USB: serial: ir-usb: make set_termios synchronous

Use a synchronous usb_bulk_msg() when switching link speed in
set_termios(). This way we do not need to keep track of outstanding URBs
in order to be able to stop them at close.

Note that there's no need to set URB_ZERO_PACKET as the one-byte
transfer will always be short.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/ir-usb.c

@@ -376,23 +376,15 @@ static void ir_process_read_urb(struct urb *urb)
 	tty_flip_buffer_push(&port->port);
 }
 
-static void ir_set_termios_callback(struct urb *urb)
-{
-	kfree(urb->transfer_buffer);
-
-	if (urb->status)
-		dev_dbg(&urb->dev->dev, "%s - non-zero urb status: %d\n",
-			__func__, urb->status);
-}
-
 static void ir_set_termios(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {
-	struct urb *urb;
+	struct usb_device *udev = port->serial->dev;
 	unsigned char *transfer_buffer;
-	int result;
+	int actual_length;
 	speed_t baud;
 	int ir_baud;
+	int ret;
 
 	baud = tty_get_baud_rate(tty);
 
@@ -447,42 +439,22 @@ static void ir_set_termios(struct tty_struct *tty,
 	/*
 	 * send the baud change out on an "empty" data packet
 	 */
-	urb = usb_alloc_urb(0, GFP_KERNEL);
-	if (!urb)
-		return;
-
 	transfer_buffer = kmalloc(1, GFP_KERNEL);
 	if (!transfer_buffer)
-		goto err_buf;
+		return;
 
 	*transfer_buffer = ir_xbof | ir_baud;
 
-	usb_fill_bulk_urb(
-		urb,
-		port->serial->dev,
-		usb_sndbulkpipe(port->serial->dev,
-			port->bulk_out_endpointAddress),
-		transfer_buffer,
-		1,
-		ir_set_termios_callback,
-		port);
-
-	urb->transfer_flags = URB_ZERO_PACKET;
-
-	result = usb_submit_urb(urb, GFP_KERNEL);
-	if (result) {
-		dev_err(&port->dev, "%s - failed to submit urb: %d\n",
-							__func__, result);
-		goto err_subm;
+	ret = usb_bulk_msg(udev,
+			usb_sndbulkpipe(udev, port->bulk_out_endpointAddress),
+			transfer_buffer, 1, &actual_length, 5000);
+	if (ret || actual_length != 1) {
+		if (actual_length != 1)
+			ret = -EIO;
+		dev_err(&port->dev, "failed to change line speed: %d\n", ret);
 	}
 
-	usb_free_urb(urb);
-
-	return;
-err_subm:
 	kfree(transfer_buffer);
-err_buf:
-	usb_free_urb(urb);
 }
 
 static int __init ir_init(void)