static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
				       struct iov_iter *from)
{
	struct file *filp = iocb->ki_filp;
	struct rpmsg_eptdev *eptdev = filp->private_data;
	size_t len = iov_iter_count(from);
	void *kbuf;
	int ret;

	kbuf = kzalloc(len, GFP_KERNEL);
	if (!kbuf)
		return -ENOMEM;

	if (!copy_from_iter_full(kbuf, len, from))
		return -EFAULT;

	if (mutex_lock_interruptible(&eptdev->ept_lock)) {
		ret = -ERESTARTSYS;
		goto free_kbuf;
	}

	if (!eptdev->ept) {
		ret = -EPIPE;
		goto unlock_eptdev;
	}

	if (filp->f_flags & O_NONBLOCK)
		ret = rpmsg_trysend(eptdev->ept, kbuf, len);
	else
		ret = rpmsg_send(eptdev->ept, kbuf, len);

unlock_eptdev:
	mutex_unlock(&eptdev->ept_lock);

free_kbuf:
	kfree(kbuf);
	return ret < 0 ? ret : len;
}
Unknown