Re: [PATCH 1/2] net: hisilicon: hns_mdio: remove incorrect ACPI_PTR annotation

[Paolo Abeni]

On 2/27/25 1:03 PM, Arnd Bergmann wrote:
> On Thu, Feb 27, 2025, at 12:53, Jijie Shao wrote:
>>
>> 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.
> 
> Those should be cleaned up eventually, but that is separate from
> the build warning.
> 
>> 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.
> 
> Setting .acpi_match_table and .of_match_table unconditionally
> is the normal case. Historically we had some drivers that
> used of_match_ptr() to assign the .of_match_table in order
> to allow drivers to #ifdef out the CONFIG_OF portion of the
> driver for platforms that did not already use devicetree
> based probing.
> 
> There are basically no platforms left that have not been
> converted to devicetree yet, so there is no point in
> micro-optimizing the kernel size for that case, but the
> (mis)use of of_match_ptr() has been copied into drivers
> after that, and most of the ACPI_PTR() users unfortunately
> copied from that when drivers started supporting both.

Makes sense, thanks!

Paolo