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Commit 9c67d28e authored by Alessio Igor Bogani's avatar Alessio Igor Bogani Committed by Greg Kroah-Hartman
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USB: ftdi_sio: Fix locking for change_speed() function 



The change_speed() function should be serialized against multiple calls.
Use the cfg_lock mutex to do this.

Signed-off-by: default avatarAlessio Igor Bogani <abogani@texware.it>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 11b10d99

drivers/usb/serial/ftdi_sio.c

+4 −2
Original line number Diff line number Diff line
@@ -91,7 +91,7 @@ struct ftdi_private { 
	unsigned long tx_outstanding_bytes;

	unsigned long tx_outstanding_urbs;

	unsigned short max_packet_size;

	struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl() */

	struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl() and change_speed() */

};



/* struct ftdi_sio_quirk is used by devices requiring special attention. */
@@ -1273,8 +1273,8 @@ static int set_serial_info(struct tty_struct *tty, 
	     (priv->flags & ASYNC_SPD_MASK)) ||

	    (((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST) &&

	     (old_priv.custom_divisor != priv->custom_divisor))) {

		mutex_unlock(&priv->cfg_lock);

		change_speed(tty, port);

		mutex_unlock(&priv->cfg_lock);

	}

	else

		mutex_unlock(&priv->cfg_lock);
@@ -2265,9 +2265,11 @@ static void ftdi_set_termios(struct tty_struct *tty, 
		clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);

	} else {

		/* set the baudrate determined before */

		mutex_lock(&priv->cfg_lock);

		if (change_speed(tty, port))

			dev_err(&port->dev, "%s urb failed to set baudrate\n",

				__func__);

		mutex_unlock(&priv->cfg_lock);

		/* Ensure RTS and DTR are raised when baudrate changed from 0 */

		if (!old_termios || (old_termios->c_cflag & CBAUD) == B0)

			set_mctrl(port, TIOCM_DTR | TIOCM_RTS);