diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index 4cd8b22..3bc0eef 100644
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -23,7 +23,7 @@
 #include <linux/seq_file.h>
 #include <linux/dmi.h>
 #include <linux/capability.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 
@@ -56,6 +56,7 @@
 
 #define I8K_TEMPERATURE_BUG	1
 
+static DEFINE_MUTEX(i8k_mutex);
 static char bios_version[4];
 
 MODULE_AUTHOR("Massimo Dal Zotto (dz@debian.org)");
@@ -399,9 +400,9 @@
 {
 	long ret;
 
-	lock_kernel();
+	mutex_lock(&i8k_mutex);
 	ret = i8k_ioctl_unlocked(fp, cmd, arg);
-	unlock_kernel();
+	mutex_unlock(&i8k_mutex);
 
 	return ret;
 }