smb: server: fix leak of active_num_conn in ksmbd_tcp_new_connection()

On kthread_run() failure in ksmbd_tcp_new_connection(), the transport is
freed via free_transport(), which does not decrement active_num_conn,
leaking this counter.

Replace free_transport() with ksmbd_tcp_disconnect().

Fixes: 0d0d468 ("ksmbd: add max connections parameter")
Cc: stable@vger.kernel.org
Signed-off-by: Henrique Carvalho <henrique.carvalho@suse.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: hac-v

fs/smb/server/transport_tcp.c

@@ -40,6 +40,7 @@ static const struct ksmbd_transport_ops ksmbd_tcp_transport_ops;
 
 static void tcp_stop_kthread(struct task_struct *kthread);
 static struct interface *alloc_iface(char *ifname);
+static void ksmbd_tcp_disconnect(struct ksmbd_transport *t);
 
 #define KSMBD_TRANS(t)	(&(t)->transport)
 #define TCP_TRANS(t)	((struct tcp_transport *)container_of(t, \
@@ -202,7 +203,7 @@ static int ksmbd_tcp_new_connection(struct socket *client_sk)
 	if (IS_ERR(handler)) {
 		pr_err("cannot start conn thread\n");
 		rc = PTR_ERR(handler);
-		free_transport(t);
+		ksmbd_tcp_disconnect(KSMBD_TRANS(t));
 	}
 	return rc;
 }