[PATCH net-next 3/6] tcp/dccp: get rid of inet_twsk_purge()

[Eric Dumazet <eric.dumazet@gmail.com>]

From: Eric Dumazet <edumazet@google.com>

Prior patches in the series made sure tw_timer_handler()
can be fired after netns has been dismantled/freed.

We no longer have to scan a potentially big TCP ehash
table at netns dismantle.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/inet_timewait_sock.h |  2 --
 net/dccp/ipv4.c                  |  6 ----
 net/dccp/ipv6.c                  |  6 ----
 net/ipv4/inet_timewait_sock.c    | 47 --------------------------------
 net/ipv4/tcp_ipv4.c              |  2 --
 net/ipv6/tcp_ipv6.c              |  6 ----
 6 files changed, 69 deletions(-)

diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index b323db969b8b6df98ad84a9bb9aad646b4a8730c..463ae5d33eb09c40caeb4d039af268609b5e563b 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -110,8 +110,6 @@ 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);
-
 static inline
 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 {
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 0ea29270d7e53730d14ec43654be8f956f891552..ae662567a6cb6a440c79a9805a2cd6d146ac5a29 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -1030,15 +1030,9 @@ static void __net_exit dccp_v4_exit_net(struct net *net)
 	inet_ctl_sock_destroy(pn->v4_ctl_sk);
 }
 
-static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
-{
-	inet_twsk_purge(&dccp_hashinfo, AF_INET);
-}
-
 static struct pernet_operations dccp_v4_ops = {
 	.init	= dccp_v4_init_net,
 	.exit	= dccp_v4_exit_net,
-	.exit_batch = dccp_v4_exit_batch,
 	.id	= &dccp_v4_pernet_id,
 	.size   = sizeof(struct dccp_v4_pernet),
 };
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index fa663518fa0e465458b7486ad0cd0672425f08b0..eab3bd1ee9a0a0064c04ff97fd8363e60daa0079 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -1115,15 +1115,9 @@ 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),
 };
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index e37e4852711c52bf8f6d01877297266cd19294ed..71808c7a7025c0a3a811b629a7796ad148152a4c 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -255,50 +255,3 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
 	}
 }
 EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
-
-void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
-{
-	struct inet_timewait_sock *tw;
-	struct sock *sk;
-	struct hlist_nulls_node *node;
-	unsigned int slot;
-
-	for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
-		struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
-restart_rcu:
-		cond_resched();
-		rcu_read_lock();
-restart:
-		sk_nulls_for_each_rcu(sk, node, &head->chain) {
-			if (sk->sk_state != TCP_TIME_WAIT)
-				continue;
-			tw = inet_twsk(sk);
-			if ((tw->tw_family != family) ||
-				refcount_read(&twsk_net(tw)->ns.count))
-				continue;
-
-			if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
-				continue;
-
-			if (unlikely((tw->tw_family != family) ||
-				     refcount_read(&twsk_net(tw)->ns.count))) {
-				inet_twsk_put(tw);
-				goto restart;
-			}
-
-			rcu_read_unlock();
-			local_bh_disable();
-			inet_twsk_deschedule_put(tw);
-			local_bh_enable();
-			goto restart_rcu;
-		}
-		/* If the nulls value we got at the end of this lookup is
-		 * not the expected one, we must restart lookup.
-		 * We probably met an item that was moved to another chain.
-		 */
-		if (get_nulls_value(node) != slot)
-			goto restart;
-		rcu_read_unlock();
-	}
-}
-EXPORT_SYMBOL_GPL(inet_twsk_purge);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index b3f34e366b27f7f1aece164aa485b1e9a7248d93..8e94b99882044d3d9927d83512d18f34dc2f5b43 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -3239,8 +3239,6 @@ static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list)
 {
 	struct net *net;
 
-	inet_twsk_purge(&tcp_hashinfo, AF_INET);
-
 	list_for_each_entry(net, net_exit_list, exit_list)
 		tcp_fastopen_ctx_destroy(net);
 }
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 075ee8a2df3b7f3759f69f1b1256f2e8c9c700c1..1e55ee98dfedac67a591a8a04ce98f334a4b8b7c 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2237,15 +2237,9 @@ 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)
-{
-	inet_twsk_purge(&tcp_hashinfo, 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)
-- 
2.35.0.rc0.227.g00780c9af4-goog