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From: Felix Fietkau <nbd@openwrt.org>
Date: Thu, 18 Feb 2016 19:30:05 +0100
Subject: [PATCH] mac80211: minstrel_ht: set A-MSDU tx limits based on selected
max_prob_rate
Prevents excessive A-MSDU aggregation at low data rates or bad
conditions.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -883,6 +883,39 @@ minstrel_ht_set_rate(struct minstrel_pri
ratetbl->rate[offset].flags = flags;
}
+static int
+minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi)
+{
+ int group = mi->max_prob_rate / MCS_GROUP_RATES;
+ const struct mcs_group *g = &minstrel_mcs_groups[group];
+ int rate = mi->max_prob_rate % MCS_GROUP_RATES;
+
+ /* Disable A-MSDU if max_prob_rate is bad */
+ if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100))
+ return 1;
+
+ /* If the rate is slower than single-stream MCS1, make A-MSDU limit small */
+ if (g->duration[rate] > MCS_DURATION(1, 0, 52))
+ return 500;
+
+ /*
+ * If the rate is slower than single-stream MCS4, limit A-MSDU to usual
+ * data packet size
+ */
+ if (g->duration[rate] > MCS_DURATION(1, 0, 104))
+ return 1500;
+
+ /*
+ * If the rate is slower than single-stream MCS7, limit A-MSDU to twice
+ * the usual data packet size
+ */
+ if (g->duration[rate] > MCS_DURATION(1, 0, 260))
+ return 3000;
+
+ /* unlimited */
+ return 0;
+}
+
static void
minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
{
@@ -907,6 +940,7 @@ minstrel_ht_update_rates(struct minstrel
minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate);
}
+ mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi);
rates->rate[i].idx = -1;
rate_control_set_rates(mp->hw, mi->sta, rates);
}
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