Merge branch 'net-add-data-race-annotations-around-dst-fields'

Eric Dumazet says:

====================
net: add data-race annotations around dst fields

Add annotations around various dst fields, which can change under us.

Add four helpers to prepare better dst->dev protection,
and start using them. More to come later.

v1: https://lore.kernel.org/[e-mail]
====================

Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

include/net/dst.h

···
 
 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
 {
-	if (unlikely(time != dst->lastuse)) {
+	if (unlikely(time != READ_ONCE(dst->lastuse))) {
 		dst->__use++;
-		dst->lastuse = time;
+		WRITE_ONCE(dst->lastuse, time);
 	}
 }
 
···
 
 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
 {
-	unsigned long expires = jiffies + timeout;
+	unsigned long old, expires = jiffies + timeout;
 
 	if (expires == 0)
 		expires = 1;
 
-	if (dst->expires == 0 || time_before(expires, dst->expires))
-		dst->expires = expires;
+	old = READ_ONCE(dst->expires);
+
+	if (!old || time_before(expires, old))
+		WRITE_ONCE(dst->expires, expires);
 }
 
 static inline unsigned int dst_dev_overhead(struct dst_entry *dst,
···
 /* Output packet to network from transport.  */
 static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	return INDIRECT_CALL_INET(skb_dst(skb)->output,
+	return INDIRECT_CALL_INET(READ_ONCE(skb_dst(skb)->output),
 				  ip6_output, ip_output,
 				  net, sk, skb);
 }
···
 /* Input packet from network to transport.  */
 static inline int dst_input(struct sk_buff *skb)
 {
-	return INDIRECT_CALL_INET(skb_dst(skb)->input,
+	return INDIRECT_CALL_INET(READ_ONCE(skb_dst(skb)->input),
 				  ip6_input, ip_local_deliver, skb);
 }
 
···
 							   u32));
 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
 {
-	if (dst->obsolete)
+	if (READ_ONCE(dst->obsolete))
 		dst = INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check,
 					 ipv4_dst_check, dst, cookie);
 	return dst;
···
 
 	if (dst && dst->ops->update_pmtu)
 		dst->ops->update_pmtu(dst, NULL, skb, mtu, false);
+}
+
+static inline struct net_device *dst_dev(const struct dst_entry *dst)
+{
+	return READ_ONCE(dst->dev);
+}
+
+static inline struct net_device *skb_dst_dev(const struct sk_buff *skb)
+{
+	return dst_dev(skb_dst(skb));
+}
+
+static inline struct net *skb_dst_dev_net(const struct sk_buff *skb)
+{
+	return dev_net(skb_dst_dev(skb));
+}
+
+static inline struct net *skb_dst_dev_net_rcu(const struct sk_buff *skb)
+{
+	return dev_net_rcu(skb_dst_dev(skb));
 }
 
 struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie);

include/net/inet6_hashtables.h

···
 					      int iif, int sdif,
 					      bool *refcounted)
 {
-	struct net *net = dev_net_rcu(skb_dst(skb)->dev);
+	struct net *net = skb_dst_dev_net_rcu(skb);
 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 	struct sock *sk;
 

include/net/inet_hashtables.h

···
 					     const int sdif,
 					     bool *refcounted)
 {
-	struct net *net = dev_net_rcu(skb_dst(skb)->dev);
+	struct net *net = skb_dst_dev_net_rcu(skb);
 	const struct iphdr *iph = ip_hdr(skb);
 	struct sock *sk;
 

include/net/ip.h

···
 
 	rcu_read_lock();
 
-	net = dev_net_rcu(dst->dev);
+	net = dev_net_rcu(dst_dev(dst));
 	if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) ||
 	    ip_mtu_locked(dst) ||
 	    !forwarding) {
 		mtu = rt->rt_pmtu;
-		if (mtu && time_before(jiffies, rt->dst.expires))
+		if (mtu && time_before(jiffies, READ_ONCE(rt->dst.expires)))
 			goto out;
 	}
 
···
 	if (mtu)
 		goto out;
 
-	mtu = READ_ONCE(dst->dev->mtu);
+	mtu = READ_ONCE(dst_dev(dst)->mtu);
 
 	if (unlikely(ip_mtu_locked(dst))) {
 		if (rt->rt_uses_gateway && mtu > 576)
···
 static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
 					  const struct sk_buff *skb)
 {
+	const struct dst_entry *dst = skb_dst(skb);
 	unsigned int mtu;
 
 	if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
 		bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
 
-		return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
+		return ip_dst_mtu_maybe_forward(dst, forwarding);
 	}
 
-	mtu = min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
-	return mtu - lwtunnel_headroom(skb_dst(skb)->lwtstate, mtu);
+	mtu = min(READ_ONCE(dst_dev(dst)->mtu), IP_MAX_MTU);
+	return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
 }
 
 struct dst_metrics *ip_fib_metrics_init(struct nlattr *fc_mx, int fc_mx_len,

include/net/ip6_route.h

···
 	unsigned int mtu;
 
 	if (np && READ_ONCE(np->pmtudisc) >= IPV6_PMTUDISC_PROBE) {
-		mtu = READ_ONCE(dst->dev->mtu);
+		mtu = READ_ONCE(dst_dev(dst)->mtu);
 		mtu -= lwtunnel_headroom(dst->lwtstate, mtu);
 	} else {
 		mtu = dst_mtu(dst);
···
 
 	mtu = IPV6_MIN_MTU;
 	rcu_read_lock();
-	idev = __in6_dev_get(dst->dev);
+	idev = __in6_dev_get(dst_dev(dst));
 	if (idev)
 		mtu = READ_ONCE(idev->cnf.mtu6);
 	rcu_read_unlock();

include/net/ip6_tunnel.h

···
 	memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
 	IP6CB(skb)->flags = ip6cb_flags;
 	pkt_len = skb->len - skb_inner_network_offset(skb);
-	err = ip6_local_out(dev_net(skb_dst(skb)->dev), sk, skb);
+	err = ip6_local_out(skb_dst_dev_net(skb), sk, skb);
 
 	if (dev) {
 		if (unlikely(net_xmit_eval(err)))

include/net/lwtunnel.h

···
 static inline void lwtunnel_set_redirect(struct dst_entry *dst)
 {
 	if (lwtunnel_output_redirect(dst->lwtstate)) {
-		dst->lwtstate->orig_output = dst->output;
-		dst->output = lwtunnel_output;
+		dst->lwtstate->orig_output = READ_ONCE(dst->output);
+		WRITE_ONCE(dst->output, lwtunnel_output);
 	}
 	if (lwtunnel_input_redirect(dst->lwtstate)) {
-		dst->lwtstate->orig_input = dst->input;
-		dst->input = lwtunnel_input;
+		dst->lwtstate->orig_input = READ_ONCE(dst->input);
+		WRITE_ONCE(dst->input, lwtunnel_input);
 	}
 }
 #else

include/net/route.h

···
 		const struct net *net;
 
 		rcu_read_lock();
-		net = dev_net_rcu(dst->dev);
+		net = dev_net_rcu(dst_dev(dst));
 		hoplimit = READ_ONCE(net->ipv4.sysctl_ip_default_ttl);
 		rcu_read_unlock();
 	}

net/core/dst.c

···
 {
 	struct net_device *dev = dst->dev;
 
