[net-next,v3,7/7] mld: add mc_lock for protecting per-interface mld data

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 882e0f88756f..71bb4cc4d05d 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -190,6 +190,7 @@  struct inet6_dev {
 
 	spinlock_t		mc_query_lock;	/* mld query queue lock */
 	spinlock_t		mc_report_lock;	/* mld query report lock */
+	struct mutex		mc_lock;	/* mld global lock */
 
 	struct ifacaddr6	*ac_list;
 	rwlock_t		lock;
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 3ad754388933..49b0cebfdcdc 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -111,6 +111,8 @@  int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;
 /*
  *	socket join on multicast group
  */
+#define mc_dereference(e, idev) \
+	rcu_dereference_protected(e, lockdep_is_held(&(idev)->mc_lock))
 
 #define for_each_pmc_rtnl(np, pmc)				\
 	for (pmc = rtnl_dereference((np)->ipv6_mc_list);	\
@@ -122,10 +124,10 @@  int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;
 	     pmc;						\
 	     pmc = rcu_dereference(pmc->next))
 
-#define for_each_psf_rtnl(mc, psf)				\
-	for (psf = rtnl_dereference((mc)->mca_sources);		\
+#define for_each_psf_mclock(mc, psf)				\
+	for (psf = mc_dereference((mc)->mca_sources, mc->idev);	\
 	     psf;						\
-	     psf = rtnl_dereference(psf->sf_next))
+	     psf = mc_dereference(psf->sf_next, mc->idev))
 
 #define for_each_psf_rcu(mc, psf)				\
 	for (psf = rcu_dereference((mc)->mca_sources);		\
@@ -133,14 +135,14 @@  int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;
 	     psf = rcu_dereference(psf->sf_next))
 
 #define for_each_psf_tomb(mc, psf)				\
-	for (psf = rtnl_dereference((mc)->mca_tomb);		\
+	for (psf = mc_dereference((mc)->mca_tomb, mc->idev);	\
 	     psf;						\
-	     psf = rtnl_dereference(psf->sf_next))
+	     psf = mc_dereference(psf->sf_next, mc->idev))
 
-#define for_each_mc_rtnl(idev, mc)				\
-	for (mc = rtnl_dereference((idev)->mc_list);		\
+#define for_each_mc_mclock(idev, mc)				\
+	for (mc = mc_dereference((idev)->mc_list, idev);	\
 	     mc;						\
-	     mc = rtnl_dereference(mc->next))
+	     mc = mc_dereference(mc->next, idev))
 
 #define for_each_mc_rcu(idev, mc)				\
 	for (mc = rcu_dereference((idev)->mc_list);             \
@@ -148,9 +150,9 @@  int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;
 	     mc = rcu_dereference(mc->next))
 
 #define for_each_mc_tomb(idev, mc)				\
-	for (mc = rtnl_dereference((idev)->mc_tomb);		\
+	for (mc = mc_dereference((idev)->mc_tomb, idev);	\
 	     mc;						\
-	     mc = rtnl_dereference(mc->next))
+	     mc = mc_dereference(mc->next, idev))
 
 static int unsolicited_report_interval(struct inet6_dev *idev)
 {
@@ -268,11 +270,12 @@  int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 			if (dev) {
 				struct inet6_dev *idev = __in6_dev_get(dev);
 
-				(void) ip6_mc_leave_src(sk, mc_lst, idev);
+				ip6_mc_leave_src(sk, mc_lst, idev);
 				if (idev)
 					__ipv6_dev_mc_dec(idev, &mc_lst->addr);
-			} else
-				(void) ip6_mc_leave_src(sk, mc_lst, NULL);
+			} else {
+				ip6_mc_leave_src(sk, mc_lst, NULL);
+			}
 
 			atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
 			kfree_rcu(mc_lst, rcu);
@@ -329,11 +332,12 @@  void __ipv6_sock_mc_close(struct sock *sk)
 		if (dev) {
 			struct inet6_dev *idev = __in6_dev_get(dev);
 
-			(void) ip6_mc_leave_src(sk, mc_lst, idev);
+			ip6_mc_leave_src(sk, mc_lst, idev);
 			if (idev)
 				__ipv6_dev_mc_dec(idev, &mc_lst->addr);
-		} else
-			(void) ip6_mc_leave_src(sk, mc_lst, NULL);
+		} else {
+			ip6_mc_leave_src(sk, mc_lst, NULL);
+		}
 
 		atomic_sub(sizeof(*mc_lst), &sk->sk_omem_alloc);
 		kfree_rcu(mc_lst, rcu);
@@ -376,6 +380,7 @@  int ip6_mc_source(int add, int omode, struct sock *sk,
 
 	err = -EADDRNOTAVAIL;
 
+	mutex_lock(&idev->mc_lock);
 	for_each_pmc_rtnl(inet6, pmc) {
 		if (pgsr->gsr_interface && pmc->ifindex != pgsr->gsr_interface)
 			continue;
@@ -469,6 +474,7 @@  int ip6_mc_source(int add, int omode, struct sock *sk,
 	/* update the interface list */
 	ip6_mc_add_src(idev, group, omode, 1, source, 1);
 done:
+	mutex_unlock(&idev->mc_lock);
 	if (leavegroup)
 		err = ipv6_sock_mc_drop(sk, pgsr->gsr_interface, group);
 	return err;
@@ -529,25 +535,33 @@  int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
 			psin6 = (struct sockaddr_in6 *)list;
 			newpsl->sl_addr[i] = psin6->sin6_addr;
 		}
+		mutex_lock(&idev->mc_lock);
 		err = ip6_mc_add_src(idev, group, gsf->gf_fmode,
-			newpsl->sl_count, newpsl->sl_addr, 0);
+				     newpsl->sl_count, newpsl->sl_addr, 0);
 		if (err) {
+			mutex_unlock(&idev->mc_lock);
 			sock_kfree_s(sk, newpsl, IP6_SFLSIZE(newpsl->sl_max));
 			goto done;
 		}
+		mutex_unlock(&idev->mc_lock);
 	} else {
 		newpsl = NULL;
-		(void) ip6_mc_add_src(idev, group, gsf->gf_fmode, 0, NULL, 0);
+		mutex_lock(&idev->mc_lock);
+		ip6_mc_add_src(idev, group, gsf->gf_fmode, 0, NULL, 0);
+		mutex_unlock(&idev->mc_lock);
 	}
 
