From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 9 Feb 2024 19:43:40 +0100
Subject: [PATCH] mac80211: add AQL support for broadcast packets

Excessive broadcast traffic with little competing unicast traffic can easily
flood hardware queues, leading to throughput issues. Additionally, filling
the hardware queues with too many packets breaks FQ for broadcast data.
Fix this by enabling AQL for broadcast packets.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -3437,6 +3437,7 @@ enum wiphy_params_flags {
 /* The per TXQ device queue limit in airtime */
 #define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_L	5000
 #define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_H	12000
+#define IEEE80211_DEFAULT_AQL_TXQ_LIMIT_BC	50000
 
 /* The per interface airtime threshold to switch to lower queue limit */
 #define IEEE80211_AQL_THRESHOLD			24000
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -215,11 +215,13 @@ static ssize_t aql_pending_read(struct f
 			"VI     %u us\n"
 			"BE     %u us\n"
 			"BK     %u us\n"
+			"BC/MC  %u us\n"
 			"total  %u us\n",
 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_VO]),
 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_VI]),
 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_BE]),
 			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_BK]),
+			atomic_read(&local->aql_bc_pending_airtime),
 			atomic_read(&local->aql_total_pending_airtime));
 	return simple_read_from_buffer(user_buf, count, ppos,
 				       buf, len);
@@ -245,7 +247,8 @@ static ssize_t aql_txq_limit_read(struct
 			"VO	%u		%u\n"
 			"VI	%u		%u\n"
 			"BE	%u		%u\n"
-			"BK	%u		%u\n",
+			"BK	%u		%u\n"
+			"BC/MC	%u\n",
 			local->aql_txq_limit_low[IEEE80211_AC_VO],
 			local->aql_txq_limit_high[IEEE80211_AC_VO],
 			local->aql_txq_limit_low[IEEE80211_AC_VI],
@@ -253,7 +256,8 @@ static ssize_t aql_txq_limit_read(struct
 			local->aql_txq_limit_low[IEEE80211_AC_BE],
 			local->aql_txq_limit_high[IEEE80211_AC_BE],
 			local->aql_txq_limit_low[IEEE80211_AC_BK],
-			local->aql_txq_limit_high[IEEE80211_AC_BK]);
+			local->aql_txq_limit_high[IEEE80211_AC_BK],
+			local->aql_txq_limit_bc);
 	return simple_read_from_buffer(user_buf, count, ppos,
 				       buf, len);
 }
@@ -279,6 +283,11 @@ static ssize_t aql_txq_limit_write(struc
 	else
 		buf[count] = '\0';
 
+	if (sscanf(buf, "mcast %u", &q_limit_low) == 1) {
+		local->aql_txq_limit_bc = q_limit_low;
+		return count;
+	}
+
 	if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3)
 		return -EINVAL;
 
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1377,10 +1377,12 @@ struct ieee80211_local {
 	spinlock_t handle_wake_tx_queue_lock;
 
 	u16 airtime_flags;
+	u32 aql_txq_limit_bc;
 	u32 aql_txq_limit_low[IEEE80211_NUM_ACS];
 	u32 aql_txq_limit_high[IEEE80211_NUM_ACS];
 	u32 aql_threshold;
 	atomic_t aql_total_pending_airtime;
+	atomic_t aql_bc_pending_airtime;
 	atomic_t aql_ac_pending_airtime[IEEE80211_NUM_ACS];
 
 	const struct ieee80211_ops *ops;
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -959,6 +959,7 @@ struct ieee80211_hw *ieee80211_alloc_hw_
 	spin_lock_init(&local->rx_path_lock);
 	spin_lock_init(&local->queue_stop_reason_lock);
 
+	local->aql_txq_limit_bc = IEEE80211_DEFAULT_AQL_TXQ_LIMIT_BC;
 	for (i = 0; i < IEEE80211_NUM_ACS; i++) {
 		INIT_LIST_HEAD(&local->active_txqs[i]);
 		spin_lock_init(&local->active_txq_lock[i]);
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -2382,13 +2382,28 @@ EXPORT_SYMBOL(ieee80211_sta_recalc_aggre
 
 void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local,
 					  struct sta_info *sta, u8 ac,
-					  u16 tx_airtime, bool tx_completed)
+					  u16 tx_airtime, bool tx_completed,
+					  bool mcast)
 {
 	int tx_pending;
 
 	if (!wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL))
 		return;
 
+	if (mcast) {
+		if (!tx_completed) {
+			atomic_add(tx_airtime, &local->aql_bc_pending_airtime);
+			return;
+		}
+
+		tx_pending = atomic_sub_return(tx_airtime,
+					       &local->aql_bc_pending_airtime);
+		if (tx_pending < 0)
+			atomic_cmpxchg(&local->aql_bc_pending_airtime,
+				       tx_pending, 0);
+		return;
+	}
+
 	if (!tx_completed) {
 		if (sta)
 			atomic_add(tx_airtime,
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2539,7 +2539,7 @@ static u16 ieee80211_store_ack_skb(struc
 
 		spin_lock_irqsave(&local->ack_status_lock, flags);
 		id = idr_alloc(&local->ack_status_frames, ack_skb,
-			       1, 0x2000, GFP_ATOMIC);
+			       1, 0x1000, GFP_ATOMIC);
 		spin_unlock_irqrestore(&local->ack_status_lock, flags);
 
 		if (id >= 0) {
@@ -3967,20 +3967,20 @@ begin:
 encap_out:
 	info->control.vif = vif;
 
