1 files changed, 130 insertions, 242 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index a2e7f55a1f61..76ea0a8be090 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -143,10 +143,9 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
 			       unsigned int log)
 {
 	struct sock *sk2;
-	struct hlist_nulls_node *node;
 	kuid_t uid = sock_i_uid(sk);
 
-	sk_nulls_for_each(sk2, node, &hslot->head) {
+	sk_for_each(sk2, &hslot->head) {
 		if (net_eq(sock_net(sk2), net) &&
 		    sk2 != sk &&
 		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
@@ -177,12 +176,11 @@ static int udp_lib_lport_inuse2(struct net *net, __u16 num,
 						  bool match_wildcard))
 {
 	struct sock *sk2;
-	struct hlist_nulls_node *node;
 	kuid_t uid = sock_i_uid(sk);
 	int res = 0;
 
 	spin_lock(&hslot2->lock);
-	udp_portaddr_for_each_entry(sk2, node, &hslot2->head) {
+	udp_portaddr_for_each_entry(sk2, &hslot2->head) {
 		if (net_eq(sock_net(sk2), net) &&
 		    sk2 != sk &&
 		    (udp_sk(sk2)->udp_port_hash == num) &&
@@ -207,11 +205,10 @@ static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot,
 						    bool match_wildcard))
 {
 	struct net *net = sock_net(sk);
-	struct hlist_nulls_node *node;
 	kuid_t uid = sock_i_uid(sk);
 	struct sock *sk2;
 
-	sk_nulls_for_each(sk2, node, &hslot->head) {
+	sk_for_each(sk2, &hslot->head) {
 		if (net_eq(sock_net(sk2), net) &&
 		    sk2 != sk &&
 		    sk2->sk_family == sk->sk_family &&
@@ -333,22 +330,23 @@ found:
 			goto fail_unlock;
 		}
 
-		sk_nulls_add_node_rcu(sk, &hslot->head);
+		sk_add_node_rcu(sk, &hslot->head);
 		hslot->count++;
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 
 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
 		spin_lock(&hslot2->lock);
 		if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
-			sk->sk_family == AF_INET6)
-			hlist_nulls_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
-						 &hslot2->head);
+		    sk->sk_family == AF_INET6)
+			hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
+					   &hslot2->head);
 		else
-			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
-						 &hslot2->head);
+			hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
+					   &hslot2->head);
 		hslot2->count++;
 		spin_unlock(&hslot2->lock);
 	}
+	sock_set_flag(sk, SOCK_RCU_FREE);
 	error = 0;
 fail_unlock:
 	spin_unlock_bh(&hslot->lock);
@@ -502,37 +500,27 @@ static struct sock *udp4_lib_lookup2(struct net *net,
 		struct sk_buff *skb)
 {
 	struct sock *sk, *result;
-	struct hlist_nulls_node *node;
 	int score, badness, matches = 0, reuseport = 0;
-	bool select_ok = true;
 	u32 hash = 0;
 
-begin:
 	result = NULL;
 	badness = 0;
-	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
+	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
 		score = compute_score2(sk, net, saddr, sport,
 				      daddr, hnum, dif);
 		if (score > badness) {
-			result = sk;
-			badness = score;
 			reuseport = sk->sk_reuseport;
 			if (reuseport) {
 				hash = udp_ehashfn(net, daddr, hnum,
 						   saddr, sport);
-				if (select_ok) {
-					struct sock *sk2;
-
-					sk2 = reuseport_select_sock(sk, hash, skb,
+				result = reuseport_select_sock(sk, hash, skb,
 							sizeof(struct udphdr));
-					if (sk2) {
-						result = sk2;
-						select_ok = false;
-						goto found;
-					}
-				}
+				if (result)
+					return result;
 				matches = 1;
 			}
+			badness = score;
+			result = sk;
 		} else if (score == badness && reuseport) {
 			matches++;
 			if (reciprocal_scale(hash, matches) == 0)
@@ -540,23 +528,6 @@ begin:
 			hash = next_pseudo_random32(hash);
 		}
 	}
-	/*
-	 * if the nulls value we got at the end of this lookup is
-	 * not the expected one, we must restart lookup.
-	 * We probably met an item that was moved to another chain.
-	 */
-	if (get_nulls_value(node) != slot2)
-		goto begin;
-	if (result) {
-found:
-		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
-			result = NULL;
-		else if (unlikely(compute_score2(result, net, saddr, sport,
-				  daddr, hnum, dif) < badness)) {
-			sock_put(result);
-			goto begin;
-		}
-	}
 	return result;
 }
 
@@ -568,15 +539,12 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 		int dif, struct udp_table *udptable, struct sk_buff *skb)
 {
 	struct sock *sk, *result;
-	struct hlist_nulls_node *node;
 	unsigned short hnum = ntohs(dport);
 	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
 	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
 	int score, badness, matches = 0, reuseport = 0;
-	bool select_ok = true;
 	u32 hash = 0;
 
-	rcu_read_lock();
 	if (hslot->count > 10) {
 		hash2 = udp4_portaddr_hash(net, daddr, hnum);
 		slot2 = hash2 & udptable->mask;
@@ -598,35 +566,27 @@ struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
 						  htonl(INADDR_ANY), hnum, dif,
 						  hslot2, slot2, skb);
 		}
-		rcu_read_unlock();
 		return result;
 	}
 begin:
 	result = NULL;
 	badness = 0;
-	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
+	sk_for_each_rcu(sk, &hslot->head) {
 		score = compute_score(sk, net, saddr, hnum, sport,
 				      daddr, dport, dif);
 		if (score > badness) {
-			result = sk;
-			badness = score;
 			reuseport = sk->sk_reuseport;
 			if (reuseport) {
 				hash = udp_ehashfn(net, daddr, hnum,
 						   saddr, sport);
-				if (select_ok) {
-					struct sock *sk2;
-
-					sk2 = reuseport_select_sock(sk, hash, skb,
+				result = reuseport_select_sock(sk, hash, skb,
 							sizeof(struct udphdr));
-					if (sk2) {
-						result = sk2;
-						select_ok = false;
-						goto found;
-					}
-				}
+				if (result)
+					return result;
 				matches = 1;
 			}
+			result = sk;
+			badness = score;
 		} else if (score == badness && reuseport) {
 			matches++;
 			if (reciprocal_scale(hash, matches) == 0)
@@ -634,25 +594,6 @@ begin:
 			hash = next_pseudo_random32(hash);
 		}
 	}
-	/*
-	 * if the nulls value we got at the end of this lookup is
-	 * not the expected one, we must restart lookup.
-	 * We probably met an item that was moved to another chain.
-	 */
-	if (get_nulls_value(node) != slot)
-		goto begin;
-
-	if (result) {
-found:
-		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
-			result = NULL;
-		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
-				  daddr, dport, dif) < badness)) {
-			sock_put(result);
-			goto begin;
-		}
-	}
-	rcu_read_unlock();
 	return result;
 }
 EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
@@ -668,13 +609,37 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 				 udptable, skb);
 }
 
+struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
+				 __be16 sport, __be16 dport)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	const struct net_device *dev =
+	    skb_dst(skb) ? skb_dst(skb)->dev : skb->dev;
+
+	return __udp4_lib_lookup(dev_net(dev), iph->saddr, sport,
+				 iph->daddr, dport, inet_iif(skb),
+				 &udp_table, skb);
+}
+EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb);
+
+/* Must be called under rcu_read_lock().
+ * Does increment socket refcount.
+ */
+#if IS_ENABLED(CONFIG_NETFILTER_XT_MATCH_SOCKET) || \
+    IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TPROXY)
 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 			     __be32 daddr, __be16 dport, int dif)
 {
-	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif,
-				 &udp_table, NULL);
+	struct sock *sk;
+
+	sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
+			       dif, &udp_table, NULL);
+	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+		sk = NULL;
+	return sk;
 }
 EXPORT_SYMBOL_GPL(udp4_lib_lookup);
+#endif
 
 static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
 				       __be16 loc_port, __be32 loc_addr,
@@ -776,7 +741,7 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 	sk->sk_err = err;
 	sk->sk_error_report(sk);
 out:
-	sock_put(sk);
+	return;
 }
 
 void udp_err(struct sk_buff *skb, u32 info)
@@ -1032,15 +997,13 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		 */
 		connected = 1;
 	}
-	ipc.addr = inet->inet_saddr;
 
