Make sure to detect short control transfers and return zero on success
when retrieving the modem status.
This fixes the TIOCMGET implementation which since e1ed212d85 ("USB:
spcp8x5: add proper modem-status support") has returned TIOCM_LE on
successful retrieval, and avoids leaking bits from the stack on short
transfers.
This also fixes the carrier-detect implementation which since the above
mentioned commit unconditionally has returned true.
Fixes: e1ed212d85 ("USB: spcp8x5: add proper modem-status support")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Johan Hovold
5ed8d41023