caif: Bugfix debugfs directory name must be unique.

Race condition caused debugfs_create_dir() to fail due to duplicate
name. Use atomic counter to create unique directory name.

net_ratelimit() is introduced to limit debug printouts.

Signed-off-by: Sjur Brændeland <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/caif/caif_socket.c

···
 #ifdef CONFIG_DEBUG_FS
 struct debug_fs_counter {
 	atomic_t caif_nr_socks;
+	atomic_t caif_sock_create;
 	atomic_t num_connect_req;
 	atomic_t num_connect_resp;
 	atomic_t num_connect_fail_resp;
···
 	atomic_t num_rx_flow_on;
 };
 static struct debug_fs_counter cnt;
-#define	dbfs_atomic_inc(v) atomic_inc(v)
-#define	dbfs_atomic_dec(v) atomic_dec(v)
+#define	dbfs_atomic_inc(v) atomic_inc_return(v)
+#define	dbfs_atomic_dec(v) atomic_dec_return(v)
 #else
-#define	dbfs_atomic_inc(v)
-#define	dbfs_atomic_dec(v)
+#define	dbfs_atomic_inc(v) 0
+#define	dbfs_atomic_dec(v) 0
 #endif
 
 struct caifsock {
···
 
 	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
 		(unsigned)sk->sk_rcvbuf && rx_flow_is_on(cf_sk)) {
-		pr_debug("sending flow OFF (queue len = %d %d)\n",
-			atomic_read(&cf_sk->sk.sk_rmem_alloc),
-			sk_rcvbuf_lowwater(cf_sk));
+		if (net_ratelimit())
+			pr_debug("sending flow OFF (queue len = %d %d)\n",
+					atomic_read(&cf_sk->sk.sk_rmem_alloc),
+					sk_rcvbuf_lowwater(cf_sk));
 		set_rx_flow_off(cf_sk);
 		dbfs_atomic_inc(&cnt.num_rx_flow_off);
 		caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
···
 		return err;
 	if (!sk_rmem_schedule(sk, skb->truesize) && rx_flow_is_on(cf_sk)) {
 		set_rx_flow_off(cf_sk);
-		pr_debug("sending flow OFF due to rmem_schedule\n");
+		if (net_ratelimit())
+			pr_debug("sending flow OFF due to rmem_schedule\n");
 		dbfs_atomic_inc(&cnt.num_rx_flow_off);
 		caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_OFF_REQ);
 	}
···
 	sock->state = SS_CONNECTING;
 	sk->sk_state = CAIF_CONNECTING;
 
-	/* Check priority value coming from socket */
+	/* Check priority value comming from socket */
 	/* if priority value is out of range it will be ajusted */
 	if (cf_sk->sk.sk_priority > CAIF_PRIO_MAX)
 		cf_sk->conn_req.priority = CAIF_PRIO_MAX;
···
 
 	dbfs_atomic_inc(&cnt.num_disconnect);
 
+	WARN_ON(IS_ERR(cf_sk->debugfs_socket_dir));
 	if (cf_sk->debugfs_socket_dir != NULL)
 		debugfs_remove_recursive(cf_sk->debugfs_socket_dir);
 
···
 	caif_assert(sk_unhashed(sk));
 	caif_assert(!sk->sk_socket);
 	if (!sock_flag(sk, SOCK_DEAD)) {
-		pr_info("Attempt to release alive CAIF socket: %p\n", sk);
+		pr_debug("Attempt to release alive CAIF socket: %p\n", sk);
 		return;
 	}
 	sk_stream_kill_queues(&cf_sk->sk);
···
 static int caif_create(struct net *net, struct socket *sock, int protocol,
 			int kern)
 {
+	int num;
 	struct sock *sk = NULL;
 	struct caifsock *cf_sk = NULL;
 	static struct proto prot = {.name = "PF_CAIF",
···
 	cf_sk->conn_req.protocol = protocol;
 	/* Increase the number of sockets created. */
 	dbfs_atomic_inc(&cnt.caif_nr_socks);
+	num = dbfs_atomic_inc(&cnt.caif_sock_create);
 #ifdef CONFIG_DEBUG_FS
 	if (!IS_ERR(debugfsdir)) {
+
 		/* Fill in some information concerning the misc socket. */
-		snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d",
-				atomic_read(&cnt.caif_nr_socks));
+		snprintf(cf_sk->name, sizeof(cf_sk->name), "cfsk%d", num);
 
 		cf_sk->debugfs_socket_dir =
 			debugfs_create_dir(cf_sk->name, debugfsdir);
+
 		debugfs_create_u32("sk_state", S_IRUSR | S_IWUSR,
 				cf_sk->debugfs_socket_dir,
 				(u32 *) &cf_sk->sk.sk_state);
···
 		debugfs_create_u32("num_sockets", S_IRUSR | S_IWUSR,
 				debugfsdir,
 				(u32 *) &cnt.caif_nr_socks);
+		debugfs_create_u32("num_create", S_IRUSR | S_IWUSR,
+				debugfsdir,
+				(u32 *) &cnt.caif_sock_create);
 		debugfs_create_u32("num_connect_req", S_IRUSR | S_IWUSR,
 				debugfsdir,
 				(u32 *) &cnt.num_connect_req);