ath10k: Fix tx hanging

While running stress tests in roaming scenarios (switching ap's every 5
seconds, we discovered a issue which leads to tx hangings of exactly 5
seconds while or after scanning for new accesspoints. We found out that
this hanging is triggered by ath10k_mac_wait_tx_complete since the
empty_tx_wq was not wake when the num_tx_pending counter reaches zero.
To fix this, we simply move the wake_up call to htt_tx_dec_pending,
since this call was missed on several locations within the ath10k code.
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20210505085806.11474-1-s.gottschall@dd-wrt.com

drivers/net/wireless/ath/ath10k/htt_tx.c

@@ -147,6 +147,9 @@ void ath10k_htt_tx_dec_pending(struct ath10k_htt *htt)
 	htt->num_pending_tx--;
 	if (htt->num_pending_tx == htt->max_num_pending_tx - 1)
 		ath10k_mac_tx_unlock(htt->ar, ATH10K_TX_PAUSE_Q_FULL);
+
+	if (htt->num_pending_tx == 0)
+		wake_up(&htt->empty_tx_wq);
 }
 
 int ath10k_htt_tx_inc_pending(struct ath10k_htt *htt)

drivers/net/wireless/ath/ath10k/txrx.c

@@ -82,8 +82,6 @@ int ath10k_txrx_tx_unref(struct ath10k_htt *htt,
 	flags = skb_cb->flags;
 	ath10k_htt_tx_free_msdu_id(htt, tx_done->msdu_id);
 	ath10k_htt_tx_dec_pending(htt);
-	if (htt->num_pending_tx == 0)
-		wake_up(&htt->empty_tx_wq);
 	spin_unlock_bh(&htt->tx_lock);
 
 	rcu_read_lock();