media: videobuf2: inverse buffer cache_hints flags

It would be less error prone if the default cache hints value
(we kzalloc() structs, so it's zeroed out by default) would be
to "always sync/flush" caches. Inverse and rename cache hints
flags.
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/common/videobuf2/videobuf2-core.c

@@ -327,12 +327,12 @@ static void __vb2_buf_mem_prepare(struct vb2_buffer *vb)
 	if (vb->synced)
 		return;
 
-	if (vb->need_cache_sync_on_prepare) {
-		for (plane = 0; plane < vb->num_planes; ++plane)
-			call_void_memop(vb, prepare,
-					vb->planes[plane].mem_priv);
-	}
 	vb->synced = 1;
+	if (vb->skip_cache_sync_on_prepare)
+		return;
+
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_void_memop(vb, prepare, vb->planes[plane].mem_priv);
 }
 
 /*
@@ -346,12 +346,12 @@ static void __vb2_buf_mem_finish(struct vb2_buffer *vb)
 	if (!vb->synced)
 		return;
 
-	if (vb->need_cache_sync_on_finish) {
-		for (plane = 0; plane < vb->num_planes; ++plane)
-			call_void_memop(vb, finish,
-					vb->planes[plane].mem_priv);
-	}
 	vb->synced = 0;
+	if (vb->skip_cache_sync_on_finish)
+		return;
+
+	for (plane = 0; plane < vb->num_planes; ++plane)
+		call_void_memop(vb, finish, vb->planes[plane].mem_priv);
 }
 
 /*
@@ -415,17 +415,6 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 		vb->index = q->num_buffers + buffer;
 		vb->type = q->type;
 		vb->memory = memory;
-		/*
-		 * We need to set these flags here so that the videobuf2 core
-		 * will call ->prepare()/->finish() cache sync/flush on vb2
-		 * buffers when appropriate. However, we can avoid explicit
-		 * ->prepare() and ->finish() cache sync for DMABUF buffers,
-		 * because DMA exporter takes care of it.
-		 */
-		if (q->memory != VB2_MEMORY_DMABUF) {
-			vb->need_cache_sync_on_prepare = 1;
-			vb->need_cache_sync_on_finish = 1;
-		}
 		for (plane = 0; plane < num_planes; ++plane) {
 			vb->planes[plane].length = plane_sizes[plane];
 			vb->planes[plane].min_length = plane_sizes[plane];

drivers/media/common/videobuf2/videobuf2-v4l2.c

@@ -351,18 +351,11 @@ static void set_buffer_cache_hints(struct vb2_queue *q,
 	 * we always need ->prepare() or/and ->finish() cache sync.
 	 */
 	if (q->memory == VB2_MEMORY_DMABUF) {
-		vb->need_cache_sync_on_finish = 0;
-		vb->need_cache_sync_on_prepare = 0;
+		vb->skip_cache_sync_on_finish = 1;
+		vb->skip_cache_sync_on_prepare = 1;
 		return;
 	}
 
-	/*
-	 * Cache sync/invalidation flags are set by default in order to
-	 * preserve existing behaviour for old apps/drivers.
-	 */
-	vb->need_cache_sync_on_prepare = 1;
-	vb->need_cache_sync_on_finish = 1;
-
 	if (!vb2_queue_allows_cache_hints(q)) {
 		/*
 		 * Clear buffer cache flags if queue does not support user
@@ -379,13 +372,13 @@ static void set_buffer_cache_hints(struct vb2_queue *q,
 	 * TO_DEVICE.
 	 */
 	if (q->dma_dir == DMA_TO_DEVICE)
-		vb->need_cache_sync_on_finish = 0;
+		vb->skip_cache_sync_on_finish = 1;
 
 	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
-		vb->need_cache_sync_on_finish = 0;
+		vb->skip_cache_sync_on_finish = 1;
 
 	if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)
-		vb->need_cache_sync_on_prepare = 0;
+		vb->skip_cache_sync_on_prepare = 1;
 }
 
 static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct media_device *mdev,

include/media/videobuf2-core.h

@@ -267,10 +267,10 @@ struct vb2_buffer {
 	 *			after the 'buf_finish' op is called.
 	 * copied_timestamp:	the timestamp of this capture buffer was copied
 	 *			from an output buffer.
-	 * need_cache_sync_on_prepare: when set buffer's ->prepare() function
-	 *			performs cache sync/invalidation.
-	 * need_cache_sync_on_finish: when set buffer's ->finish() function
-	 *			performs cache sync/invalidation.
+	 * skip_cache_sync_on_prepare: when set buffer's ->prepare() function
+	 *			skips cache sync/invalidation.
+	 * skip_cache_sync_on_finish: when set buffer's ->finish() function
+	 *			skips cache sync/invalidation.
 	 * queued_entry:	entry on the queued buffers list, which holds
 	 *			all buffers queued from userspace
 	 * done_entry:		entry on the list that stores all buffers ready
@@ -281,8 +281,8 @@ struct vb2_buffer {
 	unsigned int		synced:1;
 	unsigned int		prepared:1;
 	unsigned int		copied_timestamp:1;
-	unsigned int		need_cache_sync_on_prepare:1;
-	unsigned int		need_cache_sync_on_finish:1;
+	unsigned int		skip_cache_sync_on_prepare:1;
+	unsigned int		skip_cache_sync_on_finish:1;
 
 	struct vb2_plane	planes[VB2_MAX_PLANES];
 	struct list_head	queued_entry;