+	mutex_lock(&idev->mc_lock);
 	psl = rtnl_dereference(pmc->sflist);
 	if (psl) {
-		(void) ip6_mc_del_src(idev, group, pmc->sfmode,
-			psl->sl_count, psl->sl_addr, 0);
+		ip6_mc_del_src(idev, group, pmc->sfmode,
+			       psl->sl_count, psl->sl_addr, 0);
 		atomic_sub(IP6_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
 		kfree_rcu(psl, rcu);
-	} else
-		(void) ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0);
+	} else {
+		ip6_mc_del_src(idev, group, pmc->sfmode, 0, NULL, 0);
+	}
+	mutex_unlock(&idev->mc_lock);
 	rcu_assign_pointer(pmc->sflist, newpsl);
 	pmc->sfmode = gsf->gf_fmode;
 	err = 0;
@@ -650,6 +664,7 @@  bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr,
 	return rv;
 }
 
+/* called with mc_lock */
 static void igmp6_group_added(struct ifmcaddr6 *mc)
 {
 	struct net_device *dev = mc->idev->dev;
@@ -684,6 +699,7 @@  static void igmp6_group_added(struct ifmcaddr6 *mc)
 	mld_ifc_event(mc->idev);
 }
 
+/* called with mc_lock */
 static void igmp6_group_dropped(struct ifmcaddr6 *mc)
 {
 	struct net_device *dev = mc->idev->dev;
@@ -711,6 +727,7 @@  static void igmp6_group_dropped(struct ifmcaddr6 *mc)
 
 /*
  * deleted ifmcaddr6 manipulation
+ * called with mc_lock
  */
 static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
 {
@@ -735,13 +752,13 @@  static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
 		struct ip6_sf_list *psf;
 
 		rcu_assign_pointer(pmc->mca_tomb,
-				   rtnl_dereference(im->mca_tomb));
+				   mc_dereference(im->mca_tomb, idev));
 		rcu_assign_pointer(pmc->mca_sources,
-				   rtnl_dereference(im->mca_sources));
+				   mc_dereference(im->mca_sources, idev));
 		RCU_INIT_POINTER(im->mca_tomb, NULL);
 		RCU_INIT_POINTER(im->mca_sources, NULL);
 
-		for_each_psf_rtnl(pmc, psf)
+		for_each_psf_mclock(pmc, psf)
 			psf->sf_crcount = pmc->mca_crcount;
 	}
 
@@ -749,6 +766,7 @@  static void mld_add_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
 	rcu_assign_pointer(idev->mc_tomb, pmc);
 }
 
+/* called with mc_lock */
 static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
 {
 	struct ip6_sf_list *psf, *sources, *tomb;
@@ -772,15 +790,15 @@  static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
 		im->idev = pmc->idev;
 		if (im->mca_sfmode == MCAST_INCLUDE) {
 			tomb = rcu_replace_pointer(im->mca_tomb,
-						   rtnl_dereference(pmc->mca_tomb),
-						   lockdep_rtnl_is_held());
+						   mc_dereference(pmc->mca_tomb, pmc->idev),
+						   lockdep_is_held(&im->idev->mc_lock));
 			rcu_assign_pointer(pmc->mca_tomb, tomb);
 
 			sources = rcu_replace_pointer(im->mca_sources,
-						      rtnl_dereference(pmc->mca_sources),
-						      lockdep_rtnl_is_held());
+						      mc_dereference(pmc->mca_sources, pmc->idev),
+						      lockdep_is_held(&im->idev->mc_lock));
 			rcu_assign_pointer(pmc->mca_sources, sources);
-			for_each_psf_rtnl(im, psf)
+			for_each_psf_mclock(im, psf)
 				psf->sf_crcount = idev->mc_qrv;
 		} else {
 			im->mca_crcount = idev->mc_qrv;
@@ -791,28 +809,29 @@  static void mld_del_delrec(struct inet6_dev *idev, struct ifmcaddr6 *im)
 	}
 }
 
+/* called with mc_lock */
 static void mld_clear_delrec(struct inet6_dev *idev)
 {
 	struct ifmcaddr6 *pmc, *nextpmc;
 
-	pmc = rtnl_dereference(idev->mc_tomb);
+	pmc = mc_dereference(idev->mc_tomb, idev);
 	RCU_INIT_POINTER(idev->mc_tomb, NULL);
 
 	for (; pmc; pmc = nextpmc) {
-		nextpmc = rtnl_dereference(pmc->next);
+		nextpmc = mc_dereference(pmc->next, idev);
 		ip6_mc_clear_src(pmc);
 		in6_dev_put(pmc->idev);
 		kfree_rcu(pmc, rcu);
 	}
 
 	/* clear dead sources, too */
-	for_each_mc_rtnl(idev, pmc) {
+	for_each_mc_mclock(idev, pmc) {
 		struct ip6_sf_list *psf, *psf_next;
 
