Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit c7c71066 authored by Johannes Berg's avatar Johannes Berg
Browse files

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: default avatarJohannes Berg <johannes.berg@intel.com>
parent 272b98c6

include/net/mac80211.h

+19 −0
Original line number Diff line number Diff line
@@ -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

 *

net/mac80211/util.c

+34 −37
Original line number Diff line number Diff line
@@ -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,

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();



	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);

	__iterate_active_interfaces(local, iter_flags, iterator, data);

	rcu_read_unlock();

}

EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);



	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);

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);



	rcu_read_unlock();

	ASSERT_RTNL();



	__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