ktime: Sanitize ktime_to_us/ms conversion

With the plain nanoseconds based ktime_t we can simply use
ktime_divns() instead of going through loops and hoops of
timespec/timeval conversion.

Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index fbc64f8..74eaba9 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -157,16 +157,20 @@
 	return ktime_compare(cmp1, cmp2) < 0;
 }
 
+#if BITS_PER_LONG < 64
+extern u64 ktime_divns(const ktime_t kt, s64 div);
+#else /* BITS_PER_LONG < 64 */
+# define ktime_divns(kt, div)		(u64)((kt).tv64 / (div))
+#endif
+
 static inline s64 ktime_to_us(const ktime_t kt)
 {
-	struct timeval tv = ktime_to_timeval(kt);
-	return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
+	return ktime_divns(kt, NSEC_PER_USEC);
 }
 
 static inline s64 ktime_to_ms(const ktime_t kt)
 {
-	struct timeval tv = ktime_to_timeval(kt);
-	return (s64) tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC;
+	return ktime_divns(kt, NSEC_PER_MSEC);
 }
 
 static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)