wifi: mac80211: fix mesh airtime link metric estimating

ieee80211s_update_metric function uses sta_set_rate_info_tx
function to get struct rate_info data from ieee80211_tx_rate
struct, present in ieee80211_sta->deflink.tx_stats. However,
drivers can skip tx rate calculation by setting rate idx as
-1. Such drivers provides rate_info directly and hence
ieee80211s metric is updated incorrectly since ieee80211_tx_rate
has inconsistent data.

Add fix to use rate_info directly if present instead of
sta_set_rate_info_tx for updating ieee80211s metric.
Signed-off-by: Aditya Kumar Singh <quic_adisi@quicinc.com>
Link: https://lore.kernel.org/r/20220701133611.544-1-quic_adisi@quicinc.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mesh_hwmp.c

@@ -310,7 +310,12 @@ void ieee80211s_update_metric(struct ieee80211_local *local,
 			LINK_FAIL_THRESH)
 		mesh_plink_broken(sta);
 
-	sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
+	/* use rate info set by the driver directly if present */
+	if (st->n_rates)
+		rinfo = sta->deflink.tx_stats.last_rate_info;
+	else
+		sta_set_rate_info_tx(sta, &sta->deflink.tx_stats.last_rate, &rinfo);
+
 	ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
 				  cfg80211_calculate_bitrate(&rinfo));
 }