-	dst->obsolete = DST_OBSOLETE_DEAD;
+	WRITE_ONCE(dst->obsolete, DST_OBSOLETE_DEAD);
 	if (dst->ops->ifdown)
 		dst->ops->ifdown(dst, dev);
-	dst->input = dst_discard;
-	dst->output = dst_discard_out;
-	dst->dev = blackhole_netdev;
+	WRITE_ONCE(dst->input, dst_discard);
+	WRITE_ONCE(dst->output, dst_discard_out);
+	WRITE_ONCE(dst->dev, blackhole_netdev);
 	netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker,
 			   GFP_ATOMIC);
 }
···
 {
 	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 
-	return mtu ? : dst->dev->mtu;
+	return mtu ? : dst_dev(dst)->mtu;
 }
 EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
 

net/core/dst_cache.c

···
 
 	if (unlikely(!time_after(idst->refresh_ts,
 				 READ_ONCE(dst_cache->reset_ts)) ||
-		     (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) {
+		     (READ_ONCE(dst->obsolete) && !dst->ops->check(dst, idst->cookie)))) {
 		dst_cache_per_cpu_dst_set(idst, NULL, 0);
 		dst_release(dst);
 		goto fail;

net/core/neighbour.c

···
 			 * we can reinject the packet there.
 			 */
 			n2 = NULL;
-			if (dst && dst->obsolete != DST_OBSOLETE_DEAD) {
+			if (dst &&
+			    READ_ONCE(dst->obsolete) != DST_OBSOLETE_DEAD) {
 				n2 = dst_neigh_lookup_skb(dst, skb);
 				if (n2)
 					n1 = n2;

net/core/rtnetlink.c

···
 		.rta_error = error,
 		.rta_id =  id,
 	};
+	unsigned long delta;
 
 	if (dst) {
-		ci.rta_lastuse = jiffies_delta_to_clock_t(jiffies - dst->lastuse);
+		delta = jiffies - READ_ONCE(dst->lastuse);
+		ci.rta_lastuse = jiffies_delta_to_clock_t(delta);
 		ci.rta_used = dst->__use;
 		ci.rta_clntref = rcuref_read(&dst->__rcuref);
 	}

net/core/sock.c

···
 {
 	struct dst_entry *dst = __sk_dst_get(sk);
 
-	if (dst && dst->obsolete &&
+	if (dst && READ_ONCE(dst->obsolete) &&
 	    INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check, ipv4_dst_check,
 			       dst, cookie) == NULL) {
 		sk_tx_queue_clear(sk);
···
 {
 	struct dst_entry *dst = sk_dst_get(sk);
 
-	if (dst && dst->obsolete &&
+	if (dst && READ_ONCE(dst->obsolete) &&
 	    INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check, ipv4_dst_check,
 			       dst, cookie) == NULL) {
 		sk_dst_reset(sk);
···
 		   !ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr));
 #endif
 	/* pairs with the WRITE_ONCE() in netif_set_gso(_ipv4)_max_size() */
-	max_size = is_ipv6 ? READ_ONCE(dst->dev->gso_max_size) :
-			READ_ONCE(dst->dev->gso_ipv4_max_size);
+	max_size = is_ipv6 ? READ_ONCE(dst_dev(dst)->gso_max_size) :
+			READ_ONCE(dst_dev(dst)->gso_ipv4_max_size);
 	if (max_size > GSO_LEGACY_MAX_SIZE && !sk_is_tcp(sk))
 		max_size = GSO_LEGACY_MAX_SIZE;
 
···
 {
 	u32 max_segs = 1;
 
-	sk->sk_route_caps = dst->dev->features;
+	sk->sk_route_caps = dst_dev(dst)->features;
 	if (sk_is_tcp(sk)) {
 		struct inet_connection_sock *icsk = inet_csk(sk);
 
···
 			sk->sk_route_caps |= NETIF_F_SG | NETIF_F_HW_CSUM;
 			sk->sk_gso_max_size = sk_dst_gso_max_size(sk, dst);
 			/* pairs with the WRITE_ONCE() in netif_set_gso_max_segs() */
-			max_segs = max_t(u32, READ_ONCE(dst->dev->gso_max_segs), 1);
+			max_segs = max_t(u32, READ_ONCE(dst_dev(dst)->gso_max_segs), 1);
 		}
 	}
 	sk->sk_gso_max_segs = max_segs;

net/ipv4/datagram.c

···
 	rcu_read_lock();
 
 	dst = __sk_dst_get(sk);
-	if (!dst || !dst->obsolete || dst->ops->check(dst, 0)) {
+	if (!dst || !READ_ONCE(dst->obsolete) || dst->ops->check(dst, 0)) {
 		rcu_read_unlock();
 		return;
 	}

net/ipv4/icmp.c

···
 {
 	struct dst_entry *dst = &rt->dst;
 	struct inet_peer *peer;
+	struct net_device *dev;
 	bool rc = true;
 
 	if (!apply_ratelimit)
 		return true;
 
 	/* No rate limit on loopback */
-	if (dst->dev && (dst->dev->flags&IFF_LOOPBACK))
+	dev = dst_dev(dst);
+	if (dev && (dev->flags & IFF_LOOPBACK))
 		goto out;
 
 	rcu_read_lock();
 	peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr,
-			       l3mdev_master_ifindex_rcu(dst->dev));
+			       l3mdev_master_ifindex_rcu(dev));
 	rc = inet_peer_xrlim_allow(peer,
 				   READ_ONCE(net->ipv4.sysctl_icmp_ratelimit));
 	rcu_read_unlock();
···
  */
 static struct net_device *icmp_get_route_lookup_dev(struct sk_buff *skb)
 {
-	struct net_device *route_lookup_dev = NULL;
+	struct net_device *dev = skb->dev;
+	const struct dst_entry *dst;
 
-	if (skb->dev)
-		route_lookup_dev = skb->dev;
-	else if (skb_dst(skb))
-		route_lookup_dev = skb_dst(skb)->dev;
-	return route_lookup_dev;
+	if (dev)
+		return dev;
+	dst = skb_dst(skb);
+	return dst ? dst_dev(dst) : NULL;
 }
 
 static struct rtable *icmp_route_lookup(struct net *net, struct flowi4 *fl4,
···
 	struct net *net;
 	u32 info = 0;
 
-	net = dev_net_rcu(skb_dst(skb)->dev);
+	net = skb_dst_dev_net_rcu(skb);
 
 	/*
 	 *	Incomplete header ?
···
 	struct icmp_bxm icmp_param;
 	struct net *net;
 
-	net = dev_net_rcu(skb_dst(skb)->dev);
+	net = skb_dst_dev_net_rcu(skb);
 	/* should there be an ICMP stat for ignored echos? */
 	if (READ_ONCE(net->ipv4.sysctl_icmp_echo_ignore_all))
 		return SKB_NOT_DROPPED_YET;
···
 	return SKB_NOT_DROPPED_YET;
 
 out_err:
-	__ICMP_INC_STATS(dev_net_rcu(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
+	__ICMP_INC_STATS(skb_dst_dev_net_rcu(skb), ICMP_MIB_INERRORS);
 	return SKB_DROP_REASON_PKT_TOO_SMALL;
 }
 

net/ipv4/igmp.c

···
 
 	pig->csum = ip_compute_csum(igmp_hdr(skb), igmplen);
 
