linux-kernel - Re: [PATCH v2] acpi: handle the acpi hotplug schedule error

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Date:   Thu, 29 Jun 2017 00:06:20 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     "Lee, Chun-Yi" <joeyli.kernel@...il.com>
Cc:     linux-acpi@...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: [PATCH v2] acpi: handle the acpi hotplug schedule error

On Wednesday, June 21, 2017 03:04:34 PM Lee, Chun-Yi wrote:
> Kernel should decrements the reference count of acpi device
> when the scheduling of acpi hotplug work is failed, and
> evaluates _OST to notify BIOS the failure.
> 
> v2:
> To simplify the code. (Andy Shevchenko)
> 
> Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> Cc: Len Brown <lenb@...nel.org>
> Cc: Michal Hocko <mhocko@...e.cz>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: "Lee, Chun-Yi" <jlee@...e.com>

Well, what about:

    if (!hotplug_event) {
        acpi_bus_put_acpi_device(adev);
        return;
    }

    if (ACPI_SUCCESS(acpi_hotplug_schedule(adev, type)))
        return;

    acpi_bus_put_acpi_device(adev);

err:
    acpi_evaluate_ost(handle, type, ost_code, NULL);

This achieves the same as the patch below to my eyes, but looks
less convoluted IMO.


> ---
>  drivers/acpi/bus.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index 34fbe02..91adb71 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -427,12 +427,17 @@ static void acpi_bus_notify(acpi_handle handle, u32 type, void *data)
>  	    (driver->flags & ACPI_DRIVER_ALL_NOTIFY_EVENTS))
>  		driver->ops.notify(adev, type);
>  
> -	if (hotplug_event && ACPI_SUCCESS(acpi_hotplug_schedule(adev, type)))
> -		return;
> +	if (hotplug_event) {
> +		if (ACPI_SUCCESS(acpi_hotplug_schedule(adev, type)))
> +			return;
> +		goto err_put_device;
> +	}
>  
>  	acpi_bus_put_acpi_device(adev);
>  	return;
>  
> + err_put_device:
> +	acpi_bus_put_acpi_device(adev);
>   err:
>  	acpi_evaluate_ost(handle, type, ost_code, NULL);
>  }
>