cfg80211: simplify netlink socket owner interface deletion

There's no need to allocate a portid structure and then, for
each of those, walk the interfaces - we can just add a flag
to each interface and walk those directly. Due to padding in
the struct, we can even do it without any memory cost, and
it even simplifies the code.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -3988,6 +3988,7 @@ struct cfg80211_cqm_config;
  * @event_list: (private) list for internal event processing
  * @event_lock: (private) lock for event list
  * @owner_nlportid: (private) owner socket port ID
+ * @nl_owner_dead: (private) owner socket went away
  * @cqm_config: (private) nl80211 RSSI monitor state
  */
 struct wireless_dev {
@@ -4037,12 +4038,13 @@ struct wireless_dev {
 
 	u32 ap_unexpected_nlportid;
 
+	u32 owner_nlportid;
+	bool nl_owner_dead;
+
 	bool cac_started;
 	unsigned long cac_start_time;
 	unsigned int cac_time_ms;
 
-	u32 owner_nlportid;
-
 #ifdef CONFIG_CFG80211_WEXT
 	/* wext data */
 	struct {

net/wireless/core.c

@@ -305,30 +305,14 @@ static void cfg80211_event_work(struct work_struct *work)
 
 void cfg80211_destroy_ifaces(struct cfg80211_registered_device *rdev)
 {
-	struct cfg80211_iface_destroy *item;
+	struct wireless_dev *wdev, *tmp;
 
 	ASSERT_RTNL();
 
-	spin_lock_irq(&rdev->destroy_list_lock);
-	while ((item = list_first_entry_or_null(&rdev->destroy_list,
-						struct cfg80211_iface_destroy,
-						list))) {
-		struct wireless_dev *wdev, *tmp;
-		u32 nlportid = item->nlportid;
-
-		list_del(&item->list);
-		kfree(item);
-		spin_unlock_irq(&rdev->destroy_list_lock);
-
-		list_for_each_entry_safe(wdev, tmp,
-					 &rdev->wiphy.wdev_list, list) {
-			if (nlportid == wdev->owner_nlportid)
-				rdev_del_virtual_intf(rdev, wdev);
-		}
-
-		spin_lock_irq(&rdev->destroy_list_lock);
+	list_for_each_entry_safe(wdev, tmp, &rdev->wiphy.wdev_list, list) {
+		if (wdev->nl_owner_dead)
+			rdev_del_virtual_intf(rdev, wdev);
 	}
-	spin_unlock_irq(&rdev->destroy_list_lock);
 }
 
 static void cfg80211_destroy_iface_wk(struct work_struct *work)
@@ -484,8 +468,6 @@ struct wiphy *wiphy_new_nm(const struct cfg80211_ops *ops, int sizeof_priv,
 	rdev->wiphy.dev.platform_data = rdev;
 	device_enable_async_suspend(&rdev->wiphy.dev);
 
-	INIT_LIST_HEAD(&rdev->destroy_list);
-	spin_lock_init(&rdev->destroy_list_lock);
 	INIT_WORK(&rdev->destroy_work, cfg80211_destroy_iface_wk);
 	INIT_WORK(&rdev->sched_scan_stop_wk, cfg80211_sched_scan_stop_wk);
 	INIT_WORK(&rdev->propagate_radar_detect_wk,

net/wireless/core.h

@@ -91,10 +91,7 @@ struct cfg80211_registered_device {
 
 	struct cfg80211_coalesce *coalesce;
 
-	spinlock_t destroy_list_lock;
-	struct list_head destroy_list;
 	struct work_struct destroy_work;
-
 	struct work_struct sched_scan_stop_wk;
 
 	struct cfg80211_chan_def radar_chandef;
@@ -264,11 +261,6 @@ struct cfg80211_beacon_registration {
 	u32 nlportid;
 };
 
-struct cfg80211_iface_destroy {
-	struct list_head list;
-	u32 nlportid;
-};
-
 struct cfg80211_cqm_config {
 	u32 rssi_hyst;
 	s32 last_rssi_event_value;

net/wireless/nl80211.c

@@ -14883,7 +14883,6 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 	rcu_read_lock();
 
 	list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list) {
-		bool schedule_destroy_work = false;
 		struct cfg80211_sched_scan_request *sched_scan_req =
 			rcu_dereference(rdev->sched_scan_req);
 
@@ -14899,10 +14898,12 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 		list_for_each_entry_rcu(wdev, &rdev->wiphy.wdev_list, list) {
 			cfg80211_mlme_unregister_socket(wdev, notify->portid);
 
-			if (wdev->owner_nlportid == notify->portid)
-				schedule_destroy_work = true;
-			else if (wdev->conn_owner_nlportid == notify->portid)
+			if (wdev->owner_nlportid == notify->portid) {
+				wdev->nl_owner_dead = true;
+				schedule_work(&rdev->destroy_work);
+			} else if (wdev->conn_owner_nlportid == notify->portid) {
 				schedule_work(&wdev->disconnect_wk);
+			}
 		}
 
 		spin_lock_bh(&rdev->beacon_registrations_lock);
@@ -14915,19 +14916,6 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 			}
 		}
 		spin_unlock_bh(&rdev->beacon_registrations_lock);
-
-		if (schedule_destroy_work) {
-			struct cfg80211_iface_destroy *destroy;
-
-			destroy = kzalloc(sizeof(*destroy), GFP_ATOMIC);
-			if (destroy) {
-				destroy->nlportid = notify->portid;
-				spin_lock(&rdev->destroy_list_lock);
-				list_add(&destroy->list, &rdev->destroy_list);
-				spin_unlock(&rdev->destroy_list_lock);
-				schedule_work(&rdev->destroy_work);
-			}
-		}
 	}
 
 	rcu_read_unlock();