THP refcounting in disallowed_hugepage_adjust()?

[Joerg Roedel <joro@8bytes.org>]

Hi Paolo et al,

while looking again at the recently added IFU patches I noticed a
dicrepancy between the two _hugepage_adjust() functions which doesn't
make sense to me yet:

	* transparent_hugepage_adjust(), when changing the value of pfn,
	  does a kvm_release_pfn_clean() on the old value and a
	  kvm_get_pfn() on the new value to make sure the code holds the
	  reference to the correct pfn.

	* disallowed_hugepage_adjust() also changes the value of the pfn
	  to map, kinda reverses what transparent_hugepage_adjust() did
	  before. But that function does not care about the pfn
	  refcounting.

I was wondering what the reason for that might be, is it just not
necessary in disallowed_hugepage_adjust() or is that an oversight?


Regards,

	Joerg