USB: serial: ch341: fix type promotion bug in ch341_control_in()

The "r" variable is an int and "bufsize" is an unsigned int so the
comparison is type promoted to unsigned.  If usb_control_msg() returns a
negative that is treated as a high positive value and the error handling
doesn't work.

Fixes: 2d5a9c72d0c4 ("USB: serial: ch341: fix control-message error handling")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index bdd7a5ad3bf1c0060bcef8a3a1dc640b4a45cbcc..3bb1fff02bedd0e076581baabeff440e4552e3ce 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -128,7 +128,7 @@ static int ch341_control_in(struct usb_device *dev,
        r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
                            USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
                            value, index, buf, bufsize, DEFAULT_TIMEOUT);
-       if (r < bufsize) {
+       if (r < (int)bufsize) {
                if (r >= 0) {
                        dev_err(&dev->dev,
                                "short control message received (%d < %u)\n",