USB: ir-usb: allow custom bulk buffer size without reallocation

Use usb_serial_driver bulk_in_size and bulk_out_size to make sure
buffers of appropriate sizes are allocated in the first place rather than
reallocating them at every open.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/ir-usb.c

@@ -297,35 +297,10 @@ static int ir_startup(struct usb_serial *serial)
 
 static int ir_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
-	char *buffer;
 	int result = 0;
 
 	dbg("%s - port %d", __func__, port->number);
 
-	if (buffer_size) {
-		/* override the default buffer sizes */
-		buffer = kmalloc(buffer_size, GFP_KERNEL);
-		if (!buffer) {
-			dev_err(&port->dev, "%s - out of memory.\n", __func__);
-			return -ENOMEM;
-		}
-		kfree(port->read_urb->transfer_buffer);
-		port->read_urb->transfer_buffer = buffer;
-		port->read_urb->transfer_buffer_length = buffer_size;
-		port->bulk_in_buffer = buffer;
-
-		buffer = kmalloc(buffer_size, GFP_KERNEL);
-		if (!buffer) {
-			dev_err(&port->dev, "%s - out of memory.\n", __func__);
-			return -ENOMEM;
-		}
-		kfree(port->write_urb->transfer_buffer);
-		port->write_urb->transfer_buffer = buffer;
-		port->write_urb->transfer_buffer_length = buffer_size;
-		port->bulk_out_buffer = buffer;
-		port->bulk_out_size = buffer_size;
-	}
-
 	/* Start reading from the device */
 	usb_fill_bulk_urb(
 		port->read_urb,
@@ -585,6 +560,11 @@ static int __init ir_init(void)
 {
 	int retval;
 
+	if (buffer_size) {
+		ir_device.bulk_in_size = buffer_size;
+		ir_device.bulk_out_size = buffer_size;
+	}
+
 	retval = usb_serial_register(&ir_device);
 	if (retval)
 		goto failed_usb_serial_register;