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>
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 6b83b3b..67f58d4 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -472,6 +472,13 @@
 	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 @@
 	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 @@
 	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 */