mac80211: make software rate control optional

Some devices implement the entire rate control in
firmware in some way, like wl1271 or like iwlwifi
which does some things in software but not a lot.
Therefore generic software rate control is rather
useless for them and just adds avoidable overhead
to the transmit path.

It's fairly simple to let drivers indicate that
they do not need rate control, but they need to
fulfil a number of conditions that we encode in
WARN_ONs.

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

1 files changed, 6 insertions, 3 deletions

diff --git a/net/mac80211/rate.h b/net/mac80211/rate.h
index 2ab5ad9e71ce..cb9bd1f65e27 100644
--- a/net/mac80211/rate.h
+++ b/net/mac80211/rate.h
@@ -59,6 +59,9 @@ static inline void rate_control_rate_init(struct sta_info *sta)
         void *priv_sta = sta->rate_ctrl_priv;
         struct ieee80211_supported_band *sband;
 
+        if (!ref)
+                return;
+
         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 
         ref->ops->rate_init(ref->priv, sband, ista, priv_sta);
@@ -72,7 +75,7 @@ static inline void rate_control_rate_update(struct ieee80211_local *local,
         struct ieee80211_sta *ista = &sta->sta;
         void *priv_sta = sta->rate_ctrl_priv;
 
-        if (ref->ops->rate_update)
+        if (ref && ref->ops->rate_update)
                 ref->ops->rate_update(ref->priv, sband, ista,
                                       priv_sta, changed);
 }
@@ -97,7 +100,7 @@ static inline void rate_control_add_sta_debugfs(struct sta_info *sta)
 {
 #ifdef CONFIG_MAC80211_DEBUGFS
         struct rate_control_ref *ref = sta->rate_ctrl;
-        if (sta->debugfs.dir && ref->ops->add_sta_debugfs)
+        if (ref && sta->debugfs.dir && ref->ops->add_sta_debugfs)
                 ref->ops->add_sta_debugfs(ref->priv, sta->rate_ctrl_priv,
                                           sta->debugfs.dir);
 #endif
@@ -107,7 +110,7 @@ static inline void rate_control_remove_sta_debugfs(struct sta_info *sta)
 {
 #ifdef CONFIG_MAC80211_DEBUGFS
         struct rate_control_ref *ref = sta->rate_ctrl;
-        if (ref->ops->remove_sta_debugfs)
+        if (ref && ref->ops->remove_sta_debugfs)
                 ref->ops->remove_sta_debugfs(ref->priv, sta->rate_ctrl_priv);
 #endif
 }