-	return ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);
+	return ip_local_out(skb_dst_dev_net(skb), skb->sk, skb);
 }
 
 static int grec_size(struct ip_mc_list *pmc, int type, int gdel, int sdel)

net/ipv4/ip_fragment.c

···
 /* Process an incoming IP datagram fragment. */
 int ip_defrag(struct net *net, struct sk_buff *skb, u32 user)
 {
-	struct net_device *dev = skb->dev ? : skb_dst(skb)->dev;
+	struct net_device *dev = skb->dev ? : skb_dst_dev(skb);
 	int vif = l3mdev_master_ifindex_rcu(dev);
 	struct ipq *qp;
 

net/ipv4/ip_output.c

···
 	skb->protocol = htons(ETH_P_IP);
 
 	return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT,
-		       net, sk, skb, NULL, skb_dst(skb)->dev,
+		       net, sk, skb, NULL, skb_dst_dev(skb),
 		       dst_output);
 }
 
···
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct rtable *rt = dst_rtable(dst);
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
 	struct neighbour *neigh;
 	bool is_v6gw = false;
···
 
 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev;
+	struct net_device *dev = skb_dst_dev(skb), *indev = skb->dev;
 
 	skb->dev = dev;
 	skb->protocol = htons(ETH_P_IP);

net/ipv4/ip_vti.c

···
 		goto tx_error_icmp;
 	}
 
-	tdev = dst->dev;
+	tdev = dst_dev(dst);
 
 	if (tdev == dev) {
 		dst_release(dst);
···
 xmit:
 	skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
 	skb_dst_set(skb, dst);
-	skb->dev = skb_dst(skb)->dev;
+	skb->dev = skb_dst_dev(skb);
 
 	err = dst_output(tunnel->net, skb->sk, skb);
 	if (net_xmit_eval(err) == 0)

net/ipv4/netfilter.c

···
 /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
 int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int addr_type)
 {
+	struct net_device *dev = skb_dst_dev(skb);
 	const struct iphdr *iph = ip_hdr(skb);
 	struct rtable *rt;
 	struct flowi4 fl4 = {};
 	__be32 saddr = iph->saddr;
 	__u8 flags;
-	struct net_device *dev = skb_dst(skb)->dev;
 	struct flow_keys flkeys;
 	unsigned int hh_len;
 
···
 #endif
 
 	/* Change in oif may mean change in hh_len. */
-	hh_len = skb_dst(skb)->dev->hard_header_len;
+	hh_len = skb_dst_dev(skb)->hard_header_len;
 	if (skb_headroom(skb) < hh_len &&
 	    pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
 				0, GFP_ATOMIC))

net/ipv4/route.c

···
 					   const void *daddr)
 {
 	const struct rtable *rt = container_of(dst, struct rtable, dst);
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 	struct neighbour *n;
 
 	rcu_read_lock();
···
 static void ipv4_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 {
 	const struct rtable *rt = container_of(dst, struct rtable, dst);
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 	const __be32 *pkey = daddr;
 
 	if (rt->rt_gw_family == AF_INET) {
···
 		 */
 		rt = rcu_dereference(nhc->nhc_rth_input);
 		if (rt)
-			rt->dst.obsolete = DST_OBSOLETE_KILL;
+			WRITE_ONCE(rt->dst.obsolete, DST_OBSOLETE_KILL);
 
 		for_each_possible_cpu(i) {
 			struct rtable __rcu **prt;
···
 			prt = per_cpu_ptr(nhc->nhc_pcpu_rth_output, i);
 			rt = rcu_dereference(*prt);
 			if (rt)
-				rt->dst.obsolete = DST_OBSOLETE_KILL;
+				WRITE_ONCE(rt->dst.obsolete, DST_OBSOLETE_KILL);
 		}
 	}
 
···
 						jiffies + ip_rt_gc_timeout);
 			}
 			if (kill_route)
-				rt->dst.obsolete = DST_OBSOLETE_KILL;
+				WRITE_ONCE(rt->dst.obsolete, DST_OBSOLETE_KILL);
 			call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
 		}
 		neigh_release(n);
···
 {
 	struct rtable *rt = dst_rtable(dst);
 
-	if ((dst->obsolete > 0) ||
+	if ((READ_ONCE(dst->obsolete) > 0) ||
 	    (rt->rt_flags & RTCF_REDIRECTED) ||
-	    rt->dst.expires)
+	    READ_ONCE(rt->dst.expires))
 		sk_dst_reset(sk);
 }
 
···
 		return;
 
 	rcu_read_lock();
-	net = dev_net_rcu(dst->dev);
+	net = dev_net_rcu(dst_dev(dst));
 	if (mtu < net->ipv4.ip_rt_min_pmtu) {
 		lock = true;
 		mtu = min(old_mtu, net->ipv4.ip_rt_min_pmtu);
 	}
 
 	if (rt->rt_pmtu == mtu && !lock &&
-	    time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))
+	    time_before(jiffies, READ_ONCE(dst->expires) -
+				 net->ipv4.ip_rt_mtu_expires / 2))
 		goto out;
 
 	if (fib_lookup(net, fl4, &res, 0) == 0) {
···
 	__build_flow_key(net, &fl4, sk, iph, 0, 0, 0, 0, 0);
 
 	rt = dst_rtable(odst);
-	if (odst->obsolete && !odst->ops->check(odst, 0)) {
+	if (READ_ONCE(odst->obsolete) && !odst->ops->check(odst, 0)) {
 		rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
 		if (IS_ERR(rt))
 			goto out;
···
 	 * this is indicated by setting obsolete to DST_OBSOLETE_KILL or
 	 * DST_OBSOLETE_DEAD.
 	 */
-	if (dst->obsolete != DST_OBSOLETE_FORCE_CHK || rt_is_expired(rt))
+	if (READ_ONCE(dst->obsolete) != DST_OBSOLETE_FORCE_CHK ||
+	    rt_is_expired(rt))
 		return NULL;
 	return dst;
 }
···
 	struct net *net;
 
 	rcu_read_lock();
-	net = dev_net_rcu(dst->dev);
+	net = dev_net_rcu(dst_dev(dst));
 	advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size,
 				   net->ipv4.ip_rt_min_advmss);
 	rcu_read_unlock();
···
 static bool rt_cache_valid(const struct rtable *rt)
 {
 	return	rt &&
-		rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
+		READ_ONCE(rt->dst.obsolete) == DST_OBSOLETE_FORCE_CHK &&
 		!rt_is_expired(rt);
 }
 
···
 		else if (rt->rt_gw_family == AF_INET6)
 			new_rt->rt_gw6 = rt->rt_gw6;
 
-		new_rt->dst.input = rt->dst.input;
-		new_rt->dst.output = rt->dst.output;
+		new_rt->dst.input = READ_ONCE(rt->dst.input);
+		new_rt->dst.output = READ_ONCE(rt->dst.output);
 		new_rt->dst.error = rt->dst.error;
 		new_rt->dst.lastuse = jiffies;
 		new_rt->dst.lwtstate = lwtstate_get(rt->dst.lwtstate);
···
 		}
 	}
 
