sna: Only add the COW to the flush write if exported for writing

If the source is only being exported for reading, we can skip adding it
to the flush list only to perform a no-op.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/sna/sna.h b/src/sna/sna.h
index 8a405800..34a78812 100644
--- a/src/sna/sna.h
+++ b/src/sna/sna.h
@@ -154,6 +154,8 @@ struct sna_pixmap {
 #define MAPPED_GTT 1
 #define MAPPED_CPU 2
 	uint8_t flush :2;
+#define FLUSH_READ 1
+#define FLUSH_WRITE 2
 	uint8_t shm :1;
 	uint8_t clear :1;
 	uint8_t header :1;