mac80211: clean up rate selection

Move some code out of rc80211_simple since it's probably needed for all rate
selection algorithms, and fix iwlwifi accordingly. While at it, clean up the
rate_control_get_rate() interface.

Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 129 insertions, 116 deletions

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index d6a97a68a62e..5bf7a5bebfc9 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -859,10 +859,8 @@ void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb,
                         sta_info_put(sta);
                         return;
                 }
-        } else {
-                /* FIXME: STUPID to call this with both local and local->mdev */
-                rate_control_tx_status(local, local->mdev, skb, status);
-        }
+        } else
+                rate_control_tx_status(local->mdev, skb, status);
 
         ieee80211_led_tx(local, 0);
 
diff --git a/net/mac80211/ieee80211_rate.c b/net/mac80211/ieee80211_rate.c
index c3f278393741..e495b0998b4d 100644
--- a/net/mac80211/ieee80211_rate.c
+++ b/net/mac80211/ieee80211_rate.c
@@ -147,6 +147,53 @@ static void rate_control_release(struct kref *kref)
         kfree(ctrl_ref);
 }
 
+void rate_control_get_rate(struct net_device *dev,
+                           struct ieee80211_hw_mode *mode, struct sk_buff *skb,
+                           struct rate_selection *sel)
+{
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct rate_control_ref *ref = local->rate_ctrl;
+        struct ieee80211_sub_if_data *sdata;
+        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+        struct sta_info *sta = sta_info_get(local, hdr->addr1);
+        int i;
+        u16 fc;
+
+        memset(sel, 0, sizeof(struct rate_selection));
+
+        /* Send management frames and broadcast/multicast data using lowest
+         * rate. */
+        fc = le16_to_cpu(hdr->frame_control);
+        if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
+            is_multicast_ether_addr(hdr->addr1))
+                sel->rate = rate_lowest(local, mode, sta);
+
+        /* If a forced rate is in effect, select it. */
+        sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
+                sel->rate = &mode->rates[sdata->bss->force_unicast_rateidx];
+
+        /* If we haven't found the rate yet, ask the rate control algo. */
+        if (!sel->rate)
+                ref->ops->get_rate(ref->priv, dev, mode, skb, sel);
+
+        /* Select a non-ERP backup rate. */
+        if (!sel->nonerp) {
+                for (i = 0; i < mode->num_rates - 1; i++) {
+                        struct ieee80211_rate *rate = &mode->rates[i];
+                        if (sel->rate->rate < rate->rate)
+                                break;
+
+                        if (rate_supported(sta, mode, i) &&
+                            !(rate->flags & IEEE80211_RATE_ERP))
+                                sel->nonerp = rate;
+                }
+        }
+
+        if (sta)
+                sta_info_put(sta);
+}
+
 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
 {
         kref_get(&ref->kref);
diff --git a/net/mac80211/ieee80211_rate.h b/net/mac80211/ieee80211_rate.h
index 23688139ffb3..787134bd6abf 100644
--- a/net/mac80211/ieee80211_rate.h
+++ b/net/mac80211/ieee80211_rate.h
@@ -18,31 +18,24 @@
 #include "ieee80211_i.h"
 #include "sta_info.h"
 
-#define RATE_CONTROL_NUM_DOWN 20
-#define RATE_CONTROL_NUM_UP   15
-
-
-struct rate_control_extra {
-        /* values from rate_control_get_rate() to the caller: */
-        struct ieee80211_rate *probe; /* probe with this rate, or NULL for no
-                                       * probing */
+struct rate_selection {
+        /* Selected transmission rate */
+        struct ieee80211_rate *rate;
+        /* Non-ERP rate to use if mac80211 decides it cannot use an ERP rate */
         struct ieee80211_rate *nonerp;
-
-        /* parameters from the caller to rate_control_get_rate(): */
-        struct ieee80211_hw_mode *mode;
-        u16 ethertype;
+        /* probe with this rate, or NULL for no probing */
+        struct ieee80211_rate *probe;
 };
 
