mac80211: free all AP/VLAN keys at once

When the AP interface is stopped, free all AP and VLAN keys at
once to only require synchronize_net() once. Since that does
synchronize_net(), also move two such calls into the function
(using the new force_synchronize parameter) to avoid doing it
twice.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 43 insertions, 28 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 18b56fb7911e..8718401cbd89 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1098,10 +1098,7 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev)
                 kfree_rcu(old_probe_resp, rcu_head);
 
         __sta_info_flush(sdata, true);
-        synchronize_net();
-        list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
-                ieee80211_free_keys(vlan);
-        ieee80211_free_keys(sdata);
+        ieee80211_free_keys(sdata, true);
 
         sdata->vif.bss_conf.enable_beacon = false;
         sdata->vif.bss_conf.ssid_len = 0;
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 687d4eacd6ff..3d2168c3269e 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -889,18 +889,15 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                 cancel_work_sync(&sdata->work);
                 /*
                  * When we get here, the interface is marked down.
+                 * Free the remaining keys, if there are any
+                 * (shouldn't be, except maybe in WDS mode?)
                  *
-                 * We need synchronize_rcu() to wait for the RX path in
-                 * case it is using the interface and enqueuing frames
-                 * at this very time on another CPU.
+                 * Force the key freeing to always synchronize_net()
+                 * to wait for the RX path in case it is using this
+                 * interface enqueuing frames * at this very time on
+                 * another CPU.
                  */
-                synchronize_rcu();
-
-                /*
-                 * Free all remaining keys, there shouldn't be any,
-                 * except maybe in WDS mode?
-                 */
-                ieee80211_free_keys(sdata);
+                ieee80211_free_keys(sdata, true);
 
                 /* fall through */
         case NL80211_IFTYPE_AP:
@@ -1026,7 +1023,7 @@ static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata)
         int i;
 
         /* free extra data */
-        ieee80211_free_keys(sdata);
+        ieee80211_free_keys(sdata, false);
 
         ieee80211_debugfs_remove_netdev(sdata);
 
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 12e61543a37c..6ff65a1ebaa9 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -589,14 +589,10 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL(ieee80211_iter_keys);
 
-void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
+static void ieee80211_free_keys_iface(struct ieee80211_sub_if_data *sdata,
+                                      struct list_head *keys)
 {
         struct ieee80211_key *key, *tmp;
-        LIST_HEAD(keys);
-
-        cancel_delayed_work_sync(&sdata->dec_tailroom_needed_wk);
-
-        mutex_lock(&sdata->local->key_mtx);
 
         sdata->crypto_tx_tailroom_needed_cnt -=
                 sdata->crypto_tx_tailroom_pending_dec;
@@ -608,21 +604,45 @@ void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
                 ieee80211_key_replace(key->sdata, key->sta,
                                 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
                                 key, NULL);
-                list_add_tail(&key->list, &keys);
+                list_add_tail(&key->list, keys);
         }
 
         ieee80211_debugfs_key_update_default(sdata);
+}
 
-        if (!list_empty(&keys)) {
-                synchronize_net();
-                list_for_each_entry_safe(key, tmp, &keys, list)
-                        __ieee80211_key_destroy(key, false);
+void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata,
+                         bool force_synchronize)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_sub_if_data *vlan;
+        struct ieee80211_key *key, *tmp;
+        LIST_HEAD(keys);
+
+        cancel_delayed_work_sync(&sdata->dec_tailroom_needed_wk);
+
+        mutex_lock(&local->key_mtx);
+
+        ieee80211_free_keys_iface(sdata, &keys);
+
+        if (sdata->vif.type == NL80211_IFTYPE_AP) {
+                list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+                        ieee80211_free_keys_iface(vlan, &keys);
         }
 
+        if (!list_empty(&keys) || force_synchronize)
+                synchronize_net();
+        list_for_each_entry_safe(key, tmp, &keys, list)
+                __ieee80211_key_destroy(key, false);
+
         WARN_ON_ONCE(sdata->crypto_tx_tailroom_needed_cnt ||
                      sdata->crypto_tx_tailroom_pending_dec);
+        if (sdata->vif.type == NL80211_IFTYPE_AP) {
+                list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+                        WARN_ON_ONCE(vlan->crypto_tx_tailroom_needed_cnt ||
+                                     vlan->crypto_tx_tailroom_pending_dec);
+        }
 
-        mutex_unlock(&sdata->local->key_mtx);
+        mutex_unlock(&local->key_mtx);
 }
 
 void ieee80211_free_sta_keys(struct ieee80211_local *local,
diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index 0aebb889caba..19db68663d75 100644
--- a/net/mac80211/key.h
+++ b/net/mac80211/key.h
@@ -136,7 +136,8 @@ void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
                                bool uni, bool multi);
 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
                                     int idx);
-void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata);
+void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata,
+                         bool force_synchronize);
 void ieee80211_free_sta_keys(struct ieee80211_local *local,
                              struct sta_info *sta);
 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata);