From 7a9546ee354ec6f23af403992b8c07baa50a23d2 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Wed, 12 Nov 2008 00:54:20 -0800
Subject: net: ib_net pointer should depends on CONFIG_NET_NS

We can shrink size of "struct inet_bind_bucket" by 50%, using
read_pnet() and write_pnet()

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv4/inet_hashtables.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'net/ipv4/inet_hashtables.c')

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 44981906fb9..be41ebbec4e 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -35,7 +35,7 @@ struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
 	struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
 
 	if (tb != NULL) {
-		tb->ib_net       = hold_net(net);
+		write_pnet(&tb->ib_net, hold_net(net));
 		tb->port      = snum;
 		tb->fastreuse = 0;
 		INIT_HLIST_HEAD(&tb->owners);
@@ -51,7 +51,7 @@ void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket
 {
 	if (hlist_empty(&tb->owners)) {
 		__hlist_del(&tb->node);
-		release_net(tb->ib_net);
+		release_net(ib_net(tb));
 		kmem_cache_free(cachep, tb);
 	}
 }
@@ -449,7 +449,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 			 * unique enough.
 			 */
 			inet_bind_bucket_for_each(tb, node, &head->chain) {
-				if (tb->ib_net == net && tb->port == port) {
+				if (ib_net(tb) == net && tb->port == port) {
 					WARN_ON(hlist_empty(&tb->owners));
 					if (tb->fastreuse >= 0)
 						goto next_port;
-- 
cgit v1.2.3-70-g09d2


From 3ab5aee7fe840b5b1b35a8d1ac11c3de5281e611 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Sun, 16 Nov 2008 19:40:17 -0800
Subject: net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls

RCU was added to UDP lookups, using a fast infrastructure :
- sockets kmem_cache use SLAB_DESTROY_BY_RCU and dont pay the
  price of call_rcu() at freeing time.
- hlist_nulls permits to use few memory barriers.

This patch uses same infrastructure for TCP/DCCP established
and timewait sockets.

Thanks to SLAB_DESTROY_BY_RCU, no slowdown for applications
using short lived TCP connections. A followup patch, converting
rwlocks to spinlocks will even speedup this case.

__inet_lookup_established() is pretty fast now we dont have to
dirty a contended cache line (read_lock/read_unlock)

Only established and timewait hashtable are converted to RCU
(bind table and listen table are still using traditional locking)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/inet_hashtables.h    |  4 +--
 include/net/inet_timewait_sock.h | 10 +++---
 net/core/sock.c                  |  4 ++-
 net/dccp/ipv4.c                  |  1 +
 net/dccp/ipv6.c                  |  1 +
 net/dccp/proto.c                 |  4 +--
 net/ipv4/inet_diag.c             |  7 ++--
 net/ipv4/inet_hashtables.c       | 78 ++++++++++++++++++++++++++++------------
 net/ipv4/inet_timewait_sock.c    | 26 ++++++++------
 net/ipv4/tcp.c                   |  4 +--
 net/ipv4/tcp_ipv4.c              | 25 ++++++-------
 net/ipv6/inet6_hashtables.c      | 70 ++++++++++++++++++++++++------------
 net/ipv6/tcp_ipv6.c              |  1 +
 13 files changed, 151 insertions(+), 84 deletions(-)

(limited to 'net/ipv4/inet_hashtables.c')

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index cb31fbf8ae2..48189604511 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -41,8 +41,8 @@
  * I'll experiment with dynamic table growth later.
  */
 struct inet_ehash_bucket {
-	struct hlist_head chain;
-	struct hlist_head twchain;
+	struct hlist_nulls_head chain;
+	struct hlist_nulls_head twchain;
 };
 
 /* There are a few simple rules, which allow for local port reuse by
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 80e4977631b..4b8ece22b8e 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -110,7 +110,7 @@ struct inet_timewait_sock {
 #define tw_state		__tw_common.skc_state
 #define tw_reuse		__tw_common.skc_reuse
 #define tw_bound_dev_if		__tw_common.skc_bound_dev_if
-#define tw_node			__tw_common.skc_node
+#define tw_node			__tw_common.skc_nulls_node
 #define tw_bind_node		__tw_common.skc_bind_node
 #define tw_refcnt		__tw_common.skc_refcnt
 #define tw_hash			__tw_common.skc_hash
@@ -137,10 +137,10 @@ struct inet_timewait_sock {
 	struct hlist_node	tw_death_node;
 };
 
-static inline void inet_twsk_add_node(struct inet_timewait_sock *tw,
-				      struct hlist_head *list)
+static inline void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw,
+				      struct hlist_nulls_head *list)
 {
-	hlist_add_head(&tw->tw_node, list);
+	hlist_nulls_add_head_rcu(&tw->tw_node, list);
 }
 
 static inline void inet_twsk_add_bind_node(struct inet_timewait_sock *tw,
@@ -175,7 +175,7 @@ static inline int inet_twsk_del_dead_node(struct inet_timewait_sock *tw)
 }
 
 #define inet_twsk_for_each(tw, node, head) \
-	hlist_for_each_entry(tw, node, head, tw_node)
+	hlist_nulls_for_each_entry(tw, node, head, tw_node)
 
 #define inet_twsk_for_each_inmate(tw, node, jail) \
 	hlist_for_each_entry(tw, node, jail, tw_death_node)
diff --git a/net/core/sock.c b/net/core/sock.c
index ded1eb5d2fd..38de9c3f563 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2082,7 +2082,9 @@ int proto_register(struct proto *prot, int alloc_slab)
 			prot->twsk_prot->twsk_slab =
 				kmem_cache_create(timewait_sock_slab_name,
 						  prot->twsk_prot->twsk_obj_size,
-						  0, SLAB_HWCACHE_ALIGN,
+						  0,
+						  SLAB_HWCACHE_ALIGN |
+							prot->slab_flags,
 						  NULL);
 			if (prot->twsk_prot->twsk_slab == NULL)
 				goto out_free_timewait_sock_slab_name;
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 528baa2e5be..d1dd95289b8 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -938,6 +938,7 @@ static struct proto dccp_v4_prot = {
 	.orphan_count		= &dccp_orphan_count,
 	.max_header		= MAX_DCCP_HEADER,
 	.obj_size		= sizeof(struct dccp_sock),
+	.slab_flags		= SLAB_DESTROY_BY_RCU,
 	.rsk_prot		= &dccp_request_sock_ops,
 	.twsk_prot		= &dccp_timewait_sock_ops,
 	.h.hashinfo		= &dccp_hashinfo,
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 4aa1148cdb2..f033e845bb0 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -1140,6 +1140,7 @@ static struct proto dccp_v6_prot = {
 	.orphan_count	   = &dccp_orphan_count,
 	.max_header	   = MAX_DCCP_HEADER,
 	.obj_size	   = sizeof(struct dccp6_sock),
+	.slab_flags	   = SLAB_DESTROY_BY_RCU,
 	.rsk_prot	   = &dccp6_request_sock_ops,
 	.twsk_prot	   = &dccp6_timewait_sock_ops,
 	.h.hashinfo	   = &dccp_hashinfo,
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 46cb3490d48..1117d4d8c8f 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -1090,8 +1090,8 @@ static int __init dccp_init(void)
 	}
 
 	for (i = 0; i < dccp_hashinfo.ehash_size; i++) {
-		INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].chain);
-		INIT_HLIST_HEAD(&dccp_hashinfo.ehash[i].twchain);
+		INIT_HLIST_NULLS_HEAD(&dccp_hashinfo.ehash[i].chain, i);
+		INIT_HLIST_NULLS_HEAD(&dccp_hashinfo.ehash[i].twchain, i);
 	}
 
 	if (inet_ehash_locks_alloc(&dccp_hashinfo))
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 564230dabcb..41b36720e97 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -778,18 +778,19 @@ skip_listen_ht:
 		struct inet_ehash_bucket *head = &hashinfo->ehash[i];
 		rwlock_t *lock = inet_ehash_lockp(hashinfo, i);
 		struct sock *sk;
-		struct hlist_node *node;
+		struct hlist_nulls_node *node;
 
 		num = 0;
 
