mac80211: iterate the virtual monitor interface

If the virtual monitor interface is requested
by the driver, it should also be iterated over
when the driver wants to iterate all active
interfaces.

To allow that protect it with the iflist_mtx.

Change-Id: I58ac5de2f4ce93d12c5a98ecd2859f60158d5d69
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 19 insertions, 10 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index e3c49748ce8f..334ee0fb18ca 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -334,17 +334,21 @@ static void ieee80211_set_default_queues(struct ieee80211_sub_if_data *sdata)
 int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
 {
         struct ieee80211_sub_if_data *sdata;
-        int ret;
+        int ret = 0;
 
         if (!(local->hw.flags & IEEE80211_HW_WANT_MONITOR_VIF))
                 return 0;
 
+        mutex_lock(&local->iflist_mtx);
+
         if (local->monitor_sdata)
-                return 0;
+                goto out_unlock;
 
         sdata = kzalloc(sizeof(*sdata) + local->hw.vif_data_size, GFP_KERNEL);
-        if (!sdata)
-                return -ENOMEM;
+        if (!sdata) {
+                ret = -ENOMEM;
+                goto out_unlock;
+        }
 
         /* set up data */
         sdata->local = local;
@@ -358,18 +362,19 @@ int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
         if (WARN_ON(ret)) {
                 /* ok .. stupid driver, it asked for this! */
                 kfree(sdata);
-                return ret;
+                goto out_unlock;
         }
 
         ret = ieee80211_check_queues(sdata);
         if (ret) {
                 kfree(sdata);
-                return ret;
+                goto out_unlock;
         }
 
         rcu_assign_pointer(local->monitor_sdata, sdata);
-
-        return 0;
+ out_unlock:
+        mutex_unlock(&local->iflist_mtx);
+        return ret;
 }
 
 void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
@@ -379,10 +384,12 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
         if (!(local->hw.flags & IEEE80211_HW_WANT_MONITOR_VIF))
                 return;
 
-        sdata = rtnl_dereference(local->monitor_sdata);
+        mutex_lock(&local->iflist_mtx);
 
+        sdata = rcu_dereference_protected(local->monitor_sdata,
+                                          lockdep_is_held(&local->iflist_mtx));
         if (!sdata)
-                return;
+                goto out_unlock;
 
         rcu_assign_pointer(local->monitor_sdata, NULL);
         synchronize_net();
@@ -390,6 +397,8 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
         drv_remove_interface(local, sdata);
 
         kfree(sdata);
+ out_unlock:
+        mutex_unlock(&local->iflist_mtx);
 }
 
 /*