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

On Mon, Oct 6, 2025 at 10:30 AM Pratyush Yadav [off-list ref] wrote:

Hi Pasha,

On Mon, Sep 29 2025, Pasha Tatashin wrote:

quoted

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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@kernel.org>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>

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.

Yes, thank you Pratyush. I missed this change in my patch.

Pasha