-	expires = rt->dst.expires;
+	expires = READ_ONCE(rt->dst.expires);
 	if (expires) {
 		unsigned long now = jiffies;
 

net/ipv4/tcp_fastopen.c

···
 void tcp_fastopen_active_disable_ofo_check(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct net_device *dev;
 	struct dst_entry *dst;
 	struct sk_buff *skb;
 
···
 	} else if (tp->syn_fastopen_ch &&
 		   atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times)) {
 		dst = sk_dst_get(sk);
-		if (!(dst && dst->dev && (dst->dev->flags & IFF_LOOPBACK)))
+		dev = dst ? dst_dev(dst) : NULL;
+		if (!(dev && (dev->flags & IFF_LOOPBACK)))
 			atomic_set(&sock_net(sk)->ipv4.tfo_active_disable_times, 0);
 		dst_release(dst);
 	}

net/ipv4/tcp_ipv4.c

···
 	arg.iov[0].iov_base = (unsigned char *)&rep;
 	arg.iov[0].iov_len  = sizeof(rep.th);
 
-	net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
+	net = sk ? sock_net(sk) : skb_dst_dev_net_rcu(skb);
 
 	/* Invalid TCP option size or twice included auth */
 	if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))

net/ipv4/tcp_metrics.c

···
 					  unsigned int hash)
 {
 	struct tcp_metrics_block *tm;
-	struct net *net;
 	bool reclaim = false;
+	struct net *net;
 
 	spin_lock_bh(&tcp_metrics_lock);
-	net = dev_net_rcu(dst->dev);
+	net = dev_net_rcu(dst_dev(dst));
 
 	/* While waiting for the spin-lock the cache might have been populated
 	 * with this entry and so we have to check again.
···
 		return NULL;
 	}
 
-	net = dev_net_rcu(dst->dev);
+	net = dev_net_rcu(dst_dev(dst));
 	hash ^= net_hash_mix(net);
 	hash = hash_32(hash, tcp_metrics_hash_log);
 
···
 	else
 		return NULL;
 
-	net = dev_net_rcu(dst->dev);
+	net = dev_net_rcu(dst_dev(dst));
 	hash ^= net_hash_mix(net);
 	hash = hash_32(hash, tcp_metrics_hash_log);
 

net/ipv4/xfrm4_output.c

···
 int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
-			    net, sk, skb, skb->dev, skb_dst(skb)->dev,
+			    net, sk, skb, skb->dev, skb_dst_dev(skb),
 			    __xfrm4_output,
 			    !(IPCB(skb)->flags & IPSKB_REROUTED));
 }

net/ipv6/datagram.c

···
 
 	rcu_read_lock();
 	dst = __sk_dst_get(sk);
-	if (!dst || !dst->obsolete ||
+	if (!dst || !READ_ONCE(dst->obsolete) ||
 	    dst->ops->check(dst, inet6_sk(sk)->dst_cookie)) {
 		rcu_read_unlock();
 		return;

net/ipv6/exthdrs.c

···
 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
-		__IP6_INC_STATS(dev_net(dst->dev), idev,
+		__IP6_INC_STATS(dev_net(dst_dev(dst)), idev,
 				IPSTATS_MIB_INHDRERRORS);
 fail_and_free:
 		kfree_skb(skb);
···
 		return -1;
 	}
 
-	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+	if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
 		if (ipv6_hdr(skb)->hop_limit <= 1) {
 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
···
 		return -1;
 	}
 
-	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+	if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
 		if (ipv6_hdr(skb)->hop_limit <= 1) {
 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
···
 			kfree_skb(skb);
 			return -1;
 		}
-		if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
+		if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) {
 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 			kfree_skb(skb);
 			return -1;
···
 		return -1;
 	}
 
-	if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
+	if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) {
 		if (ipv6_hdr(skb)->hop_limit <= 1) {
 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 			icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,

net/ipv6/icmp.c

···
 			       struct flowi6 *fl6, bool apply_ratelimit)
 {
 	struct net *net = sock_net(sk);
+	struct net_device *dev;
 	struct dst_entry *dst;
 	bool res = false;
 
···
 	 * this lookup should be more aggressive (not longer than timeout).
 	 */
 	dst = ip6_route_output(net, sk, fl6);
+	dev = dst_dev(dst);
 	if (dst->error) {
 		IP6_INC_STATS(net, ip6_dst_idev(dst),
 			      IPSTATS_MIB_OUTNOROUTES);
-	} else if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) {
+	} else if (dev && (dev->flags & IFF_LOOPBACK)) {
 		res = true;
 	} else {
 		struct rt6_info *rt = dst_rt6_info(dst);

net/ipv6/ila/ila_lwt.c

···
 		 */
 
 		memset(&fl6, 0, sizeof(fl6));
-		fl6.flowi6_oif = orig_dst->dev->ifindex;
+		fl6.flowi6_oif = dst_dev(orig_dst)->ifindex;
 		fl6.flowi6_iif = LOOPBACK_IFINDEX;
 		fl6.daddr = *rt6_nexthop(dst_rt6_info(orig_dst),
 					 &ip6h->daddr);

net/ipv6/ioam6.c

···
 				    struct ioam6_schema *sc,
 				    u8 sclen, bool is_input)
 {
+	struct net_device *dev = skb_dst_dev(skb);
 	struct timespec64 ts;
 	ktime_t tstamp;
 	u64 raw64;
···
 		if (is_input)
 			byte--;
 
-		raw32 = dev_net(skb_dst(skb)->dev)->ipv6.sysctl.ioam6_id;
+		raw32 = dev_net(dev)->ipv6.sysctl.ioam6_id;
 
 		*(__be32 *)data = cpu_to_be32((byte << 24) | raw32);
 		data += sizeof(__be32);
···
 		*(__be16 *)data = cpu_to_be16(raw16);
 		data += sizeof(__be16);
 
-		if (skb_dst(skb)->dev->flags & IFF_LOOPBACK)
+		if (dev->flags & IFF_LOOPBACK)
 			raw16 = IOAM6_U16_UNAVAILABLE;
 		else
-			raw16 = (__force u16)READ_ONCE(__in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id);
+			raw16 = (__force u16)READ_ONCE(__in6_dev_get(dev)->cnf.ioam6_id);
 
 		*(__be16 *)data = cpu_to_be16(raw16);
 		data += sizeof(__be16);
···
 		struct Qdisc *qdisc;
 		__u32 qlen, backlog;
 
-		if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+		if (dev->flags & IFF_LOOPBACK) {
 			*(__be32 *)data = cpu_to_be32(IOAM6_U32_UNAVAILABLE);
 		} else {
-			queue = skb_get_tx_queue(skb_dst(skb)->dev, skb);
+			queue = skb_get_tx_queue(dev, skb);
 			qdisc = rcu_dereference(queue->qdisc);
 			qdisc_qstats_qlen_backlog(qdisc, &qlen, &backlog);
 
···
 		if (is_input)
 			byte--;
 
