cfg80211: introduce cfg80211_stop_ap

This functionality will be reused when interface
is going down. Avoids code duplication. Also adds
missing wdev locking.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/ap.c b/net/wireless/ap.c
new file mode 100644
index 0000000..45199cc
--- /dev/null
+++ b/net/wireless/ap.c
@@ -0,0 +1,44 @@
+#include <linux/ieee80211.h>
+#include <linux/export.h>
+#include <net/cfg80211.h>
+#include "nl80211.h"
+#include "core.h"
+
+
+static int __cfg80211_stop_ap(struct cfg80211_registered_device *rdev,
+			      struct net_device *dev)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	int err;
+
+	ASSERT_WDEV_LOCK(wdev);
+
+	if (!rdev->ops->stop_ap)
+		return -EOPNOTSUPP;
+
+	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
+	    dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
+		return -EOPNOTSUPP;
+
+	if (!wdev->beacon_interval)
+		return -ENOENT;
+
+	err = rdev->ops->stop_ap(&rdev->wiphy, dev);
+	if (!err)
+		wdev->beacon_interval = 0;
+
+	return err;
+}
+
+int cfg80211_stop_ap(struct cfg80211_registered_device *rdev,
+		     struct net_device *dev)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	int err;
+
+	wdev_lock(wdev);
+	err = __cfg80211_stop_ap(rdev, dev);
+	wdev_unlock(wdev);
+
+	return err;
+}