[RFC PATCH 2/4] kho: Detect preserved page types

[Mike Rapoport]

> Detect page types in kho_preserve_pages() by peeking into the refcount
> of the second page in each block of order > 0. If the second page has
> a non-zero reference count, it indicates that the block has been split.
> Otherwise, treated it as a contiguous, unsplit block.
> 
> Since the page type is now part of the radix tree key, update the
> unpreserve path to use the same detection logic to ensure it can
> correctly locate and delete existing entries.
> 
> Signed-off-by: Pranjal Shrivastava <praan at google.com>
>
> diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
> index f829ffdd00f45..d6e81f72fe5de 100644
> --- a/kernel/liveupdate/kexec_handover.c
> +++ b/kernel/liveupdate/kexec_handover.c
> @@ -918,15 +918,29 @@ static unsigned int __kho_preserve_pages_order(unsigned long start_pfn,
>  	return order;
>  }
>  
> +static bool kho_is_page_split(unsigned long pfn, unsigned int order)

You can return enum kho_page_type here directly (and rename the function
accordingly).

-- 
Sincerely yours,
Mike.