-		psf = rtnl_dereference(pmc->mca_tomb);
+		psf = mc_dereference(pmc->mca_tomb, idev);
 		RCU_INIT_POINTER(pmc->mca_tomb, NULL);
 		for (; psf; psf = psf_next) {
-			psf_next = rtnl_dereference(psf->sf_next);
+			psf_next = mc_dereference(psf->sf_next, idev);
 			kfree_rcu(psf, rcu);
 		}
 	}
@@ -851,6 +870,7 @@  static void ma_put(struct ifmcaddr6 *mc)
 	}
 }
 
+/* called with mc_lock */
 static struct ifmcaddr6 *mca_alloc(struct inet6_dev *idev,
 				   const struct in6_addr *addr,
 				   unsigned int mode)
@@ -902,10 +922,12 @@  static int __ipv6_dev_mc_inc(struct net_device *dev,
 		return -ENODEV;
 	}
 
-	for_each_mc_rtnl(idev, mc) {
+	mutex_lock(&idev->mc_lock);
+	for_each_mc_mclock(idev, mc) {
 		if (ipv6_addr_equal(&mc->mca_addr, addr)) {
 			mc->mca_users++;
 			ip6_mc_add_src(idev, &mc->mca_addr, mode, 0, NULL, 0);
+			mutex_unlock(&idev->mc_lock);
 			in6_dev_put(idev);
 			return 0;
 		}
@@ -913,6 +935,7 @@  static int __ipv6_dev_mc_inc(struct net_device *dev,
 
 	mc = mca_alloc(idev, addr, mode);
 	if (!mc) {
+		mutex_unlock(&idev->mc_lock);
 		in6_dev_put(idev);
 		return -ENOMEM;
 	}
@@ -924,6 +947,7 @@  static int __ipv6_dev_mc_inc(struct net_device *dev,
 
 	mld_del_delrec(idev, mc);
 	igmp6_group_added(mc);
+	mutex_unlock(&idev->mc_lock);
 	ma_put(mc);
 	return 0;
 }
@@ -935,7 +959,7 @@  int ipv6_dev_mc_inc(struct net_device *dev, const struct in6_addr *addr)
 EXPORT_SYMBOL(ipv6_dev_mc_inc);
 
 /*
- *	device multicast group del
+ * device multicast group del
  */
 int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr)
 {
@@ -943,8 +967,9 @@  int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr)
 
 	ASSERT_RTNL();
 
+	mutex_lock(&idev->mc_lock);
 	for (map = &idev->mc_list;
-	     (ma = rtnl_dereference(*map));
+	     (ma = mc_dereference(*map, idev));
 	     map = &ma->next) {
 		if (ipv6_addr_equal(&ma->mca_addr, addr)) {
 			if (--ma->mca_users == 0) {
@@ -952,14 +977,17 @@  int __ipv6_dev_mc_dec(struct inet6_dev *idev, const struct in6_addr *addr)
 
 				igmp6_group_dropped(ma);
 				ip6_mc_clear_src(ma);
+				mutex_unlock(&idev->mc_lock);
 
 				ma_put(ma);
 				return 0;
 			}
+			mutex_unlock(&idev->mc_lock);
 			return 0;
 		}
 	}
 
+	mutex_unlock(&idev->mc_lock);
 	return -ENOENT;
 }
 
@@ -1019,6 +1047,7 @@  bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group,
 	return rv;
 }
 
+/* called with mc_lock */
 static void mld_gq_start_work(struct inet6_dev *idev)
 {
 	unsigned long tv = prandom_u32() % idev->mc_maxdelay;
@@ -1028,6 +1057,7 @@  static void mld_gq_start_work(struct inet6_dev *idev)
 		in6_dev_hold(idev);
 }
 
+/* called with mc_lock */
 static void mld_gq_stop_work(struct inet6_dev *idev)
 {
 	idev->mc_gq_running = 0;
@@ -1035,6 +1065,7 @@  static void mld_gq_stop_work(struct inet6_dev *idev)
 		__in6_dev_put(idev);
 }
 
+/* called with mc_lock */
 static void mld_ifc_start_work(struct inet6_dev *idev, unsigned long delay)
 {
 	unsigned long tv = prandom_u32() % delay;
@@ -1043,6 +1074,7 @@  static void mld_ifc_start_work(struct inet6_dev *idev, unsigned long delay)
 		in6_dev_hold(idev);
 }
 
+/* called with mc_lock */
 static void mld_ifc_stop_work(struct inet6_dev *idev)
 {
 	idev->mc_ifc_count = 0;
@@ -1050,6 +1082,7 @@  static void mld_ifc_stop_work(struct inet6_dev *idev)
 		__in6_dev_put(idev);
 }
 
+/* called with mc_lock */
 static void mld_dad_start_work(struct inet6_dev *idev, unsigned long delay)
 {
 	unsigned long tv = prandom_u32() % delay;
@@ -1080,6 +1113,7 @@  static void mld_report_stop_work(struct inet6_dev *idev)
 
 /*
  * IGMP handling (alias multicast ICMPv6 messages)
+ * called with mc_lock
  */
 static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime)
 {
@@ -1103,7 +1137,9 @@  static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime)
 	ma->mca_flags |= MAF_TIMER_RUNNING;
 }
 
-/* mark EXCLUDE-mode sources */
+/* mark EXCLUDE-mode sources
+ * called with mc_lock
+ */
 static bool mld_xmarksources(struct ifmcaddr6 *pmc, int nsrcs,
 			     const struct in6_addr *srcs)
 {
@@ -1111,7 +1147,7 @@  static bool mld_xmarksources(struct ifmcaddr6 *pmc, int nsrcs,
 	int i, scount;
 
 	scount = 0;
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (scount == nsrcs)
 			break;
 		for (i = 0; i < nsrcs; i++) {
@@ -1132,6 +1168,7 @@  static bool mld_xmarksources(struct ifmcaddr6 *pmc, int nsrcs,
 	return true;
 }
 
