[PATCH v2 3/3] mm/vmalloc: fix vmalloc_to_page for huge vmap mappings

[Anshuman Khandual]

On 07/01/2019 12:10 PM, Nicholas Piggin wrote:
> vmalloc_to_page returns NULL for addresses mapped by larger pages[*].
> Whether or not a vmap is huge depends on the architecture details,
> alignments, boot options, etc., which the caller can not be expected
> to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page.
> 
> This change teaches vmalloc_to_page about larger pages, and returns
> the struct page that corresponds to the offset within the large page.
> This makes the API agnostic to mapping implementation details.
> 
> [*] As explained by commit 029c54b095995 ("mm/vmalloc.c: huge-vmap:
>     fail gracefully on unexpected huge vmap mappings")
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>

Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>