3 files changed, 213 insertions, 119 deletions

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 85c1e74..df90ce2 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -135,7 +135,7 @@ minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
 static int
 minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
 {
-	return GROUP_IDX((rate->idx / 8) + 1,
+	return GROUP_IDX((rate->idx / MCS_GROUP_RATES) + 1,
 			 !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
 			 !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
 }
@@ -233,12 +233,151 @@ minstrel_ht_calc_tp(struct minstrel_ht_sta *mi, int group, int rate)
 }
 
 /*
+ * Find & sort topmost throughput rates
+ *
+ * If multiple rates provide equal throughput the sorting is based on their
+ * current success probability. Higher success probability is preferred among
+ * MCS groups, CCK rates do not provide aggregation and are therefore at last.
+ */
+static void
+minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta *mi, u8 index,
+			       u8 *tp_list)
+{
+	int cur_group, cur_idx, cur_thr, cur_prob;
+	int tmp_group, tmp_idx, tmp_thr, tmp_prob;
+	int j = MAX_THR_RATES;
+
+	cur_group = index / MCS_GROUP_RATES;
+	cur_idx = index  % MCS_GROUP_RATES;
+	cur_thr = mi->groups[cur_group].rates[cur_idx].cur_tp;
+	cur_prob = mi->groups[cur_group].rates[cur_idx].probability;
+
+	tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
+	tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
+	tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
+	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
+
+	while (j > 0 && (cur_thr > tmp_thr ||
+	      (cur_thr == tmp_thr && cur_prob > tmp_prob))) {
+		j--;
+		tmp_group = tp_list[j - 1] / MCS_GROUP_RATES;
+		tmp_idx = tp_list[j - 1] % MCS_GROUP_RATES;
+		tmp_thr = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
+		tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
+	}
+
+	if (j < MAX_THR_RATES - 1) {
+		memmove(&tp_list[j + 1], &tp_list[j], (sizeof(*tp_list) *
+		       (MAX_THR_RATES - (j + 1))));
+	}
+	if (j < MAX_THR_RATES)
+		tp_list[j] = index;
+}
+
+/*
+ * Find and set the topmost probability rate per sta and per group
+ */
+static void
+minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u8 index)
+{
+	struct minstrel_mcs_group_data *mg;
+	struct minstrel_rate_stats *mr;
+	int tmp_group, tmp_idx, tmp_tp, tmp_prob, max_tp_group;
+
+	mg = &mi->groups[index / MCS_GROUP_RATES];
+	mr = &mg->rates[index % MCS_GROUP_RATES];
+
+	tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
+	tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
+	tmp_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
+	tmp_prob = mi->groups[tmp_group].rates[tmp_idx].probability;
+
+	/* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
+	 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
+	max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
+	if((index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) &&
+	    (max_tp_group != MINSTREL_CCK_GROUP))
+		return;
+
