mac80211: restructure per-rate throughput calculation into function

This patch moves Minstrels and Minstrel-HTs per-rate throughput
calculation (EWMA(thr)) into a dedicated function to be called.
Therefore the variable "unsigned int cur_tp" within struct
"minstrel_rate_stats" becomes obsolete.  and is removed to free
up its space.

Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 28 insertions, 15 deletions

diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index c86e42b67908..61a857bca971 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -69,14 +69,32 @@ rix_to_ndx(struct minstrel_sta_info *mi, int rix)
         return i;
 }
 
+/* return current EMWA throughput */
+int minstrel_get_tp_avg(struct minstrel_rate *mr)
+{
+        int usecs;
+
+        usecs = mr->perfect_tx_time;
+        if (!usecs)
+                usecs = 1000000;
+
+        /* reset thr. below 10% success */
+        if (mr->stats.prob_ewma < MINSTREL_FRAC(10, 100))
+                return 0;
+        else
+                return MINSTREL_TRUNC(mr->stats.prob_ewma * (100000 / usecs));
+}
+
 /* find & sort topmost throughput rates */
 static inline void
 minstrel_sort_best_tp_rates(struct minstrel_sta_info *mi, int i, u8 *tp_list)
 {
         int j = MAX_THR_RATES;
 
-        while (j > 0 && mi->r[i].stats.cur_tp > mi->r[tp_list[j - 1]].stats.cur_tp)
+        while (j > 0 && (minstrel_get_tp_avg(&mi->r[i]) >
+               minstrel_get_tp_avg(&mi->r[tp_list[j - 1]])))
                 j--;
+
         if (j < MAX_THR_RATES - 1)
                 memmove(&tp_list[j + 1], &tp_list[j], MAX_THR_RATES - (j + 1));
         if (j < MAX_THR_RATES)
@@ -158,8 +176,7 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
 {
         u8 tmp_tp_rate[MAX_THR_RATES];
         u8 tmp_prob_rate = 0;
-        u32 usecs;
-        int i;
+        int i, tmp_cur_tp, tmp_prob_tp;
 
         for (i = 0; i < MAX_THR_RATES; i++)
             tmp_tp_rate[i] = 0;
@@ -168,19 +185,9 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
                 struct minstrel_rate *mr = &mi->r[i];
                 struct minstrel_rate_stats *mrs = &mi->r[i].stats;
 
-                usecs = mr->perfect_tx_time;
-                if (!usecs)
-                        usecs = 1000000;
-
                 /* Update success probabilities per rate */
                 minstrel_calc_rate_stats(mrs);
 
-                /* Update throughput per rate, reset thr. below 10% success */
-                if (mrs->prob_ewma < MINSTREL_FRAC(10, 100))
-                        mrs->cur_tp = 0;
-                else
-                        mrs->cur_tp = mrs->prob_ewma * (1000000 / usecs);
-
                 /* Sample less often below the 10% chance of success.
                  * Sample less often above the 95% chance of success. */
                 if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
@@ -205,7 +212,9 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi)
                  * (2) if all success probabilities < 95%, the rate with
                  * highest success probability is chosen as max_prob_rate */
                 if (mrs->prob_ewma >= MINSTREL_FRAC(95, 100)) {
-                        if (mrs->cur_tp >= mi->r[tmp_prob_rate].stats.cur_tp)
+                        tmp_cur_tp = minstrel_get_tp_avg(mr);
+                        tmp_prob_tp = minstrel_get_tp_avg(&mi->r[tmp_prob_rate]);
+                        if (tmp_cur_tp >= tmp_prob_tp)
                                 tmp_prob_rate = i;
                 } else {
                         if (mrs->prob_ewma >= mi->r[tmp_prob_rate].stats.prob_ewma)
@@ -676,11 +685,15 @@ static u32 minstrel_get_expected_throughput(void *priv_sta)
 {
         struct minstrel_sta_info *mi = priv_sta;
         int idx = mi->max_tp_rate[0];
+        int tmp_cur_tp;
 
         /* convert pkt per sec in kbps (1200 is the average pkt size used for
          * computing cur_tp
          */
-        return MINSTREL_TRUNC(mi->r[idx].stats.cur_tp) * 1200 * 8 / 1024;
+        tmp_cur_tp = minstrel_get_tp_avg(&mi->r[idx]);
+        tmp_cur_tp = tmp_cur_tp * 1200 * 8 / 1024;
+
+        return tmp_cur_tp;
 }
 
 const struct rate_control_ops mac80211_minstrel = {