Merge branch 'tcp-refactor-bhash2'

Kuniyuki Iwashima says:

====================
tcp: Refactor bhash2 and remove sk_bind2_node.

This series refactors code around bhash2 and remove some bhash2-specific
fields; sock.sk_bind2_node, and inet_timewait_sock.tw_bind2_node.

  patch 1      : optimise bind() for non-wildcard v4-mapped-v6 address
  patch 2 -  4 : optimise bind() conflict tests
  patch 5 - 12 : Link bhash2 to bhash and unlink sk from bhash2 to
                 remove sk_bind2_node

The patch 8 will trigger a false-positive error by checkpatch.

v2: resend of https://lore.kernel.org/netdev/20231213082029.35149-1-kuniyu@amazon.com/
  * Rebase on latest net-next
  * Patch 11
    * Add change in inet_diag_dump_icsk() for recent bhash dump patch

v1: https://lore.kernel.org/netdev/20231023190255.39190-1-kuniyu@amazon.com/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Author: davem330

include/net/inet_hashtables.h

@@ -88,30 +88,25 @@ struct inet_bind_bucket {
 	unsigned short		fast_sk_family;
 	bool			fast_ipv6_only;
 	struct hlist_node	node;
-	struct hlist_head	owners;
+	struct hlist_head	bhash2;
 };
 
 struct inet_bind2_bucket {
 	possible_net_t		ib_net;
 	int			l3mdev;
 	unsigned short		port;
 #if IS_ENABLED(CONFIG_IPV6)
-	unsigned short		family;
-#endif
-	union {
-#if IS_ENABLED(CONFIG_IPV6)
-		struct in6_addr		v6_rcv_saddr;
+	unsigned short		addr_type;
+	struct in6_addr		v6_rcv_saddr;
+#define rcv_saddr		v6_rcv_saddr.s6_addr32[3]
+#else
+	__be32			rcv_saddr;
 #endif
-		__be32			rcv_saddr;
-	};
 	/* Node in the bhash2 inet_bind_hashbucket chain */
 	struct hlist_node	node;
+	struct hlist_node	bhash_node;
 	/* List of sockets hashed to this bucket */
 	struct hlist_head	owners;
-	/* bhash has twsk in owners, but bhash2 has twsk in
-	 * deathrow not to add a member in struct sock_common.
-	 */
-	struct hlist_head	deathrow;
 };
 
 static inline struct net *ib_net(const struct inet_bind_bucket *ib)
@@ -241,7 +236,7 @@ bool inet_bind_bucket_match(const struct inet_bind_bucket *tb,
 struct inet_bind2_bucket *
 inet_bind2_bucket_create(struct kmem_cache *cachep, struct net *net,
 			 struct inet_bind_hashbucket *head,
-			 unsigned short port, int l3mdev,
+			 struct inet_bind_bucket *tb,
 			 const struct sock *sk);
 
 void inet_bind2_bucket_destroy(struct kmem_cache *cachep,

include/net/inet_timewait_sock.h

@@ -75,13 +75,9 @@ struct inet_timewait_sock {
 	struct timer_list	tw_timer;
 	struct inet_bind_bucket	*tw_tb;
 	struct inet_bind2_bucket	*tw_tb2;
-	struct hlist_node		tw_bind2_node;
 };
 #define tw_tclass tw_tos
 
-#define twsk_for_each_bound_bhash2(__tw, list) \
-	hlist_for_each_entry(__tw, list, tw_bind2_node)
-
 static inline struct inet_timewait_sock *inet_twsk(const struct sock *sk)
 {
 	return (struct inet_timewait_sock *)sk;

include/net/ipv6.h

@@ -784,11 +784,6 @@ static inline bool ipv6_addr_v4mapped(const struct in6_addr *a)
 					cpu_to_be32(0x0000ffff))) == 0UL;
 }
 