+	if (mr->probability > MINSTREL_FRAC(75, 100)) {
+		if (mr->cur_tp > tmp_tp)
+			mi->max_prob_rate = index;
+		if (mr->cur_tp > mg->rates[mg->max_group_prob_rate].cur_tp)
+			mg->max_group_prob_rate = index;
+	} else {
+		if (mr->probability > tmp_prob)
+			mi->max_prob_rate = index;
+		if (mr->probability > mg->rates[mg->max_group_prob_rate].probability)
+			mg->max_group_prob_rate = index;
+	}
+}
+
+
+/*
+ * Assign new rate set per sta and use CCK rates only if the fastest
+ * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
+ * rate sets where MCS and CCK rates are mixed, because CCK rates can
+ * not use aggregation.
+ */
+static void
+minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta *mi,
+				 u8 tmp_mcs_tp_rate[MAX_THR_RATES],
+				 u8 tmp_cck_tp_rate[MAX_THR_RATES])
+{
+	unsigned int tmp_group, tmp_idx, tmp_cck_tp, tmp_mcs_tp;
+	int i;
+
+	tmp_group = tmp_cck_tp_rate[0] / MCS_GROUP_RATES;
+	tmp_idx = tmp_cck_tp_rate[0] % MCS_GROUP_RATES;
+	tmp_cck_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
+
+	tmp_group = tmp_mcs_tp_rate[0] / MCS_GROUP_RATES;
+	tmp_idx = tmp_mcs_tp_rate[0] % MCS_GROUP_RATES;
+	tmp_mcs_tp = mi->groups[tmp_group].rates[tmp_idx].cur_tp;
+
+	if (tmp_cck_tp > tmp_mcs_tp) {
+		for(i = 0; i < MAX_THR_RATES; i++) {
+			minstrel_ht_sort_best_tp_rates(mi, tmp_cck_tp_rate[i],
+						       tmp_mcs_tp_rate);
+		}
+	}
+
+}
+
+/*
+ * Try to increase robustness of max_prob rate by decrease number of
+ * streams if possible.
+ */
+static inline void
+minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta *mi)
+{
+	struct minstrel_mcs_group_data *mg;
+	struct minstrel_rate_stats *mr;
+	int tmp_max_streams, group;
+	int tmp_tp = 0;
+
+	tmp_max_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
+			  MCS_GROUP_RATES].streams;
+	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
+		mg = &mi->groups[group];
+		if (!mg->supported || group == MINSTREL_CCK_GROUP)
+			continue;
+		mr = minstrel_get_ratestats(mi, mg->max_group_prob_rate);
+		if (tmp_tp < mr->cur_tp &&
+		   (minstrel_mcs_groups[group].streams < tmp_max_streams)) {
+				mi->max_prob_rate = mg->max_group_prob_rate;
+				tmp_tp = mr->cur_tp;
+		}
+	}
+}
+
+/*
  * Update rate statistics and select new primary rates
  *
  * Rules for rate selection:
  *  - max_prob_rate must use only one stream, as a tradeoff between delivery
  *    probability and throughput during strong fluctuations
- *  - as long as the max prob rate has a probability of more than 3/4, pick
+ *  - as long as the max prob rate has a probability of more than 75%, pick
  *    higher throughput rates, even if the probablity is a bit lower
  */
 static void
@@ -246,9 +385,9 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 {
 	struct minstrel_mcs_group_data *mg;
 	struct minstrel_rate_stats *mr;
-	int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
-	int group, i, index;
-	bool mi_rates_valid = false;
+	int group, i, j;
+	u8 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
+	u8 tmp_cck_tp_rate[MAX_THR_RATES], index;
 
