# Re: \[PATCH v15 16/17\] iomap: Convert iomap\_add\_to\_ioend to take a folio

- From: Christoph Hellwig \<hch@infradead.org\>
- Date: 2021-07-20 07:21:40 
- List: linux-block
- Page: https://ratatoskr.run/linux-block/2021/07/210531
- Thread: https://ratatoskr.run/linux-fsdevel/2021/07/210470/t.md

```text
On Mon, Jul 19, 2021 at 07:40:00PM +0100, Matthew Wilcox (Oracle) wrote:
> -	merged = __bio_try_merge_page(wpc->ioend->io_bio, page, len, poff,
> -			&same_page);
>  	if (iop)
>  		atomic_add(len, &iop->write_bytes_pending);
> -
> -	if (!merged) {
> -		if (bio_full(wpc->ioend->io_bio, len)) {
> -			wpc->ioend->io_bio =
> -				iomap_chain_bio(wpc->ioend->io_bio);
> -		}
> -		bio_add_page(wpc->ioend->io_bio, page, len, poff);
> +	if (!bio_add_folio(wpc->ioend->io_bio, folio, len, poff)) {
> +		wpc->ioend->io_bio = iomap_chain_bio(wpc->ioend->io_bio);
> +		bio_add_folio(wpc->ioend->io_bio, folio, len, poff);
>  	}

I actually have pretty similar changes for the red and write path to
avoid __bio_try_merge_page in my queue.  I'll send them out ASAP as
I think such a change should be done separately from the folio
switch.

>  	/*
> -	 * Walk through the page to find areas to write back. If we run off the
> -	 * end of the current map or find the current map invalid, grab a new
> -	 * one.
> +	 * Walk through the folio to find areas to write back. If we
> +	 * run off the end of the current map or find the current map
> +	 * invalid, grab a new one.

Why the reformatting?

Otherwise this looks sane to me.
```