mac80211: fix mesh airtime link metric estimation

fix reading the per-packet rate on devices with firmware rate control

Signed-off-by: Felix Fietkau <[email protected]>

package/kernel/mac80211/patches/subsys/346-v6.0-wifi-mac80211-fix-mesh-airtime-link-metric-estimatin.patch

@@ -0,0 +1,36 @@
+From: Aditya Kumar Singh <[email protected]>
+Date: Fri, 1 Jul 2022 19:06:11 +0530
+Subject: [PATCH] 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 <[email protected]>
+Link: https://lore.kernel.org/r/[email protected]
+Signed-off-by: Johannes Berg <[email protected]>
+---
+
+--- a/net/mac80211/mesh_hwmp.c
++++ b/net/mac80211/mesh_hwmp.c
+@@ -310,7 +310,12 @@ void ieee80211s_update_metric(struct iee
+ 			LINK_FAIL_THRESH)
+ 		mesh_plink_broken(sta);
+ 
+-	sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
++	/* use rate info set by the driver directly if present */
++	if (st->rate)
++		rinfo = sta->tx_stats.last_rate_info;
++	else
++		sta_set_rate_info_tx(sta, &sta->tx_stats.last_rate, &rinfo);
++
+ 	ewma_mesh_tx_rate_avg_add(&sta->mesh->tx_rate_avg,
+ 				  cfg80211_calculate_bitrate(&rinfo));
+ }