 	if (mi->ampdu_packets > 0) {
 		mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
@@ -260,13 +399,14 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 	mi->sample_slow = 0;
 	mi->sample_count = 0;
 
-	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
-		bool mg_rates_valid = false;
+	/* Initialize global rate indexes */
+	for(j = 0; j < MAX_THR_RATES; j++){
+		tmp_mcs_tp_rate[j] = 0;
+		tmp_cck_tp_rate[j] = 0;
+	}
 
-		cur_prob = 0;
-		cur_prob_tp = 0;
-		cur_tp = 0;
-		cur_tp2 = 0;
+	/* Find best rate sets within all MCS groups*/
+	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 
 		mg = &mi->groups[group];
 		if (!mg->supported)
@@ -274,24 +414,16 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 
 		mi->sample_count++;
 
+		/* (re)Initialize group rate indexes */
+		for(j = 0; j < MAX_THR_RATES; j++)
+			tmp_group_tp_rate[j] = group;
+
 		for (i = 0; i < MCS_GROUP_RATES; i++) {
 			if (!(mg->supported & BIT(i)))
 				continue;
 
 			index = MCS_GROUP_RATES * group + i;
 
-			/* initialize rates selections starting indexes */
-			if (!mg_rates_valid) {
-				mg->max_tp_rate = mg->max_tp_rate2 =
-					mg->max_prob_rate = i;
-				if (!mi_rates_valid) {
-					mi->max_tp_rate = mi->max_tp_rate2 =
-						mi->max_prob_rate = index;
-					mi_rates_valid = true;
-				}
-				mg_rates_valid = true;
-			}
-
 			mr = &mg->rates[i];
 			mr->retry_updated = false;
 			minstrel_calc_rate_ewma(mr);
@@ -300,82 +432,47 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 			if (!mr->cur_tp)
 				continue;
 
-			if ((mr->cur_tp > cur_prob_tp && mr->probability >
-			     MINSTREL_FRAC(3, 4)) || mr->probability > cur_prob) {
-				mg->max_prob_rate = index;
-				cur_prob = mr->probability;
-				cur_prob_tp = mr->cur_tp;
-			}
-
-			if (mr->cur_tp > cur_tp) {
-				swap(index, mg->max_tp_rate);
-				cur_tp = mr->cur_tp;
-				mr = minstrel_get_ratestats(mi, index);
-			}
-
-			if (index >= mg->max_tp_rate)
-				continue;
-
-			if (mr->cur_tp > cur_tp2) {
-				mg->max_tp_rate2 = index;
-				cur_tp2 = mr->cur_tp;
+			/* Find max throughput rate set */
+			if (group != MINSTREL_CCK_GROUP) {
+				minstrel_ht_sort_best_tp_rates(mi, index,
+							       tmp_mcs_tp_rate);
+			} else if (group == MINSTREL_CCK_GROUP) {
+				minstrel_ht_sort_best_tp_rates(mi, index,
+							       tmp_cck_tp_rate);
 			}
-		}
-	}
 
-	/* try to sample all available rates during each interval */
-	mi->sample_count *= 8;
+			/* Find max throughput rate set within a group */
+			minstrel_ht_sort_best_tp_rates(mi, index,
+						       tmp_group_tp_rate);
 
-	cur_prob = 0;
-	cur_prob_tp = 0;
-	cur_tp = 0;
-	cur_tp2 = 0;
-	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
-		mg = &mi->groups[group];
-		if (!mg->supported)
-			continue;
-
-		mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
-		if (cur_tp < mr->cur_tp) {
-			mi->max_tp_rate2 = mi->max_tp_rate;
-			cur_tp2 = cur_tp;
-			mi->max_tp_rate = mg->max_tp_rate;
-			cur_tp = mr->cur_tp;
-			mi->max_prob_streams = minstrel_mcs_groups[group].streams - 1;
+			/* Find max probability rate per group and global */
+			minstrel_ht_set_best_prob_rate(mi, index);
 		}
 
-		mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
-		if (cur_tp2 < mr->cur_tp) {
-			mi->max_tp_rate2 = mg->max_tp_rate2;
-			cur_tp2 = mr->cur_tp;
-		}
+		memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
+		       sizeof(mg->max_group_tp_rate));
 	}
 
-	if (mi->max_prob_streams < 1)
-		mi->max_prob_streams = 1;
+	/* Assign new rate set per sta */
+	minstrel_ht_assign_best_tp_rates(mi, tmp_mcs_tp_rate, tmp_cck_tp_rate);
+	memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
 
-	for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
-		mg = &mi->groups[group];
-		if (!mg->supported)
-			continue;
-		mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
-		if (cur_prob_tp < mr->cur_tp &&
-		    minstrel_mcs_groups[group].streams <= mi->max_prob_streams) {
-			mi->max_prob_rate = mg->max_prob_rate;
-			cur_prob = mr->cur_prob;
-			cur_prob_tp = mr->cur_tp;
-		}
-	}
+	/* Try to increase robustness of max_prob_rate*/
+	minstrel_ht_prob_rate_reduce_streams(mi);
+
+	/* try to sample all available rates during each interval */
+	mi->sample_count *= 8;
 
