5 files changed, 84 insertions, 1 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 7ab80660218..0997a0f9620 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -606,6 +606,8 @@ struct ieee80211_local {
 	spinlock_t sta_lock;
 	unsigned long num_sta;
 	struct list_head sta_list;
+	struct list_head sta_flush_list;
+	struct work_struct sta_flush_work;
 	struct sta_info *sta_hash[STA_HASH_SIZE];
 	struct timer_list sta_cleanup;
 
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index c5a47f8d873..75b96a75433 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -2254,7 +2254,7 @@ static int ieee80211_sta_join_ibss(struct net_device *dev,
 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
 	/* Remove possible STA entries from other IBSS networks. */
-	sta_info_flush(local, sdata);
+	sta_info_flush_delayed(sdata);
 
 	if (local->ops->reset_tsf) {
 		/* Reset own TSF to allow time synchronization work. */
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index f91fb409265..5df9e0cc009 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -73,6 +73,15 @@ static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 	if (!key->local->ops->set_key)
 		return;
 
+	/*
+	 * This makes sure that all pending flushes have
+	 * actually completed prior to uploading new key
+	 * material to the hardware. That is necessary to
+	 * avoid races between flushing STAs and adding
+	 * new keys for them.
+	 */
+	__ieee80211_run_pending_flush(key->local);
+
 	addr = get_mac_for_key(key);
 
 	ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index dfca96e05d6..f5c65e89128 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -644,10 +644,41 @@ static void sta_info_debugfs_add_work(struct work_struct *work)
 }
 #endif
 
+void __ieee80211_run_pending_flush(struct ieee80211_local *local)
+{
+	struct sta_info *sta;
+	unsigned long flags;
+
+	ASSERT_RTNL();
+
+	spin_lock_irqsave(&local->sta_lock, flags);
+	while (!list_empty(&local->sta_flush_list)) {
+		sta = list_first_entry(&local->sta_flush_list,
+				       struct sta_info, list);
+		list_del(&sta->list);
+		spin_unlock_irqrestore(&local->sta_lock, flags);
+		sta_info_destroy(sta);
+		spin_lock_irqsave(&local->sta_lock, flags);
+	}
+	spin_unlock_irqrestore(&local->sta_lock, flags);
+}
+
+static void ieee80211_sta_flush_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local, sta_flush_work);
+
+	rtnl_lock();
+	__ieee80211_run_pending_flush(local);
+	rtnl_unlock();
+}
+
 void sta_info_init(struct ieee80211_local *local)
 {
 	spin_lock_init(&local->sta_lock);
 	INIT_LIST_HEAD(&local->sta_list);
+	INIT_LIST_HEAD(&local->sta_flush_list);
+	INIT_WORK(&local->sta_flush_work, ieee80211_sta_flush_work);
 
 	setup_timer(&local->sta_cleanup, sta_info_cleanup,
 		    (unsigned long)local);
@@ -668,7 +699,12 @@ int sta_info_start(struct ieee80211_local *local)
 void sta_info_stop(struct ieee80211_local *local)
 {
 	del_timer(&local->sta_cleanup);
+	cancel_work_sync(&local->sta_flush_work);
+
+	rtnl_lock();
 	sta_info_flush(local, NULL);
+	__ieee80211_run_pending_flush(local);
+	rtnl_unlock();
 }
 
 /**
@@ -688,6 +724,7 @@ int sta_info_flush(struct ieee80211_local *local,
 	unsigned long flags;
 
 	might_sleep();
+	ASSERT_RTNL();
 
 	spin_lock_irqsave(&local->sta_lock, flags);
 	list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
@@ -706,3 +743,36 @@ int sta_info_flush(struct ieee80211_local *local,
 
 	return ret;
 }
+
+/**
+ * sta_info_flush_delayed - flush matching STA entries from the STA table
+ *
+ * This function unlinks all stations for a given interface and queues
+ * them for freeing. Note that the workqueue function scheduled here has
+ * to run before any new keys can be added to the system to avoid set_key()
+ * callback ordering issues.
+ *
+ * @sdata: the interface
+ */
+void sta_info_flush_delayed(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct sta_info *sta, *tmp;
+	unsigned long flags;
+	bool work = false;
+
+	spin_lock_irqsave(&local->sta_lock, flags);
+	list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
+		if (sdata == sta->sdata) {
+			__sta_info_unlink(&sta);
+			if (sta) {
+				list_add_tail(&sta->list,
+					      &local->sta_flush_list);
+				work = true;
+			}
+		}
+	}
+	if (work)
+		schedule_work(&local->sta_flush_work);
+	spin_unlock_irqrestore(&local->sta_lock, flags);
+}
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 5e39a4164b9..b09861eb124 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -357,5 +357,7 @@ int sta_info_start(struct ieee80211_local *local);
 void sta_info_stop(struct ieee80211_local *local);
 int sta_info_flush(struct ieee80211_local *local,
 		    struct ieee80211_sub_if_data *sdata);
+void sta_info_flush_delayed(struct ieee80211_sub_if_data *sdata);
+void __ieee80211_run_pending_flush(struct ieee80211_local *local);
 
 #endif /* STA_INFO_H */