iwlwifi: serialize station management actions

We are seeing some race conditions between incoming station management
requests (station add/remove) and the internal unassoc RXON command that
modifies station table. Modify these flows to require the mutex to be held
and thus serializing them.

This fixes http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2207

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 6c353cacc8d6..a27872de4106 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -3437,10 +3437,13 @@ static int iwl3945_mac_sta_add(struct ieee80211_hw *hw,
         bool is_ap = vif->type == NL80211_IFTYPE_STATION;
         u8 sta_id;
 
-        sta_priv->common.sta_id = IWL_INVALID_STATION;
-
         IWL_DEBUG_INFO(priv, "received request to add station %pM\n",
                         sta->addr);
+        mutex_lock(&priv->mutex);
+        IWL_DEBUG_INFO(priv, "proceeding to add station %pM\n",
+                        sta->addr);
+        sta_priv->common.sta_id = IWL_INVALID_STATION;
+
 
         ret = iwl_add_station_common(priv, sta->addr, is_ap, &sta->ht_cap,
                                      &sta_id);
@@ -3448,6 +3451,7 @@ static int iwl3945_mac_sta_add(struct ieee80211_hw *hw,
                 IWL_ERR(priv, "Unable to add station %pM (%d)\n",
                         sta->addr, ret);
                 /* Should we return success if return code is EEXIST ? */
+                mutex_unlock(&priv->mutex);
                 return ret;
         }
 
@@ -3457,6 +3461,7 @@ static int iwl3945_mac_sta_add(struct ieee80211_hw *hw,
         IWL_DEBUG_INFO(priv, "Initializing rate scaling for station %pM\n",
                        sta->addr);
         iwl3945_rs_rate_init(priv, sta, sta_id);
+        mutex_unlock(&priv->mutex);
 
         return 0;
 }