 #ifdef CONFIG_MAC80211_DEBUGFS
 	/* use fixed index if set */
 	if (mp->fixed_rate_idx != -1) {
-		mi->max_tp_rate = mp->fixed_rate_idx;
-		mi->max_tp_rate2 = mp->fixed_rate_idx;
+		for (i = 0; i < 4; i++)
+			mi->max_tp_rate[i] = mp->fixed_rate_idx;
 		mi->max_prob_rate = mp->fixed_rate_idx;
 	}
 #endif
 
+	/* Reset update timer */
 	mi->stats_update = jiffies;
 }
 
@@ -420,8 +517,7 @@ minstrel_next_sample_idx(struct minstrel_ht_sta *mi)
 }
 
 static void
-minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
-			bool primary)
+minstrel_downgrade_rate(struct minstrel_ht_sta *mi, u8 *idx, bool primary)
 {
 	int group, orig_group;
 
@@ -437,9 +533,9 @@ minstrel_downgrade_rate(struct minstrel_ht_sta *mi, unsigned int *idx,
 			continue;
 
 		if (primary)
-			*idx = mi->groups[group].max_tp_rate;
+			*idx = mi->groups[group].max_group_tp_rate[0];
 		else
-			*idx = mi->groups[group].max_tp_rate2;
+			*idx = mi->groups[group].max_group_tp_rate[1];
 		break;
 	}
 }
@@ -524,19 +620,19 @@ minstrel_ht_tx_status(void *priv, struct ieee80211_supported_band *sband,
 	 * check for sudden death of spatial multiplexing,
 	 * downgrade to a lower number of streams if necessary.
 	 */
-	rate = minstrel_get_ratestats(mi, mi->max_tp_rate);
+	rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
 	if (rate->attempts > 30 &&
 	    MINSTREL_FRAC(rate->success, rate->attempts) <
 	    MINSTREL_FRAC(20, 100)) {
-		minstrel_downgrade_rate(mi, &mi->max_tp_rate, true);
+		minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
 		update = true;
 	}
 
-	rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate2);
+	rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
 	if (rate2->attempts > 30 &&
 	    MINSTREL_FRAC(rate2->success, rate2->attempts) <
 	    MINSTREL_FRAC(20, 100)) {
-		minstrel_downgrade_rate(mi, &mi->max_tp_rate2, false);
+		minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
 		update = true;
 	}
 
@@ -661,12 +757,12 @@ minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 	if (!rates)
 		return;
 
-	/* Start with max_tp_rate */
-	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate);
+	/* Start with max_tp_rate[0] */
+	minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
 
 	if (mp->hw->max_rates >= 3) {
-		/* At least 3 tx rates supported, use max_tp_rate2 next */
-		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate2);
+		/* At least 3 tx rates supported, use max_tp_rate[1] next */
+		minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[1]);
 	}
 
 	if (mp->hw->max_rates >= 2) {
@@ -691,7 +787,7 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 {
 	struct minstrel_rate_stats *mr;
 	struct minstrel_mcs_group_data *mg;
-	unsigned int sample_dur, sample_group;
+	unsigned int sample_dur, sample_group, cur_max_tp_streams;
 	int sample_idx = 0;
 
 	if (mi->sample_wait > 0) {
@@ -718,8 +814,8 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 	 * to the frame. Hence, don't use sampling for the currently
 	 * used rates.
 	 */
-	if (sample_idx == mi->max_tp_rate ||
-	    sample_idx == mi->max_tp_rate2 ||
+	if (sample_idx == mi->max_tp_rate[0] ||
+	    sample_idx == mi->max_tp_rate[1] ||
 	    sample_idx == mi->max_prob_rate)
 		return -1;
 
