iwlwifi: do not force complete scan too early
Stanislaw Gruszka [Mon, 13 Sep 2010 12:46:41 +0000 (14:46 +0200)]
Currently we force scan complete at the end of iwl_scan_cancel_timeout
function. This cause race condition when we can get a new scan request
from mac80211 and complete it by iwl_bg_complete from older scan. Change
code to force scan complete only when really needed: device goes down,
interface is removed or scan timeout occurs.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi W Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn.c
drivers/net/wireless/iwlwifi/iwl-core.c
drivers/net/wireless/iwlwifi/iwl-core.h
drivers/net/wireless/iwlwifi/iwl-scan.c
drivers/net/wireless/iwlwifi/iwl3945-base.c

index d2315de..646864a 100644 (file)
@@ -4071,13 +4071,15 @@ static void iwl_cancel_deferred_work(struct iwl_priv *priv)
                priv->cfg->ops->lib->cancel_deferred_work(priv);
 
        cancel_delayed_work_sync(&priv->init_alive_start);
-       cancel_delayed_work(&priv->scan_check);
-       cancel_work_sync(&priv->start_internal_scan);
        cancel_delayed_work(&priv->alive_start);
        cancel_work_sync(&priv->run_time_calib_work);
        cancel_work_sync(&priv->beacon_update);
+
+       iwl_cancel_scan_deferred_work(priv);
+
        cancel_work_sync(&priv->bt_full_concurrency);
        cancel_work_sync(&priv->bt_runtime_config);
+
        del_timer_sync(&priv->statistics_periodic);
        del_timer_sync(&priv->ucode_trace);
 }
index b04a4f8..393f02d 100644 (file)
@@ -2089,8 +2089,10 @@ void iwl_mac_remove_interface(struct ieee80211_hw *hw,
        WARN_ON(ctx->vif != vif);
        ctx->vif = NULL;
 
-       if (priv->scan_vif == vif)
-               iwl_scan_cancel_timeout(priv, 100);
+       if (priv->scan_vif == vif) {
+               iwl_scan_cancel_timeout(priv, 200);
+               iwl_force_scan_end(priv);
+       }
        iwl_set_mode(priv, vif);
 
        if (!ctx->always_active)
index 8dab074..f1d40c6 100644 (file)
@@ -553,6 +553,7 @@ static inline __le32 iwl_hw_set_rate_n_flags(u8 rate, u32 flags)
 void iwl_init_scan_params(struct iwl_priv *priv);
 int iwl_scan_cancel(struct iwl_priv *priv);
 int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms);
+void iwl_force_scan_end(struct iwl_priv *priv);
 int iwl_mac_hw_scan(struct ieee80211_hw *hw,
                    struct ieee80211_vif *vif,
                    struct cfg80211_scan_request *req);
@@ -568,6 +569,7 @@ u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
                               enum ieee80211_band band,
                               struct ieee80211_vif *vif);
 void iwl_setup_scan_deferred_work(struct iwl_priv *priv);
+void iwl_cancel_scan_deferred_work(struct iwl_priv *priv);
 
 /* For faster active scanning, scan will move to the next channel if fewer than
  * PLCP_QUIET_THRESH packets are heard on this channel within
index da037b2..af9a836 100644 (file)
@@ -106,14 +106,22 @@ static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
        priv->scan_request = NULL;
 }
 
-static void iwl_force_scan_end(struct iwl_priv *priv)
+void iwl_force_scan_end(struct iwl_priv *priv)
 {
+       lockdep_assert_held(&priv->mutex);
+
+       if (!test_bit(STATUS_SCANNING, &priv->status)) {
+               IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
+               return;
+       }
+
        IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
        clear_bit(STATUS_SCANNING, &priv->status);
        clear_bit(STATUS_SCAN_HW, &priv->status);
        clear_bit(STATUS_SCAN_ABORTING, &priv->status);
        iwl_complete_scan(priv, true);
 }
+EXPORT_SYMBOL(iwl_force_scan_end);
 
 static void iwl_do_scan_abort(struct iwl_priv *priv)
 {
@@ -157,7 +165,6 @@ EXPORT_SYMBOL(iwl_scan_cancel);
  */
 int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
 {
-       int ret;
        unsigned long timeout = jiffies + msecs_to_jiffies(ms);
 
        lockdep_assert_held(&priv->mutex);
@@ -172,10 +179,7 @@ int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
                msleep(20);
        }
 
-       ret = test_bit(STATUS_SCAN_HW, &priv->status);
-       if (ret)
-               iwl_force_scan_end(priv);
-       return ret;
+       return test_bit(STATUS_SCAN_HW, &priv->status);
 }
 EXPORT_SYMBOL(iwl_scan_cancel_timeout);
 
@@ -490,8 +494,11 @@ static void iwl_bg_scan_check(struct work_struct *data)
        struct iwl_priv *priv =
            container_of(data, struct iwl_priv, scan_check.work);
 
+       /* Since we are here firmware does not finish scan and
+        * most likely is in bad shape, so we don't bother to
+        * send abort command, just force scan complete to mac80211 */
        mutex_lock(&priv->mutex);
-       iwl_scan_cancel_timeout(priv, 200);
+       iwl_force_scan_end(priv);
        mutex_unlock(&priv->mutex);
 }
 
@@ -547,8 +554,8 @@ static void iwl_bg_abort_scan(struct work_struct *work)
 {
        struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
 
-       cancel_delayed_work(&priv->scan_check);
-
+       /* We keep scan_check work queued in case when firmware will not
+        * report back scan completed notification */
        mutex_lock(&priv->mutex);
        iwl_scan_cancel_timeout(priv, 200);
        mutex_unlock(&priv->mutex);
@@ -631,3 +638,16 @@ void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
 }
 EXPORT_SYMBOL(iwl_setup_scan_deferred_work);
 
+void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
+{
+       cancel_work_sync(&priv->start_internal_scan);
+       cancel_work_sync(&priv->abort_scan);
+       cancel_work_sync(&priv->scan_completed);
+
+       if (cancel_delayed_work_sync(&priv->scan_check)) {
+               mutex_lock(&priv->mutex);
+               iwl_force_scan_end(priv);
+               mutex_unlock(&priv->mutex);
+       }
+}
+EXPORT_SYMBOL(iwl_cancel_scan_deferred_work);
index 6cc5ba2..1167771 100644 (file)
@@ -3762,10 +3762,10 @@ static void iwl3945_cancel_deferred_work(struct iwl_priv *priv)
        iwl3945_hw_cancel_deferred_work(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);
+
+       iwl_cancel_scan_deferred_work(priv);
 }
 
 static struct attribute *iwl3945_sysfs_entries[] = {