[PKT_SCHED]: Potential jiffy wrap bug in dev_watchdog().

There is a potential jiffy wraparound bug in the transmit watchdog
that is easily avoided by using time_after().

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

1 files changed, 4 insertions, 2 deletions

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 31eb83717c2..138ea92ed26 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -193,8 +193,10 @@ static void dev_watchdog(unsigned long arg)
                     netif_running(dev) &&
                     netif_carrier_ok(dev)) {
                         if (netif_queue_stopped(dev) &&
-                            (jiffies - dev->trans_start) > dev->watchdog_timeo) {
-                                printk(KERN_INFO "NETDEV WATCHDOG: %s: transmit timed out\n", dev->name);
+                            time_after(jiffies, dev->trans_start + dev->watchdog_timeo)) {
+
+                                printk(KERN_INFO "NETDEV WATCHDOG: %s: transmit timed out\n",
+                                       dev->name);
                                 dev->tx_timeout(dev);
                         }
                         if (!mod_timer(&dev->watchdog_timer, jiffies + dev->watchdog_timeo))