include linux/init.h in bottomhalf.c
@@ -13,6 +13,7 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/printk.h>
+#include <linux/init.h>
/* Macro DECLARE_TASKLET_OLD exists for compatibiity.
* See https://lwn.net/Articles/830964/