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>

3 files changed, 17 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 7726e67044c0..24aff654fa9c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -3391,10 +3391,12 @@ static int iwlagn_mac_sta_add(struct ieee80211_hw *hw,
         int ret;
         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;
 
         atomic_set(&sta_priv->pending_frames, 0);
         if (vif->type == NL80211_IFTYPE_AP)
@@ -3406,6 +3408,7 @@ static int iwlagn_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;
         }
 
@@ -3415,6 +3418,7 @@ static int iwlagn_mac_sta_add(struct ieee80211_hw *hw,
         IWL_DEBUG_INFO(priv, "Initializing rate scaling for station %pM\n",
                        sta->addr);
         iwl_rs_rate_init(priv, sta, sta_id);
+        mutex_unlock(&priv->mutex);
 
         return 0;
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-sta.c b/drivers/net/wireless/iwlwifi/iwl-sta.c
index 83a26361a9b5..c27c13fbb1ae 100644
--- a/drivers/net/wireless/iwlwifi/iwl-sta.c
+++ b/drivers/net/wireless/iwlwifi/iwl-sta.c
@@ -1373,10 +1373,14 @@ int iwl_mac_sta_remove(struct ieee80211_hw *hw,
 
         IWL_DEBUG_INFO(priv, "received request to remove station %pM\n",
                         sta->addr);
+        mutex_lock(&priv->mutex);
+        IWL_DEBUG_INFO(priv, "proceeding to remove station %pM\n",
+                        sta->addr);
         ret = iwl_remove_station(priv, sta_common->sta_id, sta->addr);
         if (ret)
                 IWL_ERR(priv, "Error removing station %pM\n",
                         sta->addr);
+        mutex_unlock(&priv->mutex);
         return ret;
 }
 EXPORT_SYMBOL(iwl_mac_sta_remove);
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;
 }