From f86dcc5aa8c7908f2c287e7a211228df599e3e71 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 7 Oct 2009 00:37:59 +0000
Subject: udp: dynamically size hash tables at boot time

UDP_HTABLE_SIZE was initialy defined to 128, which is a bit small for
several setups.

4000 active UDP sockets -> 32 sockets per chain in average. An
incoming frame has to lookup all sockets to find best match, so long
chains hurt latency.

Instead of a fixed size hash table that cant be perfect for every
needs, let UDP stack choose its table size at boot time like tcp/ip
route, using alloc_large_system_hash() helper

Add an optional boot parameter, uhash_entries=x so that an admin can
force a size between 256 and 65536 if needed, like thash_entries and
rhash_entries.

dmesg logs two new lines :
[    0.647039] UDP hash table entries: 512 (order: 0, 4096 bytes)
[    0.647099] UDP Lite hash table entries: 512 (order: 0, 4096 bytes)

Maximal size on 64bit arches would be 65536 slots, ie 1 MBytes for non
debugging spinlocks.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/udp.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'include/linux/udp.h')

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 0cf5c4c0ec81..832361e3e596 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -45,11 +45,11 @@ static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
 	return (struct udphdr *)skb_transport_header(skb);
 }
 
-#define UDP_HTABLE_SIZE		128
+#define UDP_HTABLE_SIZE_MIN		(CONFIG_BASE_SMALL ? 128 : 256)
 
-static inline int udp_hashfn(struct net *net, const unsigned num)
+static inline int udp_hashfn(struct net *net, unsigned num, unsigned mask)
 {
-	return (num + net_hash_mix(net)) & (UDP_HTABLE_SIZE - 1);
+	return (num + net_hash_mix(net)) & mask;
 }
 
 struct udp_sock {
-- 
cgit v1.2.3


From d4cada4ae1c012815f95fa507eb86a0ae9d607d7 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 8 Nov 2009 10:17:30 +0000
Subject: udp: split sk_hash into two u16 hashes

Union sk_hash with two u16 hashes for udp (no extra memory taken)

One 16 bits hash on (local port) value (the previous udp 'hash')

One 16 bits hash on (local address, local port) values, initialized
but not yet used. This second hash is using jenkin hash for better
distribution.

Because the 'port' is xored later, a partial hash is performed
on local address + net_hash_mix(net)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/udp.h |  2 ++
 include/net/sock.h  |  6 +++++-
 net/ipv4/udp.c      | 25 +++++++++++++++++++------
 net/ipv6/udp.c      | 27 +++++++++++++++++++++++++--
 4 files changed, 51 insertions(+), 9 deletions(-)

(limited to 'include/linux/udp.h')

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 832361e3e596..5b4b5274e683 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -55,6 +55,8 @@ static inline int udp_hashfn(struct net *net, unsigned num, unsigned mask)
 struct udp_sock {
 	/* inet_sock has to be the first member */
 	struct inet_sock inet;
+#define udp_port_hash		inet.sk.__sk_common.skc_u16hashes[0]
+#define udp_portaddr_hash	inet.sk.__sk_common.skc_u16hashes[1]
 	int		 pending;	/* Any pending frames ? */
 	unsigned int	 corkflag;	/* Cork is required */
   	__u16		 encap_type;	/* Is this an Encapsulation socket? */
diff --git a/include/net/sock.h b/include/net/sock.h
index 55de3bd719a5..827366b62680 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -109,6 +109,7 @@ struct net;
  *	@skc_refcnt: reference count
  *	@skc_tx_queue_mapping: tx queue number for this connection
  *	@skc_hash: hash value used with various protocol lookup tables
+ *	@skc_u16hashes: two u16 hash values used by UDP lookup tables
  *	@skc_family: network address family
  *	@skc_state: Connection state
  *	@skc_reuse: %SO_REUSEADDR setting
@@ -131,7 +132,10 @@ struct sock_common {
 	atomic_t		skc_refcnt;
 	int			skc_tx_queue_mapping;
 
