diff --git a/include/linux/math64.h b/include/linux/math64.h
index c1a5f81..177785e 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -81,4 +81,6 @@
 }
 #endif
 
+u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);
+
 #endif /* _LINUX_MATH64_H */
diff --git a/include/linux/time.h b/include/linux/time.h
index d32ef0a..05f9517 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -6,6 +6,7 @@
 #ifdef __KERNEL__
 # include <linux/cache.h>
 # include <linux/seqlock.h>
+# include <linux/math64.h>
 #endif
 
 #ifndef _STRUCT_TIMESPEC
@@ -172,15 +173,7 @@
  */
 static inline void timespec_add_ns(struct timespec *a, u64 ns)
 {
-	ns += a->tv_nsec;
-	while(unlikely(ns >= NSEC_PER_SEC)) {
-		/* The following asm() prevents the compiler from
-		 * optimising this loop into a modulo operation.  */
-		asm("" : "+r"(ns));
-
-		ns -= NSEC_PER_SEC;
-		a->tv_sec++;
-	}
+	a->tv_sec += iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
 	a->tv_nsec = ns;
 }
 #endif /* __KERNEL__ */