tcp: Set NULL to sk->sk_prot->h.hashinfo.

We will soon introduce an optional per-netns ehash.

This means we cannot use the global sk->sk_prot->h.hashinfo
to fetch a TCP hashinfo.

Instead, set NULL to sk->sk_prot->h.hashinfo for TCP and get
a proper hashinfo from net->ipv4.tcp_death_row.hashinfo.

Note that we need not use sk->sk_prot->h.hashinfo if DCCP is
disabled.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/inet_hashtables.h

@@ -170,6 +170,16 @@ struct inet_hashinfo {
 	struct inet_listen_hashbucket	*lhash2;
 };
 
+static inline struct inet_hashinfo *tcp_or_dccp_get_hashinfo(const struct sock *sk)
+{
+#if IS_ENABLED(CONFIG_IP_DCCP)
+	return sk->sk_prot->h.hashinfo ? :
+		sock_net(sk)->ipv4.tcp_death_row.hashinfo;
+#else
+	return sock_net(sk)->ipv4.tcp_death_row.hashinfo;
+#endif
+}
+
 static inline struct inet_listen_hashbucket *
 inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
 {

net/ipv4/af_inet.c

@@ -1250,7 +1250,7 @@ static int inet_sk_reselect_saddr(struct sock *sk)
 	}
 
 	prev_addr_hashbucket =
-		inet_bhashfn_portaddr(sk->sk_prot->h.hashinfo, sk,
+		inet_bhashfn_portaddr(tcp_or_dccp_get_hashinfo(sk), sk,
 				      sock_net(sk), inet->inet_num);
 
 	inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;

net/ipv4/inet_connection_sock.c

@@ -285,7 +285,7 @@ inet_csk_find_open_port(const struct sock *sk, struct inet_bind_bucket **tb_ret,
 			struct inet_bind2_bucket **tb2_ret,
 			struct inet_bind_hashbucket **head2_ret, int *port_ret)
 {
-	struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
 	int i, low, high, attempt_half, port, l3mdev;
 	struct inet_bind_hashbucket *head, *head2;
 	struct net *net = sock_net(sk);
@@ -467,8 +467,8 @@ void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
  */
 int inet_csk_get_port(struct sock *sk, unsigned short snum)
 {
+	struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
 	bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
-	struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
 	bool found_port = false, check_bind_conflict = true;
 	bool bhash_created = false, bhash2_created = false;
 	struct inet_bind_hashbucket *head, *head2;
@@ -910,10 +910,9 @@ static bool reqsk_queue_unlink(struct request_sock *req)
 	bool found = false;
 
 	if (sk_hashed(sk)) {
-		struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
-		spinlock_t *lock;
+		struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
+		spinlock_t *lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
 
-		lock = inet_ehash_lockp(hashinfo, req->rsk_hash);
 		spin_lock(lock);
 		found = __sk_nulls_del_node_init_rcu(sk);
 		spin_unlock(lock);

net/ipv4/inet_hashtables.c

@@ -168,7 +168,7 @@ void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
  */
 static void __inet_put_port(struct sock *sk)
 {
-	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
 	struct inet_bind_hashbucket *head, *head2;
 	struct net *net = sock_net(sk);
 	struct inet_bind_bucket *tb;
@@ -208,7 +208,7 @@ EXPORT_SYMBOL(inet_put_port);
 
 int __inet_inherit_port(const struct sock *sk, struct sock *child)
 {
-	struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *table = tcp_or_dccp_get_hashinfo(sk);
 	unsigned short port = inet_sk(child)->inet_num;
 	struct inet_bind_hashbucket *head, *head2;
 	bool created_inet_bind_bucket = false;
@@ -629,7 +629,7 @@ static bool inet_ehash_lookup_by_sk(struct sock *sk,
  */
 bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
 {
-	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
 	struct inet_ehash_bucket *head;
 	struct hlist_nulls_head *list;
 	spinlock_t *lock;
@@ -701,7 +701,7 @@ static int inet_reuseport_add_sock(struct sock *sk,
 
 int __inet_hash(struct sock *sk, struct sock *osk)
 {
-	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
 	struct inet_listen_hashbucket *ilb2;
 	int err = 0;
 
@@ -747,7 +747,7 @@ EXPORT_SYMBOL_GPL(inet_hash);
 
 void inet_unhash(struct sock *sk)
 {
-	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hashinfo = tcp_or_dccp_get_hashinfo(sk);
 
 	if (sk_unhashed(sk))
 		return;
@@ -834,7 +834,7 @@ inet_bind2_bucket_find(const struct inet_bind_hashbucket *head, const struct net
 struct inet_bind_hashbucket *
 inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, int port)
 {
-	struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
 	u32 hash;
 #if IS_ENABLED(CONFIG_IPV6)
 	struct in6_addr addr_any = {};
@@ -850,7 +850,7 @@ inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, in
 
 int inet_bhash2_update_saddr(struct inet_bind_hashbucket *prev_saddr, struct sock *sk)
 {
-	struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
+	struct inet_hashinfo *hinfo = tcp_or_dccp_get_hashinfo(sk);
 	struct inet_bind2_bucket *tb2, *new_tb2;
 	int l3mdev = inet_sk_bound_l3mdev(sk);
 	struct inet_bind_hashbucket *head2;

net/ipv4/tcp_ipv4.c

@@ -3083,7 +3083,7 @@ struct proto tcp_prot = {
 	.slab_flags		= SLAB_TYPESAFE_BY_RCU,
 	.twsk_prot		= &tcp_timewait_sock_ops,
 	.rsk_prot		= &tcp_request_sock_ops,
-	.h.hashinfo		= &tcp_hashinfo,
+	.h.hashinfo		= NULL,
 	.no_autobind		= true,
 	.diag_destroy		= tcp_abort,
 };

net/ipv6/tcp_ipv6.c

@@ -2194,7 +2194,7 @@ struct proto tcpv6_prot = {
 	.slab_flags		= SLAB_TYPESAFE_BY_RCU,
 	.twsk_prot		= &tcp6_timewait_sock_ops,
 	.rsk_prot		= &tcp6_request_sock_ops,
-	.h.hashinfo		= &tcp_hashinfo,
+	.h.hashinfo		= NULL,
 	.no_autobind		= true,
 	.diag_destroy		= tcp_abort,
 };