-	unsigned int		skc_hash;
+	union  {
+		unsigned int	skc_hash;
+		__u16		skc_u16hashes[2];
+	};
 	unsigned short		skc_family;
 	volatile unsigned char	skc_state;
 	unsigned char		skc_reuse;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ffc837643a04..af72de1c8690 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -138,13 +138,14 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
 	sk_nulls_for_each(sk2, node, &hslot->head)
 		if (net_eq(sock_net(sk2), net)			&&
 		    sk2 != sk					&&
-		    (bitmap || sk2->sk_hash == num)		&&
+		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
 		    (!sk2->sk_reuse || !sk->sk_reuse)		&&
 		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
 			|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
 		    (*saddr_comp)(sk, sk2)) {
 			if (bitmap)
-				__set_bit(sk2->sk_hash >> log, bitmap);
+				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
+					  bitmap);
 			else
 				return 1;
 		}
@@ -215,7 +216,8 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
 	}
 found:
 	inet_sk(sk)->inet_num = snum;
-	sk->sk_hash = snum;
+	udp_sk(sk)->udp_port_hash = snum;
+	udp_sk(sk)->udp_portaddr_hash ^= snum;
 	if (sk_unhashed(sk)) {
 		sk_nulls_add_node_rcu(sk, &hslot->head);
 		hslot->count++;
@@ -238,8 +240,19 @@ static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
 		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
 }
 
+static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
+				       unsigned int port)
+{
+	return jhash_1word(saddr, net_hash_mix(net)) ^ port;
+}
+
 int udp_v4_get_port(struct sock *sk, unsigned short snum)
 {
+	/* precompute partial secondary hash */
+	udp_sk(sk)->udp_portaddr_hash =
+		udp4_portaddr_hash(sock_net(sk),
+				   inet_sk(sk)->inet_rcv_saddr,
+				   0);
 	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal);
 }
 
@@ -249,7 +262,7 @@ static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
 {
 	int score = -1;
 
-	if (net_eq(sock_net(sk), net) && sk->sk_hash == hnum &&
+	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
 			!ipv6_only_sock(sk)) {
 		struct inet_sock *inet = inet_sk(sk);
 
@@ -360,7 +373,7 @@ static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
 		struct inet_sock *inet = inet_sk(s);
 
 		if (!net_eq(sock_net(s), net)				||
-		    s->sk_hash != hnum					||
+		    udp_sk(s)->udp_port_hash != hnum			||
 		    (inet->inet_daddr && inet->inet_daddr != rmt_addr)	||
 		    (inet->inet_dport != rmt_port && inet->inet_dport)	||
 		    (inet->inet_rcv_saddr	&&
@@ -1050,7 +1063,7 @@ void udp_lib_unhash(struct sock *sk)
 	if (sk_hashed(sk)) {
 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
 		struct udp_hslot *hslot = udp_hashslot(udptable, sock_net(sk),
-						     sk->sk_hash);
+						       udp_sk(sk)->udp_port_hash);
 
 		spin_lock_bh(&hslot->lock);
 		if (sk_nulls_del_node_init_rcu(sk)) {
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 5bc7cdbf030a..1e5fadd997b7 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -81,8 +81,30 @@ int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2)
 	return 0;
 }
 
+static unsigned int udp6_portaddr_hash(struct net *net,
+				       const struct in6_addr *addr6,
+				       unsigned int port)
+{
+	unsigned int hash, mix = net_hash_mix(net);
+
+	if (ipv6_addr_any(addr6))
+		hash = jhash_1word(0, mix);
+	else if (ipv6_addr_type(addr6) == IPV6_ADDR_MAPPED)
+		hash = jhash_1word(addr6->s6_addr32[3], mix);
+	else
+		hash = jhash2(addr6->s6_addr32, 4, mix);
+
+	return hash ^ port;
+}
+
+
 int udp_v6_get_port(struct sock *sk, unsigned short snum)
 {
+	/* precompute partial secondary hash */
+	udp_sk(sk)->udp_portaddr_hash =
+		udp6_portaddr_hash(sock_net(sk),
+				   &inet6_sk(sk)->rcv_saddr,
+				   0);
 	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal);
 }
 
