iwl3945: fix scan races

Port following patch to 3945.

"commit 90c4162ff59a3281b6d2f7206740be6217bd6758
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Wed Apr 7 00:21:36 2010 -0700
    iwlwifi: fix scan races"
Signed-off-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

drivers/net/wireless/iwlwifi/iwl-core.h

@@ -515,6 +515,7 @@ int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms);
 int iwl_mac_hw_scan(struct ieee80211_hw *hw,
 		    struct ieee80211_vif *vif,
 		    struct cfg80211_scan_request *req);
+void iwl_bg_start_internal_scan(struct work_struct *work);
 void iwl_internal_short_hw_scan(struct iwl_priv *priv);
 int iwl_force_reset(struct iwl_priv *priv, int mode);
 u16 iwl_fill_probe_req(struct iwl_priv *priv, struct ieee80211_mgmt *frame,

drivers/net/wireless/iwlwifi/iwl-scan.c

@@ -367,7 +367,7 @@ void iwl_internal_short_hw_scan(struct iwl_priv *priv)
 	queue_work(priv->workqueue, &priv->start_internal_scan);
 }
 
-static void iwl_bg_start_internal_scan(struct work_struct *work)
+void iwl_bg_start_internal_scan(struct work_struct *work)
 {
 	struct iwl_priv *priv =
 		container_of(work, struct iwl_priv, start_internal_scan);
@@ -402,6 +402,7 @@ static void iwl_bg_start_internal_scan(struct work_struct *work)
  unlock:
 	mutex_unlock(&priv->mutex);
 }
+EXPORT_SYMBOL(iwl_bg_start_internal_scan);
 
 void iwl_bg_scan_check(struct work_struct *data)
 {

drivers/net/wireless/iwlwifi/iwl3945-base.c

@@ -3739,6 +3739,7 @@ static void iwl3945_setup_deferred_work(struct iwl_priv *priv)
 	INIT_DELAYED_WORK(&priv->_3945.rfkill_poll, iwl3945_rfkill_poll);
 	INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
 	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
+	INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
 	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
 
 	iwl3945_hw_setup_deferred_work(priv);
@@ -3761,6 +3762,7 @@ static void iwl3945_cancel_deferred_work(struct iwl_priv *priv)
 	cancel_delayed_work_sync(&priv->init_alive_start);
 	cancel_delayed_work(&priv->scan_check);
 	cancel_delayed_work(&priv->alive_start);
+	cancel_work_sync(&priv->start_internal_scan);
 	cancel_work_sync(&priv->beacon_update);
 	if (priv->cfg->ops->lib->recover_from_tx_stall)
 		del_timer_sync(&priv->monitor_recover);