-		if (hlist_empty(&head->chain) && hlist_empty(&head->twchain))
+		if (hlist_nulls_empty(&head->chain) &&
+			hlist_nulls_empty(&head->twchain))
 			continue;
 
 		if (i > s_i)
 			s_num = 0;
 
 		read_lock_bh(lock);
-		sk_for_each(sk, node, &head->chain) {
+		sk_nulls_for_each(sk, node, &head->chain) {
 			struct inet_sock *inet = inet_sk(sk);
 
 			if (num < s_num)
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index be41ebbec4e..fd269cfef0e 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -223,35 +223,65 @@ struct sock * __inet_lookup_established(struct net *net,
 	INET_ADDR_COOKIE(acookie, saddr, daddr)
 	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 	struct sock *sk;
-	const struct hlist_node *node;
+	const struct hlist_nulls_node *node;
 	/* Optimize here for direct hit, only listening connections can
 	 * have wildcards anyways.
 	 */
 	unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
-	struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
-	rwlock_t *lock = inet_ehash_lockp(hashinfo, hash);
+	unsigned int slot = hash & (hashinfo->ehash_size - 1);
+	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 
-	prefetch(head->chain.first);
-	read_lock(lock);
-	sk_for_each(sk, node, &head->chain) {
+	rcu_read_lock();
+begin:
+	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		if (INET_MATCH(sk, net, hash, acookie,
-					saddr, daddr, ports, dif))
-			goto hit; /* You sunk my battleship! */
+					saddr, daddr, ports, dif)) {
+			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
+				goto begintw;
+			if (unlikely(!INET_MATCH(sk, net, hash, acookie,
+				saddr, daddr, ports, dif))) {
+				sock_put(sk);
+				goto begin;
+			}
+			goto out;
+		}
 	}
+	/*
+	 * 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 begin;
 
+begintw:
 	/* Must check for a TIME_WAIT'er before going to listener hash. */
-	sk_for_each(sk, node, &head->twchain) {
+	sk_nulls_for_each_rcu(sk, node, &head->twchain) {
 		if (INET_TW_MATCH(sk, net, hash, acookie,
-					saddr, daddr, ports, dif))
-			goto hit;
+					saddr, daddr, ports, dif)) {
+			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
+				sk = NULL;
+				goto out;
+			}
+			if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
+				 saddr, daddr, ports, dif))) {
+				sock_put(sk);
+				goto begintw;
+			}
+			goto out;
+		}
 	}
+	/*
+	 * 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 begintw;
 	sk = NULL;
 out:
-	read_unlock(lock);
+	rcu_read_unlock();
 	return sk;
-hit:
-	sock_hold(sk);
-	goto out;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_established);
 
@@ -272,14 +302,14 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row,
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 	rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
 	struct sock *sk2;
-	const struct hlist_node *node;
+	const struct hlist_nulls_node *node;
 	struct inet_timewait_sock *tw;
 
 	prefetch(head->chain.first);
 	write_lock(lock);
 
 	/* Check TIME-WAIT sockets first. */
-	sk_for_each(sk2, node, &head->twchain) {
+	sk_nulls_for_each(sk2, node, &head->twchain) {
 		tw = inet_twsk(sk2);
 
 		if (INET_TW_MATCH(sk2, net, hash, acookie,
@@ -293,7 +323,7 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row,
 	tw = NULL;
 
 	/* And established part... */
-	sk_for_each(sk2, node, &head->chain) {
+	sk_nulls_for_each(sk2, node, &head->chain) {
 		if (INET_MATCH(sk2, net, hash, acookie,
 					saddr, daddr, ports, dif))
 			goto not_unique;
@@ -306,7 +336,7 @@ unique:
 	inet->sport = htons(lport);
 	sk->sk_hash = hash;
 	WARN_ON(!sk_unhashed(sk));
-	__sk_add_node(sk, &head->chain);
+	__sk_nulls_add_node_rcu(sk, &head->chain);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock(lock);
 
@@ -338,7 +368,7 @@ static inline u32 inet_sk_port_offset(const struct sock *sk)
 void __inet_hash_nolisten(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
-	struct hlist_head *list;
+	struct hlist_nulls_head *list;
 	rwlock_t *lock;
 	struct inet_ehash_bucket *head;
 
@@ -350,7 +380,7 @@ void __inet_hash_nolisten(struct sock *sk)
 	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 
 	write_lock(lock);
-	__sk_add_node(sk, list);
+	__sk_nulls_add_node_rcu(sk, list);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock(lock);
 }
@@ -400,13 +430,15 @@ void inet_unhash(struct sock *sk)
 		local_bh_disable();
 		inet_listen_wlock(hashinfo);
 		lock = &hashinfo->lhash_lock;
+		if (__sk_del_node_init(sk))
+			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	} else {
 		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 		write_lock_bh(lock);
+		if (__sk_nulls_del_node_init_rcu(sk))
+			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	}
 
-	if (__sk_del_node_init(sk))
-		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 	write_unlock_bh(lock);
 out:
 	if (sk->sk_state == TCP_LISTEN)
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 1c5fd38f882..60689951ecd 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -23,12 +23,12 @@ static void __inet_twsk_kill(struct inet_timewait_sock *tw,
 	rwlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
 
 	write_lock(lock);
-	if (hlist_unhashed(&tw->tw_node)) {
+	if (hlist_nulls_unhashed(&tw->tw_node)) {
 		write_unlock(lock);
 		return;
 	}
-	__hlist_del(&tw->tw_node);
-	sk_node_init(&tw->tw_node);
+	hlist_nulls_del_rcu(&tw->tw_node);
+	sk_nulls_node_init(&tw->tw_node);
 	write_unlock(lock);
 
 	/* Disassociate with bind bucket. */
@@ -92,13 +92,17 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 
 	write_lock(lock);
 
-	/* Step 2: Remove SK from established hash. */
-	if (__sk_del_node_init(sk))
-		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-
-	/* Step 3: Hash TW into TIMEWAIT chain. */
-	inet_twsk_add_node(tw, &ehead->twchain);
+	/*
+	 * Step 2: Hash TW into TIMEWAIT chain.
+	 * Should be done before removing sk from established chain
+	 * because readers are lockless and search established first.
+	 */
 	atomic_inc(&tw->tw_refcnt);
+	inet_twsk_add_node_rcu(tw, &ehead->twchain);
+
+	/* Step 3: Remove SK from established hash. */
+	if (__sk_nulls_del_node_init_rcu(sk))
+		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 
 	write_unlock(lock);
 }
@@ -416,7 +420,7 @@ void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
 {
 	struct inet_timewait_sock *tw;
 	struct sock *sk;
-	struct hlist_node *node;
+	struct hlist_nulls_node *node;
 	int h;
 
 	local_bh_disable();
@@ -426,7 +430,7 @@ void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
 		rwlock_t *lock = inet_ehash_lockp(hashinfo, h);
 restart:
 		write_lock(lock);
-		sk_for_each(sk, node, &head->twchain) {
+		sk_nulls_for_each(sk, node, &head->twchain) {
 
 			tw = inet_twsk(sk);
 			if (!net_eq(twsk_net(tw), net) ||
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f60a5917e54..044224a341e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2707,8 +2707,8 @@ void __init tcp_init(void)
 					thash_entries ? 0 : 512 * 1024);
 	tcp_hashinfo.ehash_size = 1 << tcp_hashinfo.ehash_size;
 	for (i = 0; i < tcp_hashinfo.ehash_size; i++) {
-		INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].chain);
-		INIT_HLIST_HEAD(&tcp_hashinfo.ehash[i].twchain);
+		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
+		INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].twchain, i);
 	}
 	if (inet_ehash_locks_alloc(&tcp_hashinfo))
 		panic("TCP: failed to alloc ehash_locks");
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d49233f409b..b2e3ab2287b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1857,16 +1857,16 @@ EXPORT_SYMBOL(tcp_v4_destroy_sock);
 #ifdef CONFIG_PROC_FS
 /* Proc filesystem TCP sock list dumping. */
 
-static inline struct inet_timewait_sock *tw_head(struct hlist_head *head)
+static inline struct inet_timewait_sock *tw_head(struct hlist_nulls_head *head)
 {
-	return hlist_empty(head) ? NULL :
+	return hlist_nulls_empty(head) ? NULL :
 		list_entry(head->first, struct inet_timewait_sock, tw_node);
 }
 
 static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
 {
-	return tw->tw_node.next ?
-		hlist_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
+	return !is_a_nulls(tw->tw_node.next) ?
+		hlist_nulls_entry(tw->tw_node.next, typeof(*tw), tw_node) : NULL;
 }
 
 static void *listening_get_next(struct seq_file *seq, void *cur)
@@ -1954,8 +1954,8 @@ static void *listening_get_idx(struct seq_file *seq, loff_t *pos)
 
 static inline int empty_bucket(struct tcp_iter_state *st)
 {
-	return hlist_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
-		hlist_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
+	return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain) &&
+		hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].twchain);
 }
 
 static void *established_get_first(struct seq_file *seq)
@@ -1966,7 +1966,7 @@ static void *established_get_first(struct seq_file *seq)
 
 	for (st->bucket = 0; st->bucket < tcp_hashinfo.ehash_size; ++st->bucket) {
 		struct sock *sk;
-		struct hlist_node *node;
+		struct hlist_nulls_node *node;
 		struct inet_timewait_sock *tw;
 		rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
 
