4 files changed, 47 insertions, 0 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index e030c6af86dd..f0d213dd8fe7 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1499,6 +1499,8 @@ struct cfg80211_gtk_rekey_data {
  *      interfaces are active this callback should reject the configuration.
  *      If no interfaces are active or the device is down, the channel should
  *      be stored for when a monitor interface becomes active.
+ * @set_monitor_enabled: Notify driver that there are only monitor
+ *      interfaces running.
  * @get_channel: Get the current operating channel, should return %NULL if
  *      there's no single defined operating channel if for example the
  *      device implements channel hopping for multi-channel virtual interfaces.
@@ -1817,6 +1819,8 @@ struct cfg80211_ops {
                                 struct ethtool_stats *stats, u64 *data);
         void    (*get_et_strings)(struct wiphy *wiphy, struct net_device *dev,
                                   u32 sset, u8 *data);
+
+        void (*set_monitor_enabled)(struct wiphy *wiphy, bool enabled);
 };
 
 /*
diff --git a/net/wireless/core.c b/net/wireless/core.c
index c65f59c952c9..8412da7d0f25 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -717,6 +717,24 @@ static struct device_type wiphy_type = {
         .name   = "wlan",
 };
 
+void cfg80211_update_iface_num(struct cfg80211_registered_device *rdev,
+                               enum nl80211_iftype iftype, int num)
+{
+        bool has_monitors_only_old = cfg80211_has_monitors_only(rdev);
+        bool has_monitors_only_new;
+
+        ASSERT_RDEV_LOCK(rdev);
+
+        rdev->num_running_ifaces += num;
+        if (iftype == NL80211_IFTYPE_MONITOR)
+                rdev->num_running_monitor_ifaces += num;
+
+        has_monitors_only_new = cfg80211_has_monitors_only(rdev);
+        if (has_monitors_only_new != has_monitors_only_old)
+                rdev->ops->set_monitor_enabled(&rdev->wiphy,
+                                               has_monitors_only_new);
+}
+
 static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
                                          unsigned long state,
                                          void *ndev)
@@ -820,6 +838,9 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
                 break;
         case NETDEV_DOWN:
                 dev_hold(dev);
+                cfg80211_lock_rdev(rdev);
+                cfg80211_update_iface_num(rdev, wdev->iftype, -1);
+                cfg80211_unlock_rdev(rdev);
                 queue_work(cfg80211_wq, &wdev->cleanup_work);
                 break;
         case NETDEV_UP:
@@ -927,6 +948,9 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
                 ret = cfg80211_can_add_interface(rdev, wdev->iftype);
                 if (ret)
                         return notifier_from_errno(ret);
+                cfg80211_lock_rdev(rdev);
+                cfg80211_update_iface_num(rdev, wdev->iftype, 1);
+                cfg80211_unlock_rdev(rdev);
                 break;
         }
 
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 56f18c2eb919..99acd51343b1 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -56,6 +56,9 @@ struct cfg80211_registered_device {
 
         u32 ap_beacons_nlpid;
 
+        int num_running_ifaces;
+        int num_running_monitor_ifaces;
+
         /* BSSes/scanning */
         spinlock_t bss_lock;
         struct list_head bss_list;
@@ -197,6 +200,14 @@ static inline void wdev_unlock(struct wireless_dev *wdev)
 #define ASSERT_RDEV_LOCK(rdev) lockdep_assert_held(&(rdev)->mtx)
 #define ASSERT_WDEV_LOCK(wdev) lockdep_assert_held(&(wdev)->mtx)
 
+static inline bool cfg80211_has_monitors_only(struct cfg80211_registered_device *rdev)
+{
+        ASSERT_RDEV_LOCK(rdev);
+
+        return rdev->num_running_ifaces == rdev->num_running_monitor_ifaces &&
+               rdev->num_running_ifaces > 0;
+}
+
 enum cfg80211_event_type {
         EVENT_CONNECT_RESULT,
         EVENT_ROAMED,
@@ -444,6 +455,9 @@ int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
 int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
                                  u32 beacon_int);
 
+void cfg80211_update_iface_num(struct cfg80211_registered_device *rdev,
+                               enum nl80211_iftype iftype, int num);
+
 #ifdef CONFIG_CFG80211_DEVELOPER_WARNINGS
 #define CFG80211_DEV_WARN_ON(cond)      WARN_ON(cond)
 #else
diff --git a/net/wireless/util.c b/net/wireless/util.c
index fc948d0a53f3..9b92ec57d07b 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -871,6 +871,11 @@ int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
                 }
         }
 
+        if (!err && ntype != otype && netif_running(dev)) {
+                cfg80211_update_iface_num(rdev, ntype, 1);
+                cfg80211_update_iface_num(rdev, otype, -1);
+        }
+
         return err;
 }