@@ -94,7 +116,7 @@ static inline int compute_score(struct sock *sk, struct net *net,
 {
 	int score = -1;
 
-	if (net_eq(sock_net(sk), net) && sk->sk_hash == hnum &&
+	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
 			sk->sk_family == PF_INET6) {
 		struct ipv6_pinfo *np = inet6_sk(sk);
 		struct inet_sock *inet = inet_sk(sk);
@@ -415,7 +437,8 @@ static struct sock *udp_v6_mcast_next(struct net *net, struct sock *sk,
 		if (!net_eq(sock_net(s), net))
 			continue;
 
-		if (s->sk_hash == num && s->sk_family == PF_INET6) {
+		if (udp_sk(s)->udp_port_hash == num &&
+		    s->sk_family == PF_INET6) {
 			struct ipv6_pinfo *np = inet6_sk(s);
 			if (inet->inet_dport) {
 				if (inet->inet_dport != rmt_port)
-- 
cgit v1.2.3


From 512615b6b843ff3ff5ad583f34c39b3f302f5f26 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 8 Nov 2009 10:17:58 +0000
Subject: udp: secondary hash on (local port, local address)

Extends udp_table to contain a secondary hash table.

socket anchor for this second hash is free, because UDP
doesnt use skc_bind_node : We define an union to hold
both skc_bind_node & a new hlist_nulls_node udp_portaddr_node

udp_lib_get_port() inserts sockets into second hash chain
(additional cost of one atomic op)

udp_lib_unhash() deletes socket from second hash chain
(additional cost of one atomic op)

Note : No spinlock lockdep annotation is needed, because
lock for the secondary hash chain is always get after
lock for primary hash chain.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/udp.h |  1 +
 include/net/sock.h  |  8 ++++++--
 include/net/udp.h   | 22 ++++++++++++++++++++--
 net/ipv4/udp.c      | 31 ++++++++++++++++++++++++++-----
 4 files changed, 53 insertions(+), 9 deletions(-)

(limited to 'include/linux/udp.h')

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 5b4b5274e683..59f0ddf2d284 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -57,6 +57,7 @@ struct udp_sock {
 	struct inet_sock inet;
 #define udp_port_hash		inet.sk.__sk_common.skc_u16hashes[0]
 #define udp_portaddr_hash	inet.sk.__sk_common.skc_u16hashes[1]
+#define udp_portaddr_node	inet.sk.__sk_common.skc_portaddr_node
 	int		 pending;	/* Any pending frames ? */
 	unsigned int	 corkflag;	/* Cork is required */
   	__u16		 encap_type;	/* Is this an Encapsulation socket? */
diff --git a/include/net/sock.h b/include/net/sock.h
index 827366b62680..3f1a4804bb3f 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -105,7 +105,7 @@ struct net;
 /**
  *	struct sock_common - minimal network layer representation of sockets
  *	@skc_node: main hash linkage for various protocol lookup tables
- *	@skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol
+ *	@skc_nulls_node: main hash linkage for TCP/UDP/UDP-Lite protocol
  *	@skc_refcnt: reference count
  *	@skc_tx_queue_mapping: tx queue number for this connection
  *	@skc_hash: hash value used with various protocol lookup tables
@@ -115,6 +115,7 @@ struct net;
  *	@skc_reuse: %SO_REUSEADDR setting
  *	@skc_bound_dev_if: bound device index if != 0
  *	@skc_bind_node: bind hash linkage for various protocol lookup tables
+ *	@skc_portaddr_node: second hash linkage for UDP/UDP-Lite protocol
  *	@skc_prot: protocol handlers inside a network family
  *	@skc_net: reference to the network namespace of this socket
  *
@@ -140,7 +141,10 @@ struct sock_common {
 	volatile unsigned char	skc_state;
 	unsigned char		skc_reuse;
 	int			skc_bound_dev_if;
-	struct hlist_node	skc_bind_node;
+	union {
+		struct hlist_node	skc_bind_node;
+		struct hlist_nulls_node skc_portaddr_node;
+	};
 	struct proto		*skc_prot;
 #ifdef CONFIG_NET_NS
 	struct net	 	*skc_net;
diff --git a/include/net/udp.h b/include/net/udp.h
index 9167281e47dc..af41850f742a 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -63,10 +63,19 @@ struct udp_hslot {
 	spinlock_t		lock;
 } __attribute__((aligned(2 * sizeof(long))));
 
