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Commit cd8db057 authored by Johan Hovold's avatar Johan Hovold
Browse files

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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 0d130367

drivers/usb/serial/mos7840.c

+15 −4
Original line number Diff line number Diff line
@@ -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)