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

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Message-ID: <mafs0bjmkp0gb.fsf@kernel.org>
Date: Mon, 06 Oct 2025 16:30:12 +0200
From: Pratyush Yadav <pratyush@...nel.org>
To: Pasha Tatashin <pasha.tatashin@...een.com>
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Subject: Re: [PATCH v4 03/30] kho: drop notifiers

Hi Pasha,

On Mon, Sep 29 2025, Pasha Tatashin wrote:

> From: "Mike Rapoport (Microsoft)" <rppt@...nel.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@...nel.org>
> Signed-off-by: Pasha Tatashin <pasha.tatashin@...een.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.

[...]

-- 
Regards,
Pratyush Yadav