-		raw64 = dev_net(skb_dst(skb)->dev)->ipv6.sysctl.ioam6_id_wide;
+		raw64 = dev_net(dev)->ipv6.sysctl.ioam6_id_wide;
 
 		*(__be64 *)data = cpu_to_be64(((u64)byte << 56) | raw64);
 		data += sizeof(__be64);
···
 		*(__be32 *)data = cpu_to_be32(raw32);
 		data += sizeof(__be32);
 
-		if (skb_dst(skb)->dev->flags & IFF_LOOPBACK)
+		if (dev->flags & IFF_LOOPBACK)
 			raw32 = IOAM6_U32_UNAVAILABLE;
 		else
-			raw32 = READ_ONCE(__in6_dev_get(skb_dst(skb)->dev)->cnf.ioam6_id_wide);
+			raw32 = READ_ONCE(__in6_dev_get(dev)->cnf.ioam6_id_wide);
 
 		*(__be32 *)data = cpu_to_be32(raw32);
 		data += sizeof(__be32);

net/ipv6/ioam6_iptunnel.c

···
 	if (has_tunsrc)
 		memcpy(&hdr->saddr, tunsrc, sizeof(*tunsrc));
 	else
-		ipv6_dev_get_saddr(net, dst->dev, &hdr->daddr,
+		ipv6_dev_get_saddr(net, dst_dev(dst), &hdr->daddr,
 				   IPV6_PREFER_SRC_PUBLIC, &hdr->saddr);
 
 	skb_postpush_rcsum(skb, hdr, len);
···
 			dst_cache_set_ip6(&ilwt->cache, dst, &fl6.saddr);
 		local_bh_enable();
 
-		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
+		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
 		if (unlikely(err))
 			goto drop;
 	}

net/ipv6/ip6_gre.c

···
 			 htonl(atomic_fetch_inc(&t->o_seqno)));
 
 	/* TooBig packet may have updated dst->dev's mtu */
-	if (!t->parms.collect_md && dst && dst_mtu(dst) > dst->dev->mtu)
-		dst->ops->update_pmtu(dst, NULL, skb, dst->dev->mtu, false);
-
+	if (!t->parms.collect_md && dst) {
+		mtu = READ_ONCE(dst_dev(dst)->mtu);
+		if (dst_mtu(dst) > mtu)
+			dst->ops->update_pmtu(dst, NULL, skb, mtu, false);
+	}
 	err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,
 			   NEXTHDR_GRE);
 	if (err != 0) {

net/ipv6/ip6_input.c

···
 	 * arrived via the sending interface (ethX), because of the
 	 * nature of scoping architecture. --yoshfuji
 	 */
-	IP6CB(skb)->iif = skb_valid_dst(skb) ? ip6_dst_idev(skb_dst(skb))->dev->ifindex : dev->ifindex;
+	IP6CB(skb)->iif = skb_valid_dst(skb) ?
+				ip6_dst_idev(skb_dst(skb))->dev->ifindex :
+				dev->ifindex;
 
 	if (unlikely(!pskb_may_pull(skb, sizeof(*hdr))))
 		goto err;
···
 
 int ip6_mc_input(struct sk_buff *skb)
 {
+	struct net_device *dev = skb->dev;
 	int sdif = inet6_sdif(skb);
 	const struct ipv6hdr *hdr;
-	struct net_device *dev;
 	bool deliver;
 
-	__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
-			 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
-			 skb->len);
+	__IP6_UPD_PO_STATS(skb_dst_dev_net_rcu(skb),
+			   __in6_dev_get_safely(dev), IPSTATS_MIB_INMCAST,
+			   skb->len);
 
 	/* skb->dev passed may be master dev for vrfs. */
 	if (sdif) {
-		rcu_read_lock();
-		dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif);
+		dev = dev_get_by_index_rcu(dev_net_rcu(dev), sdif);
 		if (!dev) {
-			rcu_read_unlock();
 			kfree_skb(skb);
 			return -ENODEV;
 		}
-	} else {
-		dev = skb->dev;
 	}
 
 	hdr = ipv6_hdr(skb);
 	deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL);
-	if (sdif)
-		rcu_read_unlock();
 
 #ifdef CONFIG_IPV6_MROUTE
 	/*
 	 *      IPv6 multicast router mode is now supported ;)
 	 */
-	if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) &&
+	if (atomic_read(&dev_net_rcu(skb->dev)->ipv6.devconf_all->mc_forwarding) &&
 	    !(ipv6_addr_type(&hdr->daddr) &
 	      (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&
 	    likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
···
 			/* unknown RA - process it normally */
 		}
 
-		if (deliver)
+		if (deliver) {
 			skb2 = skb_clone(skb, GFP_ATOMIC);
-		else {
+		} else {
 			skb2 = skb;
 			skb = NULL;
 		}
 
-		if (skb2) {
+		if (skb2)
 			ip6_mr_input(skb2);
-		}
 	}
 out:
 #endif
-	if (likely(deliver))
+	if (likely(deliver)) {
 		ip6_input(skb);
-	else {
+	} else {
 		/* discard */
 		kfree_skb(skb);
 	}

net/ipv6/ip6_output.c

···
 static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 	struct inet6_dev *idev = ip6_dst_idev(dst);
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
 	const struct in6_addr *daddr, *nexthop;
···
 
 int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev;
-	struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
+	struct dst_entry *dst = skb_dst(skb);
+	struct net_device *dev = dst_dev(dst), *indev = skb->dev;
+	struct inet6_dev *idev = ip6_dst_idev(dst);
 
 	skb->protocol = htons(ETH_P_IPV6);
 	skb->dev = dev;
···
 	const struct ipv6_pinfo *np = inet6_sk(sk);
 	struct in6_addr *first_hop = &fl6->daddr;
 	struct dst_entry *dst = skb_dst(skb);
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 	struct inet6_dev *idev = ip6_dst_idev(dst);
 	struct hop_jumbo_hdr *hop_jumbo;
 	int hoplen = sizeof(*hop_jumbo);
···
 	struct dst_entry *dst = skb_dst(skb);
 	struct ipv6hdr *hdr = ipv6_hdr(skb);
 	struct inet6_skb_parm *opt = IP6CB(skb);
-	struct net *net = dev_net(dst->dev);
+	struct net *net = dev_net(dst_dev(dst));
+	struct net_device *dev;
 	struct inet6_dev *idev;
 	SKB_DR(reason);
 	u32 mtu;
···
 		goto drop;
 	}
 	dst = skb_dst(skb);
-
+	dev = dst_dev(dst);
 	/* IPv6 specs say nothing about it, but it is clear that we cannot
 	   send redirects to source routed frames.
 	   We don't send redirects to frames decapsulated from IPsec.
 	 */
-	if (IP6CB(skb)->iif == dst->dev->ifindex &&
+	if (IP6CB(skb)->iif == dev->ifindex &&
 	    opt->srcrt == 0 && !skb_sec_path(skb)) {
 		struct in6_addr *target = NULL;
 		struct inet_peer *peer;
···
 
 	if (ip6_pkt_too_big(skb, mtu)) {
 		/* Again, force OUTPUT device used as source address */
-		skb->dev = dst->dev;
+		skb->dev = dev;
 		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);
 		__IP6_INC_STATS(net, ip6_dst_idev(dst),
···
 		return -EMSGSIZE;
 	}
 
