[PATCH] Add 64bit jiffies compares (for use with get_jiffies_64)

The current time_before/time_after macros will fail typechecks
when passed u64 values (as returned by get_jiffies_64()). On 64bit
systems, this will just result in a warning about mismatching types
without explicit casts, but since unsigned long and u64
(unsigned long long) are of same size, it will still work.
On 32bit systems, a long is 32bits, so the value from get_jiffies_64()
will be truncated by the cast and thus lose all the precision gained by
64bit jiffies.

Signed-off-by: Dmitriy Zavin <dmitriyz@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 329ebcffa106..c8d5f207c3d4 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -115,6 +115,21 @@ static inline u64 get_jiffies_64(void)
          ((long)(a) - (long)(b) >= 0))
 #define time_before_eq(a,b)     time_after_eq(b,a)
 
+/* Same as above, but does so with platform independent 64bit types.
+ * These must be used when utilizing jiffies_64 (i.e. return value of
+ * get_jiffies_64() */
+#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)
+
 /*
  * Have the 32 bit jiffies value wrap 5 minutes after boot
  * so jiffies wrap bugs show up earlier.