From fc412aab0d34534ec318b6904bb63cd75487b708 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Thu, 3 Mar 2016 21:40:11 +0100
Subject: [PATCH] mt7603: use a skb queue for status queueing

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 mt7603.h      | 22 +++++-----------------
 mt7603_init.c |  2 +-
 mt7603_mac.c  | 32 +++++++++++++++-----------------
 3 files changed, 21 insertions(+), 35 deletions(-)

diff --git a/mt7603.h b/mt7603.h
index 3fd44f82..e8549280 100644
--- a/mt7603.h
+++ b/mt7603.h
@@ -85,7 +85,6 @@ struct mt7603_vif {
 #define MT7603_CB_TXS_FAILED	BIT(2)
 
 struct mt7603_cb {
-	struct list_head list;
 	u8 wcid;
 	u8 pktid;
 	u8 flags;
@@ -107,7 +106,7 @@ struct mt7603_dev {
 	struct mt76_wcid __rcu *wcid[MT7603_WTBL_SIZE];
 
 	spinlock_t status_lock;
-	struct list_head status_list;
+	struct sk_buff_head status_list;
 
 	struct mt7603_sta global_sta;
 
@@ -159,24 +158,13 @@ static inline bool is_mt7628(struct mt7603_dev *dev)
 
 static inline struct mt7603_cb *mt7603_skb_cb(struct sk_buff *skb)
 {
-	return ((void *) IEEE80211_SKB_CB(skb)->rate_driver_data) +
-	       MT_RATE_DRIVER_DATA_OFFSET;
-}
-
-static inline struct sk_buff *mt7603_cb_skb(struct mt7603_cb *cb)
-{
-	struct ieee80211_tx_info *info;
-	void *ptr = cb;
-
 	BUILD_BUG_ON(offsetof(struct ieee80211_tx_info, status.ampdu_len) >=
 		     (offsetof(struct ieee80211_tx_info, rate_driver_data) +
 		      MT_RATE_DRIVER_DATA_OFFSET));
-	BUILD_BUG_ON(sizeof(*cb) + MT_RATE_DRIVER_DATA_OFFSET >
-		     sizeof(info->rate_driver_data));
-	info = container_of(ptr - MT_RATE_DRIVER_DATA_OFFSET,
-			    struct ieee80211_tx_info, rate_driver_data);
-	ptr = info;
-	return container_of(ptr, struct sk_buff, cb);
+	BUILD_BUG_ON(sizeof(struct mt7603_cb) + MT_RATE_DRIVER_DATA_OFFSET >
+		     IEEE80211_TX_INFO_RATE_DRIVER_DATA_SIZE);
+	return ((void *) IEEE80211_SKB_CB(skb)->rate_driver_data) +
+	       MT_RATE_DRIVER_DATA_OFFSET;
 }
 
 u32 mt7603_reg_map(struct mt7603_dev *dev, u32 addr);
diff --git a/mt7603_init.c b/mt7603_init.c
index 3d986925..9a44d7e4 100644
--- a/mt7603_init.c
+++ b/mt7603_init.c
@@ -342,7 +342,7 @@ int mt7603_register_device(struct mt7603_dev *dev)
 
 	mutex_init(&dev->mutex);
 	spin_lock_init(&dev->status_lock);
-	INIT_LIST_HEAD(&dev->status_list);
+	__skb_queue_head_init(&dev->status_list);
 
 	INIT_DELAYED_WORK(&dev->mac_work, mt7603_mac_work);
 	tasklet_init(&dev->pre_tbtt_tasklet, mt7603_pre_tbtt_tasklet, (unsigned long) dev);
diff --git a/mt7603_mac.c b/mt7603_mac.c
index de8ff372..8c52ac13 100644
--- a/mt7603_mac.c
+++ b/mt7603_mac.c
@@ -703,11 +703,12 @@ int mt7603_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 		pid = msta->pid;
 		cb->wcid = wcid->idx;
 		cb->pktid = pid;
-		list_add_tail(&cb->list, &dev->status_list);
+
+		__skb_queue_tail(&dev->status_list, skb);
 
 		spin_unlock_bh(&dev->status_lock);
 	} else {
-		INIT_LIST_HEAD(&cb->list);
+		skb->next = skb->prev = NULL;
 	}
 
 	mt7603_mac_write_txwi(dev, txwi_ptr, skb, q, wcid, sta, pid, key);
@@ -793,25 +794,22 @@ mt7603_skb_done(struct mt7603_dev *dev, struct sk_buff *skb, u8 flags)
 struct sk_buff *
 mt7603_mac_status_skb(struct mt7603_dev *dev, struct mt7603_sta *sta, int pktid)
 {
-	struct mt7603_cb *cb, *tmp;
-	struct sk_buff *skb = NULL;
+	struct sk_buff *skb, *tmp;
 
-	list_for_each_entry_safe(cb, tmp, &dev->status_list, list) {
+	skb_queue_walk_safe(&dev->status_list, skb, tmp) {
+		struct mt7603_cb *cb = mt7603_skb_cb(skb);
 		if (sta && cb->wcid != sta->wcid.idx)
 			continue;
 
-		list_del_init(&cb->list);
-		skb = mt7603_cb_skb(cb);
-
+		__skb_unlink(skb, &dev->status_list);
 		if (cb->pktid == pktid)
-			break;
+			return skb;
 
 		mt7603_skb_done(dev, skb,
 				MT7603_CB_TXS_FAILED | MT7603_CB_TXS_DONE);
-		skb = NULL;
 	}
 
-	return skb;
+	return NULL;
 }
 
 static bool
@@ -886,28 +884,28 @@ void mt7603_tx_complete_skb(struct mt76_dev *mdev, struct mt76_queue *q,
 			    struct mt76_queue_entry *e, bool flush)
 {
 	struct mt7603_dev *dev = container_of(mdev, struct mt7603_dev, mt76);
-	struct mt7603_cb *cb = mt7603_skb_cb(e->skb);
+	struct sk_buff *skb = e->skb;
 	bool free = true;
 
 	if (!e->txwi) {
-		dev_kfree_skb_any(e->skb);
+		dev_kfree_skb_any(skb);
 		return;
 	}
 
 	/* will be freed by tx status handling codepath */
-	if (!list_empty(&cb->list)) {
+	if (skb->prev) {
 		spin_lock_bh(&dev->status_lock);
 		if (!flush) {
-			mt7603_skb_done(dev, e->skb, MT7603_CB_DMA_DONE);
+			mt7603_skb_done(dev, skb, MT7603_CB_DMA_DONE);
 			free = false;
 		} else {
-			list_del_init(&cb->list);
+			__skb_unlink(skb, &dev->status_list);
 		}
 		spin_unlock_bh(&dev->status_lock);
 	}
 
 	if (free)
-		ieee80211_free_txskb(mdev->hw, e->skb);
+		ieee80211_free_txskb(mdev->hw, skb);
 }
 
 static bool