-	if (skb_cow(skb, dst->dev->hard_header_len)) {
+	if (skb_cow(skb, dev->hard_header_len)) {
 		__IP6_INC_STATS(net, ip6_dst_idev(dst),
 				IPSTATS_MIB_OUTDISCARDS);
 		goto drop;
···
 	hdr->hop_limit--;
 
 	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
-		       net, NULL, skb, skb->dev, dst->dev,
+		       net, NULL, skb, skb->dev, dev,
 		       ip6_forward_finish);
 
 error:
···
 #ifdef CONFIG_IPV6_SUBTREES
 	    ip6_rt_check(&rt->rt6i_src, &fl6->saddr, np->saddr_cache) ||
 #endif
-	   (fl6->flowi6_oif && fl6->flowi6_oif != dst->dev->ifindex)) {
+	   (fl6->flowi6_oif && fl6->flowi6_oif != dst_dev(dst)->ifindex)) {
 		dst_release(dst);
 		dst = NULL;
 	}

net/ipv6/ip6_tunnel.c

···
 	} else {
 		if (ip_route_input(skb2, eiph->daddr, eiph->saddr,
 				   ip4h_dscp(eiph), skb2->dev) ||
-		    skb_dst(skb2)->dev->type != ARPHRD_TUNNEL6)
+		    skb_dst_dev(skb2)->type != ARPHRD_TUNNEL6)
 			goto out;
 	}
 
···
 		ndst = dst;
 	}
 
-	tdev = dst->dev;
+	tdev = dst_dev(dst);
 
 	if (tdev == dev) {
 		DEV_STATS_INC(dev, collisions);
···
 	/* Calculate max headroom for all the headers and adjust
 	 * needed_headroom if necessary.
 	 */
-	max_headroom = LL_RESERVED_SPACE(dst->dev) + sizeof(struct ipv6hdr)
+	max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct ipv6hdr)
 			+ dst->header_len + t->hlen;
 	if (max_headroom > READ_ONCE(dev->needed_headroom))
 		WRITE_ONCE(dev->needed_headroom, max_headroom);

net/ipv6/ip6_udp_tunnel.c

···
 		netdev_dbg(dev, "no route to %pI6\n", &fl6.daddr);
 		return ERR_PTR(-ENETUNREACH);
 	}
-	if (dst->dev == dev) { /* is this necessary? */
+	if (dst_dev(dst) == dev) { /* is this necessary? */
 		netdev_dbg(dev, "circular route to %pI6\n", &fl6.daddr);
 		dst_release(dst);
 		return ERR_PTR(-ELOOP);

net/ipv6/ip6_vti.c

···
 			      (const struct in6_addr *)&x->id.daddr))
 		goto tx_err_link_failure;
 
-	tdev = dst->dev;
+	tdev = dst_dev(dst);
 
 	if (tdev == dev) {
 		DEV_STATS_INC(dev, collisions);
···
 xmit:
 	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
 	skb_dst_set(skb, dst);
-	skb->dev = skb_dst(skb)->dev;
+	skb->dev = dst_dev(dst);
 
 	err = dst_output(t->net, skb->sk, skb);
 	if (net_xmit_eval(err) == 0)

net/ipv6/ip6mr.c

···
 
 int ip6_mr_input(struct sk_buff *skb)
 {
+	struct net_device *dev = skb->dev;
+	struct net *net = dev_net_rcu(dev);
 	struct mfc6_cache *cache;
-	struct net *net = dev_net(skb->dev);
 	struct mr_table *mrt;
 	struct flowi6 fl6 = {
-		.flowi6_iif	= skb->dev->ifindex,
+		.flowi6_iif	= dev->ifindex,
 		.flowi6_mark	= skb->mark,
 	};
 	int err;
-	struct net_device *dev;
 
 	/* skb->dev passed in is the master dev for vrfs.
 	 * Get the proper interface that does have a vif associated with it.
 	 */
-	dev = skb->dev;
-	if (netif_is_l3_master(skb->dev)) {
+	if (netif_is_l3_master(dev)) {
 		dev = dev_get_by_index_rcu(net, IPCB(skb)->iif);
 		if (!dev) {
 			kfree_skb(skb);

net/ipv6/ndisc.c

···
 {
 	struct icmp6hdr *icmp6h = icmp6_hdr(skb);
 	struct dst_entry *dst = skb_dst(skb);
+	struct net_device *dev;
 	struct inet6_dev *idev;
 	struct net *net;
 	struct sock *sk;
···
 
 	ip6_nd_hdr(skb, saddr, daddr, READ_ONCE(inet6_sk(sk)->hop_limit), skb->len);
 
-	idev = __in6_dev_get(dst->dev);
+	dev = dst_dev(dst);
+	idev = __in6_dev_get(dev);
 	IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTREQUESTS);
 
 	err = NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
-		      net, sk, skb, NULL, dst->dev,
+		      net, sk, skb, NULL, dev,
 		      dst_output);
 	if (!err) {
 		ICMP6MSGOUT_INC_STATS(net, idev, type);

net/ipv6/netfilter.c

···
 {
 	const struct ipv6hdr *iph = ipv6_hdr(skb);
 	struct sock *sk = sk_to_full_sk(sk_partial);
-	struct net_device *dev = skb_dst(skb)->dev;
+	struct net_device *dev = skb_dst_dev(skb);
 	struct flow_keys flkeys;
 	unsigned int hh_len;
 	struct dst_entry *dst;
···
 #endif
 
 	/* Change in oif may mean change in hh_len. */
-	hh_len = skb_dst(skb)->dev->hard_header_len;
+	hh_len = skb_dst_dev(skb)->hard_header_len;
 	if (skb_headroom(skb) < hh_len &&
 	    pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
 			     0, GFP_ATOMIC))

net/ipv6/netfilter/nf_dup_ipv6.c

···
 	}
 	skb_dst_drop(skb);
 	skb_dst_set(skb, dst);
-	skb->dev      = dst->dev;
+	skb->dev      = dst_dev(dst);
 	skb->protocol = htons(ETH_P_IPV6);
 
 	return true;

net/ipv6/netfilter/nf_reject_ipv6.c

···
 		skb_dst_set(oldskb, dst);
 	}
 
-	fl6.flowi6_oif = l3mdev_master_ifindex(skb_dst(oldskb)->dev);
+	fl6.flowi6_oif = l3mdev_master_ifindex(skb_dst_dev(oldskb));
 	fl6.flowi6_mark = IP6_REPLY_MARK(net, oldskb->mark);
 	security_skb_classify_flow(oldskb, flowi6_to_flowi_common(&fl6));
 	dst = ip6_route_output(net, NULL, &fl6);

net/ipv6/output_core.c

···
 {
 	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
 	if (hoplimit == 0) {
-		struct net_device *dev = dst->dev;
+		struct net_device *dev = dst_dev(dst);
 		struct inet6_dev *idev;
 
 		rcu_read_lock();
···
 	skb->protocol = htons(ETH_P_IPV6);
 
