Re: [PATCH v4] ata: ahci: fail probe if BAR too small for claimed ports

[Niklas Cassel <cassel@kernel.org>]

On 27 April 2026 23:47:41 CEST, Damien Le Moal <dlemoal@kernel.org> wrote:
>On 2026/04/28 5:32, Niklas Cassel wrote:
>> On 27 April 2026 22:23:12 CEST, Damien Le Moal <dlemoal@kernel.org> wrote:
>>> On 2026/04/27 21:14, Niklas Cassel wrote:
>>>>> +			 max_ports, last_port_end,
>>>>> +			 (unsigned long long)bar_size);
>>>>
>>>> Print resource_size_t as %pa instead of casting to unsigned long long
>>>> and pass bar_size by reference (&bar_size):
>>>> https://docs.