+/**
+ *	struct udp_table - UDP table
+ *
+ *	@hash:	hash table, sockets are hashed on (local port)
+ *	@hash2:	hash table, sockets are hashed on (local port, local address)
+ *	@mask:	number of slots in hash tables, minus 1
+ *	@log:	log2(number of slots in hash table)
+ */
 struct udp_table {
 	struct udp_hslot	*hash;
-	unsigned int mask;
-	unsigned int log;
+	struct udp_hslot	*hash2;
+	unsigned int		mask;
+	unsigned int		log;
 };
 extern struct udp_table udp_table;
 extern void udp_table_init(struct udp_table *, const char *);
@@ -75,6 +84,15 @@ static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
 {
 	return &table->hash[udp_hashfn(net, num, table->mask)];
 }
+/*
+ * For secondary hash, net_hash_mix() is performed before calling
+ * udp_hashslot2(), this explains difference with udp_hashslot()
+ */
+static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
+					      unsigned int hash)
+{
+	return &table->hash2[hash & table->mask];
+}
 
 /* Note: this must match 'valbool' in sock_setsockopt */
 #define UDP_CSUM_NOXMIT		1
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index af72de1c8690..5f04216f35ce 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -163,7 +163,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
 		       int (*saddr_comp)(const struct sock *sk1,
 					 const struct sock *sk2))
 {
-	struct udp_hslot *hslot;
+	struct udp_hslot *hslot, *hslot2;
 	struct udp_table *udptable = sk->sk_prot->h.udp_table;
 	int    error = 1;
 	struct net *net = sock_net(sk);
@@ -222,6 +222,13 @@ found:
 		sk_nulls_add_node_rcu(sk, &hslot->head);
 		hslot->count++;
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+
+		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
+		spin_lock(&hslot2->lock);
+		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
+					 &hslot2->head);
+		hslot2->count++;
+		spin_unlock(&hslot2->lock);
 	}
 	error = 0;
 fail_unlock:
@@ -1062,14 +1069,22 @@ void udp_lib_unhash(struct sock *sk)
 {
 	if (sk_hashed(sk)) {
 		struct udp_table *udptable = sk->sk_prot->h.udp_table;
-		struct udp_hslot *hslot = udp_hashslot(udptable, sock_net(sk),
-						       udp_sk(sk)->udp_port_hash);
+		struct udp_hslot *hslot, *hslot2;
+
+		hslot  = udp_hashslot(udptable, sock_net(sk),
+				      udp_sk(sk)->udp_port_hash);
+		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
 
 		spin_lock_bh(&hslot->lock);
 		if (sk_nulls_del_node_init_rcu(sk)) {
 			hslot->count--;
 			inet_sk(sk)->inet_num = 0;
 			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+
+			spin_lock(&hslot2->lock);
+			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
+			hslot2->count--;
+			spin_unlock(&hslot2->lock);
 		}
 		spin_unlock_bh(&hslot->lock);
 	}
@@ -1857,7 +1872,7 @@ void __init udp_table_init(struct udp_table *table, const char *name)
 
