[PATCH net-2.6.26 2/6][NETNS][SOCK]: Introduce per-net inuse counters.

[Pavel Emelyanov <xemul@openvz.org>]

This is probably the most controversial part of the set.

The counters are stored in a per-cpu array on a struct net. To 
index in this array the prot->inuse is declared as int and used. 

Numbers (indices) to protos are generated with the appropriate 
enum. I though about using some existing IPPROTO_XXX numbers for
protocols but they were too large (IPPROTO_RAW is 255) and did 
not differ for ipv4 and ipv6 (there's no IP6PROTO_RAW, etc).

The sock_prot_inuse_(add|get) now use the net argument to
get the counter, but this all hides under CONFIG_NET_NS.

The sock_prot_inuse_(init|fini) are no-ops. DEFINE_PROTO_INUSE
is empty and REF_PROTO_INUSE assigns an index to a proto.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---
 include/net/net_namespace.h |    3 ++
 include/net/sock.h          |   35 +++++++++++++++++++++++++++++
 net/core/sock.c             |   52 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 0 deletions(-)

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index f8f3d1a..8a37be1 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -18,6 +18,7 @@ struct proc_dir_entry;
 struct net_device;
 struct sock;
 struct ctl_table_header;
+struct net_prot_inuse;
 
 struct net {
 	atomic_t		count;		/* To decided when the network
@@ -50,6 +51,8 @@ struct net {
 	struct ctl_table_header	*sysctl_core_hdr;
 	int			sysctl_somaxconn;
 
+	struct net_prot_inuse	*inuse;
+
 	struct netns_packet	packet;
 	struct netns_unix	unx;
 	struct netns_ipv4	ipv4;
diff --git a/include/net/sock.h b/include/net/sock.h
index a57c58f..84a672c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -562,8 +562,12 @@ struct proto {
 
 	/* Keeping track of sockets in use */
 #ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NET_NS
+	unsigned int		inuse;
+#else
 	struct pcounter		inuse;
 #endif
+#endif
 
 	/* Memory pressure */
 	void			(*enter_memory_pressure)(void);
@@ -635,6 +639,36 @@ static inline void sk_refcnt_debug_release(const struct sock *sk)
 
 
 #ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NET_NS
+enum {
+	NET_INUSE_dccp_v4,
+	NET_INUSE_dccp_v6,
+	NET_INUSE_raw,
+	NET_INUSE_tcp,
+	NET_INUSE_udp,
+	NET_INUSE_udplite,
+	NET_INUSE_rawv6,
+	NET_INUSE_tcpv6,
+	NET_INUSE_udpv6,
+	NET_INUSE_udplitev6,
+	NET_INUSE_sctp,
+	NET_INUSE_sctpv6,
+	NET_INUSE_NR,
+};
+
+# define DEFINE_PROTO_INUSE(NAME)
+# define REF_PROTO_INUSE(NAME) .inuse = NET_INUSE_##NAME,
+
+extern void sock_prot_inuse_add(struct net *net, struct proto *prot, int inc);
+static inline int sock_prot_inuse_init(struct proto *proto)
+{
+	return 0;
+}
+extern int sock_prot_inuse_get(struct net *net, struct proto *proto);
+static inline void sock_prot_inuse_free(struct proto *proto)
+{
+}
+#else /* ! CONFIG_NET_NS */
 # define DEFINE_PROTO_INUSE(NAME) DEFINE_PCOUNTER(NAME)
 # define REF_PROTO_INUSE(NAME) PCOUNTER_MEMBER_INITIALIZER(NAME, .inuse)
 /* Called with local bh disabled */
@@ -655,6 +689,7 @@ static inline void sock_prot_inuse_free(struct proto *proto)
 {
 	pcounter_free(&proto->inuse);
 }
+#endif /* CONFIG_NET_NS */
 #else
 # define DEFINE_PROTO_INUSE(NAME)
 # define REF_PROTO_INUSE(NAME)
diff --git a/net/core/sock.c b/net/core/sock.c
index 3ee9506..743f628 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2056,6 +2056,58 @@ void proto_unregister(struct proto *prot)
 EXPORT_SYMBOL(proto_unregister);
 
 #ifdef CONFIG_PROC_FS
+#ifdef CONFIG_NET_NS
+struct net_prot_inuse {
+	int val[NET_INUSE_NR];
+};
+
+void sock_prot_inuse_add(struct net *net, struct proto *prot, int val)
+{
+	per_cpu_ptr(net->inuse, get_cpu())->val[prot->inuse] += val;
+	put_cpu();
+}
+EXPORT_SYMBOL_GPL(sock_prot_inuse_add);
+
+int sock_prot_inuse_get(struct net *net, struct proto *prot)
+{
+	int cpu, idx, val;
+
+	idx = prot->inuse;
+	val = 0;
+	for_each_online_cpu(cpu)
+		val += per_cpu_ptr(net->inuse, cpu)->val[idx];
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(sock_prot_inuse_get);
+
+static int sock_inuse_init_net(struct net *net)
+{
+	net->inuse = alloc_percpu(struct net_prot_inuse);
+	return net->inuse ? 0 : -ENOMEM;
+}
+
+static void sock_inuse_exit_net(struct net *net)
+{
+	free_percpu(net->inuse);
+}
+
+static struct pernet_operations net_inuse_ops = {
+	.init = sock_inuse_init_net,
+	.exit = sock_inuse_exit_net,
+};
+
+static __init int net_inuse_init(void)
+{
+	if (register_pernet_subsys(&net_inuse_ops))
+		panic("Cannot initialize net inuse counters");
+
+	return 0;
+}
+
+core_initcall(net_inuse_init);
+#endif
+
 static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
 	__acquires(proto_list_lock)
 {
-- 
1.5.3.4