diff --git a/sys/compat/linuxkpi/common/include/linux/timer.h b/sys/compat/linuxkpi/common/include/linux/timer.h
index b4881b0b33a..87a4f1a6d0a 100644
--- a/sys/compat/linuxkpi/common/include/linux/timer.h
+++ b/sys/compat/linuxkpi/common/include/linux/timer.h
@@ -39,7 +39,10 @@
 
 struct timer_list {
 	struct callout callout;
-	void    (*function) (unsigned long);
+	union {
+		void (*function) (unsigned long);	/* < v4.15 */
+		void (*function_415) (struct timer_list *);
+	};
 	unsigned long data;
 	int expires;
 };
@@ -48,6 +51,16 @@ extern unsigned long linux_timer_hz_mask;
 
 #define	TIMER_IRQSAFE	0x0001
 
+#define	from_timer(var, arg, field)					\
+        container_of(arg, typeof(*(var)), field)
+
+#define	timer_setup(timer, func, flags) do {				\
+	CTASSERT(((flags) & ~TIMER_IRQSAFE) == 0);			\
+	(timer)->function_415 = (func);					\
+	(timer)->data = (unsigned long)(timer);				\
+	callout_init(&(timer)->callout, 1);				\
+} while (0)
+
 #define	setup_timer(timer, func, dat) do {				\
 	(timer)->function = (func);					\
 	(timer)->data = (dat);						\