netfilter: nat: fix double register in masquerade modules

[platform/kernel/linux-starfive.git] / net / ipv6 / netfilter / nf_nat_masquerade_ipv6.c

diff --git a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
index 7afd1e6..0ad0da5 100644 (file)
--- a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
+++ b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
@@ -175,15 +175,17 @@ static struct notifier_block masq_inet6_notifier = {
        .notifier_call  = masq_inet6_event,
 };
 
-static atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0);
+static int masq_refcnt;
+static DEFINE_MUTEX(masq_mutex);
 
 int nf_nat_masquerade_ipv6_register_notifier(void)
 {
-       int ret;
+       int ret = 0;
 
+       mutex_lock(&masq_mutex);
        /* check if the notifier is already set */
-       if (atomic_inc_return(&masquerade_notifier_refcount) > 1)
-               return 0;
+       if (++masq_refcnt > 1)
+               goto out_unlock;
 
        ret = register_netdevice_notifier(&masq_dev_notifier);
        if (ret)
@@ -193,22 +195,29 @@ int nf_nat_masquerade_ipv6_register_notifier(void)
        if (ret)
                goto err_unregister;
 
+       mutex_unlock(&masq_mutex);
        return ret;
+
 err_unregister:
        unregister_netdevice_notifier(&masq_dev_notifier);
 err_dec:
-       atomic_dec(&masquerade_notifier_refcount);
+       masq_refcnt--;
+out_unlock:
+       mutex_unlock(&masq_mutex);
        return ret;
 }
 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier);
 
 void nf_nat_masquerade_ipv6_unregister_notifier(void)
 {
+       mutex_lock(&masq_mutex);
        /* check if the notifier still has clients */
-       if (atomic_dec_return(&masquerade_notifier_refcount) > 0)
-               return;
+       if (--masq_refcnt > 0)
+               goto out_unlock;
 
        unregister_inet6addr_notifier(&masq_inet6_notifier);
        unregister_netdevice_notifier(&masq_dev_notifier);
+out_unlock:
+       mutex_unlock(&masq_mutex);
 }
 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);