+/* called with mc_lock */
 static bool mld_marksources(struct ifmcaddr6 *pmc, int nsrcs,
 			    const struct in6_addr *srcs)
 {
@@ -1144,7 +1181,7 @@  static bool mld_marksources(struct ifmcaddr6 *pmc, int nsrcs,
 	/* mark INCLUDE-mode sources */
 
 	scount = 0;
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (scount == nsrcs)
 			break;
 		for (i = 0; i < nsrcs; i++) {
@@ -1370,7 +1407,7 @@  static void __mld_query_work(struct sk_buff *skb)
 	int len, err;
 
 	if (!pskb_may_pull(skb, sizeof(struct in6_addr)))
-		goto out;
+		goto kfree_skb;
 
 	/* compute payload length excluding extension headers */
 	len = ntohs(ipv6_hdr(skb)->payload_len) + sizeof(struct ipv6hdr);
@@ -1387,11 +1424,11 @@  static void __mld_query_work(struct sk_buff *skb)
 	    ipv6_hdr(skb)->hop_limit != 1 ||
 	    !(IP6CB(skb)->flags & IP6SKB_ROUTERALERT) ||
 	    IP6CB(skb)->ra != htons(IPV6_OPT_ROUTERALERT_MLD))
-		goto out;
+		goto kfree_skb;
 
-	idev = __in6_dev_get(skb->dev);
+	idev = in6_dev_get(skb->dev);
 	if (!idev)
-		goto out;
+		goto kfree_skb;
 
 	mld = (struct mld_msg *)icmp6_hdr(skb);
 	group = &mld->mld_mca;
@@ -1442,11 +1479,11 @@  static void __mld_query_work(struct sk_buff *skb)
 	}
 
 	if (group_type == IPV6_ADDR_ANY) {
-		for_each_mc_rtnl(idev, ma) {
+		for_each_mc_mclock(idev, ma) {
 			igmp6_group_queried(ma, max_delay);
 		}
 	} else {
-		for_each_mc_rtnl(idev, ma) {
+		for_each_mc_mclock(idev, ma) {
 			if (!ipv6_addr_equal(group, &ma->mca_addr))
 				continue;
 			if (ma->mca_flags & MAF_TIMER_RUNNING) {
@@ -1468,6 +1505,8 @@  static void __mld_query_work(struct sk_buff *skb)
 	}
 
 out:
+	in6_dev_put(idev);
+kfree_skb:
 	consume_skb(skb);
 }
 
@@ -1495,10 +1534,10 @@  static void mld_query_work(struct work_struct *work)
 	}
 	spin_unlock_bh(&idev->mc_query_lock);
 
-	rtnl_lock();
+	mutex_lock(&idev->mc_lock);
 	while ((skb = __skb_dequeue(&q)))
 		__mld_query_work(skb);
-	rtnl_unlock();
+	mutex_unlock(&idev->mc_lock);
 
 	if (!rework)
 		in6_dev_put(idev);
@@ -1530,22 +1569,22 @@  int igmp6_event_report(struct sk_buff *skb)
 
 static void __mld_report_work(struct sk_buff *skb)
 {
-	struct ifmcaddr6 *ma;
 	struct inet6_dev *idev;
+	struct ifmcaddr6 *ma;
 	struct mld_msg *mld;
 	int addr_type;
 
 	/* Our own report looped back. Ignore it. */
 	if (skb->pkt_type == PACKET_LOOPBACK)
-		goto out;
+		goto kfree_skb;
 
 	/* send our report if the MC router may not have heard this report */
 	if (skb->pkt_type != PACKET_MULTICAST &&
 	    skb->pkt_type != PACKET_BROADCAST)
-		goto out;
+		goto kfree_skb;
 
 	if (!pskb_may_pull(skb, sizeof(*mld) - sizeof(struct icmp6hdr)))
-		goto out;
+		goto kfree_skb;
 
 	mld = (struct mld_msg *)icmp6_hdr(skb);
 
@@ -1553,17 +1592,17 @@  static void __mld_report_work(struct sk_buff *skb)
 	addr_type = ipv6_addr_type(&ipv6_hdr(skb)->saddr);
 	if (addr_type != IPV6_ADDR_ANY &&
 	    !(addr_type&IPV6_ADDR_LINKLOCAL))
-		goto out;
+		goto kfree_skb;
 
-	idev = __in6_dev_get(skb->dev);
+	idev = in6_dev_get(skb->dev);
 	if (!idev)
-		goto out;
+		goto kfree_skb;
 
 	/*
 	 *	Cancel the work for this group
 	 */
 
-	for_each_mc_rtnl(idev, ma) {
+	for_each_mc_mclock(idev, ma) {
 		if (ipv6_addr_equal(&ma->mca_addr, &mld->mld_mca)) {
 			if (cancel_delayed_work(&ma->mca_work))
 				refcount_dec(&ma->mca_refcnt);
@@ -1573,7 +1612,8 @@  static void __mld_report_work(struct sk_buff *skb)
 		}
 	}
 
-out:
+	in6_dev_put(idev);
+kfree_skb:
 	consume_skb(skb);
 }
 
@@ -1600,10 +1640,10 @@  static void mld_report_work(struct work_struct *work)
 	}
 	spin_unlock_bh(&idev->mc_report_lock);
 
-	rtnl_lock();
+	mutex_lock(&idev->mc_lock);
 	while ((skb = __skb_dequeue(&q)))
 		__mld_report_work(skb);
-	rtnl_unlock();
+	mutex_unlock(&idev->mc_lock);
 
 	if (!rework)
 		in6_dev_put(idev);
@@ -1659,7 +1699,7 @@  mld_scount(struct ifmcaddr6 *pmc, int type, int gdeleted, int sdeleted)
 	struct ip6_sf_list *psf;
 	int scount = 0;
 
