linux-kernel - Re: [RFC PATCH v4] acpi: indicate to platform when hot remove returns busy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAHp75Vcyyp2m70mCy6DJi=N4HuC8CVf=3RyRoT3yZK9j3Ue0aw@mail.gmail.com>
Date:   Mon, 3 Jul 2017 20:08:51 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     "Lee, Chun-Yi" <joeyli.kernel@...il.com>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Lee, Chun-Yi" <jlee@...e.com>, Len Brown <lenb@...nel.org>,
        Michal Hocko <mhocko@...e.cz>
Subject: Re: [RFC PATCH v4] acpi: indicate to platform when hot remove returns busy

On Mon, Jul 3, 2017 at 4:26 PM, Lee, Chun-Yi <joeyli.kernel@...il.com> wrote:
> In hotplug logic, it always indicates non-specific failure to
> platform through _OST when handing acpi hot-remove event failed. Then
> platform terminates the hot-remove process but it can not identify
> the reason.
>
> Base on current hot-remove code, there have two situations that it
> returns busy:
>  - OSPM try to offline an individual device, but the device offline
>    function returns busy.
>  - When the ejection event is applied to an "not offlined yet" container.
>    OSPM send kobject change event to userspace and returns busy.
>
> Both of them will returns -EBUSY to acpi device hotplug function then
> hotplug function indicates non-specific failure to platform just like
> any other error, e.g. -ENODEV or -EIO.
>
> The benefit to platform for identifying the OS busy state is that
> platform can be applied different approach to handle the busy but
> not just terminate the hot-remove process by unknown reason. For
> example, platform can wait for a while then triggers hot-remove
> again.
>
> This RFC patch adds one more parameter to the handler function of
> acpi generic hotplug event to give the function a chance to propose
> the return code of _OST. In this case, it sets ost return code to
> ACPI_OST_SC_DEVICE_BUSY when the acpi hot remove function returns
> -EBUSY.
>

Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>

> v4:
> Use switch-case statements to simplify code. (Andy Shevchenko, Rafael J. Wysocki)
>
> v3:
> Removed redundant 'else' in acpi_ost_status_code(). (Andy Shevchenko)
>
> v2:
> Do not overwrite ost code in acpi_generic_hotplug_event(). Move
> the "error code to ost code" logic to a help function. (Andy Shevchenko)
>
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Len Brown <lenb@...nel.org>
> Cc: Andy Shevchenko <andy.shevchenko@...il.com>
> Cc: Michal Hocko <mhocko@...e.cz>
> Signed-off-by: "Lee, Chun-Yi" <jlee@...e.com>
> ---
>  drivers/acpi/scan.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index d531629..ce88175 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -404,10 +404,6 @@ void acpi_device_hotplug(struct acpi_device *adev, u32 src)
>                 error = dock_notify(adev, src);
>         } else if (adev->flags.hotplug_notify) {
>                 error = acpi_generic_hotplug_event(adev, src);
> -               if (error == -EPERM) {
> -                       ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> -                       goto err_out;
> -               }
>         } else {
>                 int (*notify)(struct acpi_device *, u32);
>
> @@ -423,8 +419,20 @@ void acpi_device_hotplug(struct acpi_device *adev, u32 src)
>                 else
>                         goto out;
>         }
> -       if (!error)
> +       switch (error) {
> +       case 0:
>                 ost_code = ACPI_OST_SC_SUCCESS;
> +               break;
> +       case -EPERM:
> +               ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> +               break;
> +       case -EBUSY:
> +               ost_code = ACPI_OST_SC_DEVICE_BUSY;
> +               break;
> +       default:
> +               ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE;
> +               break;
> +       }
>
>   err_out:
>         acpi_evaluate_ost(adev->handle, src, ost_code, NULL);
> --
> 2.10.2
>



-- 
With Best Regards,
Andy Shevchenko