int pvcalls_front_release()

in pvcalls-front.c [1000:1081]

• 60 lines of code
• 11 McCabe index (conditional complexity)

int pvcalls_front_release(struct socket *sock)
{
	struct pvcalls_bedata *bedata;
	struct sock_mapping *map;
	int req_id, notify, ret;
	struct xen_pvcalls_request *req;

	if (sock->sk == NULL)
		return 0;

	map = pvcalls_enter_sock(sock);
	if (IS_ERR(map)) {
		if (PTR_ERR(map) == -ENOTCONN)
			return -EIO;
		else
			return 0;
	}
	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);

	spin_lock(&bedata->socket_lock);
	ret = get_request(bedata, &req_id);
	if (ret < 0) {
		spin_unlock(&bedata->socket_lock);
		pvcalls_exit_sock(sock);
		return ret;
	}
	sock->sk->sk_send_head = NULL;

	req = RING_GET_REQUEST(&bedata->ring, req_id);
	req->req_id = req_id;
	req->cmd = PVCALLS_RELEASE;
	req->u.release.id = (uintptr_t)map;

	bedata->ring.req_prod_pvt++;
	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify);
	spin_unlock(&bedata->socket_lock);
	if (notify)
		notify_remote_via_irq(bedata->irq);

	wait_event(bedata->inflight_req,
		   READ_ONCE(bedata->rsp[req_id].req_id) == req_id);

	if (map->active_socket) {
		/*
		 * Set in_error and wake up inflight_conn_req to force
		 * recvmsg waiters to exit.
		 */
		map->active.ring->in_error = -EBADF;
		wake_up_interruptible(&map->active.inflight_conn_req);

		/*
		 * We need to make sure that sendmsg/recvmsg on this socket have
		 * not started before we've cleared sk_send_head here. The
		 * easiest way to guarantee this is to see that no pvcalls
		 * (other than us) is in progress on this socket.
		 */
		while (atomic_read(&map->refcount) > 1)
			cpu_relax();

		pvcalls_front_free_map(bedata, map);
	} else {
		wake_up(&bedata->inflight_req);
		wake_up(&map->passive.inflight_accept_req);

		while (atomic_read(&map->refcount) > 1)
			cpu_relax();

		spin_lock(&bedata->socket_lock);
		list_del(&map->list);
		spin_unlock(&bedata->socket_lock);
		if (READ_ONCE(map->passive.inflight_req_id) != PVCALLS_INVALID_ID &&
			READ_ONCE(map->passive.inflight_req_id) != 0) {
			pvcalls_front_free_map(bedata,
					       map->passive.accept_map);
		}
		kfree(map);
	}
	WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID);

	pvcalls_exit();
	return 0;
}