--- zzzz-none-000/linux-3.10.107/arch/mips/kernel/spinlock_test.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/mips/kernel/spinlock_test.c	2021-02-04 17:41:59.000000000 +0000
@@ -5,7 +5,7 @@
 #include <linux/debugfs.h>
 #include <linux/export.h>
 #include <linux/spinlock.h>
-
+#include <asm/debug.h>
 
 static int ss_get(void *data, u64 *val)
 {
@@ -115,8 +115,6 @@
 
 DEFINE_SIMPLE_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n");
 
-
-extern struct dentry *mips_debugfs_dir;
 static int __init spinlock_test(void)
 {
 	struct dentry *d;