cfg80211/mac80211: correct qos-map locking

Since the RTNL can't always be held, use wdev/sdata locking for
the qos-map dereference in mac80211. This requires cfg80211 to
consistently lock it, which it was missing in one place.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/cfg.c

@@ -3854,7 +3854,7 @@ static int ieee80211_set_qos_map(struct wiphy *wiphy,
 		new_qos_map = NULL;
 	}
 
-	old_qos_map = rtnl_dereference(sdata->qos_map);
+	old_qos_map = sdata_dereference(sdata->qos_map, sdata);
 	rcu_assign_pointer(sdata->qos_map, new_qos_map);
 	if (old_qos_map)
 		kfree_rcu(old_qos_map, rcu_head);

net/wireless/util.c

@@ -879,7 +879,9 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
 
 		dev->ieee80211_ptr->use_4addr = false;
 		dev->ieee80211_ptr->mesh_id_up_len = 0;
+		wdev_lock(dev->ieee80211_ptr);
 		rdev_set_qos_map(rdev, dev, NULL);
+		wdev_unlock(dev->ieee80211_ptr);
 
 		switch (otype) {
 		case NL80211_IFTYPE_AP: