ALSA: line6: Improve line6_read/write_data() interfaces

The address cannot be negative so make it unsigned.  Also, an unsigned
int is always sufficient for the length, so no need to overdo it with a
size_t.  Finally, add in range checks to see if the values passed in
actually fit where they are used.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/line6/driver.c

@@ -302,14 +302,17 @@ static void line6_data_received(struct urb *urb)
 /*
 	Read data from device.
 */
-int line6_read_data(struct usb_line6 *line6, int address, void *data,
-		    size_t datalen)
+int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
+		    unsigned datalen)
 {
 	struct usb_device *usbdev = line6->usbdev;
 	int ret;
 	unsigned char len;
 	unsigned count;
 
+	if (address > 0xffff || datalen > 0xff)
+		return -EINVAL;
+
 	/* query the serial number: */
 	ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
 			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
@@ -370,14 +373,17 @@ EXPORT_SYMBOL_GPL(line6_read_data);
 /*
 	Write data to device.
 */
-int line6_write_data(struct usb_line6 *line6, int address, void *data,
-		     size_t datalen)
+int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
+		     unsigned datalen)
 {
 	struct usb_device *usbdev = line6->usbdev;
 	int ret;
 	unsigned char status;
 	int count;
 
+	if (address > 0xffff || datalen > 0xffff)
+		return -EINVAL;
+
 	ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
 			      USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
 			      0x0022, address, data, datalen,