-
 struct rate_control_ops {
         struct module *module;
         const char *name;
         void (*tx_status)(void *priv, struct net_device *dev,
                           struct sk_buff *skb,
                           struct ieee80211_tx_status *status);
-        struct ieee80211_rate *(*get_rate)(void *priv, struct net_device *dev,
-                                           struct sk_buff *skb,
-                                           struct rate_control_extra *extra);
+        void (*get_rate)(void *priv, struct net_device *dev,
+                         struct ieee80211_hw_mode *mode, struct sk_buff *skb,
+                         struct rate_selection *sel);
         void (*rate_init)(void *priv, void *priv_sta,
                           struct ieee80211_local *local, struct sta_info *sta);
         void (*clear)(void *priv);
@@ -75,25 +68,20 @@ void ieee80211_rate_control_unregister(struct rate_control_ops *ops);
  * first available algorithm. */
 struct rate_control_ref *rate_control_alloc(const char *name,
                                             struct ieee80211_local *local);
+void rate_control_get_rate(struct net_device *dev,
+                           struct ieee80211_hw_mode *mode, struct sk_buff *skb,
+                           struct rate_selection *sel);
 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref);
 void rate_control_put(struct rate_control_ref *ref);
 
-static inline void rate_control_tx_status(struct ieee80211_local *local,
-                                          struct net_device *dev,
+static inline void rate_control_tx_status(struct net_device *dev,
                                           struct sk_buff *skb,
                                           struct ieee80211_tx_status *status)
 {
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
         struct rate_control_ref *ref = local->rate_ctrl;
-        ref->ops->tx_status(ref->priv, dev, skb, status);
-}
 
-
-static inline struct ieee80211_rate *
-rate_control_get_rate(struct ieee80211_local *local, struct net_device *dev,
-                      struct sk_buff *skb, struct rate_control_extra *extra)
-{
-        struct rate_control_ref *ref = local->rate_ctrl;
-        return ref->ops->get_rate(ref->priv, dev, skb, extra);
+        ref->ops->tx_status(ref->priv, dev, skb, status);
 }
 
 
@@ -142,6 +130,37 @@ static inline void rate_control_remove_sta_debugfs(struct sta_info *sta)
 #endif
 }
 
+static inline int
+rate_supported(struct sta_info *sta, struct ieee80211_hw_mode *mode, int index)
+{
+        return (sta == NULL || sta->supp_rates & BIT(index)) &&
+               (mode->rates[index].flags & IEEE80211_RATE_SUPPORTED);
+}
+
+static inline int
+rate_lowest_index(struct ieee80211_local *local, struct ieee80211_hw_mode *mode,
+                  struct sta_info *sta)
+{
+        int i;
+
+        for (i = 0; i < mode->num_rates; i++) {
+                if (rate_supported(sta, mode, i))
+                        return i;
+        }
+
+        /* warn when we cannot find a rate. */
+        WARN_ON(1);
+
+        return 0;
+}
+
+static inline struct ieee80211_rate *
+rate_lowest(struct ieee80211_local *local, struct ieee80211_hw_mode *mode,
+            struct sta_info *sta)
+{
+        return &mode->rates[rate_lowest_index(local, mode, sta)];
+}
+
 
 /* functions for rate control related to a device */
 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index 3c552fed2af5..3978ad606b5c 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -2463,9 +2463,8 @@ static int ieee80211_sta_join_ibss(struct net_device *dev,
         struct sk_buff *skb;
         struct ieee80211_mgmt *mgmt;
         struct ieee80211_tx_control control;
-        struct ieee80211_rate *rate;
         struct ieee80211_hw_mode *mode;
-        struct rate_control_extra extra;
+        struct rate_selection ratesel;
         u8 *pos;
         struct ieee80211_sub_if_data *sdata;
 
@@ -2550,18 +2549,16 @@ static int ieee80211_sta_join_ibss(struct net_device *dev,
                 }
 
