-#define time_after64(a,b) \
- (typecheck(__u64, a) && \
- typecheck(__u64, b) && \
- ((__s64)(b) - (__s64)(a) < 0))
-#define time_before64(a,b) time_after64(b,a)
-
-#define time_after_eq64(a,b) \
- (typecheck(__u64, a) && \
- typecheck(__u64, b) && \
- ((__s64)(a) - (__s64)(b) >= 0))
-#define time_before_eq64(a,b) time_after_eq64(b,a)
-
-#endif /* linux kernel < 2.6.19 */
+
+#ifndef time_after64
+#define time_after64(a, b) \
+ (typecheck(__u64, a) && \
+ typecheck(__u64, b) && \
+ ((__s64)(b) - (__s64)(a) < 0))
+#endif
+
+#ifndef time_before64
+#define time_before64(a, b) time_after64(b, a)
+#endif
+
+#ifndef time_after_eq64
+#define time_after_eq64(a, b) \
+ (typecheck(__u64, a) && \
+ typecheck(__u64, b) && \
+ ((__s64)(a) - (__s64)(b) >= 0))
+#endif
+
+#ifndef time_before_eq64
+#define time_before_eq64(a, b) time_after_eq64(b, a)
+#endif