+	ipc.sockc.tsflags = sk->sk_tsflags;
+	ipc.addr = inet->inet_saddr;
 	ipc.oif = sk->sk_bound_dev_if;
 
-	sock_tx_timestamp(sk, &ipc.tx_flags);
-
 	if (msg->msg_controllen) {
-		err = ip_cmsg_send(sock_net(sk), msg, &ipc,
-				   sk->sk_family == AF_INET6);
+		err = ip_cmsg_send(sk, msg, &ipc, sk->sk_family == AF_INET6);
 		if (unlikely(err)) {
 			kfree(ipc.opt);
 			return err;
@@ -1065,6 +1028,8 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	saddr = ipc.addr;
 	ipc.addr = faddr = daddr;
 
+	sock_tx_timestamp(sk, ipc.sockc.tsflags, &ipc.tx_flags);
+
 	if (ipc.opt && ipc.opt->opt.srr) {
 		if (!daddr)
 			return -EINVAL;
@@ -1316,14 +1281,6 @@ int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 	{
 		unsigned int amount = first_packet_length(sk);
 
-		if (amount)
-			/*
-			 * We will only return the amount
-			 * of this packet since that is all
-			 * that will be read.
-			 */
-			amount -= sizeof(struct udphdr);
-
 		return put_user(amount, (int __user *)arg);
 	}
 
@@ -1347,7 +1304,7 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
 	struct sk_buff *skb;
 	unsigned int ulen, copied;
-	int peeked, off = 0;
+	int peeked, peeking, off;
 	int err;
 	int is_udplite = IS_UDPLITE(sk);
 	bool checksum_valid = false;
@@ -1357,15 +1314,16 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 		return ip_recv_error(sk, msg, len, addr_len);
 
 try_again:
+	peeking = off = sk_peek_offset(sk, flags);
 	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
 				  &peeked, &off, &err);
 	if (!skb)
-		goto out;
+		return err;
 
-	ulen = skb->len - sizeof(struct udphdr);
+	ulen = skb->len;
 	copied = len;
-	if (copied > ulen)
-		copied = ulen;
+	if (copied > ulen - off)
+		copied = ulen - off;
 	else if (copied < ulen)
 		msg->msg_flags |= MSG_TRUNC;
 
@@ -1375,18 +1333,16 @@ try_again:
 	 * coverage checksum (UDP-Lite), do it before the copy.
 	 */
 
-	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
+	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov || peeking) {
 		checksum_valid = !udp_lib_checksum_complete(skb);
 		if (!checksum_valid)
 			goto csum_copy_err;
 	}
 
 	if (checksum_valid || skb_csum_unnecessary(skb))
-		err = skb_copy_datagram_msg(skb, sizeof(struct udphdr),
-					    msg, copied);
+		err = skb_copy_datagram_msg(skb, off, msg, copied);
 	else {
-		err = skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr),
-						     msg);
+		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
 
 		if (err == -EINVAL)
 			goto csum_copy_err;
@@ -1399,7 +1355,8 @@ try_again:
 			UDP_INC_STATS_USER(sock_net(sk),
 					   UDP_MIB_INERRORS, is_udplite);
 		}
-		goto out_free;
+		skb_free_datagram_locked(sk, skb);
+		return err;
 	}
 
 	if (!peeked)
@@ -1417,15 +1374,13 @@ try_again:
 		*addr_len = sizeof(*sin);
 	}
 	if (inet->cmsg_flags)
-		ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr));
+		ip_cmsg_recv_offset(msg, skb, sizeof(struct udphdr) + off);
 
 	err = copied;
 	if (flags & MSG_TRUNC)
 		err = ulen;
 
