[PATCH ath-next] wifi: ath9k_htc: count a frame as queued before it is sent

[Mehmet Fide <mehmet.fide@gmail.com>]

From: Mehmet Fide <mehmet.fide@screeningeagle.com>

ath9k_htc_tx() hands the frame to the device and counts it in
tx.queued_cnt afterwards. The TX status of the frame is handled in the
WMI event tasklet, which can run before the sender gets to the counter.
ath9k_htc_tx_process() then takes the counter below zero, warns and
sets it to zero, and the sender's increment leaves it one too high for
good:

WARNING: CPU: 0 PID: 348 at drivers/net/wireless/ath/ath9k/htc_drv_txrx.c:510 ath9k_htc_tx_process+0x400/0x558 [ath9k_htc]
Call trace:
 ath9k_htc_tx_process+0x400/0x558 [ath9k_htc]
 ath9k_htc_txstatus+0x58/0x140 [ath9k_htc]
 ath9k_wmi_event_tasklet+0x16c/0x17c [ath9k_htc]
 tasklet_action_common+0x108/0x150

Count the frame before it is sent and take it back if the send fails.

Fixes: 8e86a54715c4 ("ath9k_htc: Fix TX queue management")
Signed-off-by: Mehmet Fide <mehmet.fide@screeningeagle.com>
---
 drivers/net/wireless/ath/ath9k/htc_drv_main.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_main.c b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
index 0d6272ac0dac..ee87352d1241 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_main.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_main.c
@@ -888,17 +888,21 @@ static void ath9k_htc_tx(struct ieee80211_hw *hw,
 		goto fail_tx;
 	}
 
+	ath9k_htc_check_stop_queues(priv);
+
 	ret = ath9k_htc_tx_start(priv, control->sta, skb, slot, false);
 	if (ret != 0) {
 		ath_dbg(common, XMIT, "Tx failed\n");
 		goto clear_slot;
 	}
 
-	ath9k_htc_check_stop_queues(priv);
-
 	return;
 
 clear_slot:
+	spin_lock_bh(&priv->tx.tx_lock);
+	priv->tx.queued_cnt--;
+	spin_unlock_bh(&priv->tx.tx_lock);
+	ath9k_htc_check_wake_queues(priv);
 	ath9k_htc_tx_clear_slot(priv, slot);
 fail_tx:
 	dev_kfree_skb_any(skb);

base-commit: ff4c7359e310744a7abe53cf66d921fa2969eb19
-- 
2.56.0