static int send_modifychannel_with_ack()

in channel.c [229:284]

• 40 lines of code
• 4 McCabe index (conditional complexity)

static int send_modifychannel_with_ack(struct vmbus_channel *channel, u32 target_vp)
{
	struct vmbus_channel_modifychannel *msg;
	struct vmbus_channel_msginfo *info;
	unsigned long flags;
	int ret;

	info = kzalloc(sizeof(struct vmbus_channel_msginfo) +
				sizeof(struct vmbus_channel_modifychannel),
		       GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	init_completion(&info->waitevent);
	info->waiting_channel = channel;

	msg = (struct vmbus_channel_modifychannel *)info->msg;
	msg->header.msgtype = CHANNELMSG_MODIFYCHANNEL;
	msg->child_relid = channel->offermsg.child_relid;
	msg->target_vp = target_vp;

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

	ret = vmbus_post_msg(msg, sizeof(*msg), true);
	trace_vmbus_send_modifychannel(msg, ret);
	if (ret != 0) {
		spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
		list_del(&info->msglistentry);
		spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
		goto free_info;
	}

	/*
	 * Release channel_mutex; otherwise, vmbus_onoffer_rescind() could block on
	 * the mutex and be unable to signal the completion.
	 *
	 * See the caller target_cpu_store() for information about the usage of the
	 * mutex.
	 */
	mutex_unlock(&vmbus_connection.channel_mutex);
	wait_for_completion(&info->waitevent);
	mutex_lock(&vmbus_connection.channel_mutex);

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

	if (info->response.modify_response.status)
		ret = -EAGAIN;

free_info:
	kfree(info);
	return ret;
}