tcp: Remove dead code and fields for bhash2.

Now all sockets including TIME_WAIT are linked to bhash2 using
sock_common.skc_bind_node.

We no longer use inet_bind2_bucket.deathrow, sock.sk_bind2_node,
and inet_timewait_sock.tw_bind2_node.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: q2ven

include/net/inet_hashtables.h

@@ -107,10 +107,6 @@ struct inet_bind2_bucket {
 	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)

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/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 {
@@ -890,8 +888,6 @@ static inline void sk_add_bind_node(struct sock *sk,
 	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

@@ -216,7 +216,6 @@ 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(sk2, &tb2->owners) {
@@ -225,25 +224,13 @@ static bool inet_bhash2_conflict(const struct sock *sk,
 			return true;
 	}
 
-	twsk_for_each_bound_bhash2(tw2, &tb2->deathrow) {
-		sk2 = (struct sock *)tw2;
-
-		if (__inet_bhash2_conflict(sk, sk2, sk_uid, relax,
-					   reuseport_cb_ok, reuseport_ok))
-			return true;
-	}
-
 	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)
 
-#define twsk_for_each_bound_bhash(__sk, __tb2, __tb)			\
-	hlist_for_each_entry(__tb2, &(__tb)->bhash2, bhash_node)	\
-		sk_for_each_bound_bhash2(sk2, &(__tb2)->deathrow)
-
 /* 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,
@@ -283,14 +270,6 @@ static int inet_csk_bind_conflict(const struct sock *sk,
 			return true;
 	}
 
-	twsk_for_each_bound_bhash(sk2, tb2, tb) {
-		if (!inet_bind_conflict(sk, sk2, uid, relax, reuseport_cb_ok, reuseport_ok))
-			continue;
-
-		if (inet_rcv_saddr_equal(sk, sk2, true))
-			return true;
-	}
-
 	return false;
 }
 

net/ipv4/inet_hashtables.c

@@ -122,7 +122,6 @@ static void inet_bind2_bucket_init(struct inet_bind2_bucket *tb2,
 	tb2->rcv_saddr = sk->sk_rcv_saddr;
 #endif
 	INIT_HLIST_HEAD(&tb2->owners);
-	INIT_HLIST_HEAD(&tb2->deathrow);
 	hlist_add_head(&tb2->node, &head->chain);
 	hlist_add_head(&tb2->bhash_node, &tb->bhash2);
 }
@@ -144,7 +143,7 @@ struct inet_bind2_bucket *inet_bind2_bucket_create(struct kmem_cache *cachep,
 /* Caller must hold hashbucket lock for this tb with local BH disabled */
 void inet_bind2_bucket_destroy(struct kmem_cache *cachep, struct inet_bind2_bucket *tb)
 {
-	if (hlist_empty(&tb->owners) && hlist_empty(&tb->deathrow)) {
+	if (hlist_empty(&tb->owners)) {
 		__hlist_del(&tb->node);
 		__hlist_del(&tb->bhash_node);
 		kmem_cache_free(cachep, tb);