-out_free:
-	skb_free_datagram_locked(sk, skb);
-out:
+	__skb_free_datagram_locked(sk, skb, peeking ? -err : err);
 	return err;
 
 csum_copy_err:
@@ -1479,13 +1434,13 @@ void udp_lib_unhash(struct sock *sk)
 		spin_lock_bh(&hslot->lock);
 		if (rcu_access_pointer(sk->sk_reuseport_cb))
 			reuseport_detach_sock(sk);
-		if (sk_nulls_del_node_init_rcu(sk)) {
+		if (sk_del_node_init_rcu(sk)) {
 			hslot->count--;
 			inet_sk(sk)->inet_num = 0;
 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 
 			spin_lock(&hslot2->lock);
-			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
+			hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
 			hslot2->count--;
 			spin_unlock(&hslot2->lock);
 		}
@@ -1518,12 +1473,12 @@ void udp_lib_rehash(struct sock *sk, u16 newhash)
 
 			if (hslot2 != nhslot2) {
 				spin_lock(&hslot2->lock);
-				hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
+				hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
 				hslot2->count--;
 				spin_unlock(&hslot2->lock);
 
 				spin_lock(&nhslot2->lock);
-				hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
+				hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
 							 &nhslot2->head);
 				nhslot2->count++;
 				spin_unlock(&nhslot2->lock);
@@ -1553,7 +1508,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		sk_incoming_cpu_update(sk);
 	}
 
-	rc = sock_queue_rcv_skb(sk, skb);
+	rc = __sock_queue_rcv_skb(sk, skb);
 	if (rc < 0) {
 		int is_udplite = IS_UDPLITE(sk);
 
@@ -1669,10 +1624,14 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		}
 	}
 
-	if (rcu_access_pointer(sk->sk_filter) &&
-	    udp_lib_checksum_complete(skb))
-		goto csum_error;
+	if (rcu_access_pointer(sk->sk_filter)) {
+		if (udp_lib_checksum_complete(skb))
+			goto csum_error;
+		if (sk_filter(sk, skb))
+			goto drop;
+	}
 
+	udp_csum_pull_header(skb);
 	if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
 		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
 				 is_udplite);
@@ -1702,35 +1661,6 @@ drop:
 	return -1;
 }
 
-static void flush_stack(struct sock **stack, unsigned int count,
-			struct sk_buff *skb, unsigned int final)
-{
-	unsigned int i;
-	struct sk_buff *skb1 = NULL;
-	struct sock *sk;
-
-	for (i = 0; i < count; i++) {
-		sk = stack[i];
-		if (likely(!skb1))
-			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
-
-		if (!skb1) {
-			atomic_inc(&sk->sk_drops);
-			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
-					 IS_UDPLITE(sk));
-			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
-					 IS_UDPLITE(sk));
-		}
-
-		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
-			skb1 = NULL;
-
-		sock_put(sk);
-	}
-	if (unlikely(skb1))
-		kfree_skb(skb1);
-}
-
 /* For TCP sockets, sk_rx_dst is protected by socket lock
  * For UDP, we use xchg() to guard against concurrent changes.
  */
@@ -1754,14 +1684,14 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 				    struct udp_table *udptable,
 				    int proto)
 {
-	struct sock *sk, *stack[256 / sizeof(struct sock *)];
-	struct hlist_nulls_node *node;
+	struct sock *sk, *first = NULL;
 	unsigned short hnum = ntohs(uh->dest);
 	struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
-	int dif = skb->dev->ifindex;
-	unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node);
 	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
-	bool inner_flushed = false;
+	unsigned int offset = offsetof(typeof(*sk), sk_node);
+	int dif = skb->dev->ifindex;
+	struct hlist_node *node;
+	struct sk_buff *nskb;
 
 	if (use_hash2) {
 		hash2_any = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
@@ -1772,23 +1702,28 @@ start_lookup:
 		offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
 	}
 
