mt76: dma: update q->queued immediately on cleanup

With threaded NAPI support it becomes more likely that tx cleanup and tx
enqueuing will run in parallel. In order to avoid queue starvation issues
under load, update q->queued immediately.

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

dma.c

@@ -153,10 +153,8 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush)
 	struct mt76_sw_queue *sq = &dev->q_tx[qid];
 	struct mt76_queue *q = sq->q;
 	struct mt76_queue_entry entry;
-	unsigned int n_swq_queued[8] = {};
-	unsigned int n_queued = 0;
 	bool wake = false;
-	int i, last;
+	int last;
 
 	if (!q)
 		return;
@@ -166,13 +164,14 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush)
 	else
 		last = readl(&q->regs->dma_idx);
 
-	while ((q->queued > n_queued) && q->tail != last) {
+	while (q->queued > 0 && q->tail != last) {
+		int swq_qid = -1;
+
 		mt76_dma_tx_cleanup_idx(dev, q, q->tail, &entry);
 		if (entry.schedule)
-			n_swq_queued[entry.qid]++;
+			swq_qid = entry.qid;
 
 		q->tail = (q->tail + 1) % q->ndesc;
-		n_queued++;
 
 		if (entry.skb)
 			dev->drv->tx_complete_skb(dev, qid, &entry);
@@ -185,29 +184,21 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush)
 
 		if (!flush && q->tail == last)
 			last = readl(&q->regs->dma_idx);
-	}
-
-	spin_lock_bh(&q->lock);
-
-	q->queued -= n_queued;
-	for (i = 0; i < 4; i++) {
-		if (!n_swq_queued[i])
-			continue;
 
-		dev->q_tx[i].swq_queued -= n_swq_queued[i];
-	}
-
-	/* ext PHY */
-	for (i = 0; i < 4; i++) {
-		if (!n_swq_queued[i])
-			continue;
-
-		dev->q_tx[__MT_TXQ_MAX + i].swq_queued -= n_swq_queued[4 + i];
+		spin_lock_bh(&q->lock);
+		if (swq_qid >= 4)
+			dev->q_tx[__MT_TXQ_MAX + swq_qid - 4].swq_queued--;
+		else if (swq_qid >= 0)
+			dev->q_tx[swq_qid].swq_queued--;
+		q->queued--;
+		spin_unlock_bh(&q->lock);
 	}
 
 	if (flush) {
+		spin_lock_bh(&q->lock);
 		mt76_dma_sync_idx(dev, q);
 		mt76_dma_kick_queue(dev, q);
+		spin_unlock_bh(&q->lock);
 	}
 
 	wake = wake && q->stopped &&
@@ -218,8 +209,6 @@ mt76_dma_tx_cleanup(struct mt76_dev *dev, enum mt76_txq_id qid, bool flush)
 	if (!q->queued)
 		wake_up(&dev->tx_wait);
 
-	spin_unlock_bh(&q->lock);
-
 	if (wake)
 		ieee80211_wake_queue(dev->hw, qid);
 }