Bluetooth: Refactor read_ext_controller_info handler

There is no need to allocate heap for reply only to copy stack data to
it. This also fix rp memory leak and missing hdev unlock if kmalloc
failed.
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/mgmt.c

@@ -881,42 +881,38 @@ static inline u16 eir_append_data(u8 *eir, u16 eir_len, u8 type, u8 *data,
 static int read_ext_controller_info(struct sock *sk, struct hci_dev *hdev,
 				    void *data, u16 data_len)
 {
-	struct mgmt_rp_read_ext_info *rp;
-	char buff[512];
+	char buf[512];
+	struct mgmt_rp_read_ext_info *rp = (void *)buf;
 	u16 eir_len = 0;
-	u8 name_len;
+	size_t name_len;
 
 	BT_DBG("sock %p %s", sk, hdev->name);
 
+	memset(&buf, 0, sizeof(buf));
+
 	hci_dev_lock(hdev);
 
+	bacpy(&rp->bdaddr, &hdev->bdaddr);
+
+	rp->version = hdev->hci_ver;
+	rp->manufacturer = cpu_to_le16(hdev->manufacturer);
+
+	rp->supported_settings = cpu_to_le32(get_supported_settings(hdev));
+	rp->current_settings = cpu_to_le32(get_current_settings(hdev));
+
 	if (hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
-		eir_len = eir_append_data(buff, eir_len,
-					  EIR_CLASS_OF_DEV,
+		eir_len = eir_append_data(rp->eir, eir_len, EIR_CLASS_OF_DEV,
 					  hdev->dev_class, 3);
 
 	name_len = strlen(hdev->dev_name);
-	eir_len = eir_append_data(buff, eir_len, EIR_NAME_COMPLETE,
+	eir_len = eir_append_data(rp->eir, eir_len, EIR_NAME_COMPLETE,
 				  hdev->dev_name, name_len);
 
 	name_len = strlen(hdev->short_name);
-	eir_len = eir_append_data(buff, eir_len, EIR_NAME_SHORT,
+	eir_len = eir_append_data(rp->eir, eir_len, EIR_NAME_SHORT,
 				  hdev->short_name, name_len);
 
-	rp = kzalloc(sizeof(*rp) + eir_len, GFP_KERNEL);
-	if (!rp)
-		return -ENOMEM;
-
 	rp->eir_len = cpu_to_le16(eir_len);
-	memcpy(rp->eir, buff, eir_len);
-
-	bacpy(&rp->bdaddr, &hdev->bdaddr);
-
-	rp->version = hdev->hci_ver;
-	rp->manufacturer = cpu_to_le16(hdev->manufacturer);
-
-	rp->supported_settings = cpu_to_le32(get_supported_settings(hdev));
-	rp->current_settings = cpu_to_le32(get_current_settings(hdev));
 
 	hci_dev_unlock(hdev);