mac80211: Add TXQ scheduling API

This adds an API to mac80211 to handle scheduling of TXQs and changes the
interface between driver and mac80211 for TXQ handling as follows:

- The wake_tx_queue callback interface no longer includes the TXQ. Instead,
  the driver is expected to retrieve that from ieee80211_next_txq()

- Two new mac80211 functions are added: ieee80211_next_txq() and
  ieee80211_schedule_txq(). The former returns the next TXQ that should be
  scheduled, and is how the driver gets a queue to pull packets from. The
  latter is called internally by mac80211 to start scheduling a queue, and
  the driver is supposed to call it to re-schedule the TXQ after it is
  finished pulling packets from it (unless the queue emptied).

The ath9k and ath10k drivers are changed to use the new API.

Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>

net/mac80211/agg-tx.c

@@ -226,9 +226,13 @@ ieee80211_agg_start_txq(struct sta_info *sta, int tid, bool enable)
 		clear_bit(IEEE80211_TXQ_AMPDU, &txqi->flags);
 
 	clear_bit(IEEE80211_TXQ_STOP, &txqi->flags);
+
+	if (!ieee80211_schedule_txq(&sta->sdata->local->hw, txq))
+		return;
+
 	local_bh_disable();
 	rcu_read_lock();
-	drv_wake_tx_queue(sta->sdata->local, txqi);
+	drv_wake_tx_queue(sta->sdata->local);
 	rcu_read_unlock();
 	local_bh_enable();
 }

net/mac80211/driver-ops.h

@@ -1158,16 +1158,10 @@ drv_tdls_recv_channel_switch(struct ieee80211_local *local,
 	trace_drv_return_void(local);
 }
 
-static inline void drv_wake_tx_queue(struct ieee80211_local *local,
-				     struct txq_info *txq)
+static inline void drv_wake_tx_queue(struct ieee80211_local *local)
 {
-	struct ieee80211_sub_if_data *sdata = vif_to_sdata(txq->txq.vif);
-
-	if (!check_sdata_in_driver(sdata))
-		return;
-
-	trace_drv_wake_tx_queue(local, sdata, txq);
-	local->ops->wake_tx_queue(&local->hw, &txq->txq);
+	trace_drv_wake_tx_queue(local);
+	local->ops->wake_tx_queue(&local->hw);
 }
 
 static inline int drv_start_nan(struct ieee80211_local *local,

net/mac80211/ieee80211_i.h

@@ -832,6 +832,7 @@ struct txq_info {
 	struct codel_vars def_cvars;
 	struct codel_stats cstats;
 	struct sk_buff_head frags;
+	struct list_head schedule_order;
 	unsigned long flags;
 
 	/* keep last! */
@@ -1122,6 +1123,10 @@ struct ieee80211_local {
 	struct codel_vars *cvars;
 	struct codel_params cparams;
 
+	/* protects active_txqs and txqi->schedule_order */
+	spinlock_t active_txq_lock;
+	struct list_head active_txqs;
+
 	const struct ieee80211_ops *ops;
 
 	/*

net/mac80211/main.c

@@ -619,6 +619,9 @@ struct ieee80211_hw *ieee80211_alloc_hw_nm(size_t priv_data_len,
 	spin_lock_init(&local->rx_path_lock);
 	spin_lock_init(&local->queue_stop_reason_lock);
 
+	INIT_LIST_HEAD(&local->active_txqs);
+	spin_lock_init(&local->active_txq_lock);
+
 	INIT_LIST_HEAD(&local->chanctx_list);
 	mutex_init(&local->chanctx_mtx);
 

net/mac80211/sta_info.c

@@ -1237,12 +1237,17 @@ void ieee80211_sta_ps_deliver_wakeup(struct sta_info *sta)
 		drv_sta_notify(local, sdata, STA_NOTIFY_AWAKE, &sta->sta);
 
 	if (sta->sta.txq[0]) {
+		bool wake = false;
+
 		for (i = 0; i < ARRAY_SIZE(sta->sta.txq); i++) {
 			if (!txq_has_queue(sta->sta.txq[i]))
 				continue;
 
