+/**
+ * usb_cache_string - read a string descriptor and cache it for later use
+ * @udev: the device whose string descriptor is being read
+ * @index: the descriptor index
+ *
+ * Returns a pointer to a kmalloc'ed buffer containing the descriptor string,
+ * or NULL if the index is 0 or the string could not be read.
+ */
+char *usb_cache_string(struct usb_device *udev, int index)
+{
+ char *buf;
+ char *smallbuf = NULL;
+ int len;
+
+ if (index > 0 && (buf = kmalloc(256, GFP_KERNEL)) != NULL) {
+ if ((len = usb_string(udev, index, buf, 256)) > 0) {
+ if ((smallbuf = kmalloc(++len, GFP_KERNEL)) == NULL)
+ return buf;
+ memcpy(smallbuf, buf, len);
+ }
+ kfree(buf);
+ }
+ return smallbuf;
+}
+