,18 @@ static void __vb2_dqbuf(struct vb2_buffer *vb)
 
 	vb->state = VB2_BUF_STATE_DEQUEUED;
 
+	/* sync buffers */
+	for (plane = 0; plane < vb->num_planes; plane++)
+		call_void_memop(vb, finish, vb->planes[plane].mem_priv);
+
 	/* unmap DMABUF buffer */
 	if (q->memory == V4L2_MEMORY_DMABUF)
-		for (i = 0; i < vb->num_planes; ++i) {
-			if (!vb->planes[i].dbuf_mapped)
+		for (plane = 0; plane < vb->num_planes; ++plane) {
+			if (!vb->planes[plane].dbuf_mapped)
 				continue;
-			call_void_memop(vb, unmap_dmabuf, vb->planes[i].mem_priv);
-			vb->planes[i].dbuf_mapped = 0;
+			call_void_memop(vb, unmap_dmabuf,
+					vb->planes[plane].mem_priv);
+			vb->planes[plane].dbuf_mapped = 0;
 		}
 }
 
-- 
2.1.0.231.g7484e3b