iwlwifi: do not force complete scan too early

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>

5 files changed, 41 insertions, 15 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index d2315debd1b..646864a26ea 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -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);
 }
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index b04a4f81ee9..393f02d94c4 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -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)
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index 8dab074e491..f1d40c6173c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -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
diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c
index da037b2f08b..af9a83669f5 100644
--- a/drivers/net/wireless/iwlwifi/iwl-scan.c
+++ b/drivers/net/wireless/iwlwifi/iwl-scan.c
@@ -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);
diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 6cc5ba2a2e3..116777122a7 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -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[] = {