diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index db7b3936aec6f3904d2d871c640b871918e25f65..b0cdc244e882a0ab26ffe9831e477c8ab242bf33 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -126,11 +126,10 @@ static void uacce_hw_err_destroy(struct uacce *uacce)
 	}
 }
 
-const char *uacce_qfrt_str(struct uacce_qfile_region *qfr)
+static const char *uacce_qfrt_str(struct uacce_qfile_region *qfr)
 {
 	return qfrt_str[qfr->type];
 }
-EXPORT_SYMBOL_GPL(uacce_qfrt_str);
 
 /**
  * uacce_wake_up - Wake up the process who is waiting this queue
@@ -1302,6 +1301,9 @@ EXPORT_SYMBOL_GPL(uacce_register);
  */
 int uacce_unregister(struct uacce *uacce)
 {
+	if (!uacce)
+		return -ENODEV;
+
 	if (atomic_read(&uacce->ref) > 0) {
 		printk_ratelimited("Fail to unregister uacce, please close all uacce queues!\n");
 		return -EAGAIN;
diff --git a/include/linux/uacce.h b/include/linux/uacce.h
index 43737c3f7f52502a0bbbb8964b7df2e5968582d4..b43b65abdce39ad8454df6388e216e75a8ff1b90 100644
--- a/include/linux/uacce.h
+++ b/include/linux/uacce.h
@@ -128,7 +128,6 @@ struct uacce {
 int uacce_register(struct uacce *uacce);
 int uacce_unregister(struct uacce *uacce);
 void uacce_wake_up(struct uacce_queue *q);
-const char *uacce_qfrt_str(struct uacce_qfile_region *qfr);
 struct uacce *dev_to_uacce(struct device *dev);
 int uacce_hw_err_isolate(struct uacce *uacce);