From 20d498a3d24a4c20a421bc6bc19a058620aa86ec Mon Sep 17 00:00:00 2001
From: Peter Chiu <chui-hao.chiu@mediatek.com>
Date: Mon, 23 Oct 2023 10:26:01 +0800
Subject: [PATCH 2015/2015] Revert "wifi: mt76: fix race condition related to
 checking tx queue fill status"

This reverts commit f1e1e67d97d1e9a8bb01b59ab20c45ebc985a958.
---
 mac80211.c |  27 --------------
 mt76.h     |   5 ---
 tx.c       | 108 ++++++++++-------------------------------------------
 3 files changed, 20 insertions(+), 120 deletions(-)

diff --git a/mac80211.c b/mac80211.c
index 37e6a627..923c6a31 100644
--- a/mac80211.c
+++ b/mac80211.c
@@ -427,9 +427,6 @@ mt76_phy_init(struct mt76_phy *phy, struct ieee80211_hw *hw)
 	struct mt76_dev *dev = phy->dev;
 	struct wiphy *wiphy = hw->wiphy;
 
-	INIT_LIST_HEAD(&phy->tx_list);
-	spin_lock_init(&phy->tx_lock);
-
 	SET_IEEE80211_DEV(hw, dev->dev);
 	SET_IEEE80211_PERM_ADDR(hw, phy->macaddr);
 
@@ -662,7 +659,6 @@ int mt76_register_device(struct mt76_dev *dev, bool vht,
 	int ret;
 
 	dev_set_drvdata(dev->dev, dev);
-	mt76_wcid_init(&dev->global_wcid);
 	ret = mt76_phy_init(phy, hw);
 	if (ret)
 		return ret;
@@ -718,7 +714,6 @@ void mt76_unregister_device(struct mt76_dev *dev)
 	if (IS_ENABLED(CONFIG_MT76_LEDS))
 		mt76_led_cleanup(&dev->phy);
 	mt76_tx_status_check(dev, true);
-	mt76_wcid_cleanup(dev, &dev->global_wcid);
 	ieee80211_unregister_hw(hw);
 }
 EXPORT_SYMBOL_GPL(mt76_unregister_device);
@@ -1460,9 +1455,6 @@ EXPORT_SYMBOL_GPL(mt76_sta_pre_rcu_remove);
 
 void mt76_wcid_init(struct mt76_wcid *wcid)
 {
-	INIT_LIST_HEAD(&wcid->tx_list);
-	skb_queue_head_init(&wcid->tx_pending);
-
 	INIT_LIST_HEAD(&wcid->list);
 	idr_init(&wcid->pktid);
 }
@@ -1470,32 +1462,13 @@ EXPORT_SYMBOL_GPL(mt76_wcid_init);
 
 void mt76_wcid_cleanup(struct mt76_dev *dev, struct mt76_wcid *wcid)
 {
-	struct mt76_phy *phy = dev->phys[wcid->phy_idx];
-	struct ieee80211_hw *hw;
 	struct sk_buff_head list;
-	struct sk_buff *skb;
 
 	mt76_tx_status_lock(dev, &list);
 	mt76_tx_status_skb_get(dev, wcid, -1, &list);
 	mt76_tx_status_unlock(dev, &list);
 
 	idr_destroy(&wcid->pktid);
-
-	spin_lock_bh(&phy->tx_lock);
-
-	if (!list_empty(&wcid->tx_list))
-		list_del_init(&wcid->tx_list);
-
-	spin_lock(&wcid->tx_pending.lock);
-	skb_queue_splice_tail_init(&wcid->tx_pending, &list);
-	spin_unlock(&wcid->tx_pending.lock);
-
-	spin_unlock_bh(&phy->tx_lock);
-
-	while ((skb = __skb_dequeue(&list)) != NULL) {
-		hw = mt76_tx_status_get_hw(dev, skb);
-		ieee80211_free_txskb(hw, skb);
-	}
 }
 EXPORT_SYMBOL_GPL(mt76_wcid_cleanup);
 
diff --git a/mt76.h b/mt76.h
index 3ff348f2..5eb571ef 100644
--- a/mt76.h
+++ b/mt76.h
@@ -354,9 +354,6 @@ struct mt76_wcid {
 	u32 tx_info;
 	bool sw_iv;
 
-	struct list_head tx_list;
-	struct sk_buff_head tx_pending;
-
 	struct list_head list;
 	struct idr pktid;
 
@@ -808,8 +805,6 @@ struct mt76_phy {
 	unsigned long state;
 	u8 band_idx;
 
-	spinlock_t tx_lock;
-	struct list_head tx_list;
 	struct mt76_queue *q_tx[__MT_TXQ_MAX];
 
 	struct cfg80211_chan_def chandef;
diff --git a/tx.c b/tx.c
index 23a1e4e2..9dfc2890 100644
--- a/tx.c
+++ b/tx.c
@@ -322,32 +322,40 @@ void
 mt76_tx(struct mt76_phy *phy, struct ieee80211_sta *sta,
 	struct mt76_wcid *wcid, struct sk_buff *skb)
 {
+	struct mt76_dev *dev = phy->dev;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+	struct mt76_queue *q;
+	int qid = skb_get_queue_mapping(skb);
 
 	if (mt76_testmode_enabled(phy)) {
 		ieee80211_free_txskb(phy->hw, skb);
 		return;
 	}
 
