[PATCH 5/6] mm/mremap: Use pmd/pud_poplulate to update page table entries

[Linus Torvalds]

On Sun, Jun 13, 2021 at 2:06 AM Aneesh Kumar K.V
<aneesh.kumar at linux.ibm.com> wrote:
>
> IIUC the reason why we do have pmd_pgtable() is that pgtable_t type
> is arch dependent. On some architecture it is pte_t * and on the other
> struct page *. The reason being highmem and level 4 page table can
> be located in highmem.

Honestly, the same confusion is real - in a different way - about
pud_page_vaddr().

I really hate that function.

Just grep for the uses, and the definitions, to see what I mean. It's crazy.

I'm perfectly happy not having a "pud_pagetable()" function, but that
cast on pud_page_vaddr() is indicative of real problems.

One solution might be to just say "pud_page_vaddr()" must return a "pmd_t *".

I think it's what all the users actually want anyway.

              Linus