diff --git a/nat46/modules/nat46-glue.c b/nat46/modules/nat46-glue.c
index 9f338bd..5176b40 100644
--- a/nat46/modules/nat46-glue.c
+++ b/nat46/modules/nat46-glue.c
@@ -18,7 +18,7 @@
 #include "nat46-glue.h"
 #include "nat46-core.h"
 
-static DEFINE_MUTEX(ref_lock);
+static DEFINE_SPINLOCK(ref_lock);
 static int is_valid_nat46(nat46_instance_t *nat46) {
   return (nat46 && (nat46->sig == NAT46_SIGNATURE));
 }
@@ -50,25 +50,25 @@ nat46_instance_t *alloc_nat46_instance(int npairs, nat46_instance_t *old, int fr
 
 nat46_instance_t *get_nat46_instance(struct sk_buff *sk) {
   nat46_instance_t *nat46 = netdev_nat46_instance(sk->dev);
-  mutex_lock(&ref_lock);
+  spin_lock_bh(&ref_lock);
   if (is_valid_nat46(nat46)) {
     nat46->refcount++;
-    mutex_unlock(&ref_lock);
+    spin_unlock_bh(&ref_lock);
     return nat46;
   } else {
     printk("[nat46] get_nat46_instance: Could not find a valid NAT46 instance!");
-    mutex_unlock(&ref_lock);
+    spin_unlock_bh(&ref_lock);
     return NULL;
   }
 }
 
 void release_nat46_instance(nat46_instance_t *nat46) {
-  mutex_lock(&ref_lock);
+  spin_lock_bh(&ref_lock);
   nat46->refcount--;
   if(0 == nat46->refcount) {
     printk("[nat46] release_nat46_instance: freeing nat46 instance with %d pairs\n", nat46->npairs);
     nat46->sig = FREED_NAT46_SIGNATURE;
     kfree(nat46);
   }
-  mutex_unlock(&ref_lock);
+  spin_unlock_bh(&ref_lock);
 }