VSOCK: Don't dec ack backlog twice for rejected connections

If a pending socket is marked as rejected, we will decrease the
sk_ack_backlog twice. So don't decrement it for rejected sockets
in vsock_pending_work().

Testing of the rejected socket path was done through code
modifications.

Reported-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jorgen Hansen <jhansen@vmware.com>
Reviewed-by: Adit Ranadive <aditr@vmware.com>
Reviewed-by: Aditya Sarwade <asarwade@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/vmw_vsock/af_vsock.c

@@ -465,6 +465,8 @@ void vsock_pending_work(struct work_struct *work)
 
 	if (vsock_is_pending(sk)) {
 		vsock_remove_pending(listener, sk);
+
+		listener->sk_ack_backlog--;
 	} else if (!vsk->rejected) {
 		/* We are not on the pending list and accept() did not reject
 		 * us, so we must have been accepted by our user process.  We
@@ -475,8 +477,6 @@ void vsock_pending_work(struct work_struct *work)
 		goto out;
 	}
 
-	listener->sk_ack_backlog--;
-
 	/* We need to remove ourself from the global connected sockets list so
 	 * incoming packets can't find this socket, and to reduce the reference
 	 * count.
@@ -2010,5 +2010,5 @@ EXPORT_SYMBOL_GPL(vsock_core_get_transport);
 
 MODULE_AUTHOR("VMware, Inc.");
 MODULE_DESCRIPTION("VMware Virtual Socket Family");
-MODULE_VERSION("1.0.1.0-k");
+MODULE_VERSION("1.0.2.0-k");
 MODULE_LICENSE("GPL v2");