diff --git a/[refs] b/[refs]
index b5fd0d00f217..77634f8dd525 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bd1939de9061dbc5cac44ffb4425aaf4c9b894f1
+refs/heads/master: 6659a0f0bb7481d0f94ca3f203a4e1e406a9694d
diff --git a/trunk/drivers/virtio/virtio_balloon.c b/trunk/drivers/virtio/virtio_balloon.c
index 622aece1acce..c8a4332d1132 100644
--- a/trunk/drivers/virtio/virtio_balloon.c
+++ b/trunk/drivers/virtio/virtio_balloon.c
@@ -23,6 +23,7 @@
 #include <linux/swap.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
+#include <linux/delay.h>
 
 struct virtio_balloon
 {