[PATCH 04/12] kho: add callback for table pages

[Mike Rapoport]

On Wed, Apr 29, 2026 at 03:39:06PM +0200, Pratyush Yadav wrote:
> From: "Pratyush Yadav (Google)" <pratyush at kernel.org>
> 
> The KHO memory preservation radix tree does not mark the table pages
> themselves as scratch. This is done to avoid a circular dependency where
> preserving a page can lead of allocating other preserved pages. This
> means any walker looking for free ranges of memory outside of scratch
> areas will ignore the table
> 
> Add a table callback that is invoked for each table page. The callback

A sentence why a table callback helps would be nice here :)

> is given the physical address of the table page.
> 
> Signed-off-by: Pratyush Yadav (Google) <pratyush at kernel.org>
> ---
>  include/linux/kho_radix_tree.h     |  3 +++
>  kernel/liveupdate/kexec_handover.c | 12 ++++++++++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/include/linux/kho_radix_tree.h b/include/linux/kho_radix_tree.h
> index 030da6399d28..fe7151d89361 100644
> --- a/include/linux/kho_radix_tree.h
> +++ b/include/linux/kho_radix_tree.h
> @@ -37,12 +37,15 @@ struct kho_radix_tree {
>  /**
>   * struct kho_radix_walk_cb - Callbacks for KHO radix tree walk.
>   * @key:      Called on each present key in the radix tree.
> + * @table:    Called on each table of the radix tree itself. Receives the
> + *            physical address of the page containing the table.
>   *
>   * For each callback, a return value of 0 continues the walk and a non-zero
>   * return value is directly returned to the caller.
>   */
>  struct kho_radix_walk_cb {
>  	int (*key)(unsigned long key);
> +	int (*table)(phys_addr_t phys);

Naming is hard ;-)

>  };
>  

-- 
Sincerely yours,
Mike.