nl80211: nl80211hdr_put() doesn't return an ERR_PTR

There are a few places which check nl80211hdr_put() for an ERR_PTR
but actually it returns NULL on error and never error values.  In
nl80211_testmode_dump() the return wasn't checked at all so I have
added one.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[some whitespace changes]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -2622,8 +2622,8 @@ static int nl80211_get_key(struct sk_buff *skb, struct genl_info *info)
 
 	hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
 			     NL80211_CMD_NEW_KEY);
-	if (IS_ERR(hdr))
-		return PTR_ERR(hdr);
+	if (!hdr)
+		return -ENOBUFS;
 
 	cookie.msg = msg;
 	cookie.idx = key_idx;
@@ -6507,6 +6507,9 @@ static int nl80211_testmode_dump(struct sk_buff *skb,
 					   NL80211_CMD_TESTMODE);
 		struct nlattr *tmdata;
 
+		if (!hdr)
+			break;
+
 		if (nla_put_u32(skb, NL80211_ATTR_WIPHY, phy_idx)) {
 			genlmsg_cancel(skb, hdr);
 			break;
@@ -6951,9 +6954,8 @@ static int nl80211_remain_on_channel(struct sk_buff *skb,
 
 	hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
 			     NL80211_CMD_REMAIN_ON_CHANNEL);
-
-	if (IS_ERR(hdr)) {
-		err = PTR_ERR(hdr);
+	if (!hdr) {
+		err = -ENOBUFS;
 		goto free_msg;
 	}
 
@@ -7251,9 +7253,8 @@ static int nl80211_tx_mgmt(struct sk_buff *skb, struct genl_info *info)
 
 		hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
 				     NL80211_CMD_FRAME);
-
-		if (IS_ERR(hdr)) {
-			err = PTR_ERR(hdr);
+		if (!hdr) {
+			err = -ENOBUFS;
 			goto free_msg;
 		}
 	}
@@ -8132,9 +8133,8 @@ static int nl80211_probe_client(struct sk_buff *skb,
 
 	hdr = nl80211hdr_put(msg, info->snd_portid, info->snd_seq, 0,
 			     NL80211_CMD_PROBE_CLIENT);
-
-	if (IS_ERR(hdr)) {
-		err = PTR_ERR(hdr);
+	if (!hdr) {
+		err = -ENOBUFS;
 		goto free_msg;
 	}