diff --git a/lib/idr.c b/lib/idr.c
index f9adf48..edd9b2b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -146,8 +146,8 @@ EXPORT_SYMBOL(idr_get_next_ext);
  * idr_alloc() and idr_remove() (as long as the ID being removed is not
  * the one being replaced!).
  *
- * Returns: 0 on success.  %-ENOENT indicates that @id was not found.
- * %-EINVAL indicates that @id or @ptr were not valid.
+ * Returns: the old value on success.  %-ENOENT indicates that @id was not
+ * found.  %-EINVAL indicates that @id or @ptr were not valid.
  */
 void *idr_replace(struct idr *idr, void *ptr, int id)
 {