net: watchdog: add net device refcount tracker

Add a netdevice_tracker inside struct net_device, to track
the self reference when a device has an active watchdog timer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 69dca1e..1a748ee 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1951,6 +1951,7 @@ enum netdev_ml_priv_type {
  *
  *     @dev_addr_shadow:       Copy of @dev_addr to catch direct writes.
  *     @linkwatch_dev_tracker: refcount tracker used by linkwatch.
+ *     @watchdog_dev_tracker:  refcount tracker used by watchdog.
  *
  *     FIXME: cleanup struct net_device such that network protocol info
  *     moves out.
@@ -2282,6 +2283,7 @@ struct net_device {
 
        u8 dev_addr_shadow[MAX_ADDR_LEN];
        netdevice_tracker       linkwatch_dev_tracker;
+       netdevice_tracker       watchdog_dev_tracker;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 8c8fbf2..b07bd1c 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -499,6 +499,7 @@ EXPORT_SYMBOL(netif_tx_unlock);
 static void dev_watchdog(struct timer_list *t)
 {
        struct net_device *dev = from_timer(dev, t, watchdog_timer);
+       bool release = true;
 
        spin_lock(&dev->tx_global_lock);
        if (!qdisc_tx_is_noop(dev)) {
@@ -534,12 +535,13 @@ static void dev_watchdog(struct timer_list *t)
                        if (!mod_timer(&dev->watchdog_timer,
                                       round_jiffies(jiffies +
                                                     dev->watchdog_timeo)))
-                               dev_hold(dev);
+                               release = false;
                }
        }
        spin_unlock(&dev->tx_global_lock);
 
-       dev_put(dev);
+       if (release)
+               dev_put_track(dev, &dev->watchdog_dev_tracker);
 }
 
 void __netdev_watchdog_up(struct net_device *dev)
@@ -549,7 +551,7 @@ void __netdev_watchdog_up(struct net_device *dev)
                        dev->watchdog_timeo = 5*HZ;
                if (!mod_timer(&dev->watchdog_timer,
                               round_jiffies(jiffies + dev->watchdog_timeo)))
-                       dev_hold(dev);
+                       dev_hold_track(dev, &dev->watchdog_dev_tracker, GFP_ATOMIC);
        }
 }
 EXPORT_SYMBOL_GPL(__netdev_watchdog_up);
@@ -563,7 +565,7 @@ static void dev_watchdog_down(struct net_device *dev)
 {
        netif_tx_lock_bh(dev);
        if (del_timer(&dev->watchdog_timer))
-               dev_put(dev);
+               dev_put_track(dev, &dev->watchdog_dev_tracker);
        netif_tx_unlock_bh(dev);
 }