                 memset(&control, 0, sizeof(control));
-                memset(&extra, 0, sizeof(extra));
-                extra.mode = local->oper_hw_mode;
-                rate = rate_control_get_rate(local, dev, skb, &extra);
-                if (!rate) {
+                rate_control_get_rate(dev, local->oper_hw_mode, skb, &ratesel);
+                if (!ratesel.rate) {
                         printk(KERN_DEBUG "%s: Failed to determine TX rate "
                                "for IBSS beacon\n", dev->name);
                         break;
                 }
                 control.tx_rate =
                         ((sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE) &&
-                        (rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
-                        rate->val2 : rate->val;
+                        (ratesel.rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
+                        ratesel.rate->val2 : ratesel.rate->val;
                 control.antenna_sel_tx = local->hw.conf.antenna_sel_tx;
                 control.power_level = local->hw.conf.power_level;
                 control.flags |= IEEE80211_TXCTL_NO_ACK;
diff --git a/net/mac80211/rc80211_simple.c b/net/mac80211/rc80211_simple.c
index da72737364e4..c1c8b76a56af 100644
--- a/net/mac80211/rc80211_simple.c
+++ b/net/mac80211/rc80211_simple.c
@@ -23,6 +23,8 @@
 /* This is a minimal implementation of TX rate controlling that can be used
  * as the default when no improved mechanisms are available. */
 
+#define RATE_CONTROL_NUM_DOWN 20
+#define RATE_CONTROL_NUM_UP   15
 
 #define RATE_CONTROL_EMERG_DEC 2
 #define RATE_CONTROL_INTERVAL (HZ / 20)
@@ -87,26 +89,6 @@ static void rate_control_rate_dec(struct ieee80211_local *local,
         }
 }
 
-
-static struct ieee80211_rate *
-rate_control_lowest_rate(struct ieee80211_local *local,
-                         struct ieee80211_hw_mode *mode)
-{
-        int i;
-
-        for (i = 0; i < mode->num_rates; i++) {
-                struct ieee80211_rate *rate = &mode->rates[i];
-
-                if (rate->flags & IEEE80211_RATE_SUPPORTED)
-                        return rate;
-        }
-
-        printk(KERN_DEBUG "rate_control_lowest_rate - no supported rates "
-               "found\n");
-        return &mode->rates[0];
-}
-
-
 struct global_rate_control {
         int dummy;
 };
@@ -216,56 +198,32 @@ static void rate_control_simple_tx_status(void *priv, struct net_device *dev,
 }
 
 
-static struct ieee80211_rate *
+static void
 rate_control_simple_get_rate(void *priv, struct net_device *dev,
+                             struct ieee80211_hw_mode *mode,
                              struct sk_buff *skb,
-                             struct rate_control_extra *extra)
+                             struct rate_selection *sel)
 {
         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
-        struct ieee80211_sub_if_data *sdata;
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
-        struct ieee80211_hw_mode *mode = extra->mode;
         struct sta_info *sta;
-        int rateidx, nonerp_idx;
-        u16 fc;
-
-        memset(extra, 0, sizeof(*extra));
-
-        fc = le16_to_cpu(hdr->frame_control);
-        if ((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
-            (hdr->addr1[0] & 0x01)) {
-                /* Send management frames and broadcast/multicast data using
-                 * lowest rate. */
-                /* TODO: this could probably be improved.. */
-                return rate_control_lowest_rate(local, mode);
-        }
+        int rateidx;
 
         sta = sta_info_get(local, hdr->addr1);
 
-        if (!sta)
-                return rate_control_lowest_rate(local, mode);
-
-        sdata = IEEE80211_DEV_TO_SUB_IF(dev);
-        if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
-                sta->txrate = sdata->bss->force_unicast_rateidx;
+        if (!sta) {
+                sel->rate = rate_lowest(local, mode, NULL);
+                return;
+        }
 
         rateidx = sta->txrate;
 
         if (rateidx >= mode->num_rates)
                 rateidx = mode->num_rates - 1;
 
-        sta->last_txrate = rateidx;
-        nonerp_idx = rateidx;
-        while (nonerp_idx > 0 &&
-               ((mode->rates[nonerp_idx].flags & IEEE80211_RATE_ERP) ||
-                !(mode->rates[nonerp_idx].flags & IEEE80211_RATE_SUPPORTED) ||
-                !(sta->supp_rates & BIT(nonerp_idx))))
-                nonerp_idx--;
-        extra->nonerp = &mode->rates[nonerp_idx];
-
         sta_info_put(sta);
 
-        return &mode->rates[rateidx];
+        sel->rate = &mode->rates[rateidx];
 }
 
