int pvcalls_front_socket()

in pvcalls-front.c [260:333]

• 49 lines of code
• 6 McCabe index (conditional complexity)

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

	/*
	 * PVCalls only supports domain AF_INET,
	 * type SOCK_STREAM and protocol 0 sockets for now.
	 *
	 * Check socket type here, AF_INET and protocol checks are done
	 * by the caller.
	 */
	if (sock->type != SOCK_STREAM)
		return -EOPNOTSUPP;

	pvcalls_enter();
	if (!pvcalls_front_dev) {
		pvcalls_exit();
		return -EACCES;
	}
	bedata = dev_get_drvdata(&pvcalls_front_dev->dev);

	map = kzalloc(sizeof(*map), GFP_KERNEL);
	if (map == NULL) {
		pvcalls_exit();
		return -ENOMEM;
	}

	spin_lock(&bedata->socket_lock);

	ret = get_request(bedata, &req_id);
	if (ret < 0) {
		kfree(map);
		spin_unlock(&bedata->socket_lock);
		pvcalls_exit();
		return ret;
	}

	/*
	 * sock->sk->sk_send_head is not used for ip sockets: reuse the
	 * field to store a pointer to the struct sock_mapping
	 * corresponding to the socket. This way, we can easily get the
	 * struct sock_mapping from the struct socket.
	 */
	sock->sk->sk_send_head = (void *)map;
	list_add_tail(&map->list, &bedata->socket_mappings);

	req = RING_GET_REQUEST(&bedata->ring, req_id);
	req->req_id = req_id;
	req->cmd = PVCALLS_SOCKET;
	req->u.socket.id = (uintptr_t) map;
	req->u.socket.domain = AF_INET;
	req->u.socket.type = SOCK_STREAM;
	req->u.socket.protocol = IPPROTO_IP;

	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);

	/* read req_id, then the content */
	smp_rmb();
	ret = bedata->rsp[req_id].ret;
	bedata->rsp[req_id].req_id = PVCALLS_INVALID_ID;

	pvcalls_exit();
	return ret;
}