+ /*
+ * event_nr holds either the event number (input and output) or the
+ * udev cookie value (input only).
+ * The DM_DEV_WAIT ioctl takes an event number as input.
+ * The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
+ * use the field as a cookie to return in the DM_COOKIE
+ * variable with the uevents they issue.
+ * For output, the ioctls return the event number, not the cookie.
+ */
+ __u32 event_nr; /* in/out */
+ __u32 padding;
+
+ __u64 dev; /* in/out */