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authorSven Eckelmann <sven@narfation.org>2012-08-20 09:03:59 +0200
committerAntonio Quartulli <ordex@autistici.org>2012-10-29 09:42:32 +0100
commit36c1d1531130dcfadf845419fd15735b9b4c004f (patch)
tree7bb3d3253eed07d3d32cb51c00ad3a17e496543e /net/batman-adv
parentc10dba051a3e287a4f023aaaeffa53fd642cf8c5 (diff)
batman-adv: Set special lockdep classes to avoid lockdep warning
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 tx queues get a special batman-adv lock class to avoid a false positive for each transmission. Reported-by: Linus Luessing <linus.luessing@web.de> Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/soft-interface.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index b9a28d2dd3e8..948860a2a576 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -347,7 +347,51 @@ out:
return;
}
+/* 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;
+
+/**
+ * batadv_set_lockdep_class_one - Set lockdep class for a single tx queue
+ * @dev: device which owns the tx queue
+ * @txq: tx queue to modify
+ * @_unused: always NULL
+ */
+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);
+}
+
+/**
+ * batadv_set_lockdep_class - Set txq and addr_list lockdep class
+ * @dev: network device to modify
+ */
+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);
+}
+
+/**
+ * batadv_softif_init - Late stage initialization of soft interface
+ * @dev: registered network device to modify
+ *
+ * Returns error code on failures
+ */
+static int batadv_softif_init(struct net_device *dev)
+{
+ batadv_set_lockdep_class(dev);
+
+ return 0;
+}
+
static const struct net_device_ops batadv_netdev_ops = {
+ .ndo_init = batadv_softif_init,
.ndo_open = batadv_interface_open,
.ndo_stop = batadv_interface_release,
.ndo_get_stats = batadv_interface_stats,