static int __vmbus_open()

in channel.c [653:789]

• 104 lines of code
• 15 McCabe index (conditional complexity)

static int __vmbus_open(struct vmbus_channel *newchannel,
		       void *userdata, u32 userdatalen,
		       void (*onchannelcallback)(void *context), void *context)
{
	struct vmbus_channel_open_channel *open_msg;
	struct vmbus_channel_msginfo *open_info = NULL;
	struct page *page = newchannel->ringbuffer_page;
	u32 send_pages, recv_pages;
	unsigned long flags;
	int err;

	if (userdatalen > MAX_USER_DEFINED_BYTES)
		return -EINVAL;

	send_pages = newchannel->ringbuffer_send_offset;
	recv_pages = newchannel->ringbuffer_pagecount - send_pages;

	if (newchannel->state != CHANNEL_OPEN_STATE)
		return -EINVAL;

	/* Create and init requestor */
	if (newchannel->rqstor_size) {
		if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size))
			return -ENOMEM;
	}

	newchannel->state = CHANNEL_OPENING_STATE;
	newchannel->onchannel_callback = onchannelcallback;
	newchannel->channel_callback_context = context;

	if (!newchannel->max_pkt_size)
		newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;

	/* Establish the gpadl for the ring buffer */
	newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0;

	err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
				      page_address(newchannel->ringbuffer_page),
				      (send_pages + recv_pages) << PAGE_SHIFT,
				      newchannel->ringbuffer_send_offset << PAGE_SHIFT,
				      &newchannel->ringbuffer_gpadlhandle);
	if (err)
		goto error_clean_ring;

	err = hv_ringbuffer_init(&newchannel->outbound,
				 page, send_pages, 0);
	if (err)
		goto error_free_gpadl;

	err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
				 recv_pages, newchannel->max_pkt_size);
	if (err)
		goto error_free_gpadl;

	/* Create and init the channel open message */
	open_info = kzalloc(sizeof(*open_info) +
			   sizeof(struct vmbus_channel_open_channel),
			   GFP_KERNEL);
	if (!open_info) {
		err = -ENOMEM;
		goto error_free_gpadl;
	}

	init_completion(&open_info->waitevent);
	open_info->waiting_channel = newchannel;

	open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
	open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
	open_msg->openid = newchannel->offermsg.child_relid;
	open_msg->child_relid = newchannel->offermsg.child_relid;
	open_msg->ringbuffer_gpadlhandle
		= newchannel->ringbuffer_gpadlhandle.gpadl_handle;
	/*
	 * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
	 * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
	 * here we calculate it into HV_HYP_PAGE.
	 */
	open_msg->downstream_ringbuffer_pageoffset =
		hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
	open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);

	if (userdatalen)
		memcpy(open_msg->userdata, userdata, userdatalen);

	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_add_tail(&open_info->msglistentry,
		      &vmbus_connection.chn_msg_list);
	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

	if (newchannel->rescind) {
		err = -ENODEV;
		goto error_clean_msglist;
	}

	err = vmbus_post_msg(open_msg,
			     sizeof(struct vmbus_channel_open_channel), true);

	trace_vmbus_open(open_msg, err);

	if (err != 0)
		goto error_clean_msglist;

	wait_for_completion(&open_info->waitevent);

	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_del(&open_info->msglistentry);
	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

	if (newchannel->rescind) {
		err = -ENODEV;
		goto error_free_info;
	}

	if (open_info->response.open_result.status) {
		err = -EAGAIN;
		goto error_free_info;
	}

	newchannel->state = CHANNEL_OPENED_STATE;
	kfree(open_info);
	return 0;

error_clean_msglist:
	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_del(&open_info->msglistentry);
	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
error_free_info:
	kfree(open_info);
error_free_gpadl:
	vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle);
error_clean_ring:
	hv_ringbuffer_cleanup(&newchannel->outbound);
	hv_ringbuffer_cleanup(&newchannel->inbound);
	vmbus_free_requestor(&newchannel->requestor);
	newchannel->state = CHANNEL_OPEN_STATE;
	return err;
}