 	if (!CONFIG_BASE_SMALL)
 		table->hash = alloc_large_system_hash(name,
-			sizeof(struct udp_hslot),
+			2 * sizeof(struct udp_hslot),
 			uhash_entries,
 			21, /* one slot per 2 MB */
 			0,
@@ -1869,17 +1884,23 @@ void __init udp_table_init(struct udp_table *table, const char *name)
 	 */
 	if (CONFIG_BASE_SMALL || table->mask < UDP_HTABLE_SIZE_MIN - 1) {
 		table->hash = kmalloc(UDP_HTABLE_SIZE_MIN *
-				      sizeof(struct udp_hslot), GFP_KERNEL);
+				      2 * sizeof(struct udp_hslot), GFP_KERNEL);
 		if (!table->hash)
 			panic(name);
 		table->log = ilog2(UDP_HTABLE_SIZE_MIN);
 		table->mask = UDP_HTABLE_SIZE_MIN - 1;
 	}
+	table->hash2 = table->hash + (table->mask + 1);
 	for (i = 0; i <= table->mask; i++) {
 		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
 		table->hash[i].count = 0;
 		spin_lock_init(&table->hash[i].lock);
 	}
+	for (i = 0; i <= table->mask; i++) {
+		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
+		table->hash2[i].count = 0;
+		spin_lock_init(&table->hash2[i].lock);
+	}
 }
 
 void __init udp_init(void)
-- 
cgit v1.2.3


From 30fff9231fad757c061285e347b33c5149c2c2e4 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 9 Nov 2009 05:26:33 +0000
Subject: udp: bind() optimisation

UDP bind() can be O(N^2) in some pathological cases.

Thanks to secondary hash tables, we can make it O(N)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/udp.h |  6 +++++
 include/net/udp.h   |  3 ++-
 net/ipv4/udp.c      | 73 +++++++++++++++++++++++++++++++++++++++++++++++------
 net/ipv6/udp.c      | 14 +++++-----
 4 files changed, 80 insertions(+), 16 deletions(-)

(limited to 'include/linux/udp.h')

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 59f0ddf2d284..03f72a2ba028 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -88,6 +88,12 @@ static inline struct udp_sock *udp_sk(const struct sock *sk)
 	return (struct udp_sock *)sk;
 }
 
+#define udp_portaddr_for_each_entry(__sk, node, list) \
+	hlist_nulls_for_each_entry(__sk, node, list, __sk_common.skc_portaddr_node)
+
+#define udp_portaddr_for_each_entry_rcu(__sk, node, list) \
+	hlist_nulls_for_each_entry_rcu(__sk, node, list, __sk_common.skc_portaddr_node)
+
 #define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)
 
 #endif
diff --git a/include/net/udp.h b/include/net/udp.h
index af41850f742a..5348d80b25bb 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -158,7 +158,8 @@ static inline void udp_lib_close(struct sock *sk, long timeout)
 }
 
 extern int	udp_lib_get_port(struct sock *sk, unsigned short snum,
-		int (*)(const struct sock*,const struct sock*));
+		int (*)(const struct sock *,const struct sock *),
+		unsigned int hash2_nulladdr);
 
 /* net/ipv4/udp.c */
 extern int	udp_get_port(struct sock *sk, unsigned short snum,
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d73e9170536b..1eaf57567ebf 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -152,16 +152,49 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
 	return 0;
 }
 