@@ -1975,7 +1975,7 @@ static void *established_get_first(struct seq_file *seq)
 			continue;
 
 		read_lock_bh(lock);
-		sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
+		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
 			if (sk->sk_family != st->family ||
 			    !net_eq(sock_net(sk), net)) {
 				continue;
@@ -2004,7 +2004,7 @@ static void *established_get_next(struct seq_file *seq, void *cur)
 {
 	struct sock *sk = cur;
 	struct inet_timewait_sock *tw;
-	struct hlist_node *node;
+	struct hlist_nulls_node *node;
 	struct tcp_iter_state *st = seq->private;
 	struct net *net = seq_file_net(seq);
 
@@ -2032,11 +2032,11 @@ get_tw:
 			return NULL;
 
 		read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
-		sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain);
+		sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
 	} else
-		sk = sk_next(sk);
+		sk = sk_nulls_next(sk);
 
-	sk_for_each_from(sk, node) {
+	sk_nulls_for_each_from(sk, node) {
 		if (sk->sk_family == st->family && net_eq(sock_net(sk), net))
 			goto found;
 	}
@@ -2375,6 +2375,7 @@ struct proto tcp_prot = {
 	.sysctl_rmem		= sysctl_tcp_rmem,
 	.max_header		= MAX_TCP_HEADER,
 	.obj_size		= sizeof(struct tcp_sock),
+	.slab_flags		= SLAB_DESTROY_BY_RCU,
 	.twsk_prot		= &tcp_timewait_sock_ops,
 	.rsk_prot		= &tcp_request_sock_ops,
 	.h.hashinfo		= &tcp_hashinfo,
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 1646a565825..c1b4d401fd9 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -25,24 +25,28 @@
 void __inet6_hash(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
-	struct hlist_head *list;
 	rwlock_t *lock;
 
 	WARN_ON(!sk_unhashed(sk));
 
 	if (sk->sk_state == TCP_LISTEN) {
+		struct hlist_head *list;
+
 		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 		lock = &hashinfo->lhash_lock;
 		inet_listen_wlock(hashinfo);
+		__sk_add_node(sk, list);
 	} else {
 		unsigned int hash;
+		struct hlist_nulls_head *list;
+
 		sk->sk_hash = hash = inet6_sk_ehashfn(sk);
 		list = &inet_ehash_bucket(hashinfo, hash)->chain;
 		lock = inet_ehash_lockp(hashinfo, hash);
 		write_lock(lock);
+		__sk_nulls_add_node_rcu(sk, list);
 	}
 
-	__sk_add_node(sk, list);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock(lock);
 }
@@ -63,33 +67,53 @@ struct sock *__inet6_lookup_established(struct net *net,
 					   const int dif)
 {
 	struct sock *sk;
-	const struct hlist_node *node;
+	const struct hlist_nulls_node *node;
 	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 	/* Optimize here for direct hit, only listening connections can
 	 * have wildcards anyways.
 	 */
 	unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
-	struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
-	rwlock_t *lock = inet_ehash_lockp(hashinfo, hash);
+	unsigned int slot = hash & (hashinfo->ehash_size - 1);
+	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 
-	prefetch(head->chain.first);
-	read_lock(lock);
-	sk_for_each(sk, node, &head->chain) {
+
+	rcu_read_lock();
+begin:
+	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		/* For IPV6 do the cheaper port and family tests first. */
-		if (INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif))
-			goto hit; /* You sunk my battleship! */
+		if (INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) {
+			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
+				goto begintw;
+			if (!INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) {
+				sock_put(sk);
+				goto begin;
+			}
+		goto out;
+		}
 	}
+	if (get_nulls_value(node) != slot)
+		goto begin;
+
+begintw:
 	/* Must check for a TIME_WAIT'er before going to listener hash. */
-	sk_for_each(sk, node, &head->twchain) {
-		if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif))
-			goto hit;
+	sk_nulls_for_each_rcu(sk, node, &head->twchain) {
+		if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) {
+			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
+				sk = NULL;
+				goto out;
+			}
+			if (!INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) {
+				sock_put(sk);
+				goto begintw;
+			}
+			goto out;
+		}
 	}
-	read_unlock(lock);
-	return NULL;
-
-hit:
-	sock_hold(sk);
-	read_unlock(lock);
+	if (get_nulls_value(node) != slot)
+		goto begintw;
+	sk = NULL;
+out:
+	rcu_read_unlock();
 	return sk;
 }
 EXPORT_SYMBOL(__inet6_lookup_established);
@@ -172,14 +196,14 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 	rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
 	struct sock *sk2;
-	const struct hlist_node *node;
+	const struct hlist_nulls_node *node;
 	struct inet_timewait_sock *tw;
 
 	prefetch(head->chain.first);
 	write_lock(lock);
 
 	/* Check TIME-WAIT sockets first. */
-	sk_for_each(sk2, node, &head->twchain) {
+	sk_nulls_for_each(sk2, node, &head->twchain) {
 		tw = inet_twsk(sk2);
 
 		if (INET6_TW_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) {
@@ -192,7 +216,7 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 	tw = NULL;
 
 	/* And established part... */
-	sk_for_each(sk2, node, &head->chain) {
+	sk_nulls_for_each(sk2, node, &head->chain) {
 		if (INET6_MATCH(sk2, net, hash, saddr, daddr, ports, dif))
 			goto not_unique;
 	}
@@ -203,7 +227,7 @@ unique:
 	inet->num = lport;
 	inet->sport = htons(lport);
 	WARN_ON(!sk_unhashed(sk));
-	__sk_add_node(sk, &head->chain);
+	__sk_nulls_add_node_rcu(sk, &head->chain);
 	sk->sk_hash = hash;
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	write_unlock(lock);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 984276463a8..b3578705631 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2043,6 +2043,7 @@ struct proto tcpv6_prot = {
 	.sysctl_rmem		= sysctl_tcp_rmem,
 	.max_header		= MAX_TCP_HEADER,
 	.obj_size		= sizeof(struct tcp6_sock),
+	.slab_flags		= SLAB_DESTROY_BY_RCU,
 	.twsk_prot		= &tcp6_timewait_sock_ops,
 	.rsk_prot		= &tcp6_request_sock_ops,
 	.h.hashinfo		= &tcp_hashinfo,
-- 
cgit v1.2.3-70-g09d2


From 5caea4ea7088e80ac5410d04660346094608b909 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Thu, 20 Nov 2008 00:40:07 -0800
Subject: net: listening_hash get a spinlock per bucket

This patch prepares RCU migration of listening_hash table for
TCP/DCCP protocols.

listening_hash table being small (32 slots per protocol), we add
a spinlock for each slot, instead of a single rwlock for whole table.

This should reduce hold time of readers, and writers concurrency.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/inet_hashtables.h | 45 ++++++++--------------
 net/dccp/proto.c              |  8 +---
 net/ipv4/inet_diag.c          | 12 +++---
 net/ipv4/inet_hashtables.c    | 86 ++++++++++++++++---------------------------
 net/ipv4/tcp_ipv4.c           | 24 ++++++------
 net/ipv6/inet6_hashtables.c   | 23 ++++++------
 6 files changed, 79 insertions(+), 119 deletions(-)

(limited to 'net/ipv4/inet_hashtables.c')

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 48189604511..62d2dd0d786 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -99,6 +99,11 @@ struct inet_bind_hashbucket {
 	struct hlist_head	chain;
 };
 
+struct inet_listen_hashbucket {
+	spinlock_t		lock;
+	struct hlist_head	head;
+};
+
 /* This is for listening sockets, thus all sockets which possess wildcards. */
 #define INET_LHTABLE_SIZE	32	/* Yes, really, this is all you need. */
 
@@ -123,22 +128,21 @@ struct inet_hashinfo {
 	unsigned int			bhash_size;
 	/* Note : 4 bytes padding on 64 bit arches */
 
-	/* All sockets in TCP_LISTEN state will be in here.  This is the only
-	 * table where wildcard'd TCP sockets can exist.  Hash function here
-	 * is just local port number.
-	 */
-	struct hlist_head		listening_hash[INET_LHTABLE_SIZE];
+	struct kmem_cache		*bind_bucket_cachep;
 