-	spin_lock(&hslot->lock);
-	sk_nulls_for_each_entry_offset(sk, node, &hslot->head, offset) {
-		if (__udp_is_mcast_sock(net, sk,
-					uh->dest, daddr,
-					uh->source, saddr,
-					dif, hnum)) {
-			if (unlikely(count == ARRAY_SIZE(stack))) {
-				flush_stack(stack, count, skb, ~0);
-				inner_flushed = true;
-				count = 0;
-			}
-			stack[count++] = sk;
-			sock_hold(sk);
+	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
+		if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr,
+					 uh->source, saddr, dif, hnum))
+			continue;
+
+		if (!first) {
+			first = sk;
+			continue;
 		}
-	}
+		nskb = skb_clone(skb, GFP_ATOMIC);
 
-	spin_unlock(&hslot->lock);
+		if (unlikely(!nskb)) {
+			atomic_inc(&sk->sk_drops);
+			UDP_INC_STATS_BH(net, UDP_MIB_RCVBUFERRORS,
+					 IS_UDPLITE(sk));
+			UDP_INC_STATS_BH(net, UDP_MIB_INERRORS,
+					 IS_UDPLITE(sk));
+			continue;
+		}
+		if (udp_queue_rcv_skb(sk, nskb) > 0)
+			consume_skb(nskb);
+	}
 
 	/* Also lookup *:port if we are using hash2 and haven't done so yet. */
 	if (use_hash2 && hash2 != hash2_any) {
@@ -1796,16 +1731,13 @@ start_lookup:
 		goto start_lookup;
 	}
 
-	/*
-	 * do the slow work with no lock held
-	 */
-	if (count) {
-		flush_stack(stack, count, skb, count - 1);
+	if (first) {
+		if (udp_queue_rcv_skb(first, skb) > 0)
+			consume_skb(skb);
 	} else {
-		if (!inner_flushed)
-			UDP_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI,
-					 proto == IPPROTO_UDPLITE);
-		consume_skb(skb);
+		kfree_skb(skb);
+		UDP_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI,
+				 proto == IPPROTO_UDPLITE);
 	}
 	return 0;
 }
@@ -1902,7 +1834,6 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 						 inet_compute_pseudo);
 
 		ret = udp_queue_rcv_skb(sk, skb);
-		sock_put(sk);
 
 		/* a return value > 0 means to resubmit the input, but
 		 * it wants the return to be -protocol, or 0
@@ -1963,49 +1894,24 @@ static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
 						  int dif)
 {
 	struct sock *sk, *result;
-	struct hlist_nulls_node *node;
 	unsigned short hnum = ntohs(loc_port);
-	unsigned int count, slot = udp_hashfn(net, hnum, udp_table.mask);
+	unsigned int slot = udp_hashfn(net, hnum, udp_table.mask);
 	struct udp_hslot *hslot = &udp_table.hash[slot];
 
 	/* Do not bother scanning a too big list */
 	if (hslot->count > 10)
 		return NULL;
 
-	rcu_read_lock();
-begin:
-	count = 0;
 	result = NULL;
-	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
-		if (__udp_is_mcast_sock(net, sk,
-					loc_port, loc_addr,
-					rmt_port, rmt_addr,
-					dif, hnum)) {
+	sk_for_each_rcu(sk, &hslot->head) {
+		if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
+					rmt_port, rmt_addr, dif, hnum)) {
+			if (result)
+				return NULL;
 			result = sk;
-			++count;
-		}
-	}
-	/*
-	 * if the nulls value we got at the end of this lookup is
-	 * not the expected one, we must restart lookup.
-	 * We probably met an item that was moved to another chain.
-	 */
-	if (get_nulls_value(node) != slot)
-		goto begin;
-
-	if (result) {
-		if (count != 1 ||
-		    unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
-			result = NULL;
-		else if (unlikely(!__udp_is_mcast_sock(net, result,
-						       loc_port, loc_addr,
-						       rmt_port, rmt_addr,
-						       dif, hnum))) {
-			sock_put(result);
-			result = NULL;
 		}
 	}
-	rcu_read_unlock();
+
 	return result;
 }
 
