static ssize_t rpmsg_eptdev_read_iter()

in rpmsg_char.c [170:215]

• 32 lines of code
• 9 McCabe index (conditional complexity)

static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
	struct file *filp = iocb->ki_filp;
	struct rpmsg_eptdev *eptdev = filp->private_data;
	unsigned long flags;
	struct sk_buff *skb;
	int use;

	if (!eptdev->ept)
		return -EPIPE;

	spin_lock_irqsave(&eptdev->queue_lock, flags);

	/* Wait for data in the queue */
	if (skb_queue_empty(&eptdev->queue)) {
		spin_unlock_irqrestore(&eptdev->queue_lock, flags);

		if (filp->f_flags & O_NONBLOCK)
			return -EAGAIN;

		/* Wait until we get data or the endpoint goes away */
		if (wait_event_interruptible(eptdev->readq,
					     !skb_queue_empty(&eptdev->queue) ||
					     !eptdev->ept))
			return -ERESTARTSYS;

		/* We lost the endpoint while waiting */
		if (!eptdev->ept)
			return -EPIPE;

		spin_lock_irqsave(&eptdev->queue_lock, flags);
	}

	skb = skb_dequeue(&eptdev->queue);
	spin_unlock_irqrestore(&eptdev->queue_lock, flags);
	if (!skb)
		return -EFAULT;

	use = min_t(size_t, iov_iter_count(to), skb->len);
	if (copy_to_iter(skb->data, use, to) != use)
		use = -EFAULT;

	kfree_skb(skb);

	return use;
}