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>

net/wireless/nl80211.c

@@ -2521,23 +2521,8 @@ static int nl80211_stop_ap(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	struct net_device *dev = info->user_ptr[1];
-	struct wireless_dev *wdev = dev->ieee80211_ptr;
-	int err;
 
-	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;
+	return cfg80211_stop_ap(rdev, dev);
 }
 
 static const struct nla_policy sta_flags_policy[NL80211_STA_FLAG_MAX + 1] = {