[PATCH 4.4 32/69] USB: serial: cp210x: fix tiocmget error handling

From: Greg Kroah-Hartman
Date: Wed Nov 09 2016 - 05:46:00 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/serial/cp210x.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -845,7 +845,9 @@ static int cp210x_tiocmget(struct tty_st
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)