[B.A.T.M.A.N.] [PATCH] batman-adv: Set special lockdep classes to avoid lockdep warning
From: Sven Eckelmann <sven@narfation.org>
Date: 2012-08-19 23:22:39
Subsystem:
the rest · Maintainer:
Linus Torvalds
Transmissions over batman-adv devices always start another nested transmission over devices attached to the batman-adv interface. These devices usually use the ethernet lockdep class for the tx_queue lock which is also set by default for all batman-adv devices. Lockdep will detect a nested locking attempt of two locks with the same class and warn about a possible deadlock. This is the default and expected behavior and should not alarm the locking correctness prove mechanism. Therefore, the locks for all netdevice specific lock get a special batman-adv lock class to avoid a false positive for each transmission. Reported-by: Linus Lüssing <redacted> Signed-off-by: Sven Eckelmann <sven@narfation.org> --- soft-interface.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)
diff --git a/soft-interface.c b/soft-interface.c
index 1aee7db..513d50a 100644
--- a/soft-interface.c
+++ b/soft-interface.c@@ -354,6 +354,27 @@ static const struct net_device_ops batadv_netdev_ops = { .ndo_validate_addr = eth_validate_addr }; +/* + * batman-adv network devices have devices nesting below it and are a special + * "super class" of normal network devices; split their locks off into a + * separate class since they always nest. + */ +static struct lock_class_key batadv_netdev_xmit_lock_key; +static struct lock_class_key batadv_netdev_addr_lock_key; + +static void batadv_set_lockdep_class_one(struct net_device *dev, + struct netdev_queue *txq, + void *_unused) +{ + lockdep_set_class(&txq->_xmit_lock, &batadv_netdev_xmit_lock_key); +} + +static void batadv_set_lockdep_class(struct net_device *dev) +{ + lockdep_set_class(&dev->addr_list_lock, &batadv_netdev_addr_lock_key); + netdev_for_each_tx_queue(dev, batadv_set_lockdep_class_one, NULL); +} + static void batadv_interface_setup(struct net_device *dev) { struct batadv_priv *priv = netdev_priv(dev);
@@ -363,6 +384,7 @@ static void batadv_interface_setup(struct net_device *dev) dev->netdev_ops = &batadv_netdev_ops; dev->destructor = free_netdev; dev->tx_queue_len = 0; + batadv_set_lockdep_class(dev); /* can't call min_mtu, because the needed variables * have not been initialized yet
--
1.7.10.4