wifi: mac80211: implement proper AP MLD HW restart

Previously, I didn't implement restarting here at all if the
interface is an MLD, so it only worked for non-MLO. Add the
needed code to restart an AP MLD correctly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230504134511.828474-12-gregory.greenman@intel.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/util.c

@@ -2475,6 +2475,35 @@ static int ieee80211_reconfig_nan(struct ieee80211_sub_if_data *sdata)
 	return 0;
 }
 
+static void ieee80211_reconfig_ap_links(struct ieee80211_local *local,
+					struct ieee80211_sub_if_data *sdata,
+					u32 changed)
+{
+	int link_id;
+
+	for (link_id = 0; link_id < ARRAY_SIZE(sdata->link); link_id++) {
+		struct ieee80211_link_data *link;
+
+		if (!(sdata->vif.active_links & BIT(link_id)))
+			continue;
+
+		link = sdata_dereference(sdata->link[link_id], sdata);
+		if (!link)
+			continue;
+
+		if (rcu_access_pointer(link->u.ap.beacon))
+			drv_start_ap(local, sdata, link->conf);
+
+		if (!link->conf->enable_beacon)
+			continue;
+
+		changed |= BSS_CHANGED_BEACON |
+			   BSS_CHANGED_BEACON_ENABLED;
+
+		ieee80211_link_info_change_notify(sdata, link, changed);
+	}
+}
+
 int ieee80211_reconfig(struct ieee80211_local *local)
 {
 	struct ieee80211_hw *hw = &local->hw;
@@ -2737,7 +2766,13 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 			changed |= BSS_CHANGED_IBSS;
 			fallthrough;
 		case NL80211_IFTYPE_AP:
-			changed |= BSS_CHANGED_SSID | BSS_CHANGED_P2P_PS;
+			changed |= BSS_CHANGED_P2P_PS;
+
+			if (sdata->vif.valid_links)
+				ieee80211_vif_cfg_change_notify(sdata,
+								BSS_CHANGED_SSID);
+			else
+				changed |= BSS_CHANGED_SSID;
 
 			if (sdata->vif.bss_conf.ftm_responder == 1 &&
 			    wiphy_ext_feature_isset(sdata->local->hw.wiphy,
@@ -2747,6 +2782,13 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 			if (sdata->vif.type == NL80211_IFTYPE_AP) {
 				changed |= BSS_CHANGED_AP_PROBE_RESP;
 
+				if (sdata->vif.valid_links) {
+					ieee80211_reconfig_ap_links(local,
+								    sdata,
+								    changed);
+					break;
+				}
+
 				if (rcu_access_pointer(sdata->deflink.u.ap.beacon))
 					drv_start_ap(local, sdata,
 						     sdata->deflink.conf);