tcp/dccp: do not care about families in inet_twsk_purge()

We lost ability to unload ipv6 module a long time ago.

Instead of calling expensive inet_twsk_purge() twice,
we can handle all families in one round.

Also remove an extra line added in my prior patch,
per Kuniyuki Iwashima feedback.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/netdev/20240327192934.6843-1-kuniyu@amazon.com/Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240329153203.345203-1-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/inet_timewait_sock.h

@@ -111,7 +111,7 @@ static inline void inet_twsk_reschedule(struct inet_timewait_sock *tw, int timeo
 
 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw);
 
-void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family);
+void inet_twsk_purge(struct inet_hashinfo *hashinfo);
 
 static inline
 struct net *twsk_net(const struct inet_timewait_sock *twsk)

include/net/tcp.h

@@ -353,7 +353,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb);
 void tcp_rcv_space_adjust(struct sock *sk);
 int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp);
 void tcp_twsk_destructor(struct sock *sk);
-void tcp_twsk_purge(struct list_head *net_exit_list, int family);
+void tcp_twsk_purge(struct list_head *net_exit_list);
 ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos,
 			struct pipe_inode_info *pipe, size_t len,
 			unsigned int flags);

net/dccp/ipv4.c

@@ -1039,7 +1039,7 @@ static void __net_exit dccp_v4_exit_net(struct net *net)
 
 static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
 {
-	inet_twsk_purge(&dccp_hashinfo, AF_INET);
+	inet_twsk_purge(&dccp_hashinfo);
 }
 
 static struct pernet_operations dccp_v4_ops = {

net/dccp/ipv6.c

@@ -1119,15 +1119,9 @@ static void __net_exit dccp_v6_exit_net(struct net *net)
 	inet_ctl_sock_destroy(pn->v6_ctl_sk);
 }
 
-static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
-{
-	inet_twsk_purge(&dccp_hashinfo, AF_INET6);
-}
-
 static struct pernet_operations dccp_v6_ops = {
 	.init   = dccp_v6_init_net,
 	.exit   = dccp_v6_exit_net,
-	.exit_batch = dccp_v6_exit_batch,
 	.id	= &dccp_v6_pernet_id,
 	.size   = sizeof(struct dccp_v6_pernet),
 };

net/ipv4/inet_timewait_sock.c

@@ -264,7 +264,7 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
 EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
 
 /* Remove all non full sockets (TIME_WAIT and NEW_SYN_RECV) for dead netns */
-void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
+void inet_twsk_purge(struct inet_hashinfo *hashinfo)
 {
 	struct inet_ehash_bucket *head = &hashinfo->ehash[0];
 	unsigned int ehash_mask = hashinfo->ehash_mask;
@@ -273,7 +273,6 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
 	struct sock *sk;
 
 	for (slot = 0; slot <= ehash_mask; slot++, head++) {
-
 		if (hlist_nulls_empty(&head->chain))
 			continue;
 
@@ -288,15 +287,13 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
 					     TCPF_NEW_SYN_RECV))
 				continue;
 
-			if (sk->sk_family != family ||
-			    refcount_read(&sock_net(sk)->ns.count))
+			if (refcount_read(&sock_net(sk)->ns.count))
 				continue;
 
 			if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 				continue;
 
-			if (unlikely(sk->sk_family != family ||
-				     refcount_read(&sock_net(sk)->ns.count))) {
+			if (refcount_read(&sock_net(sk)->ns.count)) {
 				sock_gen_put(sk);
 				goto restart;
 			}

net/ipv4/tcp_ipv4.c

@@ -3501,7 +3501,7 @@ static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
 {
 	struct net *net;
 
-	tcp_twsk_purge(net_exit_list, AF_INET);
+	tcp_twsk_purge(net_exit_list);
 
 	list_for_each_entry(net, net_exit_list, exit_list) {
 		inet_pernet_hashinfo_free(net->ipv4.tcp_death_row.hashinfo);

net/ipv4/tcp_minisocks.c

@@ -388,7 +388,7 @@ void tcp_twsk_destructor(struct sock *sk)
 }
 EXPORT_SYMBOL_GPL(tcp_twsk_destructor);
 
-void tcp_twsk_purge(struct list_head *net_exit_list, int family)
+void tcp_twsk_purge(struct list_head *net_exit_list)
 {
 	bool purged_once = false;
 	struct net *net;
@@ -396,9 +396,9 @@ void tcp_twsk_purge(struct list_head *net_exit_list, int family)
 	list_for_each_entry(net, net_exit_list, exit_list) {
 		if (net->ipv4.tcp_death_row.hashinfo->pernet) {
 			/* Even if tw_refcount == 1, we must clean up kernel reqsk */
-			inet_twsk_purge(net->ipv4.tcp_death_row.hashinfo, family);
+			inet_twsk_purge(net->ipv4.tcp_death_row.hashinfo);
 		} else if (!purged_once) {
-			inet_twsk_purge(&tcp_hashinfo, family);
+			inet_twsk_purge(&tcp_hashinfo);
 			purged_once = true;
 		}
 	}

net/ipv6/tcp_ipv6.c

@@ -2389,15 +2389,9 @@ static void __net_exit tcpv6_net_exit(struct net *net)
 	inet_ctl_sock_destroy(net->ipv6.tcp_sk);
 }
 
-static void __net_exit tcpv6_net_exit_batch(struct list_head *net_exit_list)
-{
-	tcp_twsk_purge(net_exit_list, AF_INET6);
-}
-
 static struct pernet_operations tcpv6_net_ops = {
 	.init	    = tcpv6_net_init,
 	.exit	    = tcpv6_net_exit,
-	.exit_batch = tcpv6_net_exit_batch,
 };
 
 int __init tcpv6_init(void)