mac80211/drivers: rewrite the rate control API

So after the previous changes we were still unhappy with how
convoluted the API is and decided to make things simpler for
everybody. This completely changes the rate control API, now
taking into account 802.11n with MCS rates and more control,
most drivers don't support that though.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 24 insertions, 28 deletions

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index 5d786720d935..3fa7ab285066 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -199,48 +199,44 @@ static void rate_control_release(struct kref *kref)
 }
 
 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
-                           struct ieee80211_supported_band *sband,
-                           struct sta_info *sta, struct sk_buff *skb,
-                           struct rate_selection *sel)
+                           struct sta_info *sta,
+                           struct ieee80211_tx_rate_control *txrc)
 {
         struct rate_control_ref *ref = sdata->local->rate_ctrl;
         void *priv_sta = NULL;
         struct ieee80211_sta *ista = NULL;
+        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
         int i;
 
-        sel->rate_idx = -1;
-        sel->nonerp_idx = -1;
-        sel->probe_idx = -1;
-        sel->max_rate_idx = sdata->max_ratectrl_rateidx;
-
         if (sta) {
                 ista = &sta->sta;
                 priv_sta = sta->rate_ctrl_priv;
         }
 
+        for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+                info->control.rates[i].idx = -1;
+                info->control.rates[i].flags = 0;
+                info->control.rates[i].count = 1;
+        }
+
         if (sta && sdata->force_unicast_rateidx > -1)
-                sel->rate_idx = sdata->force_unicast_rateidx;
+                info->control.rates[0].idx = sdata->force_unicast_rateidx;
         else
-                ref->ops->get_rate(ref->priv, sband, ista, priv_sta, skb, sel);
-
-        if (sdata->max_ratectrl_rateidx > -1 &&
-            sel->rate_idx > sdata->max_ratectrl_rateidx)
-                sel->rate_idx = sdata->max_ratectrl_rateidx;
-
-        BUG_ON(sel->rate_idx < 0);
-
-        /* Select a non-ERP backup rate. */
-        if (sel->nonerp_idx < 0) {
-                for (i = 0; i < sband->n_bitrates; i++) {
-                        struct ieee80211_rate *rate = &sband->bitrates[i];
-                        if (sband->bitrates[sel->rate_idx].bitrate < rate->bitrate)
-                                break;
-
-                        if (rate_supported(ista, sband->band, i) &&
-                            !(rate->flags & IEEE80211_RATE_ERP_G))
-                                sel->nonerp_idx = i;
-                }
+                ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
+
+        /*
+         * try to enforce the maximum rate the user wanted
+         */
+        if (sdata->max_ratectrl_rateidx > -1)
+                for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+                        if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS)
+                                continue;
+                        info->control.rates[i].idx =
+                                min_t(s8, info->control.rates[i].idx,
+                                      sdata->max_ratectrl_rateidx);
         }
+
+        BUG_ON(info->control.rates[0].idx < 0);
 }
 
 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)