[CCID3]: Reorganise timeval handling

Introducing functions to add to or subtract from a timeval variable
and renaming now_delta to timeval_new_delta that calls do_gettimeofday
and then timeval_delta, that should be used when there are several
deltas made relative to the current time or setting variables to it,
so as to avoid calling do_gettimeofday excessively.

I'm leaving these "timeval_" prefixed funcions internal to DCCP for a
while till we're sure there are no subtle bugs in it.

It also is more correct as it checks if the number of usecs added to
or subtracted from a tv_usec field is more than 2 seconds.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/options.c b/net/dccp/options.c
index eabcc8f..382c589 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -359,7 +359,7 @@
 #endif
 	struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
 	int len = ap->dccpap_buf_vector_len + 2;
-	const u32 elapsed_time = now_delta(ap->dccpap_time) / 10;
+	const u32 elapsed_time = timeval_now_delta(&ap->dccpap_time) / 10;
 	unsigned char *to, *from;
 
 	if (elapsed_time != 0)
@@ -451,7 +451,8 @@
 					"CLIENT TX opt: " : "server TX opt: ";
 #endif
 	u32 tstamp_echo;
-	const u32 elapsed_time = now_delta(dp->dccps_timestamp_time) / 10;
+	const u32 elapsed_time =
+			timeval_now_delta(&dp->dccps_timestamp_time) / 10;
 	const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 	const int len = 6 + elapsed_time_len;
 	unsigned char *to;