Re: [RFC PATCH 1/6] vdpa: add bind_mm callback

[Jason Wang]

在 2022/12/16 16:17, Stefano Garzarella 写道:
> On Fri, Dec 16, 2022 at 02:37:45PM +0800, Jason Wang wrote:
> > On Thu, Dec 15, 2022 at 12:30 AM Stefano Garzarella 
> > <sgarzare@xxxxxxxxxx> wrote:
> > > This new optional callback is used to bind the device to a specific
> > > address space so the vDPA framework can use VA when this callback
> > > is implemented.
> > >
> > > Suggested-by: Jason Wang <jasowang@xxxxxxxxxx>
> > > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
> > > ---
> > >  include/linux/vdpa.h | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > > index 6d0f5e4e82c2..34388e21ef3f 100644
> > > --- a/include/linux/vdpa.h
> > > +++ b/include/linux/vdpa.h
> > > @@ -282,6 +282,12 @@ struct vdpa_map_file {
> > >   *                             @iova: iova to be unmapped
> > >   *                             @size: size of the area
> > >   *                             Returns integer: success (0) or 
> > > error (< 0)
> > > + * @bind_mm:                   Bind the device to a specific 
> > > address space
> > > + *                             so the vDPA framework can use VA 
> > > when this
> > > + *                             callback is implemented. (optional)
> > > + *                             @vdev: vdpa device
> > > + *                             @mm: address space to bind
> >
> > Do we need an unbind or did a NULL mm mean unbind?
>
> Yep, your comment in patch 6 makes it necessary. I will add it!
>
> > > + *                             @owner: process that owns the 
> > > address space
> >
> > Any reason we need the task_struct here?
>
> Mainly to attach to kthread to the process cgroups, but that part is 
> still in TODO since I need to understand it better.


Ok I see.


> Maybe we can remove the task_struct here and use `current` directly in 
> the callback.


Yes, it's easier to start without cgroup and we can add it on top.

Thanks


> Thanks,
> Stefano