[PATCH] mt76: usb: avoid queue/status spinlocks while passing tx status to mac80211

[PATCH] mt76: usb: avoid queue/status spinlocks while passing tx status to mac80211

[Lorenzo Bianconi]

As already done for pcie code in commit 79d1c94c9c78 ("mt76: avoid
queue/status spinlocks while passing tx status to mac80211") make sure
that no tx related spinlocks are taken during the ieee80211_tx_status call

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
---
 drivers/net/wireless/mediatek/mt76/usb.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index 14ff06c5764e..6a2507524c6c 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -583,6 +583,7 @@ static void mt76u_stop_rx(struct mt76_dev *dev)
 static void mt76u_tx_tasklet(unsigned long data)
 {
 	struct mt76_dev *dev = (struct mt76_dev *)data;
+	struct mt76_queue_entry entry;
 	struct mt76u_buf *buf;
 	struct mt76_queue *q;
 	bool wake;
@@ -597,17 +598,18 @@ static void mt76u_tx_tasklet(unsigned long data)
 			if (!buf->done || !q->queued)
 				break;
 
-			dev->drv->tx_complete_skb(dev, q,
-						  &q->entry[q->head],
-						  false);
-
 			if (q->entry[q->head].schedule) {
 				q->entry[q->head].schedule = false;
 				q->swq_queued--;
 			}
 
+			entry = q->entry[q->head];
 			q->head = (q->head + 1) % q->ndesc;
 			q->queued--;
+
+			spin_unlock_bh(&q->lock);
+			dev->drv->tx_complete_skb(dev, q, &entry, false);
+			spin_lock_bh(&q->lock);
 		}
 		mt76_txq_schedule(dev, q);
 		wake = i < IEEE80211_NUM_ACS && q->queued < q->ndesc - 8;
-- 
2.19.2

Re: [PATCH] mt76: usb: avoid queue/status spinlocks while passing tx status to mac80211

[Felix Fietkau]

On 2018-12-06 19:11, Lorenzo Bianconi wrote:
> As already done for pcie code in commit 79d1c94c9c78 ("mt76: avoid
> queue/status spinlocks while passing tx status to mac80211") make sure
> that no tx related spinlocks are taken during the ieee80211_tx_status call
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

Applied, thanks.

- Felix