netdev - Re: [PATCH 1/2] net: hisilicon: hns_mdio: remove incorrect ACPI

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

Message-ID: <3e477135-981f-49bd-8e54-0c3ecdcc8a19@huawei.com>
Date: Thu, 27 Feb 2025 19:53:22 +0800
From: Jijie Shao <shaojijie@...wei.com>
To: Arnd Bergmann <arnd@...db.de>, Arnd Bergmann <arnd@...nel.org>, Jian Shen
	<shenjian15@...wei.com>, Salil Mehta <salil.mehta@...wei.com>, Andrew Lunn
	<andrew+netdev@...n.ch>, "David S . Miller" <davem@...emloft.net>, Eric
 Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>
CC: <shaojijie@...wei.com>, Simon Horman <horms@...nel.org>,
	Uwe Kleine-König <u.kleine-koenig@...libre.com>, Krzysztof
 Kozlowski <krzysztof.kozlowski@...aro.org>, Netdev <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] net: hisilicon: hns_mdio: remove incorrect ACPI_PTR
 annotation


on 2025/2/26 14:49, Arnd Bergmann wrote:
> On Wed, Feb 26, 2025, at 04:21, Jijie Shao wrote:
>> on 2025/2/26 0:33, Arnd Bergmann wrote:
>>> From: Arnd Bergmann <arnd@...db.de>
>>>
>>> Building with W=1 shows a warning about hns_mdio_acpi_match being unused when
>>> CONFIG_ACPI is disabled:
>>>
>>> drivers/net/ethernet/hisilicon/hns_mdio.c:631:36: error: unused variable 'hns_mdio_acpi_match' [-Werror,-Wunused-const-variable]
>>>
>>> Signed-off-by: Arnd Bergmann <arnd@...db.de>
>>> ---
>>>    drivers/net/ethernet/hisilicon/hns_mdio.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/hisilicon/hns_mdio.c b/drivers/net/ethernet/hisilicon/hns_mdio.c
>>> index a1aa6c1f966e..6812be8dc64f 100644
>>> --- a/drivers/net/ethernet/hisilicon/hns_mdio.c
>>> +++ b/drivers/net/ethernet/hisilicon/hns_mdio.c
>>> @@ -640,7 +640,7 @@ static struct platform_driver hns_mdio_driver = {
>>>    	.driver = {
>>>    		   .name = MDIO_DRV_NAME,
>>>    		   .of_match_table = hns_mdio_match,
>>> -		   .acpi_match_table = ACPI_PTR(hns_mdio_acpi_match),
>>> +		   .acpi_match_table = hns_mdio_acpi_match,
>>>    		   },
>>>    };
>>
>> But I think it can be changed to:
>>
>> + #ifdef CONFIG_ACPI
>> static const struct acpi_device_id hns_mdio_acpi_match[] = {
>> 	{ "HISI0141", 0 },
>> 	{ },
>> };
>> MODULE_DEVICE_TABLE(acpi, hns_mdio_acpi_match);
>> + #endif
>>
> That would of course avoid the build warning, but otherwise
> would be worse: the only reason ACPI_PTR()/of_match_ptr() exist
> is to work around drivers that have to put their device ID
> table inside of an #ifdef for some other reason. Adding the
> #ifdef to work around an incorrect ACPI_PTR() makes no sense.
>
>       Arnd

if CONFIG_ACPI is disabled, ACPI_PTR() will return NULL, so
hns_mdio_acpi_match is unused variable.


So use #ifdef is possible and has no side effects, and many drivers do so.



Of course, it also seems possible to remove ACPI_PTR(),
But I'm not sure if it's okay to set a value to acpi_match_table if CONFIG_ACPI is disabled.
It need maintainer to look at this.

Thanks,
Jijie Shao