ath9k: fix rx flush handling

Right now the rx flush is not doing anything useful on AR9003+, as it only
works if the buffers in the rx FIFO have not been purged yet, as is done
by ath_stoprecv.

To fix this, always call ath_flushrecv from within ath_stoprecv before
the FIFO is emptied, but still after the hw receive path has been stopped.

This ensures that frames received (and ACKed by the hardware) shortly before
a reset will be seen by the software, which should improve A-MPDU session
stability.

Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ath9k.h

@@ -328,7 +328,6 @@ struct ath_rx {
 
 int ath_startrecv(struct ath_softc *sc);
 bool ath_stoprecv(struct ath_softc *sc);
-void ath_flushrecv(struct ath_softc *sc);
 u32 ath_calcrxfilter(struct ath_softc *sc);
 int ath_rx_init(struct ath_softc *sc, int nbufs);
 void ath_rx_cleanup(struct ath_softc *sc);

drivers/net/wireless/ath/ath9k/main.c

@@ -182,7 +182,7 @@ static void ath_restart_work(struct ath_softc *sc)
 	ath_start_ani(sc);
 }
 
-static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
+static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	bool ret = true;
@@ -204,14 +204,6 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
 	if (!ath_drain_all_txq(sc, retry_tx))
 		ret = false;
 
-	if (!flush) {
-		if (ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
-			ath_rx_tasklet(sc, 1, true);
-		ath_rx_tasklet(sc, 1, false);
-	} else {
-		ath_flushrecv(sc);
-	}
-
 	tasklet_enable(&sc->intr_tq);
 
 	return ret;
@@ -266,7 +258,6 @@ static int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan,
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath9k_hw_cal_data *caldata = NULL;
 	bool fastcc = true;
-	bool flush = false;
 	int r;
 
 	__ath_cancel_work(sc);
@@ -280,11 +271,10 @@ static int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan,
 
 	if (!hchan) {
 		fastcc = false;
-		flush = true;
 		hchan = ah->curchan;
 	}
 
-	if (!ath_prepare_reset(sc, retry_tx, flush))
+	if (!ath_prepare_reset(sc, retry_tx))
 		fastcc = false;
 
 	ath_dbg(common, CONFIG, "Reset to %u MHz, HT40: %d fastcc: %d\n",
@@ -808,7 +798,7 @@ static void ath9k_stop(struct ieee80211_hw *hw)
 		ath9k_hw_cfg_gpio_input(ah, ah->led_pin);
 	}
 
-	ath_prepare_reset(sc, false, true);
+	ath_prepare_reset(sc, false);
 
 	if (sc->rx.frag) {
 		dev_kfree_skb_any(sc->rx.frag);

drivers/net/wireless/ath/ath9k/recv.c

@@ -472,6 +472,13 @@ int ath_startrecv(struct ath_softc *sc)
 	return 0;
 }
 
+static void ath_flushrecv(struct ath_softc *sc)
+{
+	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
+		ath_rx_tasklet(sc, 1, true);
+	ath_rx_tasklet(sc, 1, false);
+}
+
 bool ath_stoprecv(struct ath_softc *sc)
 {
 	struct ath_hw *ah = sc->sc_ah;
@@ -482,6 +489,8 @@ bool ath_stoprecv(struct ath_softc *sc)
 	ath9k_hw_setrxfilter(ah, 0);
 	stopped = ath9k_hw_stopdmarecv(ah, &reset);
 
+	ath_flushrecv(sc);
+
 	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
 		ath_edma_stop_recv(sc);
 	else
@@ -498,13 +507,6 @@ bool ath_stoprecv(struct ath_softc *sc)
 	return stopped && !reset;
 }
 
-void ath_flushrecv(struct ath_softc *sc)
-{
-	if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
-		ath_rx_tasklet(sc, 1, true);
-	ath_rx_tasklet(sc, 1, false);
-}
-
 static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
 {
 	/* Check whether the Beacon frame has DTIM indicating buffered bc/mc */