ath9k: prevent aggregation session deadlocks

Waiting for all subframes of an existing aggregation session to drain
before allowing mac80211 to start a new one is fragile and deadlocks
caused by this behavior have been observed.

Since mac80211 has proper synchronization for aggregation session
start/stop handling, a better approach to session handling is to simply
allow mac80211 to start a new session at any time. This requires
changing the code to discard any packets outside of the BlockAck window
in the A-MPDU software retry code.

This patch implements the above and also simplifies the code.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Felix Fietkau
2013-05-18 21:28:15 +02:00
committed by John W. Linville
parent 323a98db4d
commit 08c96abd61
4 changed files with 46 additions and 114 deletions

View File

@@ -1709,7 +1709,8 @@ static int ath9k_ampdu_action(struct ieee80211_hw *hw,
flush = true;
case IEEE80211_AMPDU_TX_STOP_CONT:
ath9k_ps_wakeup(sc);
if (ath_tx_aggr_stop(sc, sta, tid, flush))
ath_tx_aggr_stop(sc, sta, tid);
if (!flush)
ieee80211_stop_tx_ba_cb_irqsafe(vif, sta->addr, tid);
ath9k_ps_restore(sc);
break;