sctp: use time_before or time_after for comparing jiffies

The functions time_before or time_after are more robust
for comparing jiffies against other values.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index bc411c8..a367d15 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -428,7 +428,8 @@
 			 * retransmitting due to T3 timeout.
 			 */
 			if (reason == SCTP_RTXR_T3_RTX &&
-			    (jiffies - chunk->sent_at) < transport->last_rto)
+			    time_before(jiffies, chunk->sent_at +
+						 transport->last_rto))
 				continue;
 
 			/* RFC 2960 6.2.1 Processing a Received SACK