mac80211: fix AQL issues

- Remove bogus STA txq pending airtime underflow warning
- Improve tx airtime estimation for A-MPDU traffic

Signed-off-by: Felix Fietkau <nbd@nbd.name>

1 files changed, 31 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/subsys/306-mac80211-remove-STA-txq-pending-airtime-underflow-wa.patch b/package/kernel/mac80211/patches/subsys/306-mac80211-remove-STA-txq-pending-airtime-underflow-wa.patch
new file mode 100644
index 0000000000..ab3a77e19b
--- /dev/null
+++ b/package/kernel/mac80211/patches/subsys/306-mac80211-remove-STA-txq-pending-airtime-underflow-wa.patch
@@ -0,0 +1,31 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Sat, 25 Jul 2020 10:42:30 +0200
+Subject: [PATCH] mac80211: remove STA txq pending airtime underflow
+ warning
+
+This warning can trigger if there is a mismatch between frames that were
+sent with the sta pointer set vs tx status frames reported for the sta address.
+
+This can happen due to race conditions on re-creating stations, or even
+in the case of .sta_add/remove being used instead of .sta_state, which can cause
+frames to be sent to a station that has not been uploaded yet.
+
+If there is an actual underflow issue, it should show up in the device airtime
+warning below, so it is better to remove this one.
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/net/mac80211/sta_info.c
++++ b/net/mac80211/sta_info.c
+@@ -1924,9 +1924,7 @@ void ieee80211_sta_update_pending_airtim
+ 	if (sta) {
+ 		tx_pending = atomic_sub_return(tx_airtime,
+ 					       &sta->airtime[ac].aql_tx_pending);
+-		if (WARN_ONCE(tx_pending < 0,
+-			      "STA %pM AC %d txq pending airtime underflow: %u, %u",
+-			      sta->addr, ac, tx_pending, tx_airtime))
++		if (tx_pending < 0)
+ 			atomic_cmpxchg(&sta->airtime[ac].aql_tx_pending,
+ 				       tx_pending, 0);
+ 	}