mac80211: optimise synchronize_net() for sta_info_flush

[~andy/linux] / net / mac80211 / sta_info.c

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 08e50760e092911f1933b92d0bac27f0a3efd410..89d449d0de6d35e26e90d630c4df850577ed876b 100644 (file)
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -794,7 +794,7 @@ static bool sta_info_cleanup_expire_buffered(struct ieee80211_local *local,
        return have_buffered;
 }
 
-int __must_check __sta_info_destroy(struct sta_info *sta)
+static int __must_check __sta_info_destroy_part1(struct sta_info *sta)
 {
        struct ieee80211_local *local;
        struct ieee80211_sub_if_data *sdata;
@@ -831,7 +831,23 @@ int __must_check __sta_info_destroy(struct sta_info *sta)
            rcu_access_pointer(sdata->u.vlan.sta) == sta)
                RCU_INIT_POINTER(sdata->u.vlan.sta, NULL);
 
-       synchronize_net();
+       return 0;
+}
+
+static void __sta_info_destroy_part2(struct sta_info *sta)
+{
+       struct ieee80211_local *local = sta->local;
+       struct ieee80211_sub_if_data *sdata = sta->sdata;
+       int ret;
+
+       /*
+        * NOTE: This assumes at least synchronize_net() was done
+        *       after _part1 and before _part2!
+        */
+
+       might_sleep();
+       lockdep_assert_held(&local->sta_mtx);
+
        /* now keys can no longer be reached */
        ieee80211_free_sta_keys(local, sta);
 
@@ -863,6 +879,18 @@ int __must_check __sta_info_destroy(struct sta_info *sta)
        ieee80211_recalc_min_chandef(sdata);
 
        cleanup_single_sta(sta);
+}
+
+int __must_check __sta_info_destroy(struct sta_info *sta)
+{
+       int err = __sta_info_destroy_part1(sta);
+
+       if (err)
+               return err;
+
+       synchronize_net();
+
+       __sta_info_destroy_part2(sta);
 
        return 0;
 }
@@ -936,6 +964,7 @@ int sta_info_flush(struct ieee80211_sub_if_data *sdata)
 {
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta, *tmp;
+       LIST_HEAD(free_list);
        int ret = 0;
 
        might_sleep();
@@ -943,10 +972,17 @@ int sta_info_flush(struct ieee80211_sub_if_data *sdata)
        mutex_lock(&local->sta_mtx);
        list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {
                if (sdata == sta->sdata) {
-                       WARN_ON(__sta_info_destroy(sta));
+                       if (!WARN_ON(__sta_info_destroy_part1(sta)))
+                               list_add(&sta->free_list, &free_list);
                        ret++;
                }
        }
+
+       if (!list_empty(&free_list)) {
+               synchronize_net();
+               list_for_each_entry_safe(sta, tmp, &free_list, free_list)
+                       __sta_info_destroy_part2(sta);
+       }
        mutex_unlock(&local->sta_mtx);
 
        return ret;