Re: [PATCH RFC 0/4] iomap: zero range folio batch processing prototype

[Brian Foster <bfoster@redhat.com>]

On Wed, Nov 20, 2024 at 12:37:41AM -0800, Christoph Hellwig wrote:
> On Tue, Nov 19, 2024 at 10:46:52AM -0500, Brian Foster wrote:
> > I thought about using ->private along with a custom ->get_folio(), but I
> > don't think that really fits the idea of a built-in mechanism. It might
> > be more appropriate to attach to the iter, but that currently isn't
> > accessible to ->iomap_begin(). I suppose we could define an
> > iomap_to_iter() or some such helper that the fill helper could use to
> > populate the batch, but maybe there are other thoughts/ideas?
> 
> The iter is the right place, and you can get at it using
> container_of as already done by btrfs (and osme of my upcoming code):
> 
> 	struct iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
> 
> 

Ok, yeah.. that's pretty much what I meant by having an iomap_to_iter()
helper, I just wasn't aware that some things were already doing that to
poke at the iter. Thanks.

I'm assuming we'd want this to be a dynamic allocation as well, since
folio_batch is fairly large in comparison (256b compared to 208b
iomap_iter).

Brian