static int rio_mport_wait_for_async_dma()

in devices/rio_mport_cdev.c [1008:1084]

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

static int rio_mport_wait_for_async_dma(struct file *filp, void __user *arg)
{
	struct mport_cdev_priv *priv;
	struct rio_async_tx_wait w_param;
	struct mport_dma_req *req;
	dma_cookie_t cookie;
	unsigned long tmo;
	long wret;
	int found = 0;
	int ret;

	priv = (struct mport_cdev_priv *)filp->private_data;

	if (unlikely(copy_from_user(&w_param, arg, sizeof(w_param))))
		return -EFAULT;

	cookie = w_param.token;
	if (w_param.timeout)
		tmo = msecs_to_jiffies(w_param.timeout);
	else /* Use default DMA timeout */
		tmo = msecs_to_jiffies(dma_timeout);

	spin_lock(&priv->req_lock);
	list_for_each_entry(req, &priv->async_list, node) {
		if (req->cookie == cookie) {
			list_del(&req->node);
			found = 1;
			break;
		}
	}
	spin_unlock(&priv->req_lock);

	if (!found)
		return -EAGAIN;

	wret = wait_for_completion_interruptible_timeout(&req->req_comp, tmo);

	if (wret == 0) {
		/* Timeout on wait occurred */
		rmcd_error("%s(%d) timed out waiting for ASYNC DMA_%s",
		       current->comm, task_pid_nr(current),
		       (req->dir == DMA_FROM_DEVICE)?"READ":"WRITE");
		ret = -ETIMEDOUT;
		goto err_tmo;
	} else if (wret == -ERESTARTSYS) {
		/* Wait_for_completion was interrupted by a signal but DMA may
		 * be still in progress
		 */
		rmcd_error("%s(%d) wait for ASYNC DMA_%s was interrupted",
			current->comm, task_pid_nr(current),
			(req->dir == DMA_FROM_DEVICE)?"READ":"WRITE");
		ret = -EINTR;
		goto err_tmo;
	}

	if (req->status != DMA_COMPLETE) {
		/* DMA transaction completion signaled with transfer error */
		rmcd_error("%s(%d) ASYNC DMA_%s completion with status %d",
			current->comm, task_pid_nr(current),
			(req->dir == DMA_FROM_DEVICE)?"READ":"WRITE",
			req->status);
		ret = -EIO;
	} else
		ret = 0;

	if (req->status != DMA_IN_PROGRESS && req->status != DMA_PAUSED)
		kref_put(&req->refcount, dma_req_free);

	return ret;

err_tmo:
	/* Return request back into async queue */
	spin_lock(&priv->req_lock);
	list_add_tail(&req->node, &priv->async_list);
	spin_unlock(&priv->req_lock);
	return ret;
}