2 files changed, 24 insertions, 32 deletions

diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 1080d2248304..062294aeeb6d 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -78,6 +78,7 @@ struct inet6_ifaddr {
 struct ip6_sf_socklist {
 	unsigned int		sl_max;
 	unsigned int		sl_count;
+	struct rcu_head		rcu;
 	struct in6_addr		sl_addr[];
 };
 
@@ -91,8 +92,7 @@ struct ipv6_mc_socklist {
 	int			ifindex;
 	unsigned int		sfmode;		/* MCAST_{INCLUDE,EXCLUDE} */
 	struct ipv6_mc_socklist __rcu *next;
-	rwlock_t		sflock;
-	struct ip6_sf_socklist	*sflist;
+	struct ip6_sf_socklist	__rcu *sflist;
 	struct rcu_head		rcu;
 };
 
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 35962aa3cc22..9da55d23a13c 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -178,8 +178,7 @@ static int __ipv6_sock_mc_join(struct sock *sk, int ifindex,
 
 	mc_lst->ifindex = dev->ifindex;
 	mc_lst->sfmode = mode;
-	rwlock_init(&mc_lst->sflock);
-	mc_lst->sflist = NULL;
+	RCU_INIT_POINTER(mc_lst->sflist, NULL);
 
 	/*
 	 *	now add/increase the group membership on the device
@@ -335,7 +334,6 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 	struct net *net = sock_net(sk);
 	int i, j, rv;
 	int leavegroup = 0;
-	int pmclocked = 0;
 	int err;
 
 	source = &((struct sockaddr_in6 *)&pgsr->gsr_source)->sin6_addr;
@@ -364,7 +362,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 		goto done;
 	}
 	/* if a source filter was set, must be the same mode as before */
-	if (pmc->sflist) {
+	if (rcu_access_pointer(pmc->sflist)) {
 		if (pmc->sfmode != omode) {
 			err = -EINVAL;
 			goto done;
@@ -376,10 +374,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 		pmc->sfmode = omode;
 	}
 
-	write_lock(&pmc->sflock);
-	pmclocked = 1;
-
-	psl = pmc->sflist;
+	psl = rtnl_dereference(pmc->sflist);
 	if (!add) {
 		if (!psl)
 			goto done;	/* err = -EADDRNOTAVAIL */
@@ -429,9 +424,11 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
 		if (psl) {
 			for (i = 0; i < psl->sl_count; i++)
 				newpsl->sl_addr[i] = psl->sl_addr[i];
-			sock_kfree_s(sk, psl, IP6_SFLSIZE(psl->sl_max));
+			atomic_sub(IP6_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
+			kfree_rcu(psl, rcu);
 		}
-		pmc->sflist = psl = newpsl;
+		psl = newpsl;
+		rcu_assign_pointer(pmc->sflist, psl);
 	}
 	rv = 1;	/* > 0 for insert logic below if sl_count is 0 */
 	for (i = 0; i < psl->sl_count; i++) {
@@ -447,8 +444,6 @@ 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:
-	if (pmclocked)
-		write_unlock(&pmc->sflock);
 	read_unlock_bh(&idev->lock);
 	rcu_read_unlock();
 	if (leavegroup)
@@ -526,17 +521,16 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
 		(void) ip6_mc_add_src(idev, group, gsf->gf_fmode, 0, NULL, 0);
 	}
 
-	write_lock(&pmc->sflock);
-	psl = pmc->sflist;
+	psl = rtnl_dereference(pmc->sflist);
 	if (psl) {
 		(void) ip6_mc_del_src(idev, group, pmc->sfmode,
 			psl->sl_count, psl->sl_addr, 0);
-		sock_kfree_s(sk, psl, IP6_SFLSIZE(psl->sl_max));
+		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);
-	pmc->sflist = newpsl;
+	rcu_assign_pointer(pmc->sflist, newpsl);
 	pmc->sfmode = gsf->gf_fmode;
-	write_unlock(&pmc->sflock);
 	err = 0;
 done:
 	read_unlock_bh(&idev->lock);
@@ -585,16 +579,14 @@ int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
 	if (!pmc)		/* must have a prior join */
 		goto done;
 	gsf->gf_fmode = pmc->sfmode;
-	psl = pmc->sflist;
+	psl = rtnl_dereference(pmc->sflist);
 	count = psl ? psl->sl_count : 0;
 	read_unlock_bh(&idev->lock);
 	rcu_read_unlock();
 
 	copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
 	gsf->gf_numsrc = count;
-	/* changes to psl require the socket lock, and a write lock
-	 * on pmc->sflock. We have the socket lock so reading here is safe.
-	 */
+
 	for (i = 0; i < copycount; i++, p++) {
 		struct sockaddr_in6 *psin6;
 		struct sockaddr_storage ss;
@@ -630,8 +622,7 @@ bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr,
 		rcu_read_unlock();
 		return np->mc_all;
 	}
-	read_lock(&mc->sflock);
-	psl = mc->sflist;
+	psl = rcu_dereference(mc->sflist);
 	if (!psl) {
 		rv = mc->sfmode == MCAST_EXCLUDE;
 	} else {
@@ -646,7 +637,6 @@ bool inet6_mc_check(struct sock *sk, const struct in6_addr *mc_addr,
 		if (mc->sfmode == MCAST_EXCLUDE && i < psl->sl_count)
 			rv = false;
 	}
-	read_unlock(&mc->sflock);
 	rcu_read_unlock();
 
 	return rv;
@@ -2422,19 +2412,21 @@ static void igmp6_join_group(struct ifmcaddr6 *ma)
 static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
 			    struct inet6_dev *idev)
 {
+	struct ip6_sf_socklist *psl;
 	int err;
 
-	write_lock_bh(&iml->sflock);
-	if (!iml->sflist) {
+	psl = rtnl_dereference(iml->sflist);
+
+	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,
-				iml->sflist->sl_count, iml->sflist->sl_addr, 0);
-		sock_kfree_s(sk, iml->sflist, IP6_SFLSIZE(iml->sflist->sl_max));
-		iml->sflist = NULL;
+				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);
 	}
-	write_unlock_bh(&iml->sflock);
 	return err;
 }