RE: [PATCH v13 1/2] ACPI / APEI: Add a notifier chain for unknown (vendor) CPER records

[Shiju Jose]

>-----Original Message-----
>From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx]
>Sent: 24 July 2020 13:54
>To: Shiju Jose <shiju.jose@xxxxxxxxxx>
>Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx; rjw@xxxxxxxxxxxxx; bp@xxxxxxxxx;
>james.morse@xxxxxxx; lenb@xxxxxxxxxx; tony.luck@xxxxxxxxx;
>dan.carpenter@xxxxxxxxxx; zhangliguang@xxxxxxxxxxxxxxxxx;
>andriy.shevchenko@xxxxxxxxxxxxxxx; Wangkefeng (OS Kernel Lab)
><wangkefeng.wang@xxxxxxxxxx>; jroedel@xxxxxxx; Linuxarm
><linuxarm@xxxxxxxxxx>; yangyicong <yangyicong@xxxxxxxxxx>; Jonathan
>Cameron <jonathan.cameron@xxxxxxxxxx>; tanxiaofei
><tanxiaofei@xxxxxxxxxx>
>Subject: Re: [PATCH v13 1/2] ACPI / APEI: Add a notifier chain for unknown
>(vendor) CPER records
>
>On Fri, Jul 24, 2020 at 09:00:41AM +0000, Shiju Jose wrote:
>> >-----Original Message-----
>> >From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx]
>> >Sent: 24 July 2020 00:21
>> >To: Shiju Jose <shiju.jose@xxxxxxxxxx>
>> >Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-
>> >kernel@xxxxxxxxxxxxxxx; rjw@xxxxxxxxxxxxx; bp@xxxxxxxxx;
>> >james.morse@xxxxxxx; lenb@xxxxxxxxxx; tony.luck@xxxxxxxxx;
>> >dan.carpenter@xxxxxxxxxx; zhangliguang@xxxxxxxxxxxxxxxxx;
>> >andriy.shevchenko@xxxxxxxxxxxxxxx; Wangkefeng (OS Kernel Lab)
>> ><wangkefeng.wang@xxxxxxxxxx>; jroedel@xxxxxxx; Linuxarm
>> ><linuxarm@xxxxxxxxxx>; yangyicong <yangyicong@xxxxxxxxxx>;
>Jonathan
>> >Cameron <jonathan.cameron@xxxxxxxxxx>; tanxiaofei
>> ><tanxiaofei@xxxxxxxxxx>
>> >Subject: Re: [PATCH v13 1/2] ACPI / APEI: Add a notifier chain for
>> >unknown
>> >(vendor) CPER records
>> >
>> >On Wed, Jul 22, 2020 at 11:39:51AM +0100, Shiju Jose wrote:
>> >> CPER records describing a firmware-first error are identified by GUID.
>> >> The ghes driver currently logs, but ignores any unknown CPER records.
>> >> This prevents describing errors that can't be represented by a
>> >> standard entry, that would otherwise allow a driver to recover from
>> >> an
>> >error.
>> >> The UEFI spec calls these 'Non-standard Section Body' (N.2.3 of
>> >> version 2.8).
>> >
>> >> +#ifdef CONFIG_ACPI_APEI_GHES
>> >> +/**
>> >> + * ghes_register_vendor_record_notifier - register a notifier for
>> >> +vendor
>> >> + * records that the kernel would otherwise ignore.
>> >> + * @nb: pointer to the notifier_block structure of the event handler.
>> >> + *
>> >> + * return 0 : SUCCESS, non-zero : FAIL  */ int
>> >> +ghes_register_vendor_record_notifier(struct notifier_block *nb);
>> >> +
>> >> +/**
>> >> + * ghes_unregister_vendor_record_notifier - unregister the
>> >> +previously
>> >> + * registered vendor record notifier.
>> >> + * @nb: pointer to the notifier_block structure of the vendor
>> >> +record
>> >handler.
>> >> + */
>> >> +void ghes_unregister_vendor_record_notifier(struct notifier_block
>> >> +*nb); #else static inline int
>> >> +ghes_register_vendor_record_notifier(struct notifier_block *nb) {
>> >> +	return -ENODEV;
>> >> +}
>> >> +
>> >> +static inline void ghes_unregister_vendor_record_notifier(struct
>> >> +notifier_block *nb) { }
>> >
>> >If you made CONFIG_PCIE_HISI_ERR depend on CONFIG_ACPI_APEI_GHES,
>> >you'd be able to get rid of these stubs, wouldn't you?  It doesn't
>> >look like there's any point in building pcie-hisi-error.c at all
>> >unless CONFIG_ACPI_APEI_GHES is enabled.
>>
>> The stub is added because this interface is expected to use by the
>> other drivers as well.  Some drivers may not want add the build depend
>> on the CONFIG_ACPI_APEI_GHES if the error reporting has less priority
>> in the driver.  However we can add dependency on
>CONFIG_ACPI_APEI_GHES
>> for building pcie-hisi-error.c.
>
>The usual route is to add stubs when they're needed, not just in anticipation
>of some need that may never materialize.
ok. I will change in the next version.

Thanks,
Shiju