[PATCH] NTP shift_right cleanup

Create a macro shift_right() that avoids the numerous ugly conditionals in the
NTP code that look like:

        if(a < 0)
                b = -(-a >> shift);
        else
                b = a >> shift;

Replacing it with:

        b = shift_right(a, shift);

This should have zero effect on the logic, however it should probably have
a bit of testing just to be sure.

Also replace open-coded min/max with the macros.

Signed-off-by : John Stultz <johnstul@us.ibm.com>

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/timex.h b/include/linux/timex.h
index 7e050a2cc35b..04a4a8cb4ed3 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -282,6 +282,13 @@ static inline int ntp_synced(void)
         return !(time_status & STA_UNSYNC);
 }
 
+/* Required to safely shift negative values */
+#define shift_right(x, s) ({    \
+        __typeof__(x) __x = (x);        \
+        __typeof__(s) __s = (s);        \
+        __x < 0 ? -(-__x >> __s) : __x >> __s;  \
+})
+
 
 #ifdef CONFIG_TIME_INTERPOLATION