1 files changed, 18 insertions, 2 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 6cf121bebd7a..2e3adcb3ce23 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -138,9 +138,23 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
         ieee80211_debugfs_add_netdev(sdata);
 }
 
-void ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
-                              enum ieee80211_if_types type)
+int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
+                             enum ieee80211_if_types type)
 {
+        ASSERT_RTNL();
+
+        if (type == sdata->vif.type)
+                return 0;
+
+        /*
+         * We could, here, on changes between IBSS/STA/MESH modes,
+         * invoke an MLME function instead that disassociates etc.
+         * and goes into the requested mode.
+         */
+
+        if (netif_running(sdata->dev))
+                return -EBUSY;
+
         /* Purge and reset type-dependent state. */
         ieee80211_teardown_sdata(sdata->dev);
         ieee80211_setup_sdata(sdata, type);
@@ -149,6 +163,8 @@ void ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
         sdata->basic_rates = 0;
         sdata->drop_unencrypted = 0;
         sdata->sequence = 0;
+
+        return 0;
 }
 
 int ieee80211_if_add(struct ieee80211_local *local, const char *name,