linux-kernel - Re: [PATCH v6 3/7] acpi: apei: remove the unused code

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Date:   Mon, 4 Sep 2017 19:43:59 +0800
From:   gengdongjiu <gengdongjiu@...wei.com>
To:     James Morse <james.morse@....com>
CC:     <christoffer.dall@...aro.org>, <marc.zyngier@....com>,
        <rkrcmar@...hat.com>, <linux@...linux.org.uk>,
        <catalin.marinas@....com>, <will.deacon@....com>,
        <lenb@...nel.org>, <robert.moore@...el.com>, <lv.zheng@...el.com>,
        <mark.rutland@....com>, <xiexiuqi@...wei.com>,
        <cov@...eaurora.org>, <david.daney@...ium.com>,
        <suzuki.poulose@....com>, <stefan@...lo-penguin.com>,
        <Dave.Martin@....com>, <kristina.martsenko@....com>,
        <wangkefeng.wang@...wei.com>, <tbaicar@...eaurora.org>,
        <ard.biesheuvel@...aro.org>, <mingo@...nel.org>, <bp@...e.de>,
        <shiju.jose@...wei.com>, <zjzhang@...eaurora.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <kvmarm@...ts.cs.columbia.edu>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
        <devel@...ica.org>, <mst@...hat.com>, <john.garry@...wei.com>,
        <jonathan.cameron@...wei.com>,
        <shameerali.kolothum.thodi@...wei.com>, <huangdaode@...ilicon.com>,
        <wangzhou1@...ilicon.com>, <huangshaoyu@...wei.com>,
        <wuquanming@...wei.com>, <linuxarm@...wei.com>,
        <zhengqiang10@...wei.com>
Subject: Re: [PATCH v6 3/7] acpi: apei: remove the unused code

Hi James,

On 2017/9/1 1:50, James Morse wrote:
> Hi Dongjiu Geng,
> 
> On 28/08/17 11:38, Dongjiu Geng wrote:
>> In current code logic, the two functions ghes_sea_add() and
>> ghes_sea_remove() are only called when CONFIG_ACPI_APEI_SEA
>> is defined. If not, it will return errors in the ghes_probe()
>> and not contiue. Hence, remove the unnecessary handling when
>> CONFIG_ACPI_APEI_SEI is not defined.
> 
> This doesn't match what the patch does. I get this feeling this is needed for
> some future patch you haven't included.

James, let check the code, when the ghes_probe, if the CONFIG_ACPI_APEI_SEA is not defined.
it will return -ENOTSUPP and goto error, and the ghes_sea_add has no chance to execute.
similar, if the probe is failed, it should not have chance to execute ghes_sea_remove.

static int ghes_probe(struct platform_device *ghes_dev)
{
	struct acpi_hest_generic *generic;
	struct ghes *ghes = NULL;

	int rc = -EINVAL;

	generic = *(struct acpi_hest_generic **)ghes_dev->dev.platform_data;
	if (!generic->enabled)
		return -ENODEV;

	switch (generic->notify.type) {
	case ACPI_HEST_NOTIFY_POLLED:
	case ACPI_HEST_NOTIFY_EXTERNAL:
	case ACPI_HEST_NOTIFY_SCI:
	case ACPI_HEST_NOTIFY_GSIV:
	case ACPI_HEST_NOTIFY_GPIO:
		break;

	case ACPI_HEST_NOTIFY_SEA:
		if (!IS_ENABLED(CONFIG_ACPI_APEI_SEA)) {
			pr_warn(GHES_PFX "Generic hardware error source: %d notified via SEA is not supported\n",
				generic->header.source_id);
			rc = -ENOTSUPP;
			goto err;
		}
		break;

> 
> 
>> change since v5:
>> 1. remove the SEI notification type handling, because the SEI is
>>    asynchronous exception and the address is not accurate. so
>>    not call memory_failure() to handle it.
> 
> Setting NOTIFY_SEI as the GHES entry's notification type means the OS should
> check the GHES->ErrorStatusAddress for CPER records when it receives an
> SError-Interrupt, as it may be a notification of an error from this error source.
previously I added the NOTIFY_SEI support, but consider the error address in CPER is not accurate and calling memory_failure() may not make sense.
so I remove it.

> 
> If you aren't handling the notification, why is this is in the HEST at all?
> (and if its not: its not firmware-first)
For the SEI notification, may be we can parse and handle the CPER record other than the Error physical address

> 
> 
> James
> 
> 
>> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
>> index d661d452b238..c15a08db2c7c 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -813,7 +813,6 @@ static struct notifier_block ghes_notifier_hed = {
>>  	.notifier_call = ghes_notify_hed,
>>  };
>>
>> -#ifdef CONFIG_ACPI_APEI_SEA
>>  static LIST_HEAD(ghes_sea);
>>
>>  /*
>> @@ -848,19 +847,6 @@ static void ghes_sea_remove(struct ghes *ghes)
>>  	mutex_unlock(&ghes_list_mutex);
>>  	synchronize_rcu();
>>  }
>> -#else /* CONFIG_ACPI_APEI_SEA */
>> -static inline void ghes_sea_add(struct ghes *ghes)
>> -{
>> -	pr_err(GHES_PFX "ID: %d, trying to add SEA notification which is not
> supported\n",
>> -	       ghes->generic->header.source_id);
>> -}
>> -
>> -static inline void ghes_sea_remove(struct ghes *ghes)
>> -{
>> -	pr_err(GHES_PFX "ID: %d, trying to remove SEA notification which is not
> supported\n",
>> -	       ghes->generic->header.source_id);
>> -}
>> -#endif /* CONFIG_ACPI_APEI_SEA */
>>
>>  #ifdef CONFIG_HAVE_ACPI_APEI_NMI
>>  /*
>>
> 
> 
> .
>