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (!is_in(pmc, psf, type, gdeleted, sdeleted))
 			continue;
 		scount++;
@@ -1833,6 +1873,7 @@  static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc,
 
 #define AVAILABLE(skb)	((skb) ? skb_availroom(skb) : 0)
 
+/* called with mc_lock */
 static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
 				int type, int gdeleted, int sdeleted,
 				int crsend)
@@ -1878,12 +1919,12 @@  static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
 	}
 	first = 1;
 	psf_prev = NULL;
-	for (psf = rtnl_dereference(*psf_list);
+	for (psf = mc_dereference(*psf_list, idev);
 	     psf;
 	     psf = psf_next) {
 		struct in6_addr *psrc;
 
-		psf_next = rtnl_dereference(psf->sf_next);
+		psf_next = mc_dereference(psf->sf_next, idev);
 
 		if (!is_in(pmc, psf, type, gdeleted, sdeleted) && !crsend) {
 			psf_prev = psf;
@@ -1931,10 +1972,10 @@  static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
 			if ((sdeleted || gdeleted) && psf->sf_crcount == 0) {
 				if (psf_prev)
 					rcu_assign_pointer(psf_prev->sf_next,
-							   rtnl_dereference(psf->sf_next));
+							   mc_dereference(psf->sf_next, idev));
 				else
 					rcu_assign_pointer(*psf_list,
-							   rtnl_dereference(psf->sf_next));
+							   mc_dereference(psf->sf_next, idev));
 				kfree_rcu(psf, rcu);
 				continue;
 			}
@@ -1964,13 +2005,14 @@  static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc,
 	return skb;
 }
 
+/* called with mc_lock */
 static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc)
 {
 	struct sk_buff *skb = NULL;
 	int type;
 
 	if (!pmc) {
-		for_each_mc_rtnl(idev, pmc) {
+		for_each_mc_mclock(idev, pmc) {
 			if (pmc->mca_flags & MAF_NOREPORT)
 				continue;
 			if (pmc->mca_sfcount[MCAST_EXCLUDE])
@@ -1992,23 +2034,24 @@  static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc)
 
 /*
  * remove zero-count source records from a source filter list
+ * called with mc_lock
  */
-static void mld_clear_zeros(struct ip6_sf_list __rcu **ppsf)
+static void mld_clear_zeros(struct ip6_sf_list __rcu **ppsf, struct inet6_dev *idev)
 {
 	struct ip6_sf_list *psf_prev, *psf_next, *psf;
 
 	psf_prev = NULL;
-	for (psf = rtnl_dereference(*ppsf);
+	for (psf = mc_dereference(*ppsf, idev);
 	     psf;
 	     psf = psf_next) {
-		psf_next = rtnl_dereference(psf->sf_next);
+		psf_next = mc_dereference(psf->sf_next, idev);
 		if (psf->sf_crcount == 0) {
 			if (psf_prev)
 				rcu_assign_pointer(psf_prev->sf_next,
-						   rtnl_dereference(psf->sf_next));
+						   mc_dereference(psf->sf_next, idev));
 			else
 				rcu_assign_pointer(*ppsf,
-						   rtnl_dereference(psf->sf_next));
+						   mc_dereference(psf->sf_next, idev));
 			kfree_rcu(psf, rcu);
 		} else {
 			psf_prev = psf;
@@ -2016,6 +2059,7 @@  static void mld_clear_zeros(struct ip6_sf_list __rcu **ppsf)
 	}
 }
 
+/* called with mc_lock */
 static void mld_send_cr(struct inet6_dev *idev)
 {
 	struct ifmcaddr6 *pmc, *pmc_prev, *pmc_next;
@@ -2024,10 +2068,10 @@  static void mld_send_cr(struct inet6_dev *idev)
 
 	/* deleted MCA's */
 	pmc_prev = NULL;
-	for (pmc = rtnl_dereference(idev->mc_tomb);
+	for (pmc = mc_dereference(idev->mc_tomb, idev);
 	     pmc;
 	     pmc = pmc_next) {
-		pmc_next = rtnl_dereference(pmc->next);
+		pmc_next = mc_dereference(pmc->next, idev);
 		if (pmc->mca_sfmode == MCAST_INCLUDE) {
 			type = MLD2_BLOCK_OLD_SOURCES;
 			dtype = MLD2_BLOCK_OLD_SOURCES;
@@ -2041,8 +2085,8 @@  static void mld_send_cr(struct inet6_dev *idev)
 			}
 			pmc->mca_crcount--;
 			if (pmc->mca_crcount == 0) {
-				mld_clear_zeros(&pmc->mca_tomb);
-				mld_clear_zeros(&pmc->mca_sources);
+				mld_clear_zeros(&pmc->mca_tomb, idev);
+				mld_clear_zeros(&pmc->mca_sources, idev);
 			}
 		}
 		if (pmc->mca_crcount == 0 &&
@@ -2059,7 +2103,7 @@  static void mld_send_cr(struct inet6_dev *idev)
 	}
 
 	/* change recs */
-	for_each_mc_rtnl(idev, pmc) {
+	for_each_mc_mclock(idev, pmc) {
 		if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
 			type = MLD2_BLOCK_OLD_SOURCES;
 			dtype = MLD2_ALLOW_NEW_SOURCES;
@@ -2181,6 +2225,7 @@  static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
 	goto out;
 }
 