+/*
+ * Note: we still hold spinlock of primary hash chain, so no other writer
+ * can insert/delete a socket with local_port == num
+ */
+static int udp_lib_lport_inuse2(struct net *net, __u16 num,
+			       struct udp_hslot *hslot2,
+			       struct sock *sk,
+			       int (*saddr_comp)(const struct sock *sk1,
+						 const struct sock *sk2))
+{
+	struct sock *sk2;
+	struct hlist_nulls_node *node;
+	int res = 0;
+
+	spin_lock(&hslot2->lock);
+	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
+		if (net_eq(sock_net(sk2), net)			&&
+		    sk2 != sk					&&
+		    (udp_sk(sk2)->udp_port_hash == num)		&&
+		    (!sk2->sk_reuse || !sk->sk_reuse)		&&
+		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
+			|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
+		    (*saddr_comp)(sk, sk2)) {
+			res = 1;
+			break;
+		}
+	spin_unlock(&hslot2->lock);
+	return res;
+}
+
 /**
  *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
  *
  *  @sk:          socket struct in question
  *  @snum:        port number to look up
  *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
+ *  @hash2_nulladdr: AF-dependant hash value in secondary hash chains,
+ *                   with NULL address
  */
 int udp_lib_get_port(struct sock *sk, unsigned short snum,
 		       int (*saddr_comp)(const struct sock *sk1,
-					 const struct sock *sk2))
+					 const struct sock *sk2),
+		     unsigned int hash2_nulladdr)
 {
 	struct udp_hslot *hslot, *hslot2;
 	struct udp_table *udptable = sk->sk_prot->h.udp_table;
@@ -210,6 +243,30 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
 	} else {
 		hslot = udp_hashslot(udptable, net, snum);
 		spin_lock_bh(&hslot->lock);
+		if (hslot->count > 10) {
+			int exist;
+			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
+
+			slot2          &= udptable->mask;
+			hash2_nulladdr &= udptable->mask;
+
+			hslot2 = udp_hashslot2(udptable, slot2);
+			if (hslot->count < hslot2->count)
+				goto scan_primary_hash;
+
+			exist = udp_lib_lport_inuse2(net, snum, hslot2,
+						     sk, saddr_comp);
+			if (!exist && (hash2_nulladdr != slot2)) {
+				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
+				exist = udp_lib_lport_inuse2(net, snum, hslot2,
+							     sk, saddr_comp);
+			}
+			if (exist)
+				goto fail_unlock;
+			else
+				goto found;
+		}
+scan_primary_hash:
 		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
 					saddr_comp, 0))
 			goto fail_unlock;
@@ -255,12 +312,14 @@ static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
 
 int udp_v4_get_port(struct sock *sk, unsigned short snum)
 {
+	unsigned int hash2_nulladdr =
+		udp4_portaddr_hash(sock_net(sk), INADDR_ANY, snum);
+	unsigned int hash2_partial =
+		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
+
 	/* precompute partial secondary hash */
-	udp_sk(sk)->udp_portaddr_hash =
-		udp4_portaddr_hash(sock_net(sk),
-				   inet_sk(sk)->inet_rcv_saddr,
-				   0);
-	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal);
+	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
+	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
 }
 
 static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
@@ -336,8 +395,6 @@ static inline int compute_score2(struct sock *sk, struct net *net,
 	return score;
 }
 
-#define udp_portaddr_for_each_entry_rcu(__sk, node, list) \
-	hlist_nulls_for_each_entry_rcu(__sk, node, list, __sk_common.skc_portaddr_node)
 
 /* called with read_rcu_lock() */
 static struct sock *udp4_lib_lookup2(struct net *net,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 2915e1dad726..f4c85b200051 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -100,12 +100,14 @@ static unsigned int udp6_portaddr_hash(struct net *net,
 
 int udp_v6_get_port(struct sock *sk, unsigned short snum)
 {
+	unsigned int hash2_nulladdr =
+		udp6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
+	unsigned int hash2_partial = 
+		udp6_portaddr_hash(sock_net(sk), &inet6_sk(sk)->rcv_saddr, 0);
+
 	/* precompute partial secondary hash */
-	udp_sk(sk)->udp_portaddr_hash =
-		udp6_portaddr_hash(sock_net(sk),
-				   &inet6_sk(sk)->rcv_saddr,
-				   0);
-	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal);
+	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
+	return udp_lib_get_port(sk, snum, ipv6_rcv_saddr_equal, hash2_nulladdr);
 }
 
 static inline int compute_score(struct sock *sk, struct net *net,
@@ -181,8 +183,6 @@ static inline int compute_score2(struct sock *sk, struct net *net,
 	return score;
 }
 
-#define udp_portaddr_for_each_entry_rcu(__sk, node, list) \
-	hlist_nulls_for_each_entry_rcu(__sk, node, list, __sk_common.skc_portaddr_node)
 
 /* called with read_rcu_lock() */
 static struct sock *udp6_lib_lookup2(struct net *net,
-- 
cgit v1.2.3