RE: [PATCH v12 0/8] mm/gup: Introduce memfd_pin_folios() for pinning memfd folios

["Kasireddy, Vivek" <vivek.kasireddy@intel.com>]

Hi David,

> 
> On 25.02.24 08:56, Vivek Kasireddy wrote:
> > Currently, some drivers (e.g, Udmabuf) that want to longterm-pin
> > the pages/folios associated with a memfd, do so by simply taking a
> > reference on them. This is not desirable because the pages/folios
> > may reside in Movable zone or CMA block.
> >
> > Therefore, having drivers use memfd_pin_folios() API ensures that
> > the folios are appropriately pinned via FOLL_PIN for longterm DMA.
> >
> > This patchset also introduces a few helpers and converts the Udmabuf
> > driver to use folios and memfd_pin_folios() API to longterm-pin
> > the folios for DMA. Two new Udmabuf selftests are also included to
> > test the driver and the new API.
> >
> > ---
> 
> Sorry Vivek, I got distracted. What's the state of this? I assume it's
> not in an mm tree yet.
No problem. Right, they are not in any tree yet. The first two mm patches that
add the unpin_folios() and check_and_migrate_movable_folios() helpers still
need to be reviewed.

> 
> I try to get this reviewed this week. If I fail to do that, please ping me.
Ok, sounds good!

Thanks,
Vivek
> 
> --
> Cheers,
> 
> David / dhildenb