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Commit 810360a0 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: serial: grab disconnect mutex in chars_in_buffer 



Grab disconnect mutex in chars_in_buffer before checking disconnected
flag or calling driver specific function.

This allows subdrivers to query any hardware buffer status without
having to handle the locking themselves.

Signed-off-by: default avatarJohan Hovold <jhovold@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fcdb6a21

drivers/usb/serial/usb-serial.c

+10 −4
Original line number Diff line number Diff line
@@ -361,15 +361,21 @@ static int serial_write_room(struct tty_struct *tty) 
static int serial_chars_in_buffer(struct tty_struct *tty)

{

	struct usb_serial_port *port = tty->driver_data;

	struct usb_serial *serial = port->serial;

	int count = 0;



	dev_dbg(tty->dev, "%s - port %d\n", __func__, port->number);



	mutex_lock(&serial->disc_mutex);

	/* if the device was unplugged then any remaining characters

	   fell out of the connector ;) */

	if (port->serial->disconnected)

		return 0;

	/* pass on to the driver specific version of this function */

	return port->serial->type->chars_in_buffer(tty);

	if (serial->disconnected)

		count = 0;

	else

		count = serial->type->chars_in_buffer(tty);

	mutex_unlock(&serial->disc_mutex);



	return count;

}



static void serial_throttle(struct tty_struct *tty)