From: Johannes Berg <johannes.berg@xxxxxxxxx>
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 <johannes.berg@xxxxxxxxx>
---
include/net/mac80211.h | 19 ++++++++++++++
net/mac80211/util.c | 71 ++++++++++++++++++++++++--------------------------
2 files changed, 53 insertions(+), 37 deletions(-)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index e3e3037..3ecf635 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,
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
*
* Drivers and mac80211 use this to add work onto the mac80211 workqueue.
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index e1b34a1..75a1685 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
--
1.8.4.rc3
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