@@ -734,9 +830,12 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 	 * Make sure that lower rates get sampled only occasionally,
 	 * if the link is working perfectly.
 	 */
+
+	cur_max_tp_streams = minstrel_mcs_groups[mi->max_tp_rate[0] /
+		MCS_GROUP_RATES].streams;
 	sample_dur = minstrel_get_duration(sample_idx);
-	if (sample_dur >= minstrel_get_duration(mi->max_tp_rate2) &&
-	    (mi->max_prob_streams <
+	if (sample_dur >= minstrel_get_duration(mi->max_tp_rate[1]) &&
+	    (cur_max_tp_streams - 1 <
 	     minstrel_mcs_groups[sample_group].streams ||
 	     sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
 		if (mr->sample_skipped < 20)
@@ -1041,8 +1140,8 @@ static u32 minstrel_ht_get_expected_throughput(void *priv_sta)
 	if (!msp->is_ht)
 		return mac80211_minstrel.get_expected_throughput(priv_sta);
 
-	i = mi->max_tp_rate / MCS_GROUP_RATES;
-	j = mi->max_tp_rate % MCS_GROUP_RATES;
+	i = mi->max_tp_rate[0] / MCS_GROUP_RATES;
+	j = mi->max_tp_rate[0] % MCS_GROUP_RATES;
 
 	/* convert cur_tp from pkt per second in kbps */
 	return mi->groups[i].rates[j].cur_tp * AVG_PKT_SIZE * 8 / 1024;
diff --git a/net/mac80211/rc80211_minstrel_ht.h b/net/mac80211/rc80211_minstrel_ht.h
index 5fee938..01570e0 100644
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -33,10 +33,9 @@ struct minstrel_mcs_group_data {
 	/* bitfield of supported MCS rates of this group */
 	u8 supported;
 
-	/* selected primary rates */
-	unsigned int max_tp_rate;
-	unsigned int max_tp_rate2;
-	unsigned int max_prob_rate;
+	/* sorted rate set within a MCS group*/
+	u8 max_group_tp_rate[MAX_THR_RATES];
+	u8 max_group_prob_rate;
 
 	/* MCS rate statistics */
 	struct minstrel_rate_stats rates[MCS_GROUP_RATES];
@@ -52,15 +51,9 @@ struct minstrel_ht_sta {
 	/* ampdu length (EWMA) */
 	unsigned int avg_ampdu_len;
 
-	/* best throughput rate */
-	unsigned int max_tp_rate;
-
-	/* second best throughput rate */
-	unsigned int max_tp_rate2;
-
-	/* best probability rate */
-	unsigned int max_prob_rate;
-	unsigned int max_prob_streams;
+	/* overall sorted rate set */
+	u8 max_tp_rate[MAX_THR_RATES];
+	u8 max_prob_rate;
 
 	/* time of last status update */
 	unsigned long stats_update;
diff --git a/net/mac80211/rc80211_minstrel_ht_debugfs.c b/net/mac80211/rc80211_minstrel_ht_debugfs.c
index 3e7d793..a72ad46 100644
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -46,8 +46,10 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
 		else
 			p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);
 
-		*(p++) = (idx == mi->max_tp_rate) ? 'T' : ' ';
-		*(p++) = (idx == mi->max_tp_rate2) ? 't' : ' ';
+		*(p++) = (idx == mi->max_tp_rate[0]) ? 'A' : ' ';
+		*(p++) = (idx == mi->max_tp_rate[1]) ? 'B' : ' ';
+		*(p++) = (idx == mi->max_tp_rate[2]) ? 'C' : ' ';
+		*(p++) = (idx == mi->max_tp_rate[3]) ? 'D' : ' ';
 		*(p++) = (idx == mi->max_prob_rate) ? 'P' : ' ';
 
 		if (i == max_mcs) {
@@ -100,8 +102,8 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file)
 
 	file->private_data = ms;
 	p = ms->buf;
-	p += sprintf(p, "type         rate     throughput  ewma prob   this prob  "
-			"retry   this succ/attempt   success    attempts\n");
+	p += sprintf(p, "type           rate     throughput  ewma prob   "
+		     "this prob  retry   this succ/attempt   success    attempts\n");
 
 	p = minstrel_ht_stats_dump(mi, max_mcs, p);
 	for (i = 0; i < max_mcs; i++)