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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 5 Jun 2023 19:11:11 +0200
Message-ID: <CAJZ5v0i1nspPuHuUoLsWOz7MLnnB8bv=cXYbFcv0a=okBxBg3w@mail.gmail.com>
Subject: Re: [PATCH v2] apei/ghes: correctly return NULL for ghes_get_devices()
To:     Li Yang <leoyang.li@nxp.com>, Tony Luck <tony.luck@intel.com>,
        Borislav Petkov <bp@alien8.de>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, James Morse <james.morse@arm.com>,
        Jia He <justin.he@arm.com>, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Fri, May 19, 2023 at 10:13 PM Li Yang <leoyang.li@nxp.com> wrote:
>
> Since 315bada690e0 ("EDAC: Check for GHES preference in the
> chipset-specific EDAC drivers"), vendor specific EDAC driver will not
> probe correctly when CONFIG_ACPI_APEI_GHES is enabled but no GHES device
> is present.  Make ghes_get_devices() return NULL when the GHES device
> list is empty to fix the problem.
>
> Fixes: 9057a3f7ac36 ("EDAC/ghes: Prepare to make ghes_edac a proper module")
> Signed-off-by: Li Yang <leoyang.li@nxp.com>
> Cc: Jia He <justin.he@arm.com>

Boris, Tony, any comments?

> ---
>
> V2: fix the fallthrough case in x86 path
>
>  drivers/acpi/apei/ghes.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 34ad071a64e9..4382fe13ee3e 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -1544,6 +1544,8 @@ struct list_head *ghes_get_devices(void)
>
>                         pr_warn_once("Force-loading ghes_edac on an unsupported platform. You're on your own!\n");
>                 }
> +       } else if (list_empty(&ghes_devs)) {
> +               return NULL;
>         }
>
>         return &ghes_devs;
> --
> 2.38.0
>