-	if (WARN_ON(skb_get_queue_mapping(skb) >= MT_TXQ_PSD))
-		skb_set_queue_mapping(skb, MT_TXQ_BE);
+	if (WARN_ON(qid >= MT_TXQ_PSD)) {
+		qid = MT_TXQ_BE;
+		skb_set_queue_mapping(skb, qid);
+	}
+
+	if ((dev->drv->drv_flags & MT_DRV_HW_MGMT_TXQ) &&
+	    !(info->flags & IEEE80211_TX_CTL_HW_80211_ENCAP) &&
+	    !ieee80211_is_data(hdr->frame_control) &&
+	    !ieee80211_is_bufferable_mmpdu(skb)) {
+		qid = MT_TXQ_PSD;
+	}
 
 	if (wcid && !(wcid->tx_info & MT_WCID_TX_INFO_SET))
 		ieee80211_get_tx_rates(info->control.vif, sta, skb,
 				       info->control.rates, 1);
 
 	info->hw_queue |= FIELD_PREP(MT_TX_HW_QUEUE_PHY, phy->band_idx);
+	q = phy->q_tx[qid];
 
-	spin_lock_bh(&wcid->tx_pending.lock);
-	__skb_queue_tail(&wcid->tx_pending, skb);
-	spin_unlock_bh(&wcid->tx_pending.lock);
-
-	spin_lock_bh(&phy->tx_lock);
-	if (list_empty(&wcid->tx_list))
-		list_add_tail(&wcid->tx_list, &phy->tx_list);
-	spin_unlock_bh(&phy->tx_lock);
-
-	mt76_worker_schedule(&phy->dev->tx_worker);
+	spin_lock_bh(&q->lock);
+	__mt76_tx_queue_skb(phy, qid, skb, wcid, sta, NULL);
+	dev->queue_ops->kick(dev, q);
+	spin_unlock_bh(&q->lock);
 }
 EXPORT_SYMBOL_GPL(mt76_tx);
 
@@ -578,86 +586,10 @@ void mt76_txq_schedule(struct mt76_phy *phy, enum mt76_txq_id qid)
 }
 EXPORT_SYMBOL_GPL(mt76_txq_schedule);
 
-static int
-mt76_txq_schedule_pending_wcid(struct mt76_phy *phy, struct mt76_wcid *wcid)
-{
-	struct mt76_dev *dev = phy->dev;
-	struct ieee80211_sta *sta;
-	struct mt76_queue *q;
-	struct sk_buff *skb;
-	int ret = 0;
-
-	spin_lock(&wcid->tx_pending.lock);
-	while ((skb = skb_peek(&wcid->tx_pending)) != NULL) {
-		struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
-		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-		int qid = skb_get_queue_mapping(skb);
-
-		if ((dev->drv->drv_flags & MT_DRV_HW_MGMT_TXQ) &&
-		    !(info->flags & IEEE80211_TX_CTL_HW_80211_ENCAP) &&
-		    !ieee80211_is_data(hdr->frame_control) &&
-		    !ieee80211_is_bufferable_mmpdu(skb))
-			qid = MT_TXQ_PSD;
-
-		q = phy->q_tx[qid];
-		if (mt76_txq_stopped(q)) {
-			ret = -1;
-			break;
-		}
-
-		__skb_unlink(skb, &wcid->tx_pending);
-		spin_unlock(&wcid->tx_pending.lock);
-
-		sta = wcid_to_sta(wcid);
-		spin_lock(&q->lock);
-		__mt76_tx_queue_skb(phy, qid, skb, wcid, sta, NULL);
-		dev->queue_ops->kick(dev, q);
-		spin_unlock(&q->lock);
-
-		spin_lock(&wcid->tx_pending.lock);
-	}
-	spin_unlock(&wcid->tx_pending.lock);
-
-	return ret;
-}
-
-static void mt76_txq_schedule_pending(struct mt76_phy *phy)
-{
-	if (list_empty(&phy->tx_list))
-		return;
-
-	local_bh_disable();
-	rcu_read_lock();
-
-	spin_lock(&phy->tx_lock);
-	while (!list_empty(&phy->tx_list)) {
-		struct mt76_wcid *wcid = NULL;
-		int ret;
-
-		wcid = list_first_entry(&phy->tx_list, struct mt76_wcid, tx_list);
-		list_del_init(&wcid->tx_list);
-
-		spin_unlock(&phy->tx_lock);
-		ret = mt76_txq_schedule_pending_wcid(phy, wcid);
-		spin_lock(&phy->tx_lock);
-
-		if (ret) {
-			if (list_empty(&wcid->tx_list))
-				list_add_tail(&wcid->tx_list, &phy->tx_list);
-			break;
-		}
-	}
-	spin_unlock(&phy->tx_lock);
-
-	rcu_read_unlock();
-	local_bh_enable();
-}
-
 void mt76_txq_schedule_all(struct mt76_phy *phy)
 {
 	int i;
 
-	mt76_txq_schedule_pending(phy);
 	for (i = 0; i <= MT_TXQ_BK; i++)
 		mt76_txq_schedule(phy, i);
 }
-- 
2.18.0