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>

1 files changed, 4 insertions, 10 deletions

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 366002f266f8..42b03dc39d14 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -251,10 +251,9 @@ struct ath_atx_tid {
         int tidno;
         int baw_head;   /* first un-acked tx buffer */
         int baw_tail;   /* next unused tx buffer slot */
-        int sched;
-        int paused;
-        u8 state;
-        bool stop_cb;
+        bool sched;
+        bool paused;
+        bool active;
 };
 
 struct ath_node {
@@ -275,10 +274,6 @@ struct ath_node {
 #endif
 };
 
-#define AGGR_CLEANUP         BIT(1)
-#define AGGR_ADDBA_COMPLETE  BIT(2)
-#define AGGR_ADDBA_PROGRESS  BIT(3)
-
 struct ath_tx_control {
         struct ath_txq *txq;
         struct ath_node *an;
@@ -352,8 +347,7 @@ void ath_tx_tasklet(struct ath_softc *sc);
 void ath_tx_edma_tasklet(struct ath_softc *sc);
 int ath_tx_aggr_start(struct ath_softc *sc, struct ieee80211_sta *sta,
                       u16 tid, u16 *ssn);
-bool ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid,
-                      bool flush);
+void ath_tx_aggr_stop(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid);
 void ath_tx_aggr_resume(struct ath_softc *sc, struct ieee80211_sta *sta, u16 tid);
 
 void ath_tx_aggr_wakeup(struct ath_softc *sc, struct ath_node *an);