 	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
-		       net, sk, skb, NULL, skb_dst(skb)->dev,
+		       net, sk, skb, NULL, skb_dst_dev(skb),
 		       dst_output);
 }
 EXPORT_SYMBOL_GPL(__ip6_local_out);

net/ipv6/reassembly.c

···
 	return container_of(q, struct frag_queue, q);
 }
 
-static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
+static int ip6_frag_queue(struct net *net,
+			  struct frag_queue *fq, struct sk_buff *skb,
 			  struct frag_hdr *fhdr, int nhoff,
 			  u32 *prob_offset, int *refs)
 {
-	struct net *net = dev_net(skb_dst(skb)->dev);
 	int offset, end, fragsize;
 	struct sk_buff *prev_tail;
 	struct net_device *dev;
···
 
 static int ipv6_frag_rcv(struct sk_buff *skb)
 {
+	const struct ipv6hdr *hdr = ipv6_hdr(skb);
+	struct net *net = skb_dst_dev_net(skb);
 	struct frag_hdr *fhdr;
 	struct frag_queue *fq;
-	const struct ipv6hdr *hdr = ipv6_hdr(skb);
-	struct net *net = dev_net(skb_dst(skb)->dev);
 	u8 nexthdr;
 	int iif;
 
···
 		spin_lock(&fq->q.lock);
 
 		fq->iif = iif;
-		ret = ip6_frag_queue(fq, skb, fhdr, IP6CB(skb)->nhoff,
+		ret = ip6_frag_queue(net, fq, skb, fhdr, IP6CB(skb)->nhoff,
 				     &prob_offset, &refs);
 
 		spin_unlock(&fq->q.lock);

net/ipv6/route.c

···
 	const struct rt6_info *rt = dst_rt6_info(dst);
 
 	return ip6_neigh_lookup(rt6_nexthop(rt, &in6addr_any),
-				dst->dev, skb, daddr);
+				dst_dev(dst), skb, daddr);
 }
 
 static void ip6_confirm_neigh(const struct dst_entry *dst, const void *daddr)
 {
 	const struct rt6_info *rt = dst_rt6_info(dst);
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 
 	daddr = choose_neigh_daddr(rt6_nexthop(rt, &in6addr_any), NULL, daddr);
 	if (!daddr)
···
 static bool __rt6_check_expired(const struct rt6_info *rt)
 {
 	if (rt->rt6i_flags & RTF_EXPIRES)
-		return time_after(jiffies, rt->dst.expires);
-	else
-		return false;
+		return time_after(jiffies, READ_ONCE(rt->dst.expires));
+	return false;
 }
 
 static bool rt6_check_expired(const struct rt6_info *rt)
···
 	from = rcu_dereference(rt->from);
 
 	if (rt->rt6i_flags & RTF_EXPIRES) {
-		if (time_after(jiffies, rt->dst.expires))
+		if (time_after(jiffies, READ_ONCE(rt->dst.expires)))
 			return true;
 	} else if (from) {
-		return rt->dst.obsolete != DST_OBSOLETE_FORCE_CHK ||
+		return READ_ONCE(rt->dst.obsolete) != DST_OBSOLETE_FORCE_CHK ||
 			fib6_check_expired(from);
 	}
 	return false;
···
 	 * expired, independently from their aging, as per RFC 8201 section 4
 	 */
 	if (!(rt->rt6i_flags & RTF_EXPIRES)) {
-		if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
+		if (time_after_eq(now, READ_ONCE(rt->dst.lastuse) +
+				       gc_args->timeout)) {
 			pr_debug("aging clone %p\n", rt);
 			rt6_remove_exception(bucket, rt6_ex);
 			return;
 		}
-	} else if (time_after(jiffies, rt->dst.expires)) {
+	} else if (time_after(jiffies, READ_ONCE(rt->dst.expires))) {
 		pr_debug("purging expired route %p\n", rt);
 		rt6_remove_exception(bucket, rt6_ex);
 		return;
···
 					    u32 cookie)
 {
 	if (!__rt6_check_expired(rt) &&
-	    rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
+	    READ_ONCE(rt->dst.obsolete) == DST_OBSOLETE_FORCE_CHK &&
 	    fib6_check(from, cookie))
 		return &rt->dst;
-	else
-		return NULL;
+	return NULL;
 }
 
 INDIRECT_CALLABLE_SCOPE struct dst_entry *ip6_dst_check(struct dst_entry *dst,
···
 		rcu_read_lock();
 		from = rcu_dereference(rt0->from);
 		if (from)
-			rt0->dst.expires = from->expires;
+			WRITE_ONCE(rt0->dst.expires, from->expires);
 		rcu_read_unlock();
 	}
 
···
 
 		if (res.f6i->nh) {
 			struct fib6_nh_match_arg arg = {
-				.dev = dst->dev,
+				.dev = dst_dev(dst),
 				.gw = &rt6->rt6i_gateway,
 			};
 
···
 			sk_uid(sk));
 
 	dst = __sk_dst_get(sk);
-	if (!dst || !dst->obsolete ||
+	if (!dst || !READ_ONCE(dst->obsolete) ||
 	    dst->ops->check(dst, inet6_sk(sk)->dst_cookie))
 		return;
 
···
 
 static unsigned int ip6_default_advmss(const struct dst_entry *dst)
 {
-	struct net_device *dev = dst->dev;
+	struct net_device *dev = dst_dev(dst);
 	unsigned int mtu = dst_mtu(dst);
 	struct net *net;
 
···
 
 	if (res.f6i->nh) {
 		struct fib6_nh_match_arg arg = {
-			.dev = dst->dev,
+			.dev = dst_dev(dst),
 			.gw = &rt->rt6i_gateway,
 		};
 
···
 static int ip6_pkt_drop(struct sk_buff *skb, u8 code, int ipstats_mib_noroutes)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct net *net = dev_net(dst->dev);
+	struct net_device *dev = dst_dev(dst);
+	struct net *net = dev_net(dev);
 	struct inet6_dev *idev;
 	SKB_DR(reason);
 	int type;
 
 	if (netif_is_l3_master(skb->dev) ||
-	    dst->dev == net->loopback_dev)
+	    dev == net->loopback_dev)
 		idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif));
 	else
 		idev = ip6_dst_idev(dst);
···
 
 static int ip6_pkt_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	skb->dev = skb_dst(skb)->dev;
+	skb->dev = skb_dst_dev(skb);
 	return ip6_pkt_drop(skb, ICMPV6_NOROUTE, IPSTATS_MIB_OUTNOROUTES);
 }
 
···
 
 static int ip6_pkt_prohibit_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	skb->dev = skb_dst(skb)->dev;
+	skb->dev = skb_dst_dev(skb);
 	return ip6_pkt_drop(skb, ICMPV6_ADM_PROHIBITED, IPSTATS_MIB_OUTNOROUTES);
 }
 
···
 	 * each as a nexthop within RTA_MULTIPATH.
 	 */
 	if (rt6) {
+		struct net_device *dev;
+
 		if (rt6_flags & RTF_GATEWAY &&
 		    nla_put_in6_addr(skb, RTA_GATEWAY, &rt6->rt6i_gateway))
 			goto nla_put_failure;
 
