iwlwifi: mvm: wait for stop sched-scan completion

cfg80211 assumes a scheduled scan is stopped synchronously. Wait for the
FW before returning to caller.

Don't do anything in the async handler in the stop-from-above flow.
There's no need to call the mac80211 sched-scan completion as the
cleanup will be automatic. Make sure the async handler is called before
the next incoming scan changes the scan_status by flushing the async
handlers after all invocations.
Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/mac80211.c

@@ -1419,8 +1419,6 @@ static int iwl_mvm_mac_hw_scan(struct ieee80211_hw *hw,
 			       struct cfg80211_scan_request *req)
 {
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
-	struct iwl_notification_wait wait_scan_done;
-	static const u8 scan_done_notif[] = { SCAN_OFFLOAD_COMPLETE, };
 	int ret;
 
 	if (req->n_channels == 0 || req->n_channels > MAX_NUM_SCAN_CHANNELS)
@@ -1430,22 +1428,11 @@ static int iwl_mvm_mac_hw_scan(struct ieee80211_hw *hw,
 
 	switch (mvm->scan_status) {
 	case IWL_MVM_SCAN_SCHED:
-		iwl_init_notification_wait(&mvm->notif_wait, &wait_scan_done,
-					   scan_done_notif,
-					   ARRAY_SIZE(scan_done_notif),
-					   NULL, NULL);
-		iwl_mvm_sched_scan_stop(mvm);
-		ret = iwl_wait_notification(&mvm->notif_wait,
-					    &wait_scan_done, HZ);
+		ret = iwl_mvm_sched_scan_stop(mvm);
 		if (ret) {
 			ret = -EBUSY;
 			goto out;
 		}
-		/* iwl_mvm_rx_scan_offload_complete_notif() will be called
-		 * soon but will not reset the scan status as it won't be
-		 * IWL_MVM_SCAN_SCHED any more since we queue the next scan
-		 * immediately (below)
-		 */
 		break;
 	case IWL_MVM_SCAN_NONE:
 		break;
@@ -1461,7 +1448,8 @@ static int iwl_mvm_mac_hw_scan(struct ieee80211_hw *hw,
 		iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
 out:
 	mutex_unlock(&mvm->mutex);
-
+	/* make sure to flush the Rx handler before the next scan arrives */
+	iwl_mvm_wait_for_async_handlers(mvm);
 	return ret;
 }
 
@@ -1751,12 +1739,14 @@ static int iwl_mvm_mac_sched_scan_stop(struct ieee80211_hw *hw,
 				       struct ieee80211_vif *vif)
 {
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+	int ret;
 
 	mutex_lock(&mvm->mutex);
-	iwl_mvm_sched_scan_stop(mvm);
+	ret = iwl_mvm_sched_scan_stop(mvm);
 	mutex_unlock(&mvm->mutex);
+	iwl_mvm_wait_for_async_handlers(mvm);
 
-	return 0;
+	return ret;
 }
 
 static int iwl_mvm_mac_set_key(struct ieee80211_hw *hw,

drivers/net/wireless/iwlwifi/mvm/mvm.h

@@ -712,6 +712,11 @@ static inline const char *iwl_mvm_get_tx_fail_reason(u32 status) { return ""; }
 int iwl_mvm_flush_tx_path(struct iwl_mvm *mvm, u32 tfd_msk, bool sync);
 void iwl_mvm_async_handlers_purge(struct iwl_mvm *mvm);
 
+static inline void iwl_mvm_wait_for_async_handlers(struct iwl_mvm *mvm)
+{
+	flush_work(&mvm->async_handlers_wk);
+}
+
 /* Statistics */
 int iwl_mvm_rx_reply_statistics(struct iwl_mvm *mvm,
 				struct iwl_rx_cmd_buffer *rxb,
@@ -813,7 +818,7 @@ int iwl_mvm_config_sched_scan_profiles(struct iwl_mvm *mvm,
 				       struct cfg80211_sched_scan_request *req);
 int iwl_mvm_sched_scan_start(struct iwl_mvm *mvm,
 			     struct cfg80211_sched_scan_request *req);
-void iwl_mvm_sched_scan_stop(struct iwl_mvm *mvm);
+int iwl_mvm_sched_scan_stop(struct iwl_mvm *mvm);
 int iwl_mvm_rx_sched_scan_results(struct iwl_mvm *mvm,
 				  struct iwl_rx_cmd_buffer *rxb,
 				  struct iwl_device_cmd *cmd);

drivers/net/wireless/iwlwifi/mvm/scan.c

@@ -519,10 +519,11 @@ int iwl_mvm_rx_scan_offload_complete_notif(struct iwl_mvm *mvm,
 		       scan_notif->status == IWL_SCAN_OFFLOAD_COMPLETED ?
 		       "completed" : "aborted");
 
-	/* might already be something else again, don't reset if so */
-	if (mvm->scan_status == IWL_MVM_SCAN_SCHED)
+	/* only call mac80211 completion if the stop was initiated by FW */
+	if (mvm->scan_status == IWL_MVM_SCAN_SCHED) {
 		mvm->scan_status = IWL_MVM_SCAN_NONE;
 		ieee80211_sched_scan_stopped(mvm->hw);
+	}
 
 	return 0;
 }
@@ -894,26 +895,49 @@ static int iwl_mvm_send_sched_scan_abort(struct iwl_mvm *mvm)
 		 * microcode has notified us that a scan is completed.
 		 */
 		IWL_DEBUG_SCAN(mvm, "SCAN OFFLOAD ABORT ret %d.\n", status);
-		ret = -EIO;
+		ret = -ENOENT;
 	}
 
 	return ret;
 }
 
-void iwl_mvm_sched_scan_stop(struct iwl_mvm *mvm)
+int iwl_mvm_sched_scan_stop(struct iwl_mvm *mvm)
 {
 	int ret;
+	struct iwl_notification_wait wait_scan_done;
+	static const u8 scan_done_notif[] = { SCAN_OFFLOAD_COMPLETE, };
 
 	lockdep_assert_held(&mvm->mutex);
 
 	if (mvm->scan_status != IWL_MVM_SCAN_SCHED) {
 		IWL_DEBUG_SCAN(mvm, "No offloaded scan to stop\n");
-		return;
+		return 0;
 	}
 
+	iwl_init_notification_wait(&mvm->notif_wait, &wait_scan_done,
+				   scan_done_notif,
+				   ARRAY_SIZE(scan_done_notif),
+				   NULL, NULL);
+
 	ret = iwl_mvm_send_sched_scan_abort(mvm);
-	if (ret)
+	if (ret) {
 		IWL_DEBUG_SCAN(mvm, "Send stop offload scan failed %d\n", ret);
-	else
+		iwl_remove_notification(&mvm->notif_wait, &wait_scan_done);
+		return ret;
+	}
+
 	IWL_DEBUG_SCAN(mvm, "Successfully sent stop offload scan\n");
+
+	ret = iwl_wait_notification(&mvm->notif_wait, &wait_scan_done, 1 * HZ);
+	if (ret)
+		return ret;
+
+	/*
+	 * Clear the scan status so the next scan requests will succeed. This
+	 * also ensures the Rx handler doesn't do anything, as the scan was
+	 * stopped from above.
+	 */
+	mvm->scan_status = IWL_MVM_SCAN_NONE;
+
+	return 0;
 }