[PATCH 5.4 180/320] ath10k: Fix tx hanging

Greg Kroah-Hartman
2022-01-25T03:23:55Z

From: Sebastian Gottschall <s.gottschall@dd-wrt.com>

[ Upstream commit e8a91863eba3966a447d2daa1526082d52b5db2a ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/ath/ath10k/htt_tx.c | 3 +++
drivers/net/wireless/ath/ath10k/txrx.c | 2 --
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c
index c38e1963ebc05..f73ed1044390c 100644
--- a/drivers/net/wireless/ath/ath10k/htt_tx.c
+++ b/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)
diff --git a/drivers/net/wireless/ath/ath10k/txrx.c b/drivers/net/wireless/ath/ath10k/txrx.c
index f46b9083bbf10..2c254f43790d2 100644
--- a/drivers/net/wireless/ath/ath10k/txrx.c
+++ b/drivers/net/wireless/ath/ath10k/txrx.c
@@ -80,8 +80,6 @@ int ath10k_txrx_tx_unref(struct ath10k_htt *htt,

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();
--
2.34.1