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Date: Sat, 19 Jan 2013 21:27:57 +0800
From: Antonio Quartulli <ordex@...istici.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, b.a.t.m.a.n@...ts.open-mesh.org,
Simon Wunderlich <simon.wunderlich@...03.tu-chemnitz.de>,
Simon Wunderlich <siwu@....tu-chemnitz.de>,
Marek Lindner <lindner_marek@...oo.de>,
Antonio Quartulli <ordex@...istici.org>
Subject: [PATCH 11/13] batman-adv: postpone sysfs removal when unregistering
From: Simon Wunderlich <simon.wunderlich@...03.tu-chemnitz.de>
When processing the unregister notify for a hard interface, removing
the sysfs files may lead to a circular deadlock (rtnl mutex <->
s_active).
To overcome this problem, postpone the sysfs removal in a worker.
Reported-by: Sasha Levin <sasha.levin@...cle.com>
Reported-by: Sven Eckelmann <sven@...fation.org>
Signed-off-by: Simon Wunderlich <siwu@....tu-chemnitz.de>
Signed-off-by: Marek Lindner <lindner_marek@...oo.de>
Signed-off-by: Antonio Quartulli <ordex@...istici.org>
---
net/batman-adv/hard-interface.c | 24 ++++++++++++++++++++++--
net/batman-adv/soft-interface.c | 32 +++++++++++++++++++++++++++++---
net/batman-adv/types.h | 6 ++++++
3 files changed, 57 insertions(+), 5 deletions(-)
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index f1d37cd..cb3191f 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -457,6 +457,24 @@ out:
batadv_hardif_free_ref(primary_if);
}
+/**
+ * batadv_hardif_remove_interface_finish - cleans up the remains of a hardif
+ * @work: work queue item
+ *
+ * Free the parts of the hard interface which can not be removed under
+ * rtnl lock (to prevent deadlock situations).
+ */
+static void batadv_hardif_remove_interface_finish(struct work_struct *work)
+{
+ struct batadv_hard_iface *hard_iface;
+
+ hard_iface = container_of(work, struct batadv_hard_iface,
+ cleanup_work);
+
+ batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
+ batadv_hardif_free_ref(hard_iface);
+}
+
static struct batadv_hard_iface *
batadv_hardif_add_interface(struct net_device *net_dev)
{
@@ -484,6 +502,9 @@ batadv_hardif_add_interface(struct net_device *net_dev)
hard_iface->soft_iface = NULL;
hard_iface->if_status = BATADV_IF_NOT_IN_USE;
INIT_LIST_HEAD(&hard_iface->list);
+ INIT_WORK(&hard_iface->cleanup_work,
+ batadv_hardif_remove_interface_finish);
+
/* extra reference for return */
atomic_set(&hard_iface->refcount, 2);
@@ -518,8 +539,7 @@ static void batadv_hardif_remove_interface(struct batadv_hard_iface *hard_iface)
return;
hard_iface->if_status = BATADV_IF_TO_BE_REMOVED;
- batadv_sysfs_del_hardif(&hard_iface->hardif_obj);
- batadv_hardif_free_ref(hard_iface);
+ queue_work(batadv_event_workqueue, &hard_iface->cleanup_work);
}
void batadv_hardif_remove_interfaces(void)
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index 3d68166..c9962fe 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -449,6 +449,30 @@ static void batadv_interface_setup(struct net_device *dev)
memset(priv, 0, sizeof(*priv));
}
+/**
+ * batadv_softif_destroy_finish - cleans up the remains of a softif
+ * @work: work queue item
+ *
+ * Free the parts of the soft interface which can not be removed under
+ * rtnl lock (to prevent deadlock situations).
+ */
+static void batadv_softif_destroy_finish(struct work_struct *work)
+{
+ struct batadv_priv *bat_priv;
+ struct net_device *soft_iface;
+
+ bat_priv = container_of(work, struct batadv_priv,
+ cleanup_work);
+ soft_iface = bat_priv->soft_iface;
+
+ batadv_debugfs_del_meshif(soft_iface);
+ batadv_sysfs_del_meshif(soft_iface);
+
+ rtnl_lock();
+ unregister_netdevice(soft_iface);
+ rtnl_unlock();
+}
+
struct net_device *batadv_softif_create(const char *name)
{
struct net_device *soft_iface;
@@ -463,6 +487,8 @@ struct net_device *batadv_softif_create(const char *name)
goto out;
bat_priv = netdev_priv(soft_iface);
+ bat_priv->soft_iface = soft_iface;
+ INIT_WORK(&bat_priv->cleanup_work, batadv_softif_destroy_finish);
/* batadv_interface_stats() needs to be available as soon as
* register_netdevice() has been called
@@ -551,10 +577,10 @@ out:
void batadv_softif_destroy(struct net_device *soft_iface)
{
- batadv_debugfs_del_meshif(soft_iface);
- batadv_sysfs_del_meshif(soft_iface);
+ struct batadv_priv *bat_priv = netdev_priv(soft_iface);
+
batadv_mesh_free(soft_iface);
- unregister_netdevice(soft_iface);
+ queue_work(batadv_event_workqueue, &bat_priv->cleanup_work);
}
int batadv_softif_is_valid(const struct net_device *net_dev)
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 03197f5..8d4a16c 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -68,6 +68,7 @@ struct batadv_hard_iface_bat_iv {
* @soft_iface: the batman-adv interface which uses this network interface
* @rcu: struct used for freeing in an RCU-safe manner
* @bat_iv: BATMAN IV specific per hard interface data
+ * @cleanup_work: work queue callback item for hard interface deinit
*/
struct batadv_hard_iface {
struct list_head list;
@@ -81,6 +82,7 @@ struct batadv_hard_iface {
struct net_device *soft_iface;
struct rcu_head rcu;
struct batadv_hard_iface_bat_iv bat_iv;
+ struct work_struct cleanup_work;
};
/**
@@ -428,6 +430,7 @@ struct batadv_priv_dat {
/**
* struct batadv_priv - per mesh interface data
* @mesh_state: current status of the mesh (inactive/active/deactivating)
+ * @soft_iface: net device which holds this struct as private data
* @stats: structure holding the data for the ndo_get_stats() call
* @bat_counters: mesh internal traffic statistic counters (see batadv_counters)
* @aggregated_ogms: bool indicating whether OGM aggregation is enabled
@@ -457,6 +460,7 @@ struct batadv_priv_dat {
* @forw_bat_list_lock: lock protecting forw_bat_list
* @forw_bcast_list_lock: lock protecting forw_bcast_list
* @orig_work: work queue callback item for orig node purging
+ * @cleanup_work: work queue callback item for soft interface deinit
* @primary_if: one of the hard interfaces assigned to this mesh interface
* becomes the primary interface
* @bat_algo_ops: routing algorithm used by this mesh interface
@@ -469,6 +473,7 @@ struct batadv_priv_dat {
*/
struct batadv_priv {
atomic_t mesh_state;
+ struct net_device *soft_iface;
struct net_device_stats stats;
uint64_t __percpu *bat_counters; /* Per cpu counters */
atomic_t aggregated_ogms;
@@ -502,6 +507,7 @@ struct batadv_priv {
spinlock_t forw_bat_list_lock; /* protects forw_bat_list */
spinlock_t forw_bcast_list_lock; /* protects forw_bcast_list */
struct delayed_work orig_work;
+ struct work_struct cleanup_work;
struct batadv_hard_iface __rcu *primary_if; /* rcu protected pointer */
struct batadv_algo_ops *bat_algo_ops;
#ifdef CONFIG_BATMAN_ADV_BLA
--
1.8.0.2
--
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