@@ -2018,37 +1924,22 @@ static struct sock *__udp4_lib_demux_lookup(struct net *net,
 					    __be16 rmt_port, __be32 rmt_addr,
 					    int dif)
 {
-	struct sock *sk, *result;
-	struct hlist_nulls_node *node;
 	unsigned short hnum = ntohs(loc_port);
 	unsigned int hash2 = udp4_portaddr_hash(net, loc_addr, hnum);
 	unsigned int slot2 = hash2 & udp_table.mask;
 	struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
 	INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
 	const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
+	struct sock *sk;
 
-	rcu_read_lock();
-	result = NULL;
-	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
-		if (INET_MATCH(sk, net, acookie,
-			       rmt_addr, loc_addr, ports, dif))
-			result = sk;
+	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
+		if (INET_MATCH(sk, net, acookie, rmt_addr,
+			       loc_addr, ports, dif))
+			return sk;
 		/* Only check first socket in chain */
 		break;
 	}
-
-	if (result) {
-		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
-			result = NULL;
-		else if (unlikely(!INET_MATCH(sk, net, acookie,
-					      rmt_addr, loc_addr,
-					      ports, dif))) {
-			sock_put(result);
-			result = NULL;
-		}
-	}
-	rcu_read_unlock();
-	return result;
+	return NULL;
 }
 
 void udp_v4_early_demux(struct sk_buff *skb)
@@ -2056,7 +1947,7 @@ void udp_v4_early_demux(struct sk_buff *skb)
 	struct net *net = dev_net(skb->dev);
 	const struct iphdr *iph;
 	const struct udphdr *uh;
-	struct sock *sk;
+	struct sock *sk = NULL;
 	struct dst_entry *dst;
 	int dif = skb->dev->ifindex;
 	int ours;
@@ -2088,11 +1979,9 @@ void udp_v4_early_demux(struct sk_buff *skb)
 	} else if (skb->pkt_type == PACKET_HOST) {
 		sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
 					     uh->source, iph->saddr, dif);
-	} else {
-		return;
 	}
 
-	if (!sk)
+	if (!sk || !atomic_inc_not_zero_hint(&sk->sk_refcnt, 2))
 		return;
 
 	skb->sk = sk;
@@ -2392,14 +2281,13 @@ static struct sock *udp_get_first(struct seq_file *seq, int start)
 
 	for (state->bucket = start; state->bucket <= state->udp_table->mask;
 	     ++state->bucket) {
-		struct hlist_nulls_node *node;
 		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
 
-		if (hlist_nulls_empty(&hslot->head))
+		if (hlist_empty(&hslot->head))
 			continue;
 
 		spin_lock_bh(&hslot->lock);
-		sk_nulls_for_each(sk, node, &hslot->head) {
+		sk_for_each(sk, &hslot->head) {
 			if (!net_eq(sock_net(sk), net))
 				continue;
 			if (sk->sk_family == state->family)
@@ -2418,7 +2306,7 @@ static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
 	struct net *net = seq_file_net(seq);
 
 	do {
-		sk = sk_nulls_next(sk);
+		sk = sk_next(sk);
 	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
 
 	if (!sk) {
@@ -2627,12 +2515,12 @@ void __init udp_table_init(struct udp_table *table, const char *name)
 
 	table->hash2 = table->hash + (table->mask + 1);
 	for (i = 0; i <= table->mask; i++) {
-		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
+		INIT_HLIST_HEAD(&table->hash[i].head);
 		table->hash[i].count = 0;
 		spin_lock_init(&table->hash[i].lock);
 	}
 	for (i = 0; i <= table->mask; i++) {
-		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
+		INIT_HLIST_HEAD(&table->hash2[i].head);
 		table->hash2[i].count = 0;
 		spin_lock_init(&table->hash2[i].lock);
 	}