mac80211: acquire sta_lock for station suspend/resume

To avoid concurrent manipulations of the sta list (which shouldn't
be possible at this point, but anyway) we need to hold the sta_lock
around iterating the list.

At the same time, we do not need to iterate the list at all if
the driver doesn't want to be notified.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/net/mac80211/pm.c b/net/mac80211/pm.c
index c923ceb089a3..ef7be1ce2c87 100644
--- a/net/mac80211/pm.c
+++ b/net/mac80211/pm.c
@@ -10,6 +10,7 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
         struct ieee80211_sub_if_data *sdata;
         struct ieee80211_if_init_conf conf;
         struct sta_info *sta;
+        unsigned long flags;
 
         ieee80211_stop_queues_by_reason(hw,
                         IEEE80211_QUEUE_STOP_REASON_SUSPEND);
@@ -21,9 +22,9 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
                 ieee80211_disable_keys(sdata);
 
         /* remove STAs */
-        list_for_each_entry(sta, &local->sta_list, list) {
-
-                if (local->ops->sta_notify) {
+        if (local->ops->sta_notify) {
+                spin_lock_irqsave(&local->sta_lock, flags);
+                list_for_each_entry(sta, &local->sta_list, list) {
                         if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                                 sdata = container_of(sdata->bss,
                                              struct ieee80211_sub_if_data,
@@ -32,11 +33,11 @@ int __ieee80211_suspend(struct ieee80211_hw *hw)
                         local->ops->sta_notify(hw, &sdata->vif,
                                 STA_NOTIFY_REMOVE, &sta->sta);
                 }
+                spin_unlock_irqrestore(&local->sta_lock, flags);
         }
 
         /* remove all interfaces */
         list_for_each_entry(sdata, &local->interfaces, list) {
-
                 if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
                     sdata->vif.type != NL80211_IFTYPE_MONITOR &&
                     netif_running(sdata->dev)) {
@@ -64,6 +65,7 @@ int __ieee80211_resume(struct ieee80211_hw *hw)
         struct ieee80211_sub_if_data *sdata;
         struct ieee80211_if_init_conf conf;
         struct sta_info *sta;
+        unsigned long flags;
         int res;
 
         /* restart hardware */
@@ -75,7 +77,6 @@ int __ieee80211_resume(struct ieee80211_hw *hw)
 
         /* add interfaces */
         list_for_each_entry(sdata, &local->interfaces, list) {
-
                 if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
                     sdata->vif.type != NL80211_IFTYPE_MONITOR &&
                     netif_running(sdata->dev)) {
@@ -87,9 +88,9 @@ int __ieee80211_resume(struct ieee80211_hw *hw)
         }
 
         /* add STAs back */
-        list_for_each_entry(sta, &local->sta_list, list) {
-
-                if (local->ops->sta_notify) {
+        if (local->ops->sta_notify) {
+                spin_lock_irqsave(&local->sta_lock, flags);
+                list_for_each_entry(sta, &local->sta_list, list) {
                         if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                                 sdata = container_of(sdata->bss,
                                              struct ieee80211_sub_if_data,
@@ -98,6 +99,7 @@ int __ieee80211_resume(struct ieee80211_hw *hw)
                         local->ops->sta_notify(hw, &sdata->vif,
                                 STA_NOTIFY_ADD, &sta->sta);
                 }
+                spin_unlock_irqrestore(&local->sta_lock, flags);
         }
 
         /* add back keys */