Re: [PATCH 1/6] drivers/cxl: add cxl_memctrl_mode and region->memctrl

[<dan.j.williams@intel.com>]

Dave Jiang wrote:
[..]
> > Rest of this looks fine. With that fixup if we are going to have a set
> > of different region driver modes then the directory can be:
> > 
> > drivers/cxl/core/region/
> 
> Do we still have reasons to keep the region drivers in core? I know
> Fabio has been looking at moving the region drivers to drivers/cxl/ so
> the LMH cxl_test stuff doesn't doesn't need to do all the weird stuff
> to make it work. Maybe we just do the refactor now and move the region
> drivers outside of core. How about drivers/cxl/region/?

Not opposed to making it a module, just need to make sure that all
potential region drivers are loaded prior to the first
cxl_add_to_region() call. Otherwise, this breaks the expectation that
auto-assembly of regions present at boot can be flushed by
wait_for_device_probe(). Specifically, userspace module loading requests
are not flushed by this helper, only direct symbol dependencies.

It would be lovely if we had a unit test that specifically checked for
regressions like this, because the race can be difficult to see.