iwlwifi: mvm: support IEEE80211_AMPDU_TX_STOP_FLUSH

mac80211 tells us when we need to dump the frames from the
AGG queue instead of releasing them as single MPDUs.
Being able to differentiate between the different cases
(IEEE80211_AMPDU_TX_STOP_*) allows us to handle races better.

When the station is removed, mac80211 asks to flush and
removes the station right away.
This allows to avoid a case where we still have frames in
AGG queues, but the station has been remove already.

Note that we can have frames on the shared queues, but this
is not a problem: the station in the fw will be kept until
all the frames on the shared queues have been drained.
AGG queues are a special case since they are dynamically
allocated.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

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

@@ -284,9 +284,11 @@ static int iwl_mvm_mac_ampdu_action(struct ieee80211_hw *hw,
 		ret = iwl_mvm_sta_tx_agg_start(mvm, vif, sta, tid, ssn);
 		break;
 	case IEEE80211_AMPDU_TX_STOP_CONT:
+		ret = iwl_mvm_sta_tx_agg_stop(mvm, vif, sta, tid);
+		break;
 	case IEEE80211_AMPDU_TX_STOP_FLUSH:
 	case IEEE80211_AMPDU_TX_STOP_FLUSH_CONT:
-		ret = iwl_mvm_sta_tx_agg_stop(mvm, vif, sta, tid);
+		ret = iwl_mvm_sta_tx_agg_flush(mvm, vif, sta, tid);
 		break;
 	case IEEE80211_AMPDU_TX_OPERATIONAL:
 		ret = iwl_mvm_sta_tx_agg_oper(mvm, vif, sta, tid, buf_size);

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

@@ -834,6 +834,34 @@ int iwl_mvm_sta_tx_agg_stop(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 	return err;
 }
 
+int iwl_mvm_sta_tx_agg_flush(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
+			    struct ieee80211_sta *sta, u16 tid)
+{
+	struct iwl_mvm_sta *mvmsta = (void *)sta->drv_priv;
+	struct iwl_mvm_tid_data *tid_data = &mvmsta->tid_data[tid];
+	u16 txq_id;
+
+	/*
+	 * First set the agg state to OFF to avoid calling
+	 * ieee80211_stop_tx_ba_cb in iwl_mvm_check_ratid_empty.
+	 */
+	spin_lock_bh(&mvmsta->lock);
+	txq_id = tid_data->txq_id;
+	IWL_DEBUG_TX_QUEUES(mvm, "Flush AGG: sta %d tid %d q %d state %d\n",
+			    mvmsta->sta_id, tid, txq_id, tid_data->state);
+	tid_data->state = IWL_AGG_OFF;
+	spin_unlock_bh(&mvmsta->lock);
+
+	if (iwl_mvm_flush_tx_path(mvm, BIT(txq_id), true))
+		IWL_ERR(mvm, "Couldn't flush the AGG queue\n");
+
+	iwl_trans_txq_disable(mvm->trans, tid_data->txq_id);
+	mvm->queue_to_mac80211[tid_data->txq_id] =
+				IWL_INVALID_MAC80211_QUEUE;
+
+	return 0;
+}
+
 static int iwl_mvm_set_fw_key_idx(struct iwl_mvm *mvm)
 {
 	int i;

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

@@ -348,6 +348,8 @@ int iwl_mvm_sta_tx_agg_oper(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 			struct ieee80211_sta *sta, u16 tid, u8 buf_size);
 int iwl_mvm_sta_tx_agg_stop(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 			    struct ieee80211_sta *sta, u16 tid);
+int iwl_mvm_sta_tx_agg_flush(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
+			    struct ieee80211_sta *sta, u16 tid);
 
 int iwl_mvm_add_aux_sta(struct iwl_mvm *mvm);
 int iwl_mvm_allocate_int_sta(struct iwl_mvm *mvm, struct iwl_mvm_int_sta *sta,