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[PATCH] ath11k: Increment pending_mgmt_tx count before tx send invoke

From: P Praneesh <hidden>
Date: 2021-10-25 12:21:20
Also in: ath11k
Subsystem: atheros ath generic utilities, qualcomm atheros ath11k wireless driver, the rest · Maintainers: Jeff Johnson, Linus Torvalds

From: P Praneesh <redacted>

There is a race condition whereby the tx completion handler can be invoked
before the 'num_pending_mgmt_tx" count is incremented. If that occurs, we
could get warning trace indicating that 'num_pending_mgmt_tx' is 0 (because
it was not yet incremented). Ideally, this trace should be seen only if
mgmt tx has not happened but tx completion is received, and it is not
expected in this race condition.

Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.4.0.1-01386-QCAHKSWPL_SILICONZ-1

Co-developed-by: Lavanya Suresh <redacted>
Signed-off-by: Lavanya Suresh <redacted>
Signed-off-by: P Praneesh <redacted>
---
 drivers/net/wireless/ath/ath11k/mac.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 1cc5560..56f3208 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -5048,13 +5048,15 @@ static void ath11k_mgmt_over_wmi_tx_work(struct work_struct *work)
 		arvif = ath11k_vif_to_arvif(skb_cb->vif);
 		if (ar->allocated_vdev_map & (1LL << arvif->vdev_id) &&
 		    arvif->is_started) {
+			atomic_inc(&ar->num_pending_mgmt_tx);
 			ret = ath11k_mac_mgmt_tx_wmi(ar, arvif, skb);
 			if (ret) {
+				if (atomic_dec_if_positive(&ar->num_pending_mgmt_tx) < 0)
+					WARN_ON_ONCE(1);
+
 				ath11k_warn(ar->ab, "failed to tx mgmt frame, vdev_id %d :%d\n",
 					    arvif->vdev_id, ret);
 				ieee80211_free_txskb(ar->hw, skb);
-			} else {
-				atomic_inc(&ar->num_pending_mgmt_tx);
 			}
 		} else {
 			ath11k_warn(ar->ab,
-- 
2.7.4
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