[NET]: Cleanup INET_REFCNT_DEBUG code

Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/inet_common.h

@@ -29,7 +29,6 @@ extern unsigned int		inet_poll(struct file * file, struct socket *sock, struct p
 extern int			inet_listen(struct socket *sock, int backlog);
 
 extern void			inet_sock_destruct(struct sock *sk);
-extern atomic_t			inet_sock_nr;
 
 extern int			inet_bind(struct socket *sock, 
 					  struct sockaddr *uaddr, int addr_len);

include/net/ipv6.h

@@ -145,7 +145,6 @@ DECLARE_SNMP_STAT(struct udp_mib, udp_stats_in6);
 #define UDP6_INC_STATS(field)		SNMP_INC_STATS(udp_stats_in6, field)
 #define UDP6_INC_STATS_BH(field)	SNMP_INC_STATS_BH(udp_stats_in6, field)
 #define UDP6_INC_STATS_USER(field) 	SNMP_INC_STATS_USER(udp_stats_in6, field)
-extern atomic_t			inet6_sock_nr;
 
 int snmp6_register_dev(struct inet6_dev *idev);
 int snmp6_unregister_dev(struct inet6_dev *idev);

include/net/sock.h

@@ -491,6 +491,9 @@ extern int sk_wait_data(struct sock *sk, long *timeo);
 
 struct request_sock_ops;
 
+/* Here is the right place to enable sock refcounting debugging */
+#define SOCK_REFCNT_DEBUG
+
 /* Networking protocol blocks we attach to sockets.
  * socket layer -> transport layer interface
  * transport -> network interface is defined by struct inet_proto
@@ -561,7 +564,9 @@ struct proto {
 	char			name[32];
 
 	struct list_head	node;
-
+#ifdef SOCK_REFCNT_DEBUG
+	atomic_t		socks;
+#endif
 	struct {
 		int inuse;
 		u8  __pad[SMP_CACHE_BYTES - sizeof(int)];
@@ -571,6 +576,31 @@ struct proto {
 extern int proto_register(struct proto *prot, int alloc_slab);
 extern void proto_unregister(struct proto *prot);
 
+#ifdef SOCK_REFCNT_DEBUG
+static inline void sk_refcnt_debug_inc(struct sock *sk)
+{
+	atomic_inc(&sk->sk_prot->socks);
+}
+
+static inline void sk_refcnt_debug_dec(struct sock *sk)
+{
+	atomic_dec(&sk->sk_prot->socks);
+	printk(KERN_DEBUG "%s socket %p released, %d are still alive\n",
+	       sk->sk_prot->name, sk, atomic_read(&sk->sk_prot->socks));
+}
+
+static inline void sk_refcnt_debug_release(const struct sock *sk)
+{
+	if (atomic_read(&sk->sk_refcnt) != 1)
+		printk(KERN_DEBUG "Destruction of the %s socket %p delayed, refcnt=%d\n",
+		       sk->sk_prot->name, sk, atomic_read(&sk->sk_refcnt));
+}
+#else /* SOCK_REFCNT_DEBUG */
+#define sk_refcnt_debug_inc(sk) do { } while (0)
+#define sk_refcnt_debug_dec(sk) do { } while (0)
+#define sk_refcnt_debug_release(sk) do { } while (0)
+#endif /* SOCK_REFCNT_DEBUG */
+
 /* Called with local bh disabled */
 static __inline__ void sock_prot_inc_use(struct proto *prot)
 {

include/net/tcp.h

@@ -306,7 +306,7 @@ extern kmem_cache_t *tcp_timewait_cachep;
 static inline void tcp_tw_put(struct tcp_tw_bucket *tw)
 {
 	if (atomic_dec_and_test(&tw->tw_refcnt)) {
-#ifdef INET_REFCNT_DEBUG
+#ifdef SOCK_REFCNT_DEBUG
 		printk(KERN_DEBUG "tw_bucket %p released\n", tw);
 #endif
 		kmem_cache_free(tcp_timewait_cachep, tw);

net/core/sock.c

@@ -1367,11 +1367,7 @@ void sk_common_release(struct sock *sk)
 
 	xfrm_sk_free_policy(sk);
 
-#ifdef INET_REFCNT_DEBUG
-	if (atomic_read(&sk->sk_refcnt) != 1)
-		printk(KERN_DEBUG "Destruction of the socket %p delayed, c=%d\n",
-		       sk, atomic_read(&sk->sk_refcnt));
-#endif
+	sk_refcnt_debug_release(sk);
 	sock_put(sk);
 }
 

net/ipv4/af_inet.c

@@ -114,10 +114,6 @@
 
 DEFINE_SNMP_STAT(struct linux_mib, net_statistics);
 
-#ifdef INET_REFCNT_DEBUG
-atomic_t inet_sock_nr;
-#endif
-
 extern void ip_mc_drop_socket(struct sock *sk);
 
