Merge branch 'for-john' of git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi...

[~andy/linux] / drivers / net / wireless / iwlwifi / mvm / mac80211.c

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index e843080b5c0b99aee11d7807fb0f7f9576228208..c49b5073c2513e39a0c0fb3610209213e1a7e4ea 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -1212,6 +1212,28 @@ static void iwl_mvm_mac_sta_notify(struct ieee80211_hw *hw,
        }
 }
 
+static void iwl_mvm_sta_pre_rcu_remove(struct ieee80211_hw *hw,
+                                      struct ieee80211_vif *vif,
+                                      struct ieee80211_sta *sta)
+{
+       struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+       struct iwl_mvm_sta *mvm_sta = (void *)sta->drv_priv;
+
+       /*
+        * This is called before mac80211 does RCU synchronisation,
+        * so here we already invalidate our internal RCU-protected
+        * station pointer. The rest of the code will thus no longer
+        * be able to find the station this way, and we don't rely
+        * on further RCU synchronisation after the sta_state()
+        * callback deleted the station.
+        */
+       mutex_lock(&mvm->mutex);
+       if (sta == rcu_access_pointer(mvm->fw_id_to_mac_id[mvm_sta->sta_id]))
+               rcu_assign_pointer(mvm->fw_id_to_mac_id[mvm_sta->sta_id],
+                                  ERR_PTR(-ENOENT));
+       mutex_unlock(&mvm->mutex);
+}
+
 static int iwl_mvm_mac_sta_state(struct ieee80211_hw *hw,
                                 struct ieee80211_vif *vif,
                                 struct ieee80211_sta *sta,
@@ -1888,6 +1910,7 @@ struct ieee80211_ops iwl_mvm_hw_ops = {
        .bss_info_changed = iwl_mvm_bss_info_changed,
        .hw_scan = iwl_mvm_mac_hw_scan,
        .cancel_hw_scan = iwl_mvm_mac_cancel_hw_scan,
+       .sta_pre_rcu_remove = iwl_mvm_sta_pre_rcu_remove,
        .sta_state = iwl_mvm_mac_sta_state,
        .sta_notify = iwl_mvm_mac_sta_notify,
        .allow_buffered_frames = iwl_mvm_mac_allow_buffered_frames,