diff options
| -rw-r--r-- | include/net/mac80211.h | 5 | ||||
| -rw-r--r-- | net/mac80211/ieee80211_i.h | 2 | ||||
| -rw-r--r-- | net/mac80211/iface.c | 31 | ||||
| -rw-r--r-- | net/mac80211/main.c | 3 | ||||
| -rw-r--r-- | net/mac80211/util.c | 4 |
5 files changed, 40 insertions, 5 deletions
diff --git a/include/net/mac80211.h b/include/net/mac80211.h index c1e8261e899..8e65adf0a64 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -928,9 +928,8 @@ enum ieee80211_hw_flags { * @workqueue: single threaded workqueue available for driver use, * allocated by mac80211 on registration and flushed when an * interface is removed. - * NOTICE: All work performed on this workqueue should NEVER - * acquire the RTNL lock (i.e. Don't use the function - * ieee80211_iterate_active_interfaces()) + * NOTICE: All work performed on this workqueue must not + * acquire the RTNL lock. * * @priv: pointer to private area that was allocated for driver use * along with this structure. diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 927cbde8c19..eaf3603862b 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -643,7 +643,9 @@ struct ieee80211_local { struct crypto_blkcipher *wep_rx_tfm; u32 wep_iv; + /* see iface.c */ struct list_head interfaces; + struct mutex iflist_mtx; /* * Key lock, protects sdata's key_list and sta_info's diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 8dc2c2188d9..00562a8b99c 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -21,6 +21,23 @@ #include "mesh.h" #include "led.h" +/** + * DOC: Interface list locking + * + * The interface list in each struct ieee80211_local is protected + * three-fold: + * + * (1) modifications may only be done under the RTNL + * (2) modifications and readers are protected against each other by + * the iflist_mtx. + * (3) modifications are done in an RCU manner so atomic readers + * can traverse the list in RCU-safe blocks. + * + * As a consequence, reads (traversals) of the list can be protected + * by either the RTNL, the iflist_mtx or RCU. + */ + + static int ieee80211_change_mtu(struct net_device *dev, int new_mtu) { int meshhdrlen; @@ -800,7 +817,9 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name, params->mesh_id_len, params->mesh_id); + mutex_lock(&local->iflist_mtx); list_add_tail_rcu(&sdata->list, &local->interfaces); + mutex_unlock(&local->iflist_mtx); if (new_dev) *new_dev = ndev; @@ -816,7 +835,10 @@ void ieee80211_if_remove(struct ieee80211_sub_if_data *sdata) { ASSERT_RTNL(); + mutex_lock(&sdata->local->iflist_mtx); list_del_rcu(&sdata->list); + mutex_unlock(&sdata->local->iflist_mtx); + synchronize_rcu(); unregister_netdevice(sdata->dev); } @@ -832,7 +854,16 @@ void ieee80211_remove_interfaces(struct ieee80211_local *local) ASSERT_RTNL(); list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) { + /* + * we cannot hold the iflist_mtx across unregister_netdevice, + * but we only need to hold it for list modifications to lock + * out readers since we're under the RTNL here as all other + * writers. + */ + mutex_lock(&local->iflist_mtx); list_del(&sdata->list); + mutex_unlock(&local->iflist_mtx); + unregister_netdevice(sdata->dev); } } diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 210dfe3cf6c..a109c06e8e4 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -758,6 +758,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len, local->hw.conf.radio_enabled = true; INIT_LIST_HEAD(&local->interfaces); + mutex_init(&local->iflist_mtx); spin_lock_init(&local->key_lock); @@ -1008,6 +1009,8 @@ void ieee80211_free_hw(struct ieee80211_hw *hw) { struct ieee80211_local *local = hw_to_local(hw); + mutex_destroy(&local->iflist_mtx); + wiphy_free(local->hw.wiphy); } EXPORT_SYMBOL(ieee80211_free_hw); diff --git a/net/mac80211/util.c b/net/mac80211/util.c index fc30f2940e1..73c7d7345ab 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -468,7 +468,7 @@ void ieee80211_iterate_active_interfaces( struct ieee80211_local *local = hw_to_local(hw); struct ieee80211_sub_if_data *sdata; - rtnl_lock(); + mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { switch (sdata->vif.type) { @@ -489,7 +489,7 @@ void ieee80211_iterate_active_interfaces( &sdata->vif); } - rtnl_unlock(); + mutex_unlock(&local->iflist_mtx); } EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces); |