ath9k: optimize/fix ANI RSSI processing

ANI needs the RSSI average only in station mode, and only for tracking
the signal strength of beacons of the AP that it is connected to.
Adjust the code to track on the beacon RSSI, and store the average of that
in the ath_wiphy struct.
With these changes, we can get rid of this extra station lookup in the
rx path, which saves precious CPU cycles.

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

1 files changed, 12 insertions, 26 deletions

diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index fddb0129bb5..c04a940550b 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -962,36 +962,23 @@ static void ath9k_process_rssi(struct ath_common *common,
 			       struct ieee80211_hdr *hdr,
 			       struct ath_rx_status *rx_stats)
 {
+	struct ath_wiphy *aphy = hw->priv;
 	struct ath_hw *ah = common->ah;
-	struct ieee80211_sta *sta;
-	struct ath_node *an;
-	int last_rssi = ATH_RSSI_DUMMY_MARKER;
+	int last_rssi;
 	__le16 fc;
 
+	if (ah->opmode != NL80211_IFTYPE_STATION)
+		return;
+
 	fc = hdr->frame_control;
+	if (!ieee80211_is_beacon(fc) ||
+	    compare_ether_addr(hdr->addr3, common->curbssid))
+		return;
 
-	rcu_read_lock();
-	/*
-	 * XXX: use ieee80211_find_sta! This requires quite a bit of work
-	 * under the current ath9k virtual wiphy implementation as we have
-	 * no way of tying a vif to wiphy. Typically vifs are attached to
-	 * at least one sdata of a wiphy on mac80211 but with ath9k virtual
-	 * wiphy you'd have to iterate over every wiphy and each sdata.
-	 */
-	if (is_multicast_ether_addr(hdr->addr1))
-		sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr2, NULL);
-	else
-		sta = ieee80211_find_sta_by_ifaddr(hw, hdr->addr2, hdr->addr1);
-
-	if (sta) {
-		an = (struct ath_node *) sta->drv_priv;
-		if (rx_stats->rs_rssi != ATH9K_RSSI_BAD &&
-		   !rx_stats->rs_moreaggr)
-			ATH_RSSI_LPF(an->last_rssi, rx_stats->rs_rssi);
-		last_rssi = an->last_rssi;
-	}
-	rcu_read_unlock();
+	if (rx_stats->rs_rssi != ATH9K_RSSI_BAD && !rx_stats->rs_moreaggr)
+		ATH_RSSI_LPF(aphy->last_rssi, rx_stats->rs_rssi);
 
+	last_rssi = aphy->last_rssi;
 	if (likely(last_rssi != ATH_RSSI_DUMMY_MARKER))
 		rx_stats->rs_rssi = ATH_EP_RND(last_rssi,
 					      ATH_RSSI_EP_MULTIPLIER);
@@ -999,8 +986,7 @@ static void ath9k_process_rssi(struct ath_common *common,
 		rx_stats->rs_rssi = 0;
 
 	/* Update Beacon RSSI, this is used by ANI. */
-	if (ieee80211_is_beacon(fc))
-		ah->stats.avgbrssi = rx_stats->rs_rssi;
+	ah->stats.avgbrssi = rx_stats->rs_rssi;
 }
 
 /*