+/* called with mc_lock */
 static void mld_send_initial_cr(struct inet6_dev *idev)
 {
 	struct sk_buff *skb;
@@ -2191,7 +2236,7 @@  static void mld_send_initial_cr(struct inet6_dev *idev)
 		return;
 
 	skb = NULL;
-	for_each_mc_rtnl(idev, pmc) {
+	for_each_mc_mclock(idev, pmc) {
 		if (pmc->mca_sfcount[MCAST_EXCLUDE])
 			type = MLD2_CHANGE_TO_EXCLUDE;
 		else
@@ -2204,6 +2249,7 @@  static void mld_send_initial_cr(struct inet6_dev *idev)
 
 void ipv6_mc_dad_complete(struct inet6_dev *idev)
 {
+	mutex_lock(&idev->mc_lock);
 	idev->mc_dad_count = idev->mc_qrv;
 	if (idev->mc_dad_count) {
 		mld_send_initial_cr(idev);
@@ -2212,6 +2258,7 @@  void ipv6_mc_dad_complete(struct inet6_dev *idev)
 			mld_dad_start_work(idev,
 					   unsolicited_report_interval(idev));
 	}
+	mutex_unlock(&idev->mc_lock);
 }
 
 static void mld_dad_work(struct work_struct *work)
@@ -2219,8 +2266,7 @@  static void mld_dad_work(struct work_struct *work)
 	struct inet6_dev *idev = container_of(to_delayed_work(work),
 					      struct inet6_dev,
 					      mc_dad_work);
-
-	rtnl_lock();
+	mutex_lock(&idev->mc_lock);
 	mld_send_initial_cr(idev);
 	if (idev->mc_dad_count) {
 		idev->mc_dad_count--;
@@ -2228,10 +2274,11 @@  static void mld_dad_work(struct work_struct *work)
 			mld_dad_start_work(idev,
 					   unsolicited_report_interval(idev));
 	}
-	rtnl_unlock();
+	mutex_unlock(&idev->mc_lock);
 	in6_dev_put(idev);
 }
 
+/* called with mc_lock */
 static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
 	const struct in6_addr *psfsrc)
 {
@@ -2239,7 +2286,7 @@  static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
 	int rv = 0;
 
 	psf_prev = NULL;
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (ipv6_addr_equal(&psf->sf_addr, psfsrc))
 			break;
 		psf_prev = psf;
@@ -2255,16 +2302,16 @@  static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
 		/* no more filters for this source */
 		if (psf_prev)
 			rcu_assign_pointer(psf_prev->sf_next,
-					   rtnl_dereference(psf->sf_next));
+					   mc_dereference(psf->sf_next, idev));
 		else
 			rcu_assign_pointer(pmc->mca_sources,
-					   rtnl_dereference(psf->sf_next));
+					   mc_dereference(psf->sf_next, idev));
 
 		if (psf->sf_oldin && !(pmc->mca_flags & MAF_NOREPORT) &&
 		    !mld_in_v1_mode(idev)) {
 			psf->sf_crcount = idev->mc_qrv;
 			rcu_assign_pointer(psf->sf_next,
-					   rtnl_dereference(pmc->mca_tomb));
+					   mc_dereference(pmc->mca_tomb, idev));
 			rcu_assign_pointer(pmc->mca_tomb, psf);
 			rv = 1;
 		} else {
@@ -2274,6 +2321,7 @@  static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,
 	return rv;
 }
 
+/* called with mc_lock */
 static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 			  int sfmode, int sfcount, const struct in6_addr *psfsrc,
 			  int delta)
@@ -2285,7 +2333,7 @@  static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 	if (!idev)
 		return -ENODEV;
 
-	for_each_mc_rtnl(idev, pmc) {
+	for_each_mc_mclock(idev, pmc) {
 		if (ipv6_addr_equal(pmca, &pmc->mca_addr))
 			break;
 	}
@@ -2294,9 +2342,8 @@  static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 
 	sf_markstate(pmc);
 	if (!delta) {
-		if (!pmc->mca_sfcount[sfmode]) {
+		if (!pmc->mca_sfcount[sfmode])
 			return -EINVAL;
-		}
 
 		pmc->mca_sfcount[sfmode]--;
 	}
@@ -2317,16 +2364,19 @@  static int ip6_mc_del_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 		pmc->mca_sfmode = MCAST_INCLUDE;
 		pmc->mca_crcount = idev->mc_qrv;
 		idev->mc_ifc_count = pmc->mca_crcount;
-		for_each_psf_rtnl(pmc, psf)
+		for_each_psf_mclock(pmc, psf)
 			psf->sf_crcount = 0;
 		mld_ifc_event(pmc->idev);
-	} else if (sf_setstate(pmc) || changerec)
+	} else if (sf_setstate(pmc) || changerec) {
 		mld_ifc_event(pmc->idev);
+	}
+
 	return err;
 }
 
 /*
  * Add multicast single-source filter to the interface list
+ * called with mc_lock
  */
 static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode,
 	const struct in6_addr *psfsrc)
@@ -2334,7 +2384,7 @@  static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode,
 	struct ip6_sf_list *psf, *psf_prev;
 
 	psf_prev = NULL;
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (ipv6_addr_equal(&psf->sf_addr, psfsrc))
 			break;
 		psf_prev = psf;
@@ -2355,12 +2405,13 @@  static int ip6_mc_add1_src(struct ifmcaddr6 *pmc, int sfmode,
 	return 0;
 }
 
+/* called with mc_lock */
 static void sf_markstate(struct ifmcaddr6 *pmc)
 {
 	struct ip6_sf_list *psf;
 	int mca_xcount = pmc->mca_sfcount[MCAST_EXCLUDE];
 
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
 			psf->sf_oldin = mca_xcount ==
 				psf->sf_count[MCAST_EXCLUDE] &&
@@ -2371,6 +2422,7 @@  static void sf_markstate(struct ifmcaddr6 *pmc)
 	}
 }
 