-	if (tx.sta &&
-	    wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
-		bool ampdu = txq->ac != IEEE80211_AC_VO;
+	if (wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
+		bool ampdu = txq->sta && txq->ac != IEEE80211_AC_VO;
 		u32 airtime;
 
 		airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
 							     skb->len, ampdu);
-		if (airtime) {
-			airtime = ieee80211_info_set_tx_time_est(info, airtime);
-			ieee80211_sta_update_pending_airtime(local, tx.sta,
-							     txq->ac,
-							     airtime,
-							     false);
-		}
+		if (!airtime)
+			return skb;
+
+		airtime = ieee80211_info_set_tx_time_est(info, airtime);
+		info->tx_time_mc = !tx.sta;
+		ieee80211_sta_update_pending_airtime(local, tx.sta, txq->ac,
+						     airtime, false,
+						     info->tx_time_mc);
 	}
 
 	return skb;
@@ -4032,6 +4032,7 @@ struct ieee80211_txq *ieee80211_next_txq
 	struct ieee80211_txq *ret = NULL;
 	struct txq_info *txqi = NULL, *head = NULL;
 	bool found_eligible_txq = false;
+	bool aql_check;
 
 	spin_lock_bh(&local->active_txq_lock[ac]);
 
@@ -4055,26 +4056,26 @@ struct ieee80211_txq *ieee80211_next_txq
 	if (!head)
 		head = txqi;
 
+	aql_check = ieee80211_txq_airtime_check(hw, &txqi->txq);
+	if (aql_check)
+		found_eligible_txq = true;
+
 	if (txqi->txq.sta) {
 		struct sta_info *sta = container_of(txqi->txq.sta,
 						    struct sta_info, sta);
-		bool aql_check = ieee80211_txq_airtime_check(hw, &txqi->txq);
-		s32 deficit = ieee80211_sta_deficit(sta, txqi->txq.ac);
-
-		if (aql_check)
-			found_eligible_txq = true;
-
-		if (deficit < 0)
+		if (ieee80211_sta_deficit(sta, txqi->txq.ac) < 0) {
 			sta->airtime[txqi->txq.ac].deficit +=
 				sta->airtime_weight << AIRTIME_QUANTUM_SHIFT;
-
-		if (deficit < 0 || !aql_check) {
-			list_move_tail(&txqi->schedule_order,
-				       &local->active_txqs[txqi->txq.ac]);
-			goto begin;
+			aql_check = false;
 		}
 	}
 
+	if (!aql_check) {
+		list_move_tail(&txqi->schedule_order,
+				   &local->active_txqs[txqi->txq.ac]);
+		goto begin;
+	}
+
 	if (txqi->schedule_round == local->schedule_round[ac])
 		goto out;
 
@@ -4139,7 +4140,8 @@ bool ieee80211_txq_airtime_check(struct
 		return true;
 
 	if (!txq->sta)
-		return true;
+		return atomic_read(&local->aql_bc_pending_airtime) <
+		       local->aql_txq_limit_bc;
 
 	if (unlikely(txq->tid == IEEE80211_NUM_TIDS))
 		return true;
@@ -4188,15 +4190,15 @@ bool ieee80211_txq_may_transmit(struct i
 
 	spin_lock_bh(&local->active_txq_lock[ac]);
 
-	if (!txqi->txq.sta)
-		goto out;
-
 	if (list_empty(&txqi->schedule_order))
 		goto out;
 
 	if (!ieee80211_txq_schedule_airtime_check(local, ac))
 		goto out;
 
+	if (!txqi->txq.sta)
+		goto out;
+
 	list_for_each_entry_safe(iter, tmp, &local->active_txqs[ac],
 				 schedule_order) {
 		if (iter == txqi)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1245,8 +1245,8 @@ struct ieee80211_tx_info {
 	    status_data_idr:1,
 	    status_data:13,
 	    hw_queue:4,
+	    tx_time_mc:1,
 	    tx_time_est:10;
-	/* 1 free bit */
 
 	union {
 		struct {
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -147,7 +147,8 @@ struct airtime_info {
 
 void ieee80211_sta_update_pending_airtime(struct ieee80211_local *local,
 					  struct sta_info *sta, u8 ac,
-					  u16 tx_airtime, bool tx_completed);
+					  u16 tx_airtime, bool tx_completed,
+					  bool mcast);
 
 struct sta_info;
 
--- a/net/mac80211/status.c
+++ b/net/mac80211/status.c
@@ -734,7 +734,7 @@ static void ieee80211_report_used_skb(st
 		ieee80211_sta_update_pending_airtime(local, sta,
 						     skb_get_queue_mapping(skb),
 						     tx_time_est,
-						     true);
+						     true, info->tx_time_mc);
 		rcu_read_unlock();
 	}
 
@@ -1143,10 +1143,11 @@ void ieee80211_tx_status_ext(struct ieee
 		/* Do this here to avoid the expensive lookup of the sta
 		 * in ieee80211_report_used_skb().
 		 */
+		bool mcast = IEEE80211_SKB_CB(skb)->tx_time_mc;
 		ieee80211_sta_update_pending_airtime(local, sta,
 						     skb_get_queue_mapping(skb),
 						     tx_time_est,
-						     true);
+						     true, mcast);
 		ieee80211_info_set_tx_time_est(IEEE80211_SKB_CB(skb), 0);
 	}
 
