geneve: Remove socket hash table.

The hash table for open Geneve ports is used only on creation and
deletion time. It is not performance critical and is not likely to
grow to a large number of items. Therefore, this can be changed
to use a simple linked list.
Signed-off-by: NJesse Gross <jesse@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/geneve.h

@@ -68,7 +68,7 @@ struct geneve_sock;
 typedef void (geneve_rcv_t)(struct geneve_sock *gs, struct sk_buff *skb);
 
 struct geneve_sock {
-	struct hlist_node	hlist;
+	struct list_head	list;
 	geneve_rcv_t		*rcv;
 	void			*rcv_data;
 	struct socket		*sock;

net/ipv4/geneve.c

@@ -26,7 +26,6 @@
 #include <linux/etherdevice.h>
 #include <linux/if_ether.h>
 #include <linux/if_vlan.h>
-#include <linux/hash.h>
 #include <linux/ethtool.h>
 #include <linux/mutex.h>
 #include <net/arp.h>
@@ -54,12 +53,9 @@
 /* Protects sock_list and refcounts. */
 static DEFINE_MUTEX(geneve_mutex);
 
-#define PORT_HASH_BITS 8
-#define PORT_HASH_SIZE (1<<PORT_HASH_BITS)
-
 /* per-network namespace private data for this module */
 struct geneve_net {
-	struct hlist_head	sock_list[PORT_HASH_SIZE];
+	struct list_head	sock_list;
 };
 
 static int geneve_net_id;
@@ -69,19 +65,13 @@ static inline struct genevehdr *geneve_hdr(const struct sk_buff *skb)
 	return (struct genevehdr *)(udp_hdr(skb) + 1);
 }
 
-static struct hlist_head *gs_head(struct net *net, __be16 port)
-{
-	struct geneve_net *gn = net_generic(net, geneve_net_id);
-
-	return &gn->sock_list[hash_32(ntohs(port), PORT_HASH_BITS)];
-}
-
 /* Find geneve socket based on network namespace and UDP port */
 static struct geneve_sock *geneve_find_sock(struct net *net, __be16 port)
 {
+	struct geneve_net *gn = net_generic(net, geneve_net_id);
 	struct geneve_sock *gs;
 
-	hlist_for_each_entry(gs, gs_head(net, port), hlist) {
+	list_for_each_entry(gs, &gn->sock_list, list) {
 		if (inet_sk(gs->sock->sk)->inet_sport == port)
 			return gs;
 	}
@@ -339,6 +329,7 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,
 						geneve_rcv_t *rcv, void *data,
 						bool ipv6)
 {
+	struct geneve_net *gn = net_generic(net, geneve_net_id);
 	struct geneve_sock *gs;
 	struct socket *sock;
 	struct udp_tunnel_sock_cfg tunnel_cfg;
@@ -371,7 +362,7 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,
 	tunnel_cfg.encap_destroy = NULL;
 	setup_udp_tunnel_sock(net, sock, &tunnel_cfg);
 
-	hlist_add_head(&gs->hlist, gs_head(net, port));
+	list_add(&gs->list, &gn->sock_list);
 
 	return gs;
 }
@@ -407,7 +398,7 @@ void geneve_sock_release(struct geneve_sock *gs)
 	if (--gs->refcnt)
 		goto unlock;
 
-	hlist_del(&gs->hlist);
+	list_del(&gs->list);
 	geneve_notify_del_rx_port(gs);
 	udp_tunnel_sock_release(gs->sock);
 	kfree_rcu(gs, rcu);
@@ -420,17 +411,14 @@ EXPORT_SYMBOL_GPL(geneve_sock_release);
 static __net_init int geneve_init_net(struct net *net)
 {
 	struct geneve_net *gn = net_generic(net, geneve_net_id);
-	unsigned int h;
 
-	for (h = 0; h < PORT_HASH_SIZE; ++h)
-		INIT_HLIST_HEAD(&gn->sock_list[h]);
+	INIT_LIST_HEAD(&gn->sock_list);
 
 	return 0;
 }
 
 static struct pernet_operations geneve_net_ops = {
 	.init = geneve_init_net,
-	.exit = NULL,
 	.id   = &geneve_net_id,
 	.size = sizeof(struct geneve_net),
 };