mt76: schedule status timeout at dma completion

Reduce MT_TX_STATUS_SKB_TIMEOUT to 250ms

Tested-by: mrkiko.rs@gmail.com
Co-developed-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -308,8 +308,13 @@ struct mt76_rx_tid {
 #define MT_PACKET_ID_NO_SKB		1
 #define MT_PACKET_ID_FIRST		2
 #define MT_PACKET_ID_HAS_RATE		BIT(7)
-
-#define MT_TX_STATUS_SKB_TIMEOUT	HZ
+/* This is timer for when to give up when waiting for TXS callback,
+ * with starting time being the time at which the DMA_DONE callback
+ * was seen (so, we know packet was processed then, it should not take
+ * long after that for firmware to send the TXS callback if it is going
+ * to do so.)
+ */
+#define MT_TX_STATUS_SKB_TIMEOUT	(HZ / 4)
 
 struct mt76_tx_cb {
 	unsigned long jiffies;

drivers/net/wireless/mediatek/mt76/tx.c

@@ -141,7 +141,6 @@ mt76_tx_status_skb_add(struct mt76_dev *dev, struct mt76_wcid *wcid,
 
 	cb->wcid = wcid->idx;
 	cb->pktid = pid;
-	cb->jiffies = jiffies;
 
 	if (list_empty(&wcid->list))
 		list_add_tail(&wcid->list, &dev->wcid_list);
@@ -179,6 +178,9 @@ mt76_tx_status_skb_get(struct mt76_dev *dev, struct mt76_wcid *wcid, int pktid,
 				continue;
 		}
 
+		/* It has been too long since DMA_DONE, time out this packet
+		 * and stop waiting for TXS callback.
+		 */
 		idr_remove(&wcid->pktid, cb->pktid);
 		__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_TXS_FAILED |
 						    MT_TX_CB_TXS_DONE, list);
@@ -261,6 +263,7 @@ void __mt76_tx_complete_skb(struct mt76_dev *dev, u16 wcid_idx, struct sk_buff *
 	}
 
 	mt76_tx_status_lock(dev, &list);
+	cb->jiffies = jiffies;
 	__mt76_tx_status_skb_done(dev, skb, MT_TX_CB_DMA_DONE, &list);
 	mt76_tx_status_unlock(dev, &list);