-			drv_wake_tx_queue(local, to_txq_info(sta->sta.txq[i]));
+			if (ieee80211_schedule_txq(&local->hw, sta->sta.txq[i]))
+				wake = true;
 		}
+		if (wake)
+			drv_wake_tx_queue(local);
 	}
 
 	skb_queue_head_init(&pending);

net/mac80211/trace.h

@@ -2550,35 +2550,9 @@ TRACE_EVENT(drv_tdls_recv_channel_switch,
 	)
 );
 
-TRACE_EVENT(drv_wake_tx_queue,
-	TP_PROTO(struct ieee80211_local *local,
-		 struct ieee80211_sub_if_data *sdata,
-		 struct txq_info *txq),
-
-	TP_ARGS(local, sdata, txq),
-
-	TP_STRUCT__entry(
-		LOCAL_ENTRY
-		VIF_ENTRY
-		STA_ENTRY
-		__field(u8, ac)
-		__field(u8, tid)
-	),
-
-	TP_fast_assign(
-		struct ieee80211_sta *sta = txq->txq.sta;
-
-		LOCAL_ASSIGN;
-		VIF_ASSIGN;
-		STA_ASSIGN;
-		__entry->ac = txq->txq.ac;
-		__entry->tid = txq->txq.tid;
-	),
-
-	TP_printk(
-		LOCAL_PR_FMT  VIF_PR_FMT  STA_PR_FMT " ac:%d tid:%d",
-		LOCAL_PR_ARG, VIF_PR_ARG, STA_PR_ARG, __entry->ac, __entry->tid
-	)
+DEFINE_EVENT(local_only_evt, drv_wake_tx_queue,
+	     TP_PROTO(struct ieee80211_local *local),
+	     TP_ARGS(local)
 );
 
 #endif /* !__MAC80211_DRIVER_TRACE || TRACE_HEADER_MULTI_READ */

net/mac80211/tx.c

@@ -1439,6 +1439,7 @@ void ieee80211_txq_init(struct ieee80211_sub_if_data *sdata,
 	codel_vars_init(&txqi->def_cvars);
 	codel_stats_init(&txqi->cstats);
 	__skb_queue_head_init(&txqi->frags);
+	INIT_LIST_HEAD(&txqi->schedule_order);
 
 	txqi->txq.vif = &sdata->vif;
 
@@ -1462,6 +1463,7 @@ void ieee80211_txq_purge(struct ieee80211_local *local,
 
 	fq_tin_reset(fq, tin, fq_skb_free_func);
 	ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
+	list_del_init(&txqi->schedule_order);
 }
 
 int ieee80211_txq_setup_flows(struct ieee80211_local *local)
@@ -1558,7 +1560,8 @@ static bool ieee80211_queue_skb(struct ieee80211_local *local,
 	ieee80211_txq_enqueue(local, txqi, skb);
 	spin_unlock_bh(&fq->lock);
 
-	drv_wake_tx_queue(local, txqi);
+	if (ieee80211_schedule_txq(&local->hw, &txqi->txq))
+		drv_wake_tx_queue(local);
 
 	return true;
 }
@@ -3553,6 +3556,50 @@ out:
 }
 EXPORT_SYMBOL(ieee80211_tx_dequeue);
 
+bool ieee80211_schedule_txq(struct ieee80211_hw *hw,
+			    struct ieee80211_txq *txq)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct txq_info *txqi = to_txq_info(txq);
+	bool ret = false;
+
+	spin_lock_bh(&local->active_txq_lock);
+
+	if (list_empty(&txqi->schedule_order)) {
+		list_add_tail(&txqi->schedule_order, &local->active_txqs);
+		ret = true;
+	}
+
+	spin_unlock_bh(&local->active_txq_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(ieee80211_schedule_txq);
+
+struct ieee80211_txq *ieee80211_next_txq(struct ieee80211_hw *hw)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct txq_info *txqi = NULL;
+
+	spin_lock_bh(&local->active_txq_lock);
+
+	if (list_empty(&local->active_txqs))
+		goto out;
+
+	txqi = list_first_entry(&local->active_txqs,
+				struct txq_info, schedule_order);
+	list_del_init(&txqi->schedule_order);
+
+out:
+	spin_unlock_bh(&local->active_txq_lock);
+
+	if (!txqi)
+		return NULL;
+
+	return &txqi->txq;
+}
+EXPORT_SYMBOL(ieee80211_next_txq);
+
 void __ieee80211_subif_start_xmit(struct sk_buff *skb,
 				  struct net_device *dev,
 				  u32 info_flags)