Re: [PATCH v4 03/30] kho: drop notifiers

From: Pratyush Yadav

Date: Mon Oct 06 2025 - 10:30:22 EST


Hi Pasha,

On Mon, Sep 29 2025, Pasha Tatashin wrote:

> From: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
>
> The KHO framework uses a notifier chain as the mechanism for clients to
> participate in the finalization process. While this works for a single,
> central state machine, it is too restrictive for kernel-internal
> components like pstore/reserve_mem or IMA. These components need a
> simpler, direct way to register their state for preservation (e.g.,
> during their initcall) without being part of a complex,
> shutdown-time notifier sequence. The notifier model forces all
> participants into a single finalization flow and makes direct
> preservation from an arbitrary context difficult.
> This patch refactors the client participation model by removing the
> notifier chain and introducing a direct API for managing FDT subtrees.
>
> The core kho_finalize() and kho_abort() state machine remains, but
> clients now register their data with KHO beforehand.
>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>

This patch breaks build of test_kho.c (under CONFIG_TEST_KEXEC_HANDOVER):

lib/test_kho.c:49:14: error: ‘KEXEC_KHO_ABORT’ undeclared (first use in this function)
49 | case KEXEC_KHO_ABORT:
| ^~~~~~~~~~~~~~~
[...]
lib/test_kho.c:51:14: error: ‘KEXEC_KHO_FINALIZE’ undeclared (first use in this function)
51 | case KEXEC_KHO_FINALIZE:
| ^~~~~~~~~~~~~~~~~~
[...]

I think you need to update it as well to drop notifier usage.

[...]

--
Regards,
Pratyush Yadav