mac80211: clean up association better in suspend

When suspending, bss_info_changed() is called to
disable beacons, but managed mode interfaces are
simply removed (bss_info_changed() is called with
"no change" only). This can lead to problems.

To fix this and copy the BSS configuration, clear
it during suspend and restore it on resume.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -783,6 +783,11 @@ struct ieee80211_sub_if_data {
 		struct dentry *default_mgmt_key;
 	} debugfs;
 #endif
+
+#ifdef CONFIG_PM
+	struct ieee80211_bss_conf suspend_bss_conf;
+#endif
+
 	/* must be last, dynamically sized area in this! */
 	struct ieee80211_vif vif;
 };

net/mac80211/pm.c

@@ -121,6 +121,8 @@ int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
 
 	/* remove all interfaces */
 	list_for_each_entry(sdata, &local->interfaces, list) {
+		u32 changed = BSS_CHANGED_BEACON_ENABLED;
+
 		if (!ieee80211_sdata_running(sdata))
 			continue;
 
@@ -129,14 +131,25 @@ int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
 		case NL80211_IFTYPE_MONITOR:
 			/* skip these */
 			continue;
+		case NL80211_IFTYPE_STATION:
+			if (sdata->vif.bss_conf.assoc)
+				changed = BSS_CHANGED_ASSOC |
+					  BSS_CHANGED_BSSID |
+					  BSS_CHANGED_IDLE;
+			else
+				changed = 0;
+			/* fall through */
 		default:
 			ieee80211_quiesce(sdata);
 			break;
 		}
 
-		/* disable beaconing */
-		ieee80211_bss_info_change_notify(sdata,
-			BSS_CHANGED_BEACON_ENABLED);
+		sdata->suspend_bss_conf = sdata->vif.bss_conf;
+		memset(&sdata->vif.bss_conf, 0, sizeof(sdata->vif.bss_conf));
+		sdata->vif.bss_conf.idle = true;
+
+		/* disable beaconing or remove association */
+		ieee80211_bss_info_change_notify(sdata, changed);
 
 		if (sdata->vif.type == NL80211_IFTYPE_AP &&
 		    rcu_access_pointer(sdata->u.ap.beacon))

net/mac80211/util.c

@@ -1526,6 +1526,11 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 			  BSS_CHANGED_IDLE |
 			  BSS_CHANGED_TXPOWER;
 
+#ifdef CONFIG_PM
+		if (local->resuming)
+			sdata->vif.bss_conf = sdata->suspend_bss_conf;
+#endif
+
 		switch (sdata->vif.type) {
 		case NL80211_IFTYPE_STATION:
 			changed |= BSS_CHANGED_ASSOC |