diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 7635bb1..622029b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -64,6 +64,9 @@
 #ifdef CONFIG_BSD_PROCESS_ACCT
 #include <linux/acct.h>
 #endif
+#ifdef CONFIG_RT_MUTEXES
+#include <linux/rtmutex.h>
+#endif
 #ifdef CONFIG_CHR_DEV_SG
 #include <scsi/sg.h>
 #endif
@@ -150,10 +153,6 @@
 
 extern struct ratelimit_state printk_ratelimit_state;
 
-#ifdef CONFIG_RT_MUTEXES
-extern int max_lock_depth;
-#endif
-
 #ifdef CONFIG_PROC_SYSCTL
 static int proc_do_cad_pid(struct ctl_table *table, int write,
 		  void __user *buffer, size_t *lenp, loff_t *ppos);