-		if (dst->dev && nla_put_u32(skb, RTA_OIF, dst->dev->ifindex))
+		dev = dst_dev(dst);
+		if (dev && nla_put_u32(skb, RTA_OIF, dev->ifindex))
 			goto nla_put_failure;
 
 		if (lwtunnel_fill_encap(skb, dst->lwtstate, RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
···
 	}
 
 	if (rt6_flags & RTF_EXPIRES) {
-		expires = dst ? dst->expires : rt->expires;
+		expires = dst ? READ_ONCE(dst->expires) : rt->expires;
 		expires -= jiffies;
 	}
 

net/ipv6/rpl_iptunnel.c

···
 			local_bh_enable();
 		}
 
-		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
+		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
 		if (unlikely(err))
 			goto drop;
 	}
···
 			local_bh_enable();
 		}
 
-		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
+		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
 		if (unlikely(err))
 			goto drop;
 	} else {

net/ipv6/seg6_iptunnel.c

···
 			       int proto, struct dst_entry *cache_dst)
 {
 	struct dst_entry *dst = skb_dst(skb);
-	struct net *net = dev_net(dst->dev);
+	struct net_device *dev = dst_dev(dst);
+	struct net *net = dev_net(dev);
 	struct ipv6hdr *hdr, *inner_hdr;
 	struct ipv6_sr_hdr *isrh;
 	int hdrlen, tot_len, err;
···
 	isrh->nexthdr = proto;
 
 	hdr->daddr = isrh->segments[isrh->first_segment];
-	set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
+	set_tun_src(net, dev, &hdr->daddr, &hdr->saddr);
 
 #ifdef CONFIG_IPV6_SEG6_HMAC
 	if (sr_has_hmac(isrh)) {
···
 {
 	__u8 first_seg = osrh->first_segment;
 	struct dst_entry *dst = skb_dst(skb);
-	struct net *net = dev_net(dst->dev);
+	struct net_device *dev = dst_dev(dst);
+	struct net *net = dev_net(dev);
 	struct ipv6hdr *hdr, *inner_hdr;
 	int hdrlen = ipv6_optlen(osrh);
 	int red_tlv_offset, tlv_offset;
···
 	if (skip_srh) {
 		hdr->nexthdr = proto;
 
-		set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
+		set_tun_src(net, dev, &hdr->daddr, &hdr->saddr);
 		goto out;
 	}
 
···
 
 srcaddr:
 	isrh->nexthdr = proto;
-	set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
+	set_tun_src(net, dev, &hdr->daddr, &hdr->saddr);
 
 #ifdef CONFIG_IPV6_SEG6_HMAC
 	if (unlikely(!skip_srh && sr_has_hmac(isrh))) {
···
 
 #ifdef CONFIG_IPV6_SEG6_HMAC
 	if (sr_has_hmac(isrh)) {
-		struct net *net = dev_net(skb_dst(skb)->dev);
+		struct net *net = skb_dst_dev_net(skb);
 
 		err = seg6_push_hmac(net, &hdr->saddr, isrh);
 		if (unlikely(err))
···
 			local_bh_enable();
 		}
 
-		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
+		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
 		if (unlikely(err))
 			goto drop;
 	} else {
···
 	if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
 		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
 			       dev_net(skb->dev), NULL, skb, NULL,
-			       skb_dst(skb)->dev, seg6_input_finish);
+			       skb_dst_dev(skb), seg6_input_finish);
 
 	return seg6_input_finish(dev_net(skb->dev), NULL, skb);
 drop:
···
 
 static int seg6_input_nf(struct sk_buff *skb)
 {
-	struct net_device *dev = skb_dst(skb)->dev;
+	struct net_device *dev = skb_dst_dev(skb);
 	struct net *net = dev_net(skb->dev);
 
 	switch (skb->protocol) {
···
 			local_bh_enable();
 		}
 
-		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
+		err = skb_cow_head(skb, LL_RESERVED_SPACE(dst_dev(dst)));
 		if (unlikely(err))
 			goto drop;
 	}
···
 
 	if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
 		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, net, sk, skb,
-			       NULL, skb_dst(skb)->dev, dst_output);
+			       NULL, dst_dev(dst), dst_output);
 
 	return dst_output(net, sk, skb);
 drop:
···
 
 static int seg6_output_nf(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	struct net_device *dev = skb_dst(skb)->dev;
+	struct net_device *dev = skb_dst_dev(skb);
 
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):

net/ipv6/seg6_local.c

···
 	if (!local_delivery)
 		dev_flags |= IFF_LOOPBACK;
 
-	if (dst && (dst->dev->flags & dev_flags) && !dst->error) {
+	if (dst && (dst_dev(dst)->flags & dev_flags) && !dst->error) {
 		dst_release(dst);
 		dst = NULL;
 	}

net/ipv6/tcp_ipv6.c

···
 				 int oif, int rst, u8 tclass, __be32 label,
 				 u32 priority, u32 txhash, struct tcp_key *key)
 {
-	struct net *net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
+	struct net *net = sk ? sock_net(sk) : skb_dst_dev_net_rcu(skb);
 	unsigned int tot_len = sizeof(struct tcphdr);
 	struct sock *ctl_sk = net->ipv6.tcp_sk;
 	const struct tcphdr *th = tcp_hdr(skb);
···
 	if (!sk && !ipv6_unicast_destination(skb))
 		return;
 
-	net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
+	net = sk ? sock_net(sk) : skb_dst_dev_net_rcu(skb);
 	/* Invalid TCP option size or twice included auth */
 	if (tcp_parse_auth_options(th, &md5_hash_location, &aoh))
 		return;

net/ipv6/xfrm6_output.c

···
 int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
-			    net, sk, skb,  skb->dev, skb_dst(skb)->dev,
+			    net, sk, skb,  skb->dev, skb_dst_dev(skb),
 			    __xfrm6_output,
 			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
 }

net/netfilter/ipvs/ip_vs_xmit.c

···
 	if (!dest_dst)
 		return NULL;
 	dst = dest_dst->dst_cache;
-	if (dst->obsolete &&
+	if (READ_ONCE(dst->obsolete) &&
 	    dst->ops->check(dst, dest_dst->dst_cookie) == NULL)
 		return NULL;
 	return dest_dst;

net/sctp/transport.c

···
 void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk)
 {
 	/* If we don't have a fresh route, look one up */
-	if (!transport->dst || transport->dst->obsolete) {
+	if (!transport->dst || READ_ONCE(transport->dst->obsolete)) {
 		sctp_transport_dst_release(transport);
 		transport->af_specific->get_dst(transport, &transport->saddr,
 						&transport->fl, sk);

net/xfrm/xfrm_policy.c

···
 	 * This will force stale_bundle() to fail on any xdst bundle with
 	 * this dst linked in it.
 	 */
-	if (dst->obsolete < 0 && !stale_bundle(dst))
+	if (READ_ONCE(dst->obsolete) < 0 && !stale_bundle(dst))
 		return dst;
 
 	return NULL;
···
 
 static void xfrm_negative_advice(struct sock *sk, struct dst_entry *dst)
 {
-	if (dst->obsolete)
+	if (READ_ONCE(dst->obsolete))
 		sk_dst_reset(sk);
 }