Re: [PATCH 03/10] iomap: convert misc simple ops to incremental advance

[Christoph Hellwig <hch@infradead.org>]

> +	u64 length = iomap_length(iter);
> +
>  	switch (iomap->type) {
>  	case IOMAP_MAPPED:
>  	case IOMAP_UNWRITTEN:
> @@ -132,7 +134,8 @@ static loff_t iomap_swapfile_iter(const struct iomap_iter *iter,
>  			return error;
>  		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
>  	}
> -	return iomap_length(iter);
> +
> +	return iomap_iter_advance(iter, &length);

I notice that for many of these callers passing in the length as in/out
argument isn't all that great.  Not sure that's worth changing now (or
adding another helper?).  The conversion itself looks good.