mac80211: simplify key locking

Since I recently made station management able
to sleep, I can now rework key management as
well; since it will no longer need a spinlock
and can also use a mutex instead, a bunch of
code to allow drivers' set_key to sleep while
key management is protected by a spinlock can
now be removed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/cfg.c

@@ -120,6 +120,9 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 	struct ieee80211_key *key;
 	int err;
 
+	if (!netif_running(dev))
+		return -ENETDOWN;
+
 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
 	switch (params->cipher) {
@@ -145,7 +148,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 	if (!key)
 		return -ENOMEM;
 
-	rcu_read_lock();
+	mutex_lock(&sdata->local->sta_mtx);
 
 	if (mac_addr) {
 		sta = sta_info_get_bss(sdata, mac_addr);
@@ -160,7 +163,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 
 	err = 0;
  out_unlock:
-	rcu_read_unlock();
+	mutex_unlock(&sdata->local->sta_mtx);
 
 	return err;
 }
@@ -174,7 +177,7 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
 
 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
-	rcu_read_lock();
+	mutex_lock(&sdata->local->sta_mtx);
 
 	if (mac_addr) {
 		ret = -ENOENT;
@@ -202,7 +205,7 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
 
 	ret = 0;
  out_unlock:
-	rcu_read_unlock();
+	mutex_unlock(&sdata->local->sta_mtx);
 
 	return ret;
 }
@@ -305,15 +308,10 @@ static int ieee80211_config_default_key(struct wiphy *wiphy,
 					struct net_device *dev,
 					u8 key_idx)
 {
-	struct ieee80211_sub_if_data *sdata;
-
-	rcu_read_lock();
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
-	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 	ieee80211_set_default_key(sdata, key_idx);
 
-	rcu_read_unlock();
-
 	return 0;
 }
 

net/mac80211/ieee80211_i.h

@@ -746,10 +746,10 @@ struct ieee80211_local {
 	struct mutex iflist_mtx;
 
 	/*
-	 * Key lock, protects sdata's key_list and sta_info's
+	 * Key mutex, protects sdata's key_list and sta_info's
 	 * key pointers (write access, they're RCU.)
 	 */
-	spinlock_t key_lock;
+	struct mutex key_mtx;
 
 
 	/* Scanning and BSS list */

net/mac80211/iface.c

@@ -268,7 +268,6 @@ static int ieee80211_open(struct net_device *dev)
 
 		changed |= ieee80211_reset_erp_info(sdata);
 		ieee80211_bss_info_change_notify(sdata, changed);
-		ieee80211_enable_keys(sdata);
 
 		if (sdata->vif.type == NL80211_IFTYPE_STATION)
 			netif_carrier_off(dev);
@@ -522,8 +521,8 @@ static int ieee80211_stop(struct net_device *dev)
 				BSS_CHANGED_BEACON_ENABLED);
 		}
 
-		/* disable all keys for as long as this netdev is down */
-		ieee80211_disable_keys(sdata);
+		/* free all remaining keys, there shouldn't be any */
+		ieee80211_free_keys(sdata);
 		drv_remove_interface(local, &sdata->vif);
 	}
 

net/mac80211/key.h

@@ -38,25 +38,9 @@ struct sta_info;
  *
  * @KEY_FLAG_UPLOADED_TO_HARDWARE: Indicates that this key is present
  *	in the hardware for TX crypto hardware acceleration.
- * @KEY_FLAG_TODO_DELETE: Key is marked for deletion and will, after an
- *	RCU grace period, no longer be reachable other than from the
- *	todo list.
- * @KEY_FLAG_TODO_HWACCEL_ADD: Key needs to be added to hardware acceleration.
- * @KEY_FLAG_TODO_HWACCEL_REMOVE: Key needs to be removed from hardware
- *	acceleration.
- * @KEY_FLAG_TODO_DEFKEY: Key is default key and debugfs needs to be updated.
- * @KEY_FLAG_TODO_ADD_DEBUGFS: Key needs to be added to debugfs.
- * @KEY_FLAG_TODO_DEFMGMTKEY: Key is default management key and debugfs needs
- *	to be updated.
  */
 enum ieee80211_internal_key_flags {
 	KEY_FLAG_UPLOADED_TO_HARDWARE	= BIT(0),
-	KEY_FLAG_TODO_DELETE		= BIT(1),
-	KEY_FLAG_TODO_HWACCEL_ADD	= BIT(2),
-	KEY_FLAG_TODO_HWACCEL_REMOVE	= BIT(3),
-	KEY_FLAG_TODO_DEFKEY		= BIT(4),
-	KEY_FLAG_TODO_ADD_DEBUGFS	= BIT(5),
-	KEY_FLAG_TODO_DEFMGMTKEY	= BIT(6),
 };
 
 enum ieee80211_internal_tkip_state {
@@ -79,10 +63,8 @@ struct ieee80211_key {
 
 	/* for sdata list */
 	struct list_head list;
-	/* for todo list */
-	struct list_head todo;
 
-	/* protected by todo lock! */
+	/* protected by key mutex */
 	unsigned int flags;
 
 	union {
@@ -155,6 +137,4 @@ void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata);
 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata);
 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata);
 
-void ieee80211_key_todo(void);
-
 #endif /* IEEE80211_KEY_H */

net/mac80211/main.c

@@ -448,7 +448,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	mutex_init(&local->iflist_mtx);
 	mutex_init(&local->scan_mtx);
 
-	spin_lock_init(&local->key_lock);
+	mutex_init(&local->key_mtx);
 	spin_lock_init(&local->filter_lock);
 	spin_lock_init(&local->queue_stop_reason_lock);
 

net/mac80211/sta_info.c

@@ -648,14 +648,6 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
 
 	if (sta->key) {
 		ieee80211_key_free(sta->key);
-		/*
-		 * We have only unlinked the key, and actually destroying it
-		 * may mean it is removed from hardware which requires that
-		 * the key->sta pointer is still valid, so flush the key todo
-		 * list here.
-		 */
-		ieee80211_key_todo();
-
 		WARN_ON(sta->key);
 	}