Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
index aa2543b..4652896 100644
--- a/drivers/bluetooth/hci_serdev.c
+++ b/drivers/bluetooth/hci_serdev.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *  Bluetooth HCI serdev driver lib
  *
@@ -8,17 +9,6 @@
  *  Copyright (C) 2000-2001  Qualcomm Incorporated
  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
  */
 
 #include <linux/kernel.h>
@@ -57,9 +47,10 @@
 {
 	struct sk_buff *skb = hu->tx_skb;
 
-	if (!skb)
-		skb = hu->proto->dequeue(hu);
-	else
+	if (!skb) {
+		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+			skb = hu->proto->dequeue(hu);
+	} else
 		hu->tx_skb = NULL;
 
 	return skb;
@@ -94,7 +85,7 @@
 			hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
 			kfree_skb(skb);
 		}
-	} while(test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
+	} while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
 
 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
 }
@@ -332,9 +323,6 @@
 	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
 		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
 
-	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
-		set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
-
 	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
 		hdev->dev_type = HCI_AMP;
 	else
@@ -368,6 +356,7 @@
 {
 	struct hci_dev *hdev = hu->hdev;
 
+	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 	hci_unregister_dev(hdev);
 	hci_free_dev(hdev);