On the other hand I would like to see the global lock to go away
because
it causes scalability issues and I would like to change it to a range
lock. This would make this race possible.
That being said this is more of a preparatory work than a fix. One
could
argue that pgdat resize lock is abused here but I am not convinced a
dedicated lock is much better. We do take this lock already and
spanning
its scope seems reasonable. An update to the documentation is due.
Would not make more sense to move it within the pgdat lock
in move_pfn_range_to_zone?
The call from free_area_init_core is safe as we are single-thread there.
And if we want to move towards a range locking, I even think it would be
more
consistent if we move it within the zone's span lock (which is already
wrapped with a pgdat lock).
