decnet: Use time_after_eq

The functions time_before, time_before_eq, time_after, and time_after_eq
are more robust for comparing jiffies against other values.

A simplified version of the Coccinelle semantic patch making this change
is as follows:

@change@
expression E1,E2;
@@
- (jiffies - E1) >= E2
+ time_after_eq(jiffies, E1+E2)

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/decnet/dn_timer.c

@@ -23,6 +23,7 @@
 #include <linux/spinlock.h>
 #include <net/sock.h>
 #include <linux/atomic.h>
+#include <linux/jiffies.h>
 #include <net/flow.h>
 #include <net/dn.h>
 
@@ -91,7 +92,7 @@ static void dn_slow_timer(unsigned long arg)
 	 * since the last successful transmission.
 	 */
 	if (scp->keepalive && scp->keepalive_fxn && (scp->state == DN_RUN)) {
-		if ((jiffies - scp->stamp) >= scp->keepalive)
+		if (time_after_eq(jiffies, scp->stamp + scp->keepalive))
 			scp->keepalive_fxn(sk);
 	}