mac80211: Add RTNL version of ieee80211_iterate_active_interfaces

Since commit e38bad4766a110b61fa6038f10be16ced8c6cc38
	mac80211: make ieee80211_iterate_active_interfaces not need rtnl
rt2500usb and rt73usb broke down due to attempting register access
in atomic context (which is not possible for USB hardware).

This patch restores ieee80211_iterate_active_interfaces() to use RTNL lock,
and provides the non-RTNL version under a new name:
	ieee80211_iterate_active_interfaces_atomic()

So far only rt2x00 uses ieee80211_iterate_active_interfaces(), and those
drivers require the RTNL version of ieee80211_iterate_active_interfaces().
Since they already call that function directly, this patch will automatically
fix the USB rt2x00 drivers.

v2: Rename ieee80211_iterate_active_interfaces_rtnl

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 59 insertions, 3 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 4a80d74975e8..dae3f9ec1154 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1594,13 +1594,16 @@ void ieee80211_wake_queues(struct ieee80211_hw *hw);
 void ieee80211_scan_completed(struct ieee80211_hw *hw);
 
 /**
- * ieee80211_iterate_active_interfaces - iterate active interfaces
+ * ieee80211_iterate_active_interfaces- 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 function allows the iterator function to sleep, when the iterator
+ * function is atomic @ieee80211_iterate_active_interfaces_atomic can
+ * be used.
  *
  * @hw: the hardware struct of which the interfaces should be iterated over
- * @iterator: the iterator function to call, cannot sleep
+ * @iterator: the iterator function to call
  * @data: first argument of the iterator function
  */
 void ieee80211_iterate_active_interfaces(struct ieee80211_hw *hw,
@@ -1609,6 +1612,24 @@ void ieee80211_iterate_active_interfaces(struct ieee80211_hw *hw,
                                          void *data);
 
 /**
+ * ieee80211_iterate_active_interfaces_atomic - 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 function requires the iterator callback function to be atomic,
+ * if that is not desired, use @ieee80211_iterate_active_interfaces instead.
+ *
+ * @hw: the hardware struct of which the interfaces should be iterated over
+ * @iterator: the iterator function to call, cannot sleep
+ * @data: first argument of the iterator function
+ */
+void ieee80211_iterate_active_interfaces_atomic(struct ieee80211_hw *hw,
+                                                void (*iterator)(void *data,
+                                                    u8 *mac,
+                                                    struct ieee80211_vif *vif),
+                                                void *data);
+
+/**
  * ieee80211_start_tx_ba_session - Start a tx Block Ack session.
  * @hw: pointer as obtained from ieee80211_alloc_hw().
  * @ra: receiver address of the BA session recipient
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 24a465c4df09..131e9e6c8a32 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -389,6 +389,41 @@ void ieee80211_iterate_active_interfaces(
         struct ieee80211_local *local = hw_to_local(hw);
         struct ieee80211_sub_if_data *sdata;
 
+        rtnl_lock();
+
+        list_for_each_entry(sdata, &local->interfaces, list) {
+                switch (sdata->vif.type) {
+                case IEEE80211_IF_TYPE_INVALID:
+                case IEEE80211_IF_TYPE_MNTR:
+                case IEEE80211_IF_TYPE_VLAN:
+                        continue;
+                case IEEE80211_IF_TYPE_AP:
+                case IEEE80211_IF_TYPE_STA:
+                case IEEE80211_IF_TYPE_IBSS:
+                case IEEE80211_IF_TYPE_WDS:
+                case IEEE80211_IF_TYPE_MESH_POINT:
+                        break;
+                }
+                if (sdata->dev == local->mdev)
+                        continue;
+                if (netif_running(sdata->dev))
+                        iterator(data, sdata->dev->dev_addr,
+                                 &sdata->vif);
+        }
+
+        rtnl_unlock();
+}
+EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
+
+void ieee80211_iterate_active_interfaces_atomic(
+        struct ieee80211_hw *hw,
+        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;
+
         rcu_read_lock();
 
         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
@@ -413,4 +448,4 @@ void ieee80211_iterate_active_interfaces(
 
         rcu_read_unlock();
 }
-EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
+EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);