diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 64f8d55..2ac20b4 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -121,6 +121,12 @@
 extern unsigned long hrtimer_forward(struct hrtimer *timer,
 				     const ktime_t interval);
 
+/* Precise sleep: */
+extern long hrtimer_nanosleep(struct timespec *rqtp,
+			      struct timespec __user *rmtp,
+			      const enum hrtimer_mode mode,
+			      const clockid_t clockid);
+
 /* Soft interrupt function to run the hrtimer queues: */
 extern void hrtimer_run_queues(void);