tcp: convert to dev_net_rcu()

TCP uses of dev_net() are under RCU protection, change them
to dev_net_rcu() to get LOCKDEP support.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250301201424.2046477-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/inet6_hashtables.h

@@ -150,7 +150,7 @@ static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
 					      int iif, int sdif,
 					      bool *refcounted)
 {
-	struct net *net = dev_net(skb_dst(skb)->dev);
+	struct net *net = dev_net_rcu(skb_dst(skb)->dev);
 	const struct ipv6hdr *ip6h = ipv6_hdr(skb);
 	struct sock *sk;
 

include/net/inet_hashtables.h

@@ -492,7 +492,7 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
 					     const int sdif,
 					     bool *refcounted)
 {
-	struct net *net = dev_net(skb_dst(skb)->dev);
+	struct net *net = dev_net_rcu(skb_dst(skb)->dev);
 	const struct iphdr *iph = ip_hdr(skb);
 	struct sock *sk;
 

net/ipv4/tcp_ipv4.c

@@ -494,14 +494,14 @@ int tcp_v4_err(struct sk_buff *skb, u32 info)
 {
 	const struct iphdr *iph = (const struct iphdr *)skb->data;
 	struct tcphdr *th = (struct tcphdr *)(skb->data + (iph->ihl << 2));
-	struct tcp_sock *tp;
+	struct net *net = dev_net_rcu(skb->dev);
 	const int type = icmp_hdr(skb)->type;
 	const int code = icmp_hdr(skb)->code;
-	struct sock *sk;
 	struct request_sock *fastopen;
+	struct tcp_sock *tp;
 	u32 seq, snd_una;
+	struct sock *sk;
 	int err;
-	struct net *net = dev_net(skb->dev);
 
 	sk = __inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo,
 				       iph->daddr, th->dest, iph->saddr,
@@ -786,7 +786,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb,
 	arg.iov[0].iov_base = (unsigned char *)&rep;
 	arg.iov[0].iov_len  = sizeof(rep.th);
 
-	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
+	net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
 
 	/* Invalid TCP option size or twice included auth */
 	if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
@@ -1961,7 +1961,7 @@ EXPORT_SYMBOL(tcp_v4_do_rcv);
 
 int tcp_v4_early_demux(struct sk_buff *skb)
 {
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
 	const struct iphdr *iph;
 	const struct tcphdr *th;
 	struct sock *sk;
@@ -2172,7 +2172,7 @@ static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
 
 int tcp_v4_rcv(struct sk_buff *skb)
 {
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
 	enum skb_drop_reason drop_reason;
 	int sdif = inet_sdif(skb);
 	int dif = inet_iif(skb);

net/ipv4/tcp_metrics.c

@@ -170,7 +170,7 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
 	bool reclaim = false;
 
 	spin_lock_bh(&tcp_metrics_lock);
-	net = dev_net(dst->dev);
+	net = dev_net_rcu(dst->dev);
 
 	/* While waiting for the spin-lock the cache might have been populated
 	 * with this entry and so we have to check again.
@@ -273,7 +273,7 @@ static struct tcp_metrics_block *__tcp_get_metrics_req(struct request_sock *req,
 		return NULL;
 	}
 
-	net = dev_net(dst->dev);
+	net = dev_net_rcu(dst->dev);
 	hash ^= net_hash_mix(net);
 	hash = hash_32(hash, tcp_metrics_hash_log);
 
@@ -318,7 +318,7 @@ static struct tcp_metrics_block *tcp_get_metrics(struct sock *sk,
 	else
 		return NULL;
 
-	net = dev_net(dst->dev);
+	net = dev_net_rcu(dst->dev);
 	hash ^= net_hash_mix(net);
 	hash = hash_32(hash, tcp_metrics_hash_log);
 

net/ipv6/tcp_ipv6.c

@@ -376,7 +376,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 {
 	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
 	const struct tcphdr *th = (struct tcphdr *)(skb->data+offset);
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
 	struct request_sock *fastopen;
 	struct ipv6_pinfo *np;
 	struct tcp_sock *tp;
@@ -866,16 +866,16 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
 				 int oif, int rst, u8 tclass, __be32 label,
 				 u32 priority, u32 txhash, struct tcp_key *key)
 {
-	const struct tcphdr *th = tcp_hdr(skb);
-	struct tcphdr *t1;
-	struct sk_buff *buff;
-	struct flowi6 fl6;
-	struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
-	struct sock *ctl_sk = net->ipv6.tcp_sk;
+	struct net *net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
 	unsigned int tot_len = sizeof(struct tcphdr);
+	struct sock *ctl_sk = net->ipv6.tcp_sk;
+	const struct tcphdr *th = tcp_hdr(skb);
 	__be32 mrst = 0, *topt;
 	struct dst_entry *dst;
-	__u32 mark = 0;
+	struct sk_buff *buff;
+	struct tcphdr *t1;
+	struct flowi6 fl6;
+	u32 mark = 0;
 
 	if (tsecr)
 		tot_len += TCPOLEN_TSTAMP_ALIGNED;
@@ -1041,7 +1041,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb,
 	if (!sk && !ipv6_unicast_destination(skb))
 		return;
 
-	net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
+	net = sk ? sock_net(sk) : dev_net_rcu(skb_dst(skb)->dev);
 	/* Invalid TCP option size or twice included auth */
 	if (tcp_parse_auth_options(th, &md5_hash_location, &aoh))
 		return;
@@ -1740,6 +1740,7 @@ static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
 
 INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 {
+	struct net *net = dev_net_rcu(skb->dev);
 	enum skb_drop_reason drop_reason;
 	int sdif = inet6_sdif(skb);
 	int dif = inet6_iif(skb);
@@ -1749,7 +1750,6 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 	bool refcounted;
 	int ret;
 	u32 isn;
-	struct net *net = dev_net(skb->dev);
 
 	drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	if (skb->pkt_type != PACKET_HOST)
@@ -2001,7 +2001,7 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 
 void tcp_v6_early_demux(struct sk_buff *skb)
 {
-	struct net *net = dev_net(skb->dev);
+	struct net *net = dev_net_rcu(skb->dev);
 	const struct ipv6hdr *hdr;
 	const struct tcphdr *th;
 	struct sock *sk;