Re: [PATCH 8/9] io_uring: utilize the io_batch infrastructure for more efficient polled IO

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Wed, Oct 13, 2021 at 10:54:15AM -0600, Jens Axboe wrote:
> @@ -2404,6 +2406,11 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
>  		struct kiocb *kiocb = &req->rw.kiocb;
>  		int ret;
>  
> +		if (!file)
> +			file = kiocb->ki_filp;
> +		else if (file != kiocb->ki_filp)
> +			break;
> +

Can you explain why we now can only poll for a single file (independent
of the fact that batching is used)?

> +	if (!pos && !iob.req_list)
>  		return 0;
> +	if (iob.req_list)
> +		iob.complete(&iob);

Why not:

	if (iob.req_list)
		iob.complete(&iob);
	else if (!pos)
		return 0;

?