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From:   Myungho Jung <mhjungk@gmail.com>
To:     marcel@holtmann.org
Cc:     johan.hedberg@gmail.com, linux-bluetooth@vger.kernel.org,
        linux-kernel@vger.kernel.org, Myungho Jung <mhjungk@gmail.com>,
        stable@vger.kernel.org
Subject: [PATCH v3 2/2] Bluetooth: hci_ldisc: Add NULL check for tiocmget() and tiocmset() in hci_uart_set_flow_control()
Date:   Mon,  4 Feb 2019 22:41:42 -0800
Message-Id: <4cc3a826614822661dbedad74d9970172cbfa6d7.1549346039.git.mhjungk@gmail.com>
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tiocmget() or tiocmset() operations are optional. Just return from
hci_uart_set_flow_control() if tiocmget() or tiocmset() operation is
NULL.

Fixes: 2a973dfada2b ("hci_uart: Add new line discipline enhancements")
Cc: <stable@vger.kernel.org> # 4.2
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
---
Changes in v2:
  - Remove braces in if statment

Changes in v3:
  - Split into 2 patches
  - Add stable CC and fixes tags

 drivers/bluetooth/hci_ldisc.c | 4 ++++
 1 file changed, 4 insertions(+)

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