diff --git a/include/sys/spa_impl.h b/include/sys/spa_impl.h
index 69de75fb6..3eb87d2bb 100644
--- a/include/sys/spa_impl.h
+++ b/include/sys/spa_impl.h
@@ -377,7 +377,7 @@ struct spa {
 	kcondvar_t	spa_proc_cv;		/* spa_proc_state transitions */
 	spa_proc_state_t spa_proc_state;	/* see definition */
 	proc_t		*spa_proc;		/* "zpool-poolname" process */
-	uint64_t	spa_did;		/* if procp != p0, did of t1 */
+	uintptr_t	spa_did;		/* if procp != p0, did of t1 */
 	boolean_t	spa_autoreplace;	/* autoreplace set in open */
 	int		spa_vdev_locks;		/* locks grabbed */
 	uint64_t	spa_creation_version;	/* version at pool creation */