ath9k: Use correct channel for RX packets

Accessing the current channel definition in mac80211
when processing RX packets is problematic because it
could have been updated when a scan is issued. Since a
channel change involves flushing the existing packets
in the RX queue before a chip-reset is done, they would
be processed using the wrong band/channel information.

To avoid this, use the current channel information
maintained in the driver.

Cc: stable@vger.kernel.org
Reported-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -850,20 +850,15 @@ static int ath9k_process_rate(struct ath_common *common,
 	enum ieee80211_band band;
 	unsigned int i = 0;
 	struct ath_softc __maybe_unused *sc = common->priv;
+	struct ath_hw *ah = sc->sc_ah;
 
-	band = hw->conf.chandef.chan->band;
+	band = ah->curchan->chan->band;
 	sband = hw->wiphy->bands[band];
 
-	switch (hw->conf.chandef.width) {
-	case NL80211_CHAN_WIDTH_5:
+	if (IS_CHAN_QUARTER_RATE(ah->curchan))
 		rxs->flag |= RX_FLAG_5MHZ;
-		break;
-	case NL80211_CHAN_WIDTH_10:
+	else if (IS_CHAN_HALF_RATE(ah->curchan))
 		rxs->flag |= RX_FLAG_10MHZ;
-		break;
-	default:
-		break;
-	}
 
 	if (rx_stats->rs_rate & 0x80) {
 		/* HT rate */
@@ -1078,6 +1073,14 @@ static int ath9k_rx_skb_preprocess(struct ath_softc *sc,
 
 	rx_stats->is_mybeacon = ath9k_is_mybeacon(sc, hdr);
 
+	/*
+	 * This shouldn't happen, but have a safety check anyway.
+	 */
+	if (WARN_ON(!ah->curchan)) {
+		ret = -EINVAL;
+		goto exit;
+	}
+
 	if (ath9k_process_rate(common, hw, rx_stats, rx_status)) {
 		ret =-EINVAL;
 		goto exit;
@@ -1085,8 +1088,8 @@ static int ath9k_rx_skb_preprocess(struct ath_softc *sc,
 
 	ath9k_process_rssi(common, hw, rx_stats, rx_status);
 
-	rx_status->band = hw->conf.chandef.chan->band;
-	rx_status->freq = hw->conf.chandef.chan->center_freq;
+	rx_status->band = ah->curchan->chan->band;
+	rx_status->freq = ah->curchan->chan->center_freq;
 	rx_status->antenna = rx_stats->rs_antenna;
 	rx_status->flag |= RX_FLAG_MACTIME_END;