[PATCH v2] Bluetooth: Add NULL check for tiocmget() and tiocmset()

[Myungho Jung]

tiocmget() and tiocmset() operations are optional and some tty drivers
like pty miss the operations. We need NULL check to prevent from
dereference.

Signed-off-by: Myungho Jung <mhju...@gmail.com>
---
 drivers/bluetooth/hci_ath.c   | 6 ++++++
 drivers/bluetooth/hci_ldisc.c | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c
index d568fbd94d6c..fb9f6323a911 100644
--- a/drivers/bluetooth/hci_ath.c
+++ b/drivers/bluetooth/hci_ath.c
@@ -185,8 +185,14 @@ static int ath_set_bdaddr(struct hci_dev *hdev, const 
bdaddr_t *bdaddr)
 
 static int ath_setup(struct hci_uart *hu)
 {
+       struct tty_struct *tty = hu->tty;
+
        BT_DBG("hu %p", hu);
 
+       /* tty driver should support operations to set RTS */
+       if (!tty->driver->ops->tiocmget || !tty->driver->ops->tiocmset)
+               return -EOPNOTSUPP;
+
        hu->hdev->set_bdaddr = ath_set_bdaddr;
 
        return 0;
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index fbf7b4df23ab..cb31c2d8d826 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -314,6 +314,10 @@ void hci_uart_set_flow_control(struct hci_uart *hu, bool 
enable)
                return;
        }
 
+       /* tiocmget() and tiocmset() operations are optional */
+       if (!tty->driver->ops->tiocmget || !tty->driver->ops->tiocmset)
+               return;
+
        if (enable) {
                /* Disable hardware flow control */
                ktermios = tty->termios;
-- 
2.17.1