 	/* All the above members are written once at bootup and
 	 * never written again _or_ are predominantly read-access.
 	 *
 	 * Now align to a new cache line as all the following members
-	 * are often dirty.
+	 * might be often dirty.
+	 */
+	/* All sockets in TCP_LISTEN state will be in here.  This is the only
+	 * table where wildcard'd TCP sockets can exist.  Hash function here
+	 * is just local port number.
 	 */
-	rwlock_t			lhash_lock ____cacheline_aligned;
-	atomic_t			lhash_users;
-	wait_queue_head_t		lhash_wait;
-	struct kmem_cache			*bind_bucket_cachep;
+	struct inet_listen_hashbucket	listening_hash[INET_LHTABLE_SIZE]
+					____cacheline_aligned_in_smp;
+
 };
 
 static inline struct inet_ehash_bucket *inet_ehash_bucket(
@@ -236,26 +240,7 @@ extern void __inet_inherit_port(struct sock *sk, struct sock *child);
 
 extern void inet_put_port(struct sock *sk);
 
-extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);
-
-/*
- * - We may sleep inside this lock.
- * - If sleeping is not required (or called from BH),
- *   use plain read_(un)lock(&inet_hashinfo.lhash_lock).
- */
-static inline void inet_listen_lock(struct inet_hashinfo *hashinfo)
-{
-	/* read_lock synchronizes to candidates to writers */
-	read_lock(&hashinfo->lhash_lock);
-	atomic_inc(&hashinfo->lhash_users);
-	read_unlock(&hashinfo->lhash_lock);
-}
-
-static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
-{
-	if (atomic_dec_and_test(&hashinfo->lhash_users))
-		wake_up(&hashinfo->lhash_wait);
-}
+void inet_hashinfo_init(struct inet_hashinfo *h);
 
 extern void __inet_hash_nolisten(struct sock *sk);
 extern void inet_hash(struct sock *sk);
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index bdf784c422b..8b63394ec24 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -44,12 +44,7 @@ atomic_t dccp_orphan_count = ATOMIC_INIT(0);
 
 EXPORT_SYMBOL_GPL(dccp_orphan_count);
 
-struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
-	.lhash_lock	= RW_LOCK_UNLOCKED,
-	.lhash_users	= ATOMIC_INIT(0),
-	.lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
-};
-
+struct inet_hashinfo dccp_hashinfo;
 EXPORT_SYMBOL_GPL(dccp_hashinfo);
 
 /* the maximum queue length for tx in packets. 0 is no limit */
@@ -1030,6 +1025,7 @@ static int __init dccp_init(void)
 	BUILD_BUG_ON(sizeof(struct dccp_skb_cb) >
 		     FIELD_SIZEOF(struct sk_buff, cb));
 
+	inet_hashinfo_init(&dccp_hashinfo);
 	dccp_hashinfo.bind_bucket_cachep =
 		kmem_cache_create("dccp_bind_bucket",
 				  sizeof(struct inet_bind_bucket), 0,
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 41b36720e97..1cb154ed75a 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -718,13 +718,15 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 		if (!(r->idiag_states & (TCPF_LISTEN | TCPF_SYN_RECV)))
 			goto skip_listen_ht;
 
-		inet_listen_lock(hashinfo);
 		for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
 			struct sock *sk;
 			struct hlist_node *node;
+			struct inet_listen_hashbucket *ilb;
 
 			num = 0;
-			sk_for_each(sk, node, &hashinfo->listening_hash[i]) {
+			ilb = &hashinfo->listening_hash[i];
+			spin_lock_bh(&ilb->lock);
+			sk_for_each(sk, node, &ilb->head) {
 				struct inet_sock *inet = inet_sk(sk);
 
 				if (num < s_num) {
@@ -742,7 +744,7 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 					goto syn_recv;
 
 				if (inet_csk_diag_dump(sk, skb, cb) < 0) {
-					inet_listen_unlock(hashinfo);
+					spin_unlock_bh(&ilb->lock);
 					goto done;
 				}
 
@@ -751,7 +753,7 @@ syn_recv:
 					goto next_listen;
 
 				if (inet_diag_dump_reqs(skb, sk, cb) < 0) {
-					inet_listen_unlock(hashinfo);
+					spin_unlock_bh(&ilb->lock);
 					goto done;
 				}
 
@@ -760,12 +762,12 @@ next_listen:
 				cb->args[4] = 0;
 				++num;
 			}
+			spin_unlock_bh(&ilb->lock);
 
 			s_num = 0;
 			cb->args[3] = 0;
 			cb->args[4] = 0;
 		}
-		inet_listen_unlock(hashinfo);
 skip_listen_ht:
 		cb->args[0] = 1;
 		s_i = num = s_num = 0;
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index fd269cfef0e..377d004e572 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -110,35 +110,6 @@ void __inet_inherit_port(struct sock *sk, struct sock *child)
 
 EXPORT_SYMBOL_GPL(__inet_inherit_port);
 
-/*
- * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
- * Look, when several writers sleep and reader wakes them up, all but one
- * immediately hit write lock and grab all the cpus. Exclusive sleep solves
- * this, _but_ remember, it adds useless work on UP machines (wake up each
- * exclusive lock release). It should be ifdefed really.
- */
-void inet_listen_wlock(struct inet_hashinfo *hashinfo)
-	__acquires(hashinfo->lhash_lock)
-{
-	write_lock(&hashinfo->lhash_lock);
-
-	if (atomic_read(&hashinfo->lhash_users)) {
-		DEFINE_WAIT(wait);
-
-		for (;;) {
-			prepare_to_wait_exclusive(&hashinfo->lhash_wait,
-						  &wait, TASK_UNINTERRUPTIBLE);
-			if (!atomic_read(&hashinfo->lhash_users))
-				break;
-			write_unlock_bh(&hashinfo->lhash_lock);
-			schedule();
-			write_lock_bh(&hashinfo->lhash_lock);
-		}
-
-		finish_wait(&hashinfo->lhash_wait, &wait);
-	}
-}
-
 /*
  * Don't inline this cruft. Here are some nice properties to exploit here. The
  * BSD API does not allow a listening sock to specify the remote port nor the
@@ -191,25 +162,25 @@ struct sock *__inet_lookup_listener(struct net *net,
 				    const int dif)
 {
 	struct sock *sk = NULL;
-	const struct hlist_head *head;
+	struct inet_listen_hashbucket *ilb;
 
-	read_lock(&hashinfo->lhash_lock);
-	head = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
-	if (!hlist_empty(head)) {
-		const struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
+	ilb = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
+	spin_lock(&ilb->lock);
+	if (!hlist_empty(&ilb->head)) {
+		const struct inet_sock *inet = inet_sk((sk = __sk_head(&ilb->head)));
 
 		if (inet->num == hnum && !sk->sk_node.next &&
 		    (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
 		    (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
 		    !sk->sk_bound_dev_if && net_eq(sock_net(sk), net))
 			goto sherry_cache;
-		sk = inet_lookup_listener_slow(net, head, daddr, hnum, dif);
+		sk = inet_lookup_listener_slow(net, &ilb->head, daddr, hnum, dif);
 	}
 	if (sk) {
 sherry_cache:
 		sock_hold(sk);
 	}
-	read_unlock(&hashinfo->lhash_lock);
+	spin_unlock(&ilb->lock);
 	return sk;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
@@ -389,8 +360,7 @@ EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
 static void __inet_hash(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
-	struct hlist_head *list;
-	rwlock_t *lock;
+	struct inet_listen_hashbucket *ilb;
 
 	if (sk->sk_state != TCP_LISTEN) {
 		__inet_hash_nolisten(sk);
@@ -398,14 +368,12 @@ static void __inet_hash(struct sock *sk)
 	}
 
 	WARN_ON(!sk_unhashed(sk));
-	list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
-	lock = &hashinfo->lhash_lock;
+	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 
-	inet_listen_wlock(hashinfo);
-	__sk_add_node(sk, list);
+	spin_lock(&ilb->lock);
+	__sk_add_node(sk, &ilb->head);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
-	write_unlock(lock);
-	wake_up(&hashinfo->lhash_wait);
+	spin_unlock(&ilb->lock);
 }
 
 void inet_hash(struct sock *sk)
@@ -420,29 +388,27 @@ EXPORT_SYMBOL_GPL(inet_hash);
 
 void inet_unhash(struct sock *sk)
 {
-	rwlock_t *lock;
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 
 	if (sk_unhashed(sk))
-		goto out;
+		return;
 
 	if (sk->sk_state == TCP_LISTEN) {
-		local_bh_disable();
-		inet_listen_wlock(hashinfo);
-		lock = &hashinfo->lhash_lock;
+		struct inet_listen_hashbucket *ilb;
+
+		ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+		spin_lock_bh(&ilb->lock);
 		if (__sk_del_node_init(sk))
 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+		spin_unlock_bh(&ilb->lock);
 	} else {
-		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+		rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+
 		write_lock_bh(lock);
 		if (__sk_nulls_del_node_init_rcu(sk))
 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+		write_unlock_bh(lock);
 	}
-
-	write_unlock_bh(lock);
-out:
-	if (sk->sk_state == TCP_LISTEN)
-		wake_up(&hashinfo->lhash_wait);
 }
 EXPORT_SYMBOL_GPL(inet_unhash);
 
