diff --git a/xen/common/domain.c b/xen/common/domain.c
index 8f2bfcae28..53ac1d6c40 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -58,7 +58,7 @@ bool opt_dom0_vcpus_pin;
 boolean_param("dom0_vcpus_pin", opt_dom0_vcpus_pin);
 
 /* Protect updates/reads (resp.) of domain_list and domain_hash. */
-DEFINE_SPINLOCK(domlist_update_lock);
+static DEFINE_SPINLOCK(domlist_update_lock);
 DEFINE_RCU_READ_LOCK(domlist_read_lock);
 
 #define DOMAIN_HASH_SIZE 256
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 91f6db7a32..011292e9f7 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -697,8 +697,10 @@ static inline unsigned int domain_tot_pages(const struct domain *d)
     return d->tot_pages - d->extra_pages;
 }
 
-/* Protect updates/reads (resp.) of domain_list and domain_hash. */
-extern spinlock_t domlist_update_lock;
+/*
+ * Protect updates/reads (resp.) of domain_list and domain_hash, together with
+ * domlist_update_lock.
+ */
 extern rcu_read_lock_t domlist_read_lock;
 
 extern struct vcpu *idle_vcpu[NR_CPUS];