+/* called with mc_lock */
 static int sf_setstate(struct ifmcaddr6 *pmc)
 {
 	struct ip6_sf_list *psf, *dpsf;
@@ -2379,7 +2431,7 @@  static int sf_setstate(struct ifmcaddr6 *pmc)
 	int new_in, rv;
 
 	rv = 0;
-	for_each_psf_rtnl(pmc, psf) {
+	for_each_psf_mclock(pmc, psf) {
 		if (pmc->mca_sfcount[MCAST_EXCLUDE]) {
 			new_in = mca_xcount == psf->sf_count[MCAST_EXCLUDE] &&
 				!psf->sf_count[MCAST_INCLUDE];
@@ -2398,10 +2450,12 @@  static int sf_setstate(struct ifmcaddr6 *pmc)
 				if (dpsf) {
 					if (prev)
 						rcu_assign_pointer(prev->sf_next,
-								   rtnl_dereference(dpsf->sf_next));
+								   mc_dereference(dpsf->sf_next,
+										  pmc->idev));
 					else
 						rcu_assign_pointer(pmc->mca_tomb,
-								   rtnl_dereference(dpsf->sf_next));
+								   mc_dereference(dpsf->sf_next,
+										  pmc->idev));
 					kfree_rcu(dpsf, rcu);
 				}
 				psf->sf_crcount = qrv;
@@ -2424,7 +2478,7 @@  static int sf_setstate(struct ifmcaddr6 *pmc)
 					continue;
 				*dpsf = *psf;
 				rcu_assign_pointer(dpsf->sf_next,
-						   rtnl_dereference(pmc->mca_tomb));
+						   mc_dereference(pmc->mca_tomb, pmc->idev));
 				rcu_assign_pointer(pmc->mca_tomb, dpsf);
 			}
 			dpsf->sf_crcount = qrv;
@@ -2436,6 +2490,7 @@  static int sf_setstate(struct ifmcaddr6 *pmc)
 
 /*
  * Add multicast source filter list to the interface list
+ * called with mc_lock
  */
 static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 			  int sfmode, int sfcount, const struct in6_addr *psfsrc,
@@ -2448,7 +2503,7 @@  static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 	if (!idev)
 		return -ENODEV;
 
-	for_each_mc_rtnl(idev, pmc) {
+	for_each_mc_mclock(idev, pmc) {
 		if (ipv6_addr_equal(pmca, &pmc->mca_addr))
 			break;
 	}
@@ -2484,7 +2539,7 @@  static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 
 		pmc->mca_crcount = idev->mc_qrv;
 		idev->mc_ifc_count = pmc->mca_crcount;
-		for_each_psf_rtnl(pmc, psf)
+		for_each_psf_mclock(pmc, psf)
 			psf->sf_crcount = 0;
 		mld_ifc_event(idev);
 	} else if (sf_setstate(pmc)) {
@@ -2493,21 +2548,22 @@  static int ip6_mc_add_src(struct inet6_dev *idev, const struct in6_addr *pmca,
 	return err;
 }
 
+/* called with mc_lock */
 static void ip6_mc_clear_src(struct ifmcaddr6 *pmc)
 {
 	struct ip6_sf_list *psf, *nextpsf;
 
-	for (psf = rtnl_dereference(pmc->mca_tomb);
+	for (psf = mc_dereference(pmc->mca_tomb, pmc->idev);
 	     psf;
 	     psf = nextpsf) {
-		nextpsf = rtnl_dereference(psf->sf_next);
+		nextpsf = mc_dereference(psf->sf_next, pmc->idev);
 		kfree_rcu(psf, rcu);
 	}
 	RCU_INIT_POINTER(pmc->mca_tomb, NULL);
-	for (psf = rtnl_dereference(pmc->mca_sources);
+	for (psf = mc_dereference(pmc->mca_sources, pmc->idev);
 	     psf;
 	     psf = nextpsf) {
-		nextpsf = rtnl_dereference(psf->sf_next);
+		nextpsf = mc_dereference(psf->sf_next, pmc->idev);
 		kfree_rcu(psf, rcu);
 	}
 	RCU_INIT_POINTER(pmc->mca_sources, NULL);
@@ -2516,7 +2572,7 @@  static void ip6_mc_clear_src(struct ifmcaddr6 *pmc)
 	pmc->mca_sfcount[MCAST_EXCLUDE] = 1;
 }
 
-
+/* called with mc_lock */
 static void igmp6_join_group(struct ifmcaddr6 *ma)
 {
 	unsigned long delay;
@@ -2546,19 +2602,27 @@  static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
 
 	psl = rtnl_dereference(iml->sflist);
 
+	if (idev)
+		mutex_lock(&idev->mc_lock);
+
 	if (!psl) {
 		/* any-source empty exclude case */
 		err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode, 0, NULL, 0);
 	} else {
 		err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode,
-				psl->sl_count, psl->sl_addr, 0);
+				     psl->sl_count, psl->sl_addr, 0);
 		RCU_INIT_POINTER(iml->sflist, NULL);
 		atomic_sub(IP6_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
 		kfree_rcu(psl, rcu);
 	}
+
+	if (idev)
+		mutex_unlock(&idev->mc_lock);
+
 	return err;
 }
 
+/* called with mc_lock */
 static void igmp6_leave_group(struct ifmcaddr6 *ma)
 {
 	if (mld_in_v1_mode(ma->idev)) {
@@ -2578,10 +2642,10 @@  static void mld_gq_work(struct work_struct *work)
 					      struct inet6_dev,
 					      mc_gq_work);
 