@@ -556,3 +522,13 @@ int inet_hash_connect(struct inet_timewait_death_row *death_row,
 }
 
 EXPORT_SYMBOL_GPL(inet_hash_connect);
+
+void inet_hashinfo_init(struct inet_hashinfo *h)
+{
+	int i;
+
+	for (i = 0; i < INET_LHTABLE_SIZE; i++)
+		spin_lock_init(&h->listening_hash[i].lock);
+}
+
+EXPORT_SYMBOL_GPL(inet_hashinfo_init);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5559fea61e8..330b08a1227 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -97,11 +97,7 @@ struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
 }
 #endif
 
-struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
-	.lhash_lock  = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
-	.lhash_users = ATOMIC_INIT(0),
-	.lhash_wait  = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
-};
+struct inet_hashinfo tcp_hashinfo;
 
 static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
 {
@@ -1874,15 +1870,18 @@ static void *listening_get_next(struct seq_file *seq, void *cur)
 	struct inet_connection_sock *icsk;
 	struct hlist_node *node;
 	struct sock *sk = cur;
+	struct inet_listen_hashbucket *ilb;
 	struct tcp_iter_state *st = seq->private;
 	struct net *net = seq_file_net(seq);
 
 	if (!sk) {
 		st->bucket = 0;
-		sk = sk_head(&tcp_hashinfo.listening_hash[0]);
+		ilb = &tcp_hashinfo.listening_hash[0];
+		spin_lock_bh(&ilb->lock);
+		sk = sk_head(&ilb->head);
 		goto get_sk;
 	}
-
+	ilb = &tcp_hashinfo.listening_hash[st->bucket];
 	++st->num;
 
 	if (st->state == TCP_SEQ_STATE_OPENREQ) {
@@ -1932,8 +1931,11 @@ start_req:
 		}
 		read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
 	}
+	spin_unlock_bh(&ilb->lock);
 	if (++st->bucket < INET_LHTABLE_SIZE) {
-		sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
+		ilb = &tcp_hashinfo.listening_hash[st->bucket];
+		spin_lock_bh(&ilb->lock);
+		sk = sk_head(&ilb->head);
 		goto get_sk;
 	}
 	cur = NULL;
@@ -2066,12 +2068,10 @@ static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
 	void *rc;
 	struct tcp_iter_state *st = seq->private;
 
-	inet_listen_lock(&tcp_hashinfo);
 	st->state = TCP_SEQ_STATE_LISTENING;
 	rc	  = listening_get_idx(seq, &pos);
 
 	if (!rc) {
-		inet_listen_unlock(&tcp_hashinfo);
 		st->state = TCP_SEQ_STATE_ESTABLISHED;
 		rc	  = established_get_idx(seq, pos);
 	}
@@ -2103,7 +2103,6 @@ static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	case TCP_SEQ_STATE_LISTENING:
 		rc = listening_get_next(seq, v);
 		if (!rc) {
-			inet_listen_unlock(&tcp_hashinfo);
 			st->state = TCP_SEQ_STATE_ESTABLISHED;
 			rc	  = established_get_first(seq);
 		}
@@ -2130,7 +2129,7 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
 		}
 	case TCP_SEQ_STATE_LISTENING:
 		if (v != SEQ_START_TOKEN)
-			inet_listen_unlock(&tcp_hashinfo);
+			spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
 		break;
 	case TCP_SEQ_STATE_TIME_WAIT:
 	case TCP_SEQ_STATE_ESTABLISHED:
@@ -2405,6 +2404,7 @@ static struct pernet_operations __net_initdata tcp_sk_ops = {
 
 void __init tcp_v4_init(void)
 {
+	inet_hashinfo_init(&tcp_hashinfo);
 	if (register_pernet_device(&tcp_sk_ops))
 		panic("Failed to create the TCP control socket.\n");
 }
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index c1b4d401fd9..21544b9be25 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -25,30 +25,30 @@
 void __inet6_hash(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
-	rwlock_t *lock;
 
 	WARN_ON(!sk_unhashed(sk));
 
 	if (sk->sk_state == TCP_LISTEN) {
-		struct hlist_head *list;
+		struct inet_listen_hashbucket *ilb;
 
-		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
-		lock = &hashinfo->lhash_lock;
-		inet_listen_wlock(hashinfo);
-		__sk_add_node(sk, list);
+		ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+		spin_lock(&ilb->lock);
+		__sk_add_node(sk, &ilb->head);
+		spin_unlock(&ilb->lock);
 	} else {
 		unsigned int hash;
 		struct hlist_nulls_head *list;
+		rwlock_t *lock;
 
 		sk->sk_hash = hash = inet6_sk_ehashfn(sk);
 		list = &inet_ehash_bucket(hashinfo, hash)->chain;
 		lock = inet_ehash_lockp(hashinfo, hash);
 		write_lock(lock);
 		__sk_nulls_add_node_rcu(sk, list);
+		write_unlock(lock);
 	}
 
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
-	write_unlock(lock);
 }
 EXPORT_SYMBOL(__inet6_hash);
 
@@ -126,10 +126,11 @@ struct sock *inet6_lookup_listener(struct net *net,
 	const struct hlist_node *node;
 	struct sock *result = NULL;
 	int score, hiscore = 0;
+	struct inet_listen_hashbucket *ilb;
 
-	read_lock(&hashinfo->lhash_lock);
-	sk_for_each(sk, node,
-			&hashinfo->listening_hash[inet_lhashfn(net, hnum)]) {
+	ilb = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
+	spin_lock(&ilb->lock);
+	sk_for_each(sk, node, &ilb->head) {
 		if (net_eq(sock_net(sk), net) && inet_sk(sk)->num == hnum &&
 				sk->sk_family == PF_INET6) {
 			const struct ipv6_pinfo *np = inet6_sk(sk);
@@ -157,7 +158,7 @@ struct sock *inet6_lookup_listener(struct net *net,
 	}
 	if (result)
 		sock_hold(result);
-	read_unlock(&hashinfo->lhash_lock);
+	spin_unlock(&ilb->lock);
 	return result;
 }
 
-- 
cgit v1.2.3-70-g09d2


From 9db66bdcc83749affe61c61eb8ff3cf08f42afec Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Thu, 20 Nov 2008 20:39:09 -0800
Subject: net: convert TCP/DCCP ehash rwlocks to spinlocks

Now TCP & DCCP use RCU lookups, we can convert ehash rwlocks to spinlocks.

/proc/net/tcp and other seq_file 'readers' can safely be converted to 'writers'.

This should speedup writers, since spin_lock()/spin_unlock()
only use one atomic operation instead of two for write_lock()/write_unlock()

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/inet_hashtables.h | 14 +++++++-------
 net/ipv4/inet_hashtables.c    | 21 ++++++++++-----------
 net/ipv4/inet_timewait_sock.c | 22 +++++++++++-----------
 net/ipv4/tcp_ipv4.c           | 12 ++++++------
 net/ipv6/inet6_hashtables.c   | 15 +++++++--------
 5 files changed, 41 insertions(+), 43 deletions(-)

(limited to 'net/ipv4/inet_hashtables.c')

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 62d2dd0d786..28b3ee3e8d6 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -116,7 +116,7 @@ struct inet_hashinfo {
 	 * TIME_WAIT sockets use a separate chain (twchain).
 	 */
 	struct inet_ehash_bucket	*ehash;
-	rwlock_t			*ehash_locks;
+	spinlock_t			*ehash_locks;
 	unsigned int			ehash_size;
 	unsigned int			ehash_locks_mask;
 
@@ -152,7 +152,7 @@ static inline struct inet_ehash_bucket *inet_ehash_bucket(
 	return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)];
 }
 
