Re: [PATCH 1/3] mm: add apply_to_existing_pages helper

[Andrey Ryabinin]

On 12/5/19 5:04 PM, Daniel Axtens wrote:
> apply_to_page_range takes an address range, and if any parts of it
> are not covered by the existing page table hierarchy, it allocates
> memory to fill them in.
> 
> In some use cases, this is not what we want - we want to be able to
> operate exclusively on PTEs that are already in the tables.
> 
> Add apply_to_existing_pages for this. Adjust the walker functions
> for apply_to_page_range to take 'create', which switches them between
> the old and new modes.
> 
> This will be used in KASAN vmalloc.
> 
> Signed-off-by: Daniel Axtens <dja@xxxxxxxxxx>

Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>