-static inline bool ipv6_addr_v4mapped_any(const struct in6_addr *a)
-{
-	return ipv6_addr_v4mapped(a) && ipv4_is_zeronet(a->s6_addr32[3]);
-}
-
 static inline bool ipv6_addr_v4mapped_loopback(const struct in6_addr *a)
 {
 	return ipv6_addr_v4mapped(a) && ipv4_is_loopback(a->s6_addr32[3]);

include/net/sock.h

@@ -352,7 +352,6 @@ struct sk_filter;
   *	@sk_txtime_report_errors: set report errors mode for SO_TXTIME
   *	@sk_txtime_unused: unused txtime flags
   *	@ns_tracker: tracker for netns reference
-  *	@sk_bind2_node: bind node in the bhash2 table
   */
 struct sock {
 	/*
@@ -544,7 +543,6 @@ struct sock {
 #endif
 	struct rcu_head		sk_rcu;
 	netns_tracker		ns_tracker;
-	struct hlist_node	sk_bind2_node;
 };
 
 enum sk_pacing {
@@ -873,16 +871,6 @@ static inline void sk_add_bind_node(struct sock *sk,
 	hlist_add_head(&sk->sk_bind_node, list);
 }
 
-static inline void __sk_del_bind2_node(struct sock *sk)
-{
-	__hlist_del(&sk->sk_bind2_node);
-}
-
-static inline void sk_add_bind2_node(struct sock *sk, struct hlist_head *list)
-{
-	hlist_add_head(&sk->sk_bind2_node, list);
-}
-
 #define sk_for_each(__sk, list) \
 	hlist_for_each_entry(__sk, list, sk_node)
 #define sk_for_each_rcu(__sk, list) \
@@ -900,8 +888,6 @@ static inline void sk_add_bind2_node(struct sock *sk, struct hlist_head *list)
 	hlist_for_each_entry_safe(__sk, tmp, list, sk_node)
 #define sk_for_each_bound(__sk, list) \
 	hlist_for_each_entry(__sk, list, sk_bind_node)
-#define sk_for_each_bound_bhash2(__sk, list) \
-	hlist_for_each_entry(__sk, list, sk_bind2_node)
 
 /**
  * sk_for_each_entry_offset_rcu - iterate over a list at a given struct offset

net/ipv4/inet_connection_sock.c

@@ -159,8 +159,11 @@ static bool inet_use_bhash2_on_bind(const struct sock *sk)
 	if (sk->sk_family == AF_INET6) {
 		int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr);
 
-		return addr_type != IPV6_ADDR_ANY &&
-			addr_type != IPV6_ADDR_MAPPED;
+		if (addr_type == IPV6_ADDR_ANY)
+			return false;
+
+		if (addr_type != IPV6_ADDR_MAPPED)
+			return true;
 	}
 #endif
 	return sk->sk_rcv_saddr != htonl(INADDR_ANY);
@@ -213,18 +216,9 @@ static bool inet_bhash2_conflict(const struct sock *sk,
 				 bool relax, bool reuseport_cb_ok,
 				 bool reuseport_ok)
 {
-	struct inet_timewait_sock *tw2;
 	struct sock *sk2;
 
-	sk_for_each_bound_bhash2(sk2, &tb2->owners) {
-		if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
-					   reuseport_cb_ok, reuseport_ok))
-			return true;
-	}
-
-	twsk_for_each_bound_bhash2(tw2, &tb2->deathrow) {
-		sk2 = (struct sock *)tw2;
-
+	sk_for_each_bound(sk2, &tb2->owners) {
 		if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
 					   reuseport_cb_ok, reuseport_ok))
 			return true;
@@ -233,48 +227,50 @@ static bool inet_bhash2_conflict(const struct sock *sk,
 	return false;
 }
 
+#define sk_for_each_bound_bhash(__sk, __tb2, __tb)			\
+	hlist_for_each_entry(__tb2, &(__tb)->bhash2, bhash_node)	\
+		sk_for_each_bound(sk2, &(__tb2)->owners)
+
 /* This should be called only when the tb and tb2 hashbuckets' locks are held */
 static int inet_csk_bind_conflict(const struct sock *sk,
 				  const struct inet_bind_bucket *tb,
 				  const struct inet_bind2_bucket *tb2, /* may be null */
 				  bool relax, bool reuseport_ok)
 {
-	bool reuseport_cb_ok;
-	struct sock_reuseport *reuseport_cb;
 	kuid_t uid = sock_i_uid((struct sock *)sk);
+	struct sock_reuseport *reuseport_cb;
+	bool reuseport_cb_ok;
+	struct sock *sk2;
 
 	rcu_read_lock();
 	reuseport_cb = rcu_dereference(sk->sk_reuseport_cb);
 	/* paired with WRITE_ONCE() in __reuseport_(add|detach)_closed_sock */
 	reuseport_cb_ok = !reuseport_cb || READ_ONCE(reuseport_cb->num_closed_socks);
 	rcu_read_unlock();
 
