ipv6: make mc_forwarding atomic

This fixes minor data-races in ip6_mc_input() and
batadv_mcast_mla_rtr_flags_softif_get_ipv6()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 1e0f8a3..16870f8 100644 (file)
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -51,7 +51,7 @@ struct ipv6_devconf {
        __s32           use_optimistic;
 #endif
 #ifdef CONFIG_IPV6_MROUTE
-       __s32           mc_forwarding;
+       atomic_t        mc_forwarding;
 #endif
        __s32           disable_ipv6;
        __s32           drop_unicast_in_l2_multicast;

diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index f4004cf..9f311fd 100644 (file)
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -134,7 +134,7 @@ static u8 batadv_mcast_mla_rtr_flags_softif_get_ipv6(struct net_device *dev)
 {
        struct inet6_dev *in6_dev = __in6_dev_get(dev);
 
-       if (in6_dev && in6_dev->cnf.mc_forwarding)
+       if (in6_dev && atomic_read(&in6_dev->cnf.mc_forwarding))
                return BATADV_NO_FLAGS;
        else
                return BATADV_MCAST_WANT_NO_RTR6;

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index f927c19..ff1b248 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -554,7 +554,7 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex,
 #ifdef CONFIG_IPV6_MROUTE
        if ((all || type == NETCONFA_MC_FORWARDING) &&
            nla_put_s32(skb, NETCONFA_MC_FORWARDING,
-                       devconf->mc_forwarding) < 0)
+                       atomic_read(&devconf->mc_forwarding)) < 0)
                goto nla_put_failure;
 #endif
        if ((all || type == NETCONFA_PROXY_NEIGH) &&
@@ -5533,7 +5533,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
        array[DEVCONF_USE_OPTIMISTIC] = cnf->use_optimistic;
 #endif
 #ifdef CONFIG_IPV6_MROUTE
-       array[DEVCONF_MC_FORWARDING] = cnf->mc_forwarding;
+       array[DEVCONF_MC_FORWARDING] = atomic_read(&cnf->mc_forwarding);
 #endif
        array[DEVCONF_DISABLE_IPV6] = cnf->disable_ipv6;
        array[DEVCONF_ACCEPT_DAD] = cnf->accept_dad;

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 8025671..d4b1e2c 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -508,7 +508,7 @@ int ip6_mc_input(struct sk_buff *skb)
        /*
         *      IPv6 multicast router mode is now supported ;)
         */
-       if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding &&
+       if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) &&
            !(ipv6_addr_type(&hdr->daddr) &
              (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
            likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 7cf73e6..541cd08 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -732,7 +732,7 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify,
 
        in6_dev = __in6_dev_get(dev);
        if (in6_dev) {
-               in6_dev->cnf.mc_forwarding--;
+               atomic_dec(&in6_dev->cnf.mc_forwarding);
                inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,
                                             NETCONFA_MC_FORWARDING,
                                             dev->ifindex, &in6_dev->cnf);
@@ -900,7 +900,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt,
 
        in6_dev = __in6_dev_get(dev);
        if (in6_dev) {
-               in6_dev->cnf.mc_forwarding++;
+               atomic_inc(&in6_dev->cnf.mc_forwarding);
                inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF,
                                             NETCONFA_MC_FORWARDING,
                                             dev->ifindex, &in6_dev->cnf);
@@ -1551,7 +1551,7 @@ static int ip6mr_sk_init(struct mr_table *mrt, struct sock *sk)
        } else {
                rcu_assign_pointer(mrt->mroute_sk, sk);
                sock_set_flag(sk, SOCK_RCU_FREE);
-               net->ipv6.devconf_all->mc_forwarding++;
+               atomic_inc(&net->ipv6.devconf_all->mc_forwarding);
        }
        write_unlock_bh(&mrt_lock);
 
@@ -1584,7 +1584,7 @@ int ip6mr_sk_done(struct sock *sk)
                         * so the RCU grace period before sk freeing
                         * is guaranteed by sk_destruct()
                         */
-                       net->ipv6.devconf_all->mc_forwarding--;
+                       atomic_dec(&net->ipv6.devconf_all->mc_forwarding);
                        write_unlock_bh(&mrt_lock);
                        inet6_netconf_notify_devconf(net, RTM_NEWNETCONF,
                                                     NETCONFA_MC_FORWARDING,