-	rtnl_lock();
+	mutex_lock(&idev->mc_lock);
 	mld_send_report(idev, NULL);
 	idev->mc_gq_running = 0;
-	rtnl_unlock();
+	mutex_unlock(&idev->mc_lock);
 
 	in6_dev_put(idev);
 }
@@ -2592,7 +2656,7 @@  static void mld_ifc_work(struct work_struct *work)
 					      struct inet6_dev,
 					      mc_ifc_work);
 
-	rtnl_lock();
+	mutex_lock(&idev->mc_lock);
 	mld_send_cr(idev);
 
 	if (idev->mc_ifc_count) {
@@ -2601,10 +2665,11 @@  static void mld_ifc_work(struct work_struct *work)
 			mld_ifc_start_work(idev,
 					   unsolicited_report_interval(idev));
 	}
-	rtnl_unlock();
+	mutex_unlock(&idev->mc_lock);
 	in6_dev_put(idev);
 }
 
+/* called with mc_lock */
 static void mld_ifc_event(struct inet6_dev *idev)
 {
 	if (mld_in_v1_mode(idev))
@@ -2619,14 +2684,14 @@  static void mld_mca_work(struct work_struct *work)
 	struct ifmcaddr6 *ma = container_of(to_delayed_work(work),
 					    struct ifmcaddr6, mca_work);
 
-	rtnl_lock();
+	mutex_lock(&ma->idev->mc_lock);
 	if (mld_in_v1_mode(ma->idev))
 		igmp6_send(&ma->mca_addr, ma->idev->dev, ICMPV6_MGM_REPORT);
 	else
 		mld_send_report(ma->idev, ma);
 	ma->mca_flags |=  MAF_LAST_REPORTER;
 	ma->mca_flags &= ~MAF_TIMER_RUNNING;
-	rtnl_unlock();
+	mutex_unlock(&ma->idev->mc_lock);
 
 	ma_put(ma);
 }
@@ -2639,8 +2704,10 @@  void ipv6_mc_unmap(struct inet6_dev *idev)
 
 	/* Install multicast list, except for all-nodes (already installed) */
 
-	for_each_mc_rtnl(idev, i)
+	mutex_lock(&idev->mc_lock);
+	for_each_mc_mclock(idev, i)
 		igmp6_group_dropped(i);
+	mutex_unlock(&idev->mc_lock);
 }
 
 void ipv6_mc_remap(struct inet6_dev *idev)
@@ -2649,14 +2716,15 @@  void ipv6_mc_remap(struct inet6_dev *idev)
 }
 
 /* Device going down */
-
 void ipv6_mc_down(struct inet6_dev *idev)
 {
 	struct ifmcaddr6 *i;
 
+	mutex_lock(&idev->mc_lock);
 	/* Withdraw multicast list */
-	for_each_mc_rtnl(idev, i)
+	for_each_mc_mclock(idev, i)
 		igmp6_group_dropped(i);
+	mutex_unlock(&idev->mc_lock);
 
 	/* Should stop work after group drop. or we will
 	 * start work again in mld_ifc_event()
@@ -2687,10 +2755,12 @@  void ipv6_mc_up(struct inet6_dev *idev)
 	/* Install multicast list, except for all-nodes (already installed) */
 
 	ipv6_mc_reset(idev);
-	for_each_mc_rtnl(idev, i) {
+	mutex_lock(&idev->mc_lock);
+	for_each_mc_mclock(idev, i) {
 		mld_del_delrec(idev, i);
 		igmp6_group_added(i);
 	}
+	mutex_unlock(&idev->mc_lock);
 }
 
 /* IPv6 device initialization. */
@@ -2709,6 +2779,7 @@  void ipv6_mc_init_dev(struct inet6_dev *idev)
 	skb_queue_head_init(&idev->mc_report_queue);
 	spin_lock_init(&idev->mc_query_lock);
 	spin_lock_init(&idev->mc_report_lock);
+	mutex_init(&idev->mc_lock);
 	ipv6_mc_reset(idev);
 }
 
@@ -2722,7 +2793,9 @@  void ipv6_mc_destroy_dev(struct inet6_dev *idev)
 
 	/* Deactivate works */
 	ipv6_mc_down(idev);
+	mutex_lock(&idev->mc_lock);
 	mld_clear_delrec(idev);
+	mutex_unlock(&idev->mc_lock);
 	mld_clear_query(idev);
 	mld_clear_report(idev);
 
@@ -2736,12 +2809,14 @@  void ipv6_mc_destroy_dev(struct inet6_dev *idev)
 	if (idev->cnf.forwarding)
 		__ipv6_dev_mc_dec(idev, &in6addr_linklocal_allrouters);
 
-	while ((i = rtnl_dereference(idev->mc_list))) {
-		rcu_assign_pointer(idev->mc_list, rtnl_dereference(i->next));
+	mutex_lock(&idev->mc_lock);
+	while ((i = mc_dereference(idev->mc_list, idev))) {
+		rcu_assign_pointer(idev->mc_list, mc_dereference(i->next, idev));
 
 		ip6_mc_clear_src(i);
 		ma_put(i);
 	}
+	mutex_unlock(&idev->mc_lock);
 }
 
 static void ipv6_mc_rejoin_groups(struct inet6_dev *idev)
@@ -2750,12 +2825,14 @@  static void ipv6_mc_rejoin_groups(struct inet6_dev *idev)
 
 	ASSERT_RTNL();
 
+	mutex_lock(&idev->mc_lock);
 	if (mld_in_v1_mode(idev)) {
-		for_each_mc_rtnl(idev, pmc)
+		for_each_mc_mclock(idev, pmc)
 			igmp6_join_group(pmc);
 	} else {
 		mld_send_report(idev, NULL);
 	}
+	mutex_unlock(&idev->mc_lock);
 }
 
 static int ipv6_mc_netdev_event(struct notifier_block *this,