-static inline rwlock_t *inet_ehash_lockp(
+static inline spinlock_t *inet_ehash_lockp(
 	struct inet_hashinfo *hashinfo,
 	unsigned int hash)
 {
@@ -177,16 +177,16 @@ static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 		size = 4096;
 	if (sizeof(rwlock_t) != 0) {
 #ifdef CONFIG_NUMA
-		if (size * sizeof(rwlock_t) > PAGE_SIZE)
-			hashinfo->ehash_locks = vmalloc(size * sizeof(rwlock_t));
+		if (size * sizeof(spinlock_t) > PAGE_SIZE)
+			hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));
 		else
 #endif
-		hashinfo->ehash_locks =	kmalloc(size * sizeof(rwlock_t),
+		hashinfo->ehash_locks =	kmalloc(size * sizeof(spinlock_t),
 						GFP_KERNEL);
 		if (!hashinfo->ehash_locks)
 			return ENOMEM;
 		for (i = 0; i < size; i++)
-			rwlock_init(&hashinfo->ehash_locks[i]);
+			spin_lock_init(&hashinfo->ehash_locks[i]);
 	}
 	hashinfo->ehash_locks_mask = size - 1;
 	return 0;
@@ -197,7 +197,7 @@ static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
 	if (hashinfo->ehash_locks) {
 #ifdef CONFIG_NUMA
 		unsigned int size = (hashinfo->ehash_locks_mask + 1) *
-							sizeof(rwlock_t);
+							sizeof(spinlock_t);
 		if (size > PAGE_SIZE)
 			vfree(hashinfo->ehash_locks);
 		else
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 377d004e572..4c273a9981a 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -271,13 +271,12 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row,
 	struct net *net = sock_net(sk);
 	unsigned int hash = inet_ehashfn(net, daddr, lport, saddr, inet->dport);
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
-	rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
+	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 	struct sock *sk2;
 	const struct hlist_nulls_node *node;
 	struct inet_timewait_sock *tw;
 
-	prefetch(head->chain.first);
-	write_lock(lock);
+	spin_lock(lock);
 
 	/* Check TIME-WAIT sockets first. */
 	sk_nulls_for_each(sk2, node, &head->twchain) {
@@ -308,8 +307,8 @@ unique:
 	sk->sk_hash = hash;
 	WARN_ON(!sk_unhashed(sk));
 	__sk_nulls_add_node_rcu(sk, &head->chain);
+	spin_unlock(lock);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
-	write_unlock(lock);
 
 	if (twp) {
 		*twp = tw;
@@ -325,7 +324,7 @@ unique:
 	return 0;
 
 not_unique:
-	write_unlock(lock);
+	spin_unlock(lock);
 	return -EADDRNOTAVAIL;
 }
 
@@ -340,7 +339,7 @@ void __inet_hash_nolisten(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	struct hlist_nulls_head *list;
-	rwlock_t *lock;
+	spinlock_t *lock;
 	struct inet_ehash_bucket *head;
 
 	WARN_ON(!sk_unhashed(sk));
@@ -350,10 +349,10 @@ void __inet_hash_nolisten(struct sock *sk)
 	list = &head->chain;
 	lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 
-	write_lock(lock);
+	spin_lock(lock);
 	__sk_nulls_add_node_rcu(sk, list);
+	spin_unlock(lock);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
-	write_unlock(lock);
 }
 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
 
@@ -402,12 +401,12 @@ void inet_unhash(struct sock *sk)
 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 		spin_unlock_bh(&ilb->lock);
 	} else {
-		rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+		spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 
-		write_lock_bh(lock);
+		spin_lock_bh(lock);
 		if (__sk_nulls_del_node_init_rcu(sk))
 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-		write_unlock_bh(lock);
+		spin_unlock_bh(lock);
 	}
 }
 EXPORT_SYMBOL_GPL(inet_unhash);
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 60689951ecd..8554d0ea171 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -20,16 +20,16 @@ static void __inet_twsk_kill(struct inet_timewait_sock *tw,
 	struct inet_bind_hashbucket *bhead;
 	struct inet_bind_bucket *tb;
 	/* Unlink from established hashes. */
-	rwlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
+	spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
 
-	write_lock(lock);
+	spin_lock(lock);
 	if (hlist_nulls_unhashed(&tw->tw_node)) {
-		write_unlock(lock);
+		spin_unlock(lock);
 		return;
 	}
 	hlist_nulls_del_rcu(&tw->tw_node);
 	sk_nulls_node_init(&tw->tw_node);
-	write_unlock(lock);
+	spin_unlock(lock);
 
 	/* Disassociate with bind bucket. */
 	bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,
@@ -76,7 +76,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 	const struct inet_sock *inet = inet_sk(sk);
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash);
-	rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+	spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 	struct inet_bind_hashbucket *bhead;
 	/* Step 1: Put TW into bind hash. Original socket stays there too.
 	   Note, that any socket with inet->num != 0 MUST be bound in
@@ -90,7 +90,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 	inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
 	spin_unlock(&bhead->lock);
 
-	write_lock(lock);
+	spin_lock(lock);
 
 	/*
 	 * Step 2: Hash TW into TIMEWAIT chain.
@@ -104,7 +104,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 	if (__sk_nulls_del_node_init_rcu(sk))
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 
-	write_unlock(lock);
+	spin_unlock(lock);
 }
 
 EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);
@@ -427,9 +427,9 @@ void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
 	for (h = 0; h < (hashinfo->ehash_size); h++) {
 		struct inet_ehash_bucket *head =
 			inet_ehash_bucket(hashinfo, h);
-		rwlock_t *lock = inet_ehash_lockp(hashinfo, h);
+		spinlock_t *lock = inet_ehash_lockp(hashinfo, h);
 restart:
-		write_lock(lock);
+		spin_lock(lock);
 		sk_nulls_for_each(sk, node, &head->twchain) {
 
 			tw = inet_twsk(sk);
@@ -438,13 +438,13 @@ restart:
 				continue;
 
 			atomic_inc(&tw->tw_refcnt);
-			write_unlock(lock);
+			spin_unlock(lock);
 			inet_twsk_deschedule(tw, twdr);
 			inet_twsk_put(tw);
 
 			goto restart;
 		}
-		write_unlock(lock);
+		spin_unlock(lock);
 	}
 	local_bh_enable();
 }
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 330b08a1227..a81caa1be0c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1970,13 +1970,13 @@ static void *established_get_first(struct seq_file *seq)
 		struct sock *sk;
 		struct hlist_nulls_node *node;
 		struct inet_timewait_sock *tw;
-		rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
+		spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
 
 		/* Lockless fast path for the common case of empty buckets */
 		if (empty_bucket(st))
 			continue;
 
-		read_lock_bh(lock);
+		spin_lock_bh(lock);
 		sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
 			if (sk->sk_family != st->family ||
 			    !net_eq(sock_net(sk), net)) {
@@ -1995,7 +1995,7 @@ static void *established_get_first(struct seq_file *seq)
 			rc = tw;
 			goto out;
 		}
-		read_unlock_bh(lock);
+		spin_unlock_bh(lock);
 		st->state = TCP_SEQ_STATE_ESTABLISHED;
 	}
 out:
@@ -2023,7 +2023,7 @@ get_tw:
 			cur = tw;
 			goto out;
 		}
-		read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+		spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
 		st->state = TCP_SEQ_STATE_ESTABLISHED;
 
 		/* Look for next non empty bucket */
@@ -2033,7 +2033,7 @@ get_tw:
 		if (st->bucket >= tcp_hashinfo.ehash_size)
 			return NULL;
 
-		read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+		spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
 		sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
 	} else
 		sk = sk_nulls_next(sk);
@@ -2134,7 +2134,7 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
 	case TCP_SEQ_STATE_TIME_WAIT:
 	case TCP_SEQ_STATE_ESTABLISHED:
 		if (v)
-			read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+			spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
 		break;
 	}
 }
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 21544b9be25..e0fd68187f8 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -38,14 +38,14 @@ void __inet6_hash(struct sock *sk)
 	} else {
 		unsigned int hash;
 		struct hlist_nulls_head *list;
-		rwlock_t *lock;
+		spinlock_t *lock;
 
 		sk->sk_hash = hash = inet6_sk_ehashfn(sk);
 		list = &inet_ehash_bucket(hashinfo, hash)->chain;
 		lock = inet_ehash_lockp(hashinfo, hash);
-		write_lock(lock);
+		spin_lock(lock);
 		__sk_nulls_add_node_rcu(sk, list);
-		write_unlock(lock);
+		spin_unlock(lock);
 	}
 
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
@@ -195,13 +195,12 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 	const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
 						inet->dport);
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
-	rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
+	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 	struct sock *sk2;
 	const struct hlist_nulls_node *node;
 	struct inet_timewait_sock *tw;
 
-	prefetch(head->chain.first);
-	write_lock(lock);
+	spin_lock(lock);
 
 	/* Check TIME-WAIT sockets first. */
 	sk_nulls_for_each(sk2, node, &head->twchain) {
@@ -230,8 +229,8 @@ unique:
 	WARN_ON(!sk_unhashed(sk));
 	__sk_nulls_add_node_rcu(sk, &head->chain);
 	sk->sk_hash = hash;
+	spin_unlock(lock);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
-	write_unlock(lock);
 
 	if (twp != NULL) {
 		*twp = tw;
@@ -246,7 +245,7 @@ unique:
 	return 0;
 
 not_unique:
-	write_unlock(lock);
+	spin_unlock(lock);
 	return -EADDRNOTAVAIL;
 }
 
-- 
cgit v1.2.3-70-g09d2


From c25eb3bfb97294d0543a81230fbc237046b4b84c Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Sun, 23 Nov 2008 17:22:55 -0800
Subject: net: Convert TCP/DCCP listening hash tables to use RCU

This is the last step to be able to perform full RCU lookups
in __inet_lookup() : After established/timewait tables, we
add RCU lookups to listening hash table.

