Re: [PATCH 3/4] aio: implement IOCB_CMD_POLL

[Al Viro]

On Mon, Jul 30, 2018 at 09:15:43AM +0200, Christoph Hellwig wrote:

> +	apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */

> +	mask = vfs_poll(req->file, &apt.pt) & req->events;
> +	if (mask || apt.error) {
> +		bool removed = false;
> +
> +		/* we did not manage to set up a waitqueue, done */
> +		if (unlikely(!req->head))
> +			goto out_fput;

> +out_fput:
> +	fput(req->file);
> +	return apt.error;

Ugh...  So anything that simply returns a constant value, without
even bothering to do poll_wait() (on the theory that no matter how
much you wait, nothing will change) is going to git -EINVAL?
What am I missing here?