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 12c15588af68..4655e3038658 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -569,21 +569,17 @@ ieee80211_tx_h_encrypt(struct ieee80211_txrx_data *tx)
 static ieee80211_txrx_result
 ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx)
 {
-        struct rate_control_extra extra;
+        struct rate_selection rsel;
 
         if (likely(!tx->u.tx.rate)) {
-                memset(&extra, 0, sizeof(extra));
-                extra.mode = tx->u.tx.mode;
-                extra.ethertype = tx->ethertype;
-
-                tx->u.tx.rate = rate_control_get_rate(tx->local, tx->dev,
-                                                      tx->skb, &extra);
-                if (unlikely(extra.probe != NULL)) {
+                rate_control_get_rate(tx->dev, tx->u.tx.mode, tx->skb, &rsel);
+                tx->u.tx.rate = rsel.rate;
+                if (unlikely(rsel.probe != NULL)) {
                         tx->u.tx.control->flags |=
                                 IEEE80211_TXCTL_RATE_CTRL_PROBE;
                         tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
                         tx->u.tx.control->alt_retry_rate = tx->u.tx.rate->val;
-                        tx->u.tx.rate = extra.probe;
+                        tx->u.tx.rate = rsel.probe;
                 } else
                         tx->u.tx.control->alt_retry_rate = -1;
 
@@ -594,14 +590,14 @@ ieee80211_tx_h_rate_ctrl(struct ieee80211_txrx_data *tx)
 
         if (tx->u.tx.mode->mode == MODE_IEEE80211G &&
             (tx->sdata->flags & IEEE80211_SDATA_USE_PROTECTION) &&
-            (tx->flags & IEEE80211_TXRXD_FRAGMENTED) && extra.nonerp) {
+            (tx->flags & IEEE80211_TXRXD_FRAGMENTED) && rsel.nonerp) {
                 tx->u.tx.last_frag_rate = tx->u.tx.rate;
-                if (extra.probe)
+                if (rsel.probe)
                         tx->flags &= ~IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
                 else
                         tx->flags |= IEEE80211_TXRXD_TXPROBE_LAST_FRAG;
-                tx->u.tx.rate = extra.nonerp;
-                tx->u.tx.control->rate = extra.nonerp;
+                tx->u.tx.rate = rsel.nonerp;
+                tx->u.tx.control->rate = rsel.nonerp;
                 tx->u.tx.control->flags &= ~IEEE80211_TXCTL_RATE_CTRL_PROBE;
         } else {
                 tx->u.tx.last_frag_rate = tx->u.tx.rate;
@@ -1667,8 +1663,7 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw, int if_id,
         struct net_device *bdev;
         struct ieee80211_sub_if_data *sdata = NULL;
         struct ieee80211_if_ap *ap = NULL;
-        struct ieee80211_rate *rate;
-        struct rate_control_extra extra;
+        struct rate_selection rsel;
         u8 *b_head, *b_tail;
         int bh_len, bt_len;
 
@@ -1712,14 +1707,13 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw, int if_id,
         }
 
         if (control) {
-                memset(&extra, 0, sizeof(extra));
-                extra.mode = local->oper_hw_mode;
-
-                rate = rate_control_get_rate(local, local->mdev, skb, &extra);
-                if (!rate) {
+                rate_control_get_rate(local->mdev, local->oper_hw_mode, skb,
+                                      &rsel);
+                if (!rsel.rate) {
                         if (net_ratelimit()) {
-                                printk(KERN_DEBUG "%s: ieee80211_beacon_get: no rate "
-                                       "found\n", wiphy_name(local->hw.wiphy));
+                                printk(KERN_DEBUG "%s: ieee80211_beacon_get: "
+                                       "no rate found\n",
+                                       wiphy_name(local->hw.wiphy));
                         }
                         dev_kfree_skb(skb);
                         return NULL;
@@ -1727,8 +1721,8 @@ struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw, int if_id,
 
                 control->tx_rate =
                         ((sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE) &&
-                        (rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
-                        rate->val2 : rate->val;
+                        (rsel.rate->flags & IEEE80211_RATE_PREAMBLE2)) ?
+                        rsel.rate->val2 : rsel.rate->val;
                 control->antenna_sel_tx = local->hw.conf.antenna_sel_tx;
                 control->power_level = local->hw.conf.power_level;
                 control->flags |= IEEE80211_TXCTL_NO_ACK;