 /* The inetsw table contains everything that inet_create needs to
@@ -153,11 +149,7 @@ void inet_sock_destruct(struct sock *sk)
 	if (inet->opt)
 		kfree(inet->opt);
 	dst_release(sk->sk_dst_cache);
-#ifdef INET_REFCNT_DEBUG
-	atomic_dec(&inet_sock_nr);
-	printk(KERN_DEBUG "INET socket %p released, %d are still alive\n",
-	       sk, atomic_read(&inet_sock_nr));
-#endif
+	sk_refcnt_debug_dec(sk);
 }
 
 /*
@@ -317,9 +309,7 @@ static int inet_create(struct socket *sock, int protocol)
 	inet->mc_index	= 0;
 	inet->mc_list	= NULL;
 
-#ifdef INET_REFCNT_DEBUG
-	atomic_inc(&inet_sock_nr);
-#endif
+	sk_refcnt_debug_inc(sk);
 
 	if (inet->num) {
 		/* It assumes that any protocol which allows
@@ -1205,7 +1195,3 @@ EXPORT_SYMBOL(inet_stream_ops);
 EXPORT_SYMBOL(inet_unregister_protosw);
 EXPORT_SYMBOL(net_statistics);
 EXPORT_SYMBOL(sysctl_ip_nonlocal_bind);
-
-#ifdef INET_REFCNT_DEBUG
-EXPORT_SYMBOL(inet_sock_nr);
-#endif

net/ipv4/tcp.c

@@ -1580,12 +1580,7 @@ void tcp_destroy_sock(struct sock *sk)
 
 	xfrm_sk_free_policy(sk);
 
-#ifdef INET_REFCNT_DEBUG
-	if (atomic_read(&sk->sk_refcnt) != 1) {
-		printk(KERN_DEBUG "Destruction TCP %p delayed, c=%d\n",
-		       sk, atomic_read(&sk->sk_refcnt));
-	}
-#endif
+	sk_refcnt_debug_release(sk);
 
 	atomic_dec(&tcp_orphan_count);
 	sock_put(sk);

net/ipv4/tcp_minisocks.c

@@ -84,7 +84,7 @@ static void tcp_timewait_kill(struct tcp_tw_bucket *tw)
 	tcp_bucket_destroy(tb);
 	spin_unlock(&bhead->lock);
 
-#ifdef INET_REFCNT_DEBUG
+#ifdef SOCK_REFCNT_DEBUG
 	if (atomic_read(&tw->tw_refcnt) != 1) {
 		printk(KERN_DEBUG "tw_bucket %p refcnt=%d\n", tw,
 		       atomic_read(&tw->tw_refcnt));
@@ -799,9 +799,21 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
 		newsk->sk_err = 0;
 		newsk->sk_priority = 0;
 		atomic_set(&newsk->sk_refcnt, 2);
-#ifdef INET_REFCNT_DEBUG
-		atomic_inc(&inet_sock_nr);
-#endif
+
+		/*
+		 * Increment the counter in the same struct proto as the master
+		 * sock (sk_refcnt_debug_inc uses newsk->sk_prot->socks, that
+		 * is the same as sk->sk_prot->socks, as this field was copied
+		 * with memcpy), same rationale as the first comment in this
+		 * function.
+		 *
+		 * This _changes_ the previous behaviour, where
+		 * tcp_create_openreq_child always was incrementing the
+		 * equivalent to tcp_prot->socks (inet_sock_nr), so this have
+		 * to be taken into account in all callers. -acme
+		 */
+		sk_refcnt_debug_inc(newsk);
+
 		atomic_inc(&tcp_sockets_allocated);
 
 		if (sock_flag(newsk, SOCK_KEEPOPEN))

net/ipv6/af_inet6.c

@@ -86,26 +86,12 @@ extern void if6_proc_exit(void);
 
 int sysctl_ipv6_bindv6only;
 
-#ifdef INET_REFCNT_DEBUG
-atomic_t inet6_sock_nr;
-EXPORT_SYMBOL(inet6_sock_nr);
-#endif
-
 /* The inetsw table contains everything that inet_create needs to
  * build a new socket.
  */
 static struct list_head inetsw6[SOCK_MAX];
 static DEFINE_SPINLOCK(inetsw6_lock);
 
-static void inet6_sock_destruct(struct sock *sk)
-{
-	inet_sock_destruct(sk);
-
-#ifdef INET_REFCNT_DEBUG
-	atomic_dec(&inet6_sock_nr);
-#endif
-}
-
 static __inline__ struct ipv6_pinfo *inet6_sk_generic(struct sock *sk)
 {
 	const int offset = sk->sk_prot->obj_size - sizeof(struct ipv6_pinfo);
@@ -186,7 +172,7 @@ static int inet6_create(struct socket *sock, int protocol)
 			inet->hdrincl = 1;
 	}
 
