nl80211: allow enabling WoWLAN without triggers

It may be desirable to use WoWLAN without triggers to
keep the connection alive to the AP while suspended.
Allow this use by enabling WoWLAN without triggers if
no triggers were requested.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -6466,8 +6466,8 @@ static int nl80211_set_wowlan(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	struct nlattr *tb[NUM_NL80211_WOWLAN_TRIG];
-	struct cfg80211_wowlan no_triggers = {};
 	struct cfg80211_wowlan new_triggers = {};
+	struct cfg80211_wowlan *ntrig;
 	struct wiphy_wowlan_support *wowlan = &rdev->wiphy.wowlan;
 	int err, i;
 	bool prev_enabled = rdev->wowlan;
@@ -6475,8 +6475,11 @@ static int nl80211_set_wowlan(struct sk_buff *skb, struct genl_info *info)
 	if (!rdev->wiphy.wowlan.flags && !rdev->wiphy.wowlan.n_patterns)
 		return -EOPNOTSUPP;
 
-	if (!info->attrs[NL80211_ATTR_WOWLAN_TRIGGERS])
-		goto no_triggers;
+	if (!info->attrs[NL80211_ATTR_WOWLAN_TRIGGERS]) {
+		cfg80211_rdev_free_wowlan(rdev);
+		rdev->wowlan = NULL;
+		goto set_wakeup;
+	}
 
 	err = nla_parse(tb, MAX_NL80211_WOWLAN_TRIG,
 			nla_data(info->attrs[NL80211_ATTR_WOWLAN_TRIGGERS]),
@@ -6587,22 +6590,15 @@ static int nl80211_set_wowlan(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
-	if (memcmp(&new_triggers, &no_triggers, sizeof(new_triggers))) {
-		struct cfg80211_wowlan *ntrig;
-		ntrig = kmemdup(&new_triggers, sizeof(new_triggers),
-				GFP_KERNEL);
-		if (!ntrig) {
-			err = -ENOMEM;
-			goto error;
-		}
-		cfg80211_rdev_free_wowlan(rdev);
-		rdev->wowlan = ntrig;
-	} else {
- no_triggers:
-		cfg80211_rdev_free_wowlan(rdev);
-		rdev->wowlan = NULL;
+	ntrig = kmemdup(&new_triggers, sizeof(new_triggers), GFP_KERNEL);
+	if (!ntrig) {
+		err = -ENOMEM;
+		goto error;
 	}
+	cfg80211_rdev_free_wowlan(rdev);
+	rdev->wowlan = ntrig;
 
+ set_wakeup:
 	if (rdev->ops->set_wakeup && prev_enabled != !!rdev->wowlan)
 		rdev->ops->set_wakeup(&rdev->wiphy, rdev->wowlan);