USB: serial: mos7840: fix control-message error handling

Make sure to detect short transfers when reading a device register.

The modem-status handling had sufficient error checks in place, but move
handling of short transfers into the register accessor function itself
for consistency.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2017-01-12 14:56:18 +01:00
parent 0d130367ab
commit cd8db057e9

View File

@ -284,9 +284,15 @@ static int mos7840_get_reg_sync(struct usb_serial_port *port, __u16 reg,
ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
MCS_RD_RTYPE, 0, reg, buf, VENDOR_READ_LENGTH,
MOS_WDR_TIMEOUT);
if (ret < VENDOR_READ_LENGTH) {
if (ret >= 0)
ret = -EIO;
goto out;
}
*val = buf[0];
dev_dbg(&port->dev, "%s offset is %x, return val %x\n", __func__, reg, *val);
out:
kfree(buf);
return ret;
}
@ -352,8 +358,13 @@ static int mos7840_get_uart_reg(struct usb_serial_port *port, __u16 reg,
ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
MCS_RD_RTYPE, Wval, reg, buf, VENDOR_READ_LENGTH,
MOS_WDR_TIMEOUT);
if (ret < VENDOR_READ_LENGTH) {
if (ret >= 0)
ret = -EIO;
goto out;
}
*val = buf[0];
out:
kfree(buf);
return ret;
}
@ -1479,10 +1490,10 @@ static int mos7840_tiocmget(struct tty_struct *tty)
return -ENODEV;
status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
if (status != 1)
if (status < 0)
return -EIO;
status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
if (status != 1)
if (status < 0)
return -EIO;
result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)
| ((mcr & MCR_RTS) ? TIOCM_RTS : 0)