-	sk->sk_destruct		= inet6_sock_destruct;
+	sk->sk_destruct		= inet_sock_destruct;
 	sk->sk_family		= PF_INET6;
 	sk->sk_protocol		= protocol;
 
@@ -213,12 +199,17 @@ static int inet6_create(struct socket *sock, int protocol)
 		inet->pmtudisc = IP_PMTUDISC_DONT;
 	else
 		inet->pmtudisc = IP_PMTUDISC_WANT;
+	/* 
+	 * Increment only the relevant sk_prot->socks debug field, this changes
+	 * the previous behaviour of incrementing both the equivalent to
+	 * answer->prot->socks (inet6_sock_nr) and inet_sock_nr.
+	 *
+	 * This allows better debug granularity as we'll know exactly how many
+	 * UDPv6, TCPv6, etc socks were allocated, not the sum of all IPv6
+	 * transport protocol socks. -acme
+	 */
+	sk_refcnt_debug_inc(sk);
 
-
-#ifdef INET_REFCNT_DEBUG
-	atomic_inc(&inet6_sock_nr);
-	atomic_inc(&inet_sock_nr);
-#endif
 	if (inet->num) {
 		/* It assumes that any protocol which allows
 		 * the user to assign a number at socket

net/ipv6/ipv6_sockglue.c

@@ -163,6 +163,13 @@ int ipv6_setsockopt(struct sock *sk, int level, int optname,
 			fl6_free_socklist(sk);
 			ipv6_sock_mc_close(sk);
 
+			/*
+			 * Sock is moving from IPv6 to IPv4 (sk_prot), so
+			 * remove it from the refcnt debug socks count in the
+			 * original family...
+			 */
+			sk_refcnt_debug_dec(sk);
+
 			if (sk->sk_protocol == IPPROTO_TCP) {
 				struct tcp_sock *tp = tcp_sk(sk);
 
@@ -192,9 +199,11 @@ int ipv6_setsockopt(struct sock *sk, int level, int optname,
 				kfree_skb(pktopt);
 
 			sk->sk_destruct = inet_sock_destruct;
-#ifdef INET_REFCNT_DEBUG
-			atomic_dec(&inet6_sock_nr);
-#endif
+			/*
+			 * ... and add it to the refcnt debug socks count
+			 * in the new family. -acme
+			 */
+			sk_refcnt_debug_inc(sk);
 			module_put(THIS_MODULE);
 			retv = 0;
 			break;

net/ipv6/tcp_ipv6.c

@@ -1407,12 +1407,11 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 		newnp->mcast_oif   = tcp_v6_iif(skb);
 		newnp->mcast_hops  = skb->nh.ipv6h->hop_limit;
 
-		/* Charge newly allocated IPv6 socket. Though it is mapped,
-		 * it is IPv6 yet.
+		/*
+		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
+		 * here, tcp_create_openreq_child now does this for us, see the comment in
+		 * that function for the gory details. -acme
 		 */
-#ifdef INET_REFCNT_DEBUG
-		atomic_inc(&inet6_sock_nr);
-#endif
 
 		/* It is tricky place. Until this moment IPv4 tcp
 		   worked with IPv6 af_tcp.af_specific.
@@ -1467,10 +1466,11 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 	if (newsk == NULL)
 		goto out;
 
-	/* Charge newly allocated IPv6 socket */
-#ifdef INET_REFCNT_DEBUG
-	atomic_inc(&inet6_sock_nr);
-#endif
+	/*
+	 * No need to charge this sock to the relevant IPv6 refcnt debug socks
+	 * count here, tcp_create_openreq_child now does this for us, see the
+	 * comment in that function for the gory details. -acme
+	 */
 
 	ip6_dst_store(newsk, dst, NULL);
 	newsk->sk_route_caps = dst->dev->features &

net/sctp/ipv6.c

@@ -641,10 +641,7 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
 	else
 		newinet->pmtudisc = IP_PMTUDISC_WANT;
 
-#ifdef INET_REFCNT_DEBUG
-	atomic_inc(&inet6_sock_nr);
-	atomic_inc(&inet_sock_nr);
-#endif
+	sk_refcnt_debug_inc(newsk);
 
 	if (newsk->sk_prot->init(newsk)) {
 		sk_common_release(newsk);

net/sctp/protocol.c

@@ -593,9 +593,7 @@ static struct sock *sctp_v4_create_accept_sk(struct sock *sk,
 	newinet->mc_index = 0;
 	newinet->mc_list = NULL;
 
-#ifdef INET_REFCNT_DEBUG
-	atomic_inc(&inet_sock_nr);
-#endif
+	sk_refcnt_debug_inc(newsk);
 
 	if (newsk->sk_prot->init(newsk)) {
 		sk_common_release(newsk);