-	/*
-	 * Unlike other sk lookup places we do not check
+	/* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if
+	 * ipv4) should have been checked already. We need to do these two
+	 * checks separately because their spinlocks have to be acquired/released
+	 * independently of each other, to prevent possible deadlocks
+	 */
+	if (inet_use_bhash2_on_bind(sk))
+		return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax,
+						   reuseport_cb_ok, reuseport_ok);
+
+	/* Unlike other sk lookup places we do not check
 	 * for sk_net here, since _all_ the socks listed
 	 * in tb->owners and tb2->owners list belong
 	 * to the same net - the one this bucket belongs to.
 	 */
+	sk_for_each_bound_bhash(sk2, tb2, tb) {
+		if (!inet_bind_conflict(sk, sk2, uid, relax, reuseport_cb_ok, reuseport_ok))
+			continue;
 
-	if (!inet_use_bhash2_on_bind(sk)) {
-		struct sock *sk2;
-
-		sk_for_each_bound(sk2, &tb->owners)
-			if (inet_bind_conflict(sk, sk2, uid, relax,
-					       reuseport_cb_ok, reuseport_ok) &&
-			    inet_rcv_saddr_equal(sk, sk2, true))
-				return true;
-
-		return false;
+		if (inet_rcv_saddr_equal(sk, sk2, true))
+			return true;
 	}
 
-	/* Conflicts with an existing IPV6_ADDR_ANY (if ipv6) or INADDR_ANY (if
-	 * ipv4) should have been checked already. We need to do these two
-	 * checks separately because their spinlocks have to be acquired/released
-	 * independently of each other, to prevent possible deadlocks
-	 */
-	return tb2 && inet_bhash2_conflict(sk, tb2, uid, relax, reuseport_cb_ok,
-					   reuseport_ok);
+	return false;
 }
 
 /* Determine if there is a bind conflict with an existing IPV6_ADDR_ANY (if ipv6) or
@@ -457,7 +453,7 @@ void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
 	kuid_t uid = sock_i_uid(sk);
 	bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
 
-	if (hlist_empty(&tb->owners)) {
+	if (hlist_empty(&tb->bhash2)) {
 		tb->fastreuse = reuse;
 		if (sk->sk_reuseport) {
 			tb->fastreuseport = FASTREUSEPORT_ANY;
@@ -549,7 +545,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
 	}
 
 	if (!found_port) {
-		if (!hlist_empty(&tb->owners)) {
+		if (!hlist_empty(&tb->bhash2)) {
 			if (sk->sk_reuse == SK_FORCE_REUSE ||
 			    (tb->fastreuse > 0 && reuse) ||
 			    sk_reuseport_match(tb, sk))
@@ -569,7 +565,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
 
 	if (!tb2) {
 		tb2 = inet_bind2_bucket_create(hinfo->bind2_bucket_cachep,
-					       net, head2, port, l3mdev, sk);
+					       net, head2, tb, sk);
 		if (!tb2)
 			goto fail_unlock;
 		bhash2_created = true;
@@ -591,11 +587,10 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
 
 fail_unlock:
 	if (ret) {
+		if (bhash2_created)
+			inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep, tb2);
 		if (bhash_created)
 			inet_bind_bucket_destroy(hinfo->bind_bucket_cachep, tb);
-		if (bhash2_created)
-			inet_bind2_bucket_destroy(hinfo->bind2_bucket_cachep,
-						  tb2);
 	}
 	if (head2_lock_acquired)
 		spin_unlock(&head2->lock);

net/ipv4/inet_diag.c

@@ -1104,7 +1104,7 @@ void inet_diag_dump_icsk(struct inet_hashinfo *hashinfo, struct sk_buff *skb,
 				if (!net_eq(ib2_net(tb2), net))
 					continue;
 
-				sk_for_each_bound_bhash2(sk, &tb2->owners) {
+				sk_for_each_bound(sk, &tb2->owners) {
 					struct inet_sock *inet = inet_sk(sk);
 
 					if (num < s_num)