wifi: mac80211: introduce ieee80211_refresh_tx_agg_session_timer()

This allows low level drivers to refresh the tx agg session timer, based on
querying stats from the firmware usually. Especially for some mt76 devices
support .net_fill_forward_path would bypass mac80211, which leads to tx BA
session timeout clients that set a timeout in their AddBA response to our
request, even if our request is without a timeout.
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Link: https://lore.kernel.org/r/7c3f72eac1c34921cd84a462e60d71e125862152.1676616450.git.ryder.lee@mediatek.com
[slightly clarify commit message, add note about RCU]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -5973,6 +5973,20 @@ void ieee80211_queue_delayed_work(struct ieee80211_hw *hw,
 				  struct delayed_work *dwork,
 				  unsigned long delay);
 
+/**
+ * ieee80211_refresh_tx_agg_session_timer - Refresh a tx agg session timer.
+ * @sta: the station for which to start a BA session
+ * @tid: the TID to BA on.
+ *
+ * This function allows low level driver to refresh tx agg session timer
+ * to maintain BA session, the session level will still be managed by the
+ * mac80211.
+ *
+ * Note: must be called in an RCU critical section.
+ */
+void ieee80211_refresh_tx_agg_session_timer(struct ieee80211_sta *sta,
+					    u16 tid);
+
 /**
  * ieee80211_start_tx_ba_session - Start a tx Block Ack session.
  * @sta: the station for which to start a BA session

net/mac80211/agg-tx.c

@@ -554,6 +554,23 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
 	ieee80211_send_addba_with_timeout(sta, tid_tx);
 }
 
+void ieee80211_refresh_tx_agg_session_timer(struct ieee80211_sta *pubsta,
+					    u16 tid)
+{
+	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
+	struct tid_ampdu_tx *tid_tx;
+
+	if (WARN_ON_ONCE(tid >= IEEE80211_NUM_TIDS))
+		return;
+
+	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
+	if (!tid_tx)
+		return;
+
+	tid_tx->last_tx = jiffies;
+}
+EXPORT_SYMBOL(ieee80211_refresh_tx_agg_session_timer);
+
 /*
  * After accepting the AddBA Response we activated a timer,
  * resetting it after each frame that we send.