mac80211: remove TX latency measurement code

Revert commit ad38bfc916da ("mac80211: Tx frame latency statistics")
(along with some follow-up fixes).

This code turned out not to be as useful in the current form as we
thought, and we've internally hacked it up more, but that's not
very suitable for upstream (for now), and we might just do that
with tracing instead.

Therefore, for now at least, remove this code. We might also need
to use the skb->tstamp field for the TCP performance issue, which
is more important than the debugging.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 5 insertions, 49 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 00ca8dcc2bcf..d94004e7ce37 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -229,17 +229,9 @@ struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
  */
 void sta_info_free(struct ieee80211_local *local, struct sta_info *sta)
 {
-	int i;
-
 	if (sta->rate_ctrl)
 		rate_control_free_sta(sta);
 
-	if (sta->tx_lat) {
-		for (i = 0; i < IEEE80211_NUM_TIDS; i++)
-			kfree(sta->tx_lat[i].bins);
-		kfree(sta->tx_lat);
-	}
-
 	sta_dbg(sta->sdata, "Destroyed STA %pM\n", sta->sta.addr);
 
 	kfree(rcu_dereference_raw(sta->sta.rates));
@@ -295,42 +287,12 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_local *local = sdata->local;
 	struct sta_info *sta;
 	struct timespec uptime;
-	struct ieee80211_tx_latency_bin_ranges *tx_latency;
 	int i;
 
 	sta = kzalloc(sizeof(*sta) + local->hw.sta_data_size, gfp);
 	if (!sta)
 		return NULL;
 
-	rcu_read_lock();
-	tx_latency = rcu_dereference(local->tx_latency);
-	/* init stations Tx latency statistics && TID bins */
-	if (tx_latency) {
-		sta->tx_lat = kzalloc(IEEE80211_NUM_TIDS *
-				      sizeof(struct ieee80211_tx_latency_stat),
-				      GFP_ATOMIC);
-		if (!sta->tx_lat) {
-			rcu_read_unlock();
-			goto free;
-		}
-
-		if (tx_latency->n_ranges) {
-			for (i = 0; i < IEEE80211_NUM_TIDS; i++) {
-				/* size of bins is size of the ranges +1 */
-				sta->tx_lat[i].bin_count =
-					tx_latency->n_ranges + 1;
-				sta->tx_lat[i].bins =
-					kcalloc(sta->tx_lat[i].bin_count,
-						sizeof(u32), GFP_ATOMIC);
-				if (!sta->tx_lat[i].bins) {
-					rcu_read_unlock();
-					goto free;
-				}
-			}
-		}
-	}
-	rcu_read_unlock();
-
 	spin_lock_init(&sta->lock);
 	spin_lock_init(&sta->ps_lock);
 	INIT_WORK(&sta->drv_deliver_wk, sta_deliver_ps_frames);
@@ -359,8 +321,10 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 	for (i = 0; i < ARRAY_SIZE(sta->chain_signal_avg); i++)
 		ewma_init(&sta->chain_signal_avg[i], 1024, 8);
 
-	if (sta_prepare_rate_control(local, sta, gfp))
-		goto free;
+	if (sta_prepare_rate_control(local, sta, gfp)) {
+		kfree(sta);
+		return NULL;
+	}
 
 	for (i = 0; i < IEEE80211_NUM_TIDS; i++) {
 		/*
@@ -405,16 +369,8 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata,
 	}
 
 	sta_dbg(sdata, "Allocated STA %pM\n", sta->sta.addr);
-	return sta;
 
-free:
-	if (sta->tx_lat) {
-		for (i = 0; i < IEEE80211_NUM_TIDS; i++)
-			kfree(sta->tx_lat[i].bins);
-		kfree(sta->tx_lat);
-	}
-	kfree(sta);
-	return NULL;
+	return sta;
 }
 
 static int sta_info_insert_check(struct sta_info *sta)