USB: serial: cp210x: fix tiocmget error handling

commit de24e0a108bc48062e1c7acaa97014bce32a919f upstream.

The current tiocmget implementation would fail to report errors up the
stack and instead leaked a few bits from the stack as a mask of
modem-status flags.

Fixes: 39a66b8d22a3 ("[PATCH] USB: CP2101 Add support for flow control")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index d1582d83342c7b3448016ecb08c6f30250f8ddf2..003f8ddbfc3afc4a7f0918ea1de6a8daa758651c 100644 (file)
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -853,7 +853,9 @@ static int cp210x_tiocmget(struct tty_struct *tty)
        unsigned int control;
        int result;
 
-       cp210x_get_config(port, CP210X_GET_MDMSTS, &control, 1);
+       result = cp210x_get_config(port, CP210X_GET_MDMSTS, &control, 1);
+       if (result)
+               return result;
 
        result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
                |((control & CONTROL_RTS) ? TIOCM_RTS : 0)