The only trick here is that a socket of a given type (TCP ipv4,
TCP ipv6, ...) can now flight between two different tables
(established and listening) during a RCU grace period, so we
must use different 'nulls' end-of-chain values for two tables.

We define a large value :

#define LISTENING_NULLS_BASE (1U << 29)

So that slots in listening table are guaranteed to have different
end-of-chain values than slots in established table. A reader can
still detect it finished its lookup in the right chain.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/net/inet_hashtables.h |   9 ++-
 net/ipv4/inet_diag.c          |   4 +-
 net/ipv4/inet_hashtables.c    | 148 +++++++++++++++++++++---------------------
 net/ipv4/tcp_ipv4.c           |   8 +--
 net/ipv6/inet6_hashtables.c   |  94 +++++++++++++++++----------
 5 files changed, 147 insertions(+), 116 deletions(-)

(limited to 'net/ipv4/inet_hashtables.c')

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index ec7ee2e46d8..f44bb5c77a7 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -99,9 +99,16 @@ struct inet_bind_hashbucket {
 	struct hlist_head	chain;
 };
 
+/*
+ * Sockets can be hashed in established or listening table
+ * We must use different 'nulls' end-of-chain value for listening
+ * hash table, or we might find a socket that was closed and
+ * reallocated/inserted into established hash table
+ */
+#define LISTENING_NULLS_BASE (1U << 29)
 struct inet_listen_hashbucket {
 	spinlock_t		lock;
-	struct hlist_head	head;
+	struct hlist_nulls_head	head;
 };
 
 /* This is for listening sockets, thus all sockets which possess wildcards. */
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 998a78f169f..588a7796e3e 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -720,13 +720,13 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
 
 		for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
 			struct sock *sk;
-			struct hlist_node *node;
+			struct hlist_nulls_node *node;
 			struct inet_listen_hashbucket *ilb;
 
 			num = 0;
 			ilb = &hashinfo->listening_hash[i];
 			spin_lock_bh(&ilb->lock);
-			sk_for_each(sk, node, &ilb->head) {
+			sk_nulls_for_each(sk, node, &ilb->head) {
 				struct inet_sock *inet = inet_sk(sk);
 
 				if (num < s_num) {
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 4c273a9981a..11fcb87a1fd 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -110,78 +110,79 @@ void __inet_inherit_port(struct sock *sk, struct sock *child)
 
 EXPORT_SYMBOL_GPL(__inet_inherit_port);
 
+static inline int compute_score(struct sock *sk, struct net *net,
+				const unsigned short hnum, const __be32 daddr,
+				const int dif)
+{
+	int score = -1;
+	struct inet_sock *inet = inet_sk(sk);
+
+	if (net_eq(sock_net(sk), net) && inet->num == hnum &&
+			!ipv6_only_sock(sk)) {
+		__be32 rcv_saddr = inet->rcv_saddr;
+		score = sk->sk_family == PF_INET ? 1 : 0;
+		if (rcv_saddr) {
+			if (rcv_saddr != daddr)
+				return -1;
+			score += 2;
+		}
+		if (sk->sk_bound_dev_if) {
+			if (sk->sk_bound_dev_if != dif)
+				return -1;
+			score += 2;
+		}
+	}
+	return score;
+}
+
 /*
  * Don't inline this cruft. Here are some nice properties to exploit here. The
  * BSD API does not allow a listening sock to specify the remote port nor the
  * remote address for the connection. So always assume those are both
  * wildcarded during the search since they can never be otherwise.
  */
-static struct sock *inet_lookup_listener_slow(struct net *net,
-					      const struct hlist_head *head,
-					      const __be32 daddr,
-					      const unsigned short hnum,
-					      const int dif)
-{
-	struct sock *result = NULL, *sk;
-	const struct hlist_node *node;
-	int hiscore = -1;
-
-	sk_for_each(sk, node, head) {
-		const struct inet_sock *inet = inet_sk(sk);
-
-		if (net_eq(sock_net(sk), net) && inet->num == hnum &&
-				!ipv6_only_sock(sk)) {
-			const __be32 rcv_saddr = inet->rcv_saddr;
-			int score = sk->sk_family == PF_INET ? 1 : 0;
-
-			if (rcv_saddr) {
-				if (rcv_saddr != daddr)
-					continue;
-				score += 2;
-			}
-			if (sk->sk_bound_dev_if) {
-				if (sk->sk_bound_dev_if != dif)
-					continue;
-				score += 2;
-			}
-			if (score == 5)
-				return sk;
-			if (score > hiscore) {
-				hiscore	= score;
-				result	= sk;
-			}
-		}
-	}
-	return result;
-}
 
-/* Optimize the common listener case. */
+
 struct sock *__inet_lookup_listener(struct net *net,
 				    struct inet_hashinfo *hashinfo,
 				    const __be32 daddr, const unsigned short hnum,
 				    const int dif)
 {
-	struct sock *sk = NULL;
-	struct inet_listen_hashbucket *ilb;
+	struct sock *sk, *result;
+	struct hlist_nulls_node *node;
+	unsigned int hash = inet_lhashfn(net, hnum);
+	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
+	int score, hiscore;
 
-	ilb = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
-	spin_lock(&ilb->lock);
-	if (!hlist_empty(&ilb->head)) {
-		const struct inet_sock *inet = inet_sk((sk = __sk_head(&ilb->head)));
-
-		if (inet->num == hnum && !sk->sk_node.next &&
-		    (!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
-		    (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
-		    !sk->sk_bound_dev_if && net_eq(sock_net(sk), net))
-			goto sherry_cache;
-		sk = inet_lookup_listener_slow(net, &ilb->head, daddr, hnum, dif);
+	rcu_read_lock();
+begin:
+	result = NULL;
+	hiscore = -1;
+	sk_nulls_for_each_rcu(sk, node, &ilb->head) {
+		score = compute_score(sk, net, hnum, daddr, dif);
+		if (score > hiscore) {
+			result = sk;
+			hiscore = score;
+		}
 	}
-	if (sk) {
-sherry_cache:
-		sock_hold(sk);
+	/*
+	 * 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) != hash + LISTENING_NULLS_BASE)
+		goto begin;
+	if (result) {
+		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+			result = NULL;
+		else if (unlikely(compute_score(result, net, hnum, daddr,
+				  dif) < hiscore)) {
+			sock_put(result);
+			goto begin;
+		}
 	}
-	spin_unlock(&ilb->lock);
-	return sk;
+	rcu_read_unlock();
+	return result;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
 
@@ -370,7 +371,7 @@ static void __inet_hash(struct sock *sk)
 	ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 
 	spin_lock(&ilb->lock);
-	__sk_add_node(sk, &ilb->head);
+	__sk_nulls_add_node_rcu(sk, &ilb->head);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 	spin_unlock(&ilb->lock);
 }
@@ -388,26 +389,22 @@ EXPORT_SYMBOL_GPL(inet_hash);
 void inet_unhash(struct sock *sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+	spinlock_t *lock;
+	int done;
 
 	if (sk_unhashed(sk))
 		return;
 
-	if (sk->sk_state == TCP_LISTEN) {
-		struct inet_listen_hashbucket *ilb;
+	if (sk->sk_state == TCP_LISTEN)
+		lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
+	else
+		lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 
-		ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
-		spin_lock_bh(&ilb->lock);
-		if (__sk_del_node_init(sk))
-			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-		spin_unlock_bh(&ilb->lock);
-	} else {
-		spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
-
-		spin_lock_bh(lock);
-		if (__sk_nulls_del_node_init_rcu(sk))
-			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-		spin_unlock_bh(lock);
-	}
+	spin_lock_bh(lock);
+	done =__sk_nulls_del_node_init_rcu(sk);
+	spin_unlock_bh(lock);
+	if (done)
+		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 }
 EXPORT_SYMBOL_GPL(inet_unhash);
 
@@ -526,8 +523,11 @@ void inet_hashinfo_init(struct inet_hashinfo *h)
 {
 	int i;
 
-	for (i = 0; i < INET_LHTABLE_SIZE; i++)
+	for (i = 0; i < INET_LHTABLE_SIZE; i++) {
 		spin_lock_init(&h->listening_hash[i].lock);
+		INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
+				      i + LISTENING_NULLS_BASE);
+		}
 }
 
 EXPORT_SYMBOL_GPL(inet_hashinfo_init);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a81caa1be0c..cab2458f86f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1868,7 +1868,7 @@ static inline struct inet_timewait_sock *tw_next(struct inet_timewait_sock *tw)
 static void *listening_get_next(struct seq_file *seq, void *cur)
 {
 	struct inet_connection_sock *icsk;
-	struct hlist_node *node;
+	struct hlist_nulls_node *node;
 	struct sock *sk = cur;
 	struct inet_listen_hashbucket *ilb;
 	struct tcp_iter_state *st = seq->private;
@@ -1878,7 +1878,7 @@ static void *listening_get_next(struct seq_file *seq, void *cur)
 		st->bucket = 0;
 		ilb = &tcp_hashinfo.listening_hash[0];
 		spin_lock_bh(&ilb->lock);
-		sk = sk_head(&ilb->head);
+		sk = sk_nulls_head(&ilb->head);
 		goto get_sk;
 	}
 	ilb = &tcp_hashinfo.listening_hash[st->bucket];
@@ -1914,7 +1914,7 @@ get_req:
 		sk = sk_next(sk);
 	}
 get_sk:
-	sk_for_each_from(sk, node) {
+	sk_nulls_for_each_from(sk, node) {
 		if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) {
 			cur = sk;
 			goto out;
@@ -1935,7 +1935,7 @@ start_req:
 	if (++st->bucket < INET_LHTABLE_SIZE) {
 		ilb = &tcp_hashinfo.listening_hash[st->bucket];
 		spin_lock_bh(&ilb->lock);
-		sk = sk_head(&ilb->head);
+		sk = sk_nulls_head(&ilb->head);
 		goto get_sk;
 	}
 	cur = NULL;
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index e0fd68187f8..8fe267feb81 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -33,7 +33,7 @@ void __inet6_hash(struct sock *sk)
 
 		ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 		spin_lock(&ilb->lock);
-		__sk_add_node(sk, &ilb->head);
+		__sk_nulls_add_node_rcu(sk, &ilb->head);
 		spin_unlock(&ilb->lock);
 	} else {
 		unsigned int hash;
@@ -118,47 +118,71 @@ out:
 }
 EXPORT_SYMBOL(__inet6_lookup_established);
 
+static int inline compute_score(struct sock *sk, struct net *net,
+				const unsigned short hnum,
+				const struct in6_addr *daddr,
+				const int dif)
+{
+	int score = -1;
+
+	if (net_eq(sock_net(sk), net) && inet_sk(sk)->num == hnum &&
+	    sk->sk_family == PF_INET6) {
+		const struct ipv6_pinfo *np = inet6_sk(sk);
+
+		score = 1;
+		if (!ipv6_addr_any(&np->rcv_saddr)) {
+			if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
+				return -1;
+			score++;
+		}
+		if (sk->sk_bound_dev_if) {
+			if (sk->sk_bound_dev_if != dif)
+				return -1;
+			score++;
+		}
+	}
+	return score;
+}
+
 struct sock *inet6_lookup_listener(struct net *net,
 		struct inet_hashinfo *hashinfo, const struct in6_addr *daddr,
 		const unsigned short hnum, const int dif)
 {
 	struct sock *sk;
-	const struct hlist_node *node;
-	struct sock *result = NULL;
-	int score, hiscore = 0;
-	struct inet_listen_hashbucket *ilb;
-
-	ilb = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
-	spin_lock(&ilb->lock);
-	sk_for_each(sk, node, &ilb->head) {
-		if (net_eq(sock_net(sk), net) && inet_sk(sk)->num == hnum &&
-				sk->sk_family == PF_INET6) {
-			const struct ipv6_pinfo *np = inet6_sk(sk);
-
-			score = 1;
-			if (!ipv6_addr_any(&np->rcv_saddr)) {
-				if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
-					continue;
-				score++;
-			}
-			if (sk->sk_bound_dev_if) {
-				if (sk->sk_bound_dev_if != dif)
-					continue;
-				score++;
-			}
-			if (score == 3) {
-				result = sk;
-				break;
-			}
-			if (score > hiscore) {
-				hiscore = score;
-				result = sk;
-			}
+	const struct hlist_nulls_node *node;
+	struct sock *result;
+	int score, hiscore;
+	unsigned int hash = inet_lhashfn(net, hnum);
+	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
+
+	rcu_read_lock();
+begin:
+	result = NULL;
+	hiscore = -1;
+	sk_nulls_for_each(sk, node, &ilb->head) {
+		score = compute_score(sk, net, hnum, daddr, dif);
+		if (score > hiscore) {
+			hiscore = score;
+			result = sk;
 		}
 	}
-	if (result)
-		sock_hold(result);
-	spin_unlock(&ilb->lock);
+	/*
+	 * 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) != hash + LISTENING_NULLS_BASE)
+		goto begin;
+	if (result) {
+		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
+			result = NULL;
+		else if (unlikely(compute_score(result, net, hnum, daddr,
+				  dif) < hiscore)) {
+			sock_put(result);
+			goto begin;
+		}
+	}
+	rcu_read_unlock();
 	return result;
 }
 
-- 
cgit v1.2.3-70-g09d2


From 920de804bca61f88643bc9171bcd06f1a56c6258 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <dada1@cosmosbay.com>
Date: Mon, 24 Nov 2008 00:09:29 -0800
Subject: net: Make sure BHs are disabled in sock_prot_inuse_add()

The rule of calling sock_prot_inuse_add() is that BHs must
be disabled.  Some new calls were added where this was not
true and this tiggers warnings as reported by Ilpo.

Fix this by adding explicit BH disabling around those call sites,
or moving sock_prot_inuse_add() call inside an existing BH disabled
section.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/ipv4/inet_hashtables.c | 2 +-
 net/packet/af_packet.c     | 4 ++--
 net/unix/af_unix.c         | 6 ++++--
 3 files changed, 7 insertions(+), 5 deletions(-)

(limited to 'net/ipv4/inet_hashtables.c')

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 11fcb87a1fd..6a1045da48d 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -402,9 +402,9 @@ void inet_unhash(struct sock *sk)
 
 	spin_lock_bh(lock);
 	done =__sk_nulls_del_node_init_rcu(sk);
-	spin_unlock_bh(lock);
 	if (done)
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+	spin_unlock_bh(lock);
 }
 EXPORT_SYMBOL_GPL(inet_unhash);
 
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index b4870a34c43..5f94db2f3e9 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -872,6 +872,7 @@ static int packet_release(struct socket *sock)
 
 	write_lock_bh(&net->packet.sklist_lock);
 	sk_del_node_init(sk);
+	sock_prot_inuse_add(net, sk->sk_prot, -1);
 	write_unlock_bh(&net->packet.sklist_lock);
 
 	/*
@@ -910,7 +911,6 @@ static int packet_release(struct socket *sock)
 	skb_queue_purge(&sk->sk_receive_queue);
 	sk_refcnt_debug_release(sk);
 
-	sock_prot_inuse_add(net, sk->sk_prot, -1);
 	sock_put(sk);
 	return 0;
 }
@@ -1085,8 +1085,8 @@ static int packet_create(struct net *net, struct socket *sock, int protocol)
 
 	write_lock_bh(&net->packet.sklist_lock);
 	sk_add_node(sk, &net->packet.sklist);
-	write_unlock_bh(&net->packet.sklist_lock);
 	sock_prot_inuse_add(net, &packet_proto, 1);
+	write_unlock_bh(&net->packet.sklist_lock);
 	return(0);
 out:
 	return err;
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index a45a9f7369e..3a35a6e8bf9 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -615,9 +615,11 @@ static struct sock *unix_create1(struct net *net, struct socket *sock)
 out:
 	if (sk == NULL)
 		atomic_dec(&unix_nr_socks);
-	else
+	else {
+		local_bh_disable();
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
-
+		local_bh_enable();
+	}
 	return sk;
 }
 
-- 
cgit v1.2.3-70-g09d2