[TCP] tcp_probe: improvements for net-2.6.22

Change tcp_probe to use ktime (needed to add one export).
Add option to only get events when cwnd changes - from Doug Leith

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

kernel/time.c

@@ -452,6 +452,7 @@ struct timespec ns_to_timespec(const s64 nsec)
 
 	return ts;
 }
+EXPORT_SYMBOL(ns_to_timespec);
 
 /**
  * ns_to_timeval - Convert nanoseconds to timeval