mac80211: add min required channel definition field

Add a new field to ieee80211_chanctx_conf to indicate
the min required channel configuration.

Tuning to a narrower channel might help reducing
the noise level and saving some power.

The min required channel definition is the max of
all min required channel definitions of the interfaces
bound to this channel context.

In AP mode, use 20MHz when there are no connected station.
When a new station is added/removed, calculate the new max
bandwidth supported by any of the stations (e.g. 80MHz when
80MHz and 40MHz stations are connected).

In other cases, simply use bss_conf.chandef as the
min required chandef.

Notify drivers about changes to this field by calling
drv_change_chanctx with a new CHANGE_MIN_WIDTH notification.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index bb92f8e0f84e..06265d7f8cc3 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1804,6 +1804,26 @@ void ieee80211_recalc_smps(struct ieee80211_sub_if_data *sdata)
 	mutex_unlock(&local->chanctx_mtx);
 }
 
+void ieee80211_recalc_min_chandef(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx_conf *chanctx_conf;
+	struct ieee80211_chanctx *chanctx;
+
+	mutex_lock(&local->chanctx_mtx);
+
+	chanctx_conf = rcu_dereference_protected(sdata->vif.chanctx_conf,
+					lockdep_is_held(&local->chanctx_mtx));
+
+	if (WARN_ON_ONCE(!chanctx_conf))
+		goto unlock;
+
+	chanctx = container_of(chanctx_conf, struct ieee80211_chanctx, conf);
+	ieee80211_recalc_chanctx_min_def(local, chanctx);
+ unlock:
+	mutex_unlock(&local->chanctx_mtx);
+}
+
 static bool ieee80211_id_in_list(const u8 *ids, int n_ids, u8 id)
 {
 	int i;