ipv6: make mc_forwarding atomic

[ Upstream commit 145c7a793838add5e004e7d49a67654dc7eba147 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index f514a7dd8c9cf6ab57bd63b2e20754fe2ef4115b..510f876564796e10fd8632f78486fd54524b1290 100644 (file)
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -50,7 +50,7 @@ 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 139894ca788b95f5e5af57123d318625a1cbb7a5..c8a341cd652c74a4b9ded015d049e922f347fbde 100644 (file)
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -136,7 +136,7 @@ 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 7c5bf39dca5d1a5375071642b01f87a2094f77ab..86bcb18256982da54a153ece3059661ac2956d0b 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -542,7 +542,7 @@ 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) &&
@@ -5515,7 +5515,7 @@ 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 06d60662717d1672dfeb9631cc21f5d6f1c92ab3..15ea3d082534d2e6616e3eaecc6623f2b453c12a 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -509,7 +509,7 @@ 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 41cb348a7c3c4904ba4111d1c0e48044c7963ee2..5f0ac47acc74ba014589d2a44de2f38fd145d636 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -740,7 +740,7 @@ 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);
@@ -908,7 +908,7 @@ 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);
@@ -1558,7 +1558,7 @@ 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);
 
@@ -1591,7 +1591,7 @@ 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,