RE: [PATCH v1] migration: fail the cap check if it requires the use of deferred incoming

[Wang, Wei W]

On Tuesday, May 23, 2023 7:36 AM, Peter Xu wrote:
> > > We may also want to trap the channel setups on num:
> > >
> > > migrate_params_test_apply():
> > >
> > >     if (params->has_multifd_channels) {
> > >         dest->multifd_channels = params->multifd_channels;
> > >     }
> >
> > Didn’t get this one. What do you want to add to above?
> 
> I meant after listen() is called with an explicit number in this case, should 
> we
> disallow changing of multifd number of channels?

Got you, thanks. That seems unnecessary to me, as the cap setting is required
for the use of multifd and patching there already achieves below what we want:
- users get the error message when deferred -incoming isn’t used;
- fail the cap setting for multifd, meaning that multifd won't be used (i.e.
no place that will care about multifd_channels).