net: sctp: migrate most recently used transport to ktime

Be more precise in transport path selection and use ktime
helpers instead of jiffies to compare and pick the better
primary and secondary recently used transports. This also
avoids any side-effects during a possible roll-over, and
could lead to better path decision-making.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index 0dfcc92..f38588b 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -838,10 +838,10 @@
 	unsigned long sackdelay;
 	__u32 sackfreq;
 
-	/* When was the last time (in jiffies) that we heard from this
-	 * transport?  We use this to pick new active and retran paths.
+	/* When was the last time that we heard from this transport? We use
+	 * this to pick new active and retran paths.
 	 */
-	unsigned long last_time_heard;
+	ktime_t last_time_heard;
 
 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
 	 * indication based on ECNE chunk.