wifi: mac80211: Support multi link in ieee80211_recalc_min_chandef()

Recalculate min channel context for the given or all interface
links, depending on the caller. For a station state change, we
need to recalculate all of them since we don't know which link
(or multiple) it might be on.
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -2335,7 +2335,8 @@ int __ieee80211_request_smps_mgd(struct ieee80211_sub_if_data *sdata,
 				 enum ieee80211_smps_mode smps_mode);
 void ieee80211_recalc_smps(struct ieee80211_sub_if_data *sdata,
 			   struct ieee80211_link_data *link);
-void ieee80211_recalc_min_chandef(struct ieee80211_sub_if_data *sdata);
+void ieee80211_recalc_min_chandef(struct ieee80211_sub_if_data *sdata,
+				  int link_id);
 
 size_t ieee80211_ie_split_vendor(const u8 *ies, size_t ielen, size_t offset);
 u8 *ieee80211_ie_build_ht_cap(u8 *pos, struct ieee80211_sta_ht_cap *ht_cap,

net/mac80211/sta_info.c

@@ -780,7 +780,7 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU)
 	 * change, this enables driver using the updated channel context right away.
 	 */
 	if (sta->sta_state >= IEEE80211_STA_ASSOC) {
-		ieee80211_recalc_min_chandef(sta->sdata);
+		ieee80211_recalc_min_chandef(sta->sdata, -1);
 		if (!sta->sta.support_p2p_ps)
 			ieee80211_recalc_p2p_go_ps_allowed(sta->sdata);
 	}
@@ -2136,7 +2136,7 @@ int sta_info_move_state(struct sta_info *sta,
 			set_bit(WLAN_STA_AUTH, &sta->_flags);
 		} else if (sta->sta_state == IEEE80211_STA_ASSOC) {
 			clear_bit(WLAN_STA_ASSOC, &sta->_flags);
-			ieee80211_recalc_min_chandef(sta->sdata);
+			ieee80211_recalc_min_chandef(sta->sdata, -1);
 			if (!sta->sta.support_p2p_ps)
 				ieee80211_recalc_p2p_go_ps_allowed(sta->sdata);
 		}
@@ -2145,7 +2145,7 @@ int sta_info_move_state(struct sta_info *sta,
 		if (sta->sta_state == IEEE80211_STA_AUTH) {
 			set_bit(WLAN_STA_ASSOC, &sta->_flags);
 			sta->assoc_at = ktime_get_boottime_ns();
-			ieee80211_recalc_min_chandef(sta->sdata);
+			ieee80211_recalc_min_chandef(sta->sdata, -1);
 			if (!sta->sta.support_p2p_ps)
 				ieee80211_recalc_p2p_go_ps_allowed(sta->sdata);
 		} else if (sta->sta_state == IEEE80211_STA_AUTHORIZED) {

net/mac80211/util.c

@@ -2839,22 +2839,48 @@ 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)
+void ieee80211_recalc_min_chandef(struct ieee80211_sub_if_data *sdata,
+				  int link_id)
 {
 	struct ieee80211_local *local = sdata->local;
 	struct ieee80211_chanctx_conf *chanctx_conf;
 	struct ieee80211_chanctx *chanctx;
+	int i;
 
 	mutex_lock(&local->chanctx_mtx);
 
-	chanctx_conf = rcu_dereference_protected(sdata->vif.bss_conf.chanctx_conf,
-						 lockdep_is_held(&local->chanctx_mtx));
+	for (i = 0; i < ARRAY_SIZE(sdata->vif.link_conf); i++) {
+		struct ieee80211_bss_conf *bss_conf;
 
-	if (WARN_ON_ONCE(!chanctx_conf))
-		goto unlock;
+		if (link_id >= 0 && link_id != i)
+			continue;
 
-	chanctx = container_of(chanctx_conf, struct ieee80211_chanctx, conf);
-	ieee80211_recalc_chanctx_min_def(local, chanctx);
+		rcu_read_lock();
+		bss_conf = rcu_dereference(sdata->vif.link_conf[i]);
+		if (!bss_conf) {
+			rcu_read_unlock();
+			continue;
+		}
+
+		chanctx_conf = rcu_dereference_protected(bss_conf->chanctx_conf,
+							 lockdep_is_held(&local->chanctx_mtx));
+		/*
+		 * Since we hold the chanctx_mtx (checked above)
+		 * we can take the chanctx_conf pointer out of the
+		 * RCU critical section, it cannot go away without
+		 * the mutex. Just the way we reached it could - in
+		 * theory - go away, but we don't really care and
+		 * it really shouldn't happen anyway.
+		 */
+		rcu_read_unlock();
+
+		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);
 }

net/mac80211/vht.c

@@ -731,7 +731,7 @@ void ieee80211_vht_handle_opmode(struct ieee80211_sub_if_data *sdata,
 						    opmode, band);
 
 	if (changed > 0) {
-		ieee80211_recalc_min_chandef(sdata);
+		ieee80211_recalc_min_chandef(sdata, link_sta->link_id);
 		rate_control_rate_update(local, sband, link_sta->sta,
 					 link_sta->link_id, changed);
 	}