From: Johannes Berg Date: Wed, 21 Aug 2013 20:07:20 +0000 (+0200) Subject: mac80211: add ieee80211_iterate_active_interfaces_rtnl() X-Git-Tag: firefly_0821_release~176^2~4570^2~3^2^2~309^2~50 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c7c71066c27f2bafb2ce3b10c407c0285f56acfa;p=firefly-linux-kernel-4.4.55.git mac80211: add ieee80211_iterate_active_interfaces_rtnl() If it is needed to disconnect multiple virtual interfaces after (WoWLAN-) suspend, the most obvious approach would be to iterate all interfaces by calling ieee80211_iterate_active_interfaces() and then call ieee80211_resume_disconnect() for each one. This is what the iwlmvm driver does. Unfortunately, this causes a locking dependency from mac80211's iflist_mtx to the key_mtx. This is problematic as the former is intentionally never held while calling any driver operation to allow drivers to iterate with their own locks held. The key_mtx is held while installing a key into the driver though, so this new lock dependency means drivers implementing the logic above can no longer hold their own lock while iterating. To fix this, add a new ieee80211_iterate_active_interfaces_rtnl() function that iterates while the RTNL is already held. This is true during suspend/resume, so that then the locking dependency isn't introduced. While at it, also refactor the various interface iterators and keep only a single implementation called by the various cases. Signed-off-by: Johannes Berg --- diff --git a/include/net/mac80211.h b/include/net/mac80211.h index cc6035f1a2f1..3411c59b636b 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -3919,6 +3919,25 @@ void ieee80211_iterate_active_interfaces_atomic(struct ieee80211_hw *hw, struct ieee80211_vif *vif), void *data); +/** + * ieee80211_iterate_active_interfaces_rtnl - iterate active interfaces + * + * This function iterates over the interfaces associated with a given + * hardware that are currently active and calls the callback for them. + * This version can only be used while holding the RTNL. + * + * @hw: the hardware struct of which the interfaces should be iterated over + * @iter_flags: iteration flags, see &enum ieee80211_interface_iteration_flags + * @iterator: the iterator function to call, cannot sleep + * @data: first argument of the iterator function + */ +void ieee80211_iterate_active_interfaces_rtnl(struct ieee80211_hw *hw, + u32 iter_flags, + void (*iterator)(void *data, + u8 *mac, + struct ieee80211_vif *vif), + void *data); + /** * ieee80211_queue_work - add work onto the mac80211 workqueue * diff --git a/net/mac80211/util.c b/net/mac80211/util.c index e1b34a18b243..75a16853fb45 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -567,18 +567,15 @@ void ieee80211_flush_queues(struct ieee80211_local *local, IEEE80211_QUEUE_STOP_REASON_FLUSH); } -void ieee80211_iterate_active_interfaces( - struct ieee80211_hw *hw, u32 iter_flags, - void (*iterator)(void *data, u8 *mac, - struct ieee80211_vif *vif), - void *data) +static void __iterate_active_interfaces(struct ieee80211_local *local, + u32 iter_flags, + void (*iterator)(void *data, u8 *mac, + struct ieee80211_vif *vif), + void *data) { - struct ieee80211_local *local = hw_to_local(hw); struct ieee80211_sub_if_data *sdata; - mutex_lock(&local->iflist_mtx); - - list_for_each_entry(sdata, &local->interfaces, list) { + list_for_each_entry_rcu(sdata, &local->interfaces, list) { switch (sdata->vif.type) { case NL80211_IFTYPE_MONITOR: if (!(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE)) @@ -597,13 +594,25 @@ void ieee80211_iterate_active_interfaces( &sdata->vif); } - sdata = rcu_dereference_protected(local->monitor_sdata, - lockdep_is_held(&local->iflist_mtx)); + sdata = rcu_dereference_check(local->monitor_sdata, + lockdep_is_held(&local->iflist_mtx) || + lockdep_rtnl_is_held()); if (sdata && (iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL || sdata->flags & IEEE80211_SDATA_IN_DRIVER)) iterator(data, sdata->vif.addr, &sdata->vif); +} +void ieee80211_iterate_active_interfaces( + struct ieee80211_hw *hw, u32 iter_flags, + void (*iterator)(void *data, u8 *mac, + struct ieee80211_vif *vif), + void *data) +{ + struct ieee80211_local *local = hw_to_local(hw); + + mutex_lock(&local->iflist_mtx); + __iterate_active_interfaces(local, iter_flags, iterator, data); mutex_unlock(&local->iflist_mtx); } EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces); @@ -615,38 +624,26 @@ void ieee80211_iterate_active_interfaces_atomic( void *data) { struct ieee80211_local *local = hw_to_local(hw); - struct ieee80211_sub_if_data *sdata; rcu_read_lock(); + __iterate_active_interfaces(local, iter_flags, iterator, data); + rcu_read_unlock(); +} +EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic); - list_for_each_entry_rcu(sdata, &local->interfaces, list) { - switch (sdata->vif.type) { - case NL80211_IFTYPE_MONITOR: - if (!(sdata->u.mntr_flags & MONITOR_FLAG_ACTIVE)) - continue; - break; - case NL80211_IFTYPE_AP_VLAN: - continue; - default: - break; - } - if (!(iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL) && - !(sdata->flags & IEEE80211_SDATA_IN_DRIVER)) - continue; - if (ieee80211_sdata_running(sdata)) - iterator(data, sdata->vif.addr, - &sdata->vif); - } +void ieee80211_iterate_active_interfaces_rtnl( + struct ieee80211_hw *hw, u32 iter_flags, + void (*iterator)(void *data, u8 *mac, + struct ieee80211_vif *vif), + void *data) +{ + struct ieee80211_local *local = hw_to_local(hw); - sdata = rcu_dereference(local->monitor_sdata); - if (sdata && - (iter_flags & IEEE80211_IFACE_ITER_RESUME_ALL || - sdata->flags & IEEE80211_SDATA_IN_DRIVER)) - iterator(data, sdata->vif.addr, &sdata->vif); + ASSERT_RTNL(); - rcu_read_unlock(); + __iterate_active_interfaces(local, iter_flags, iterator, data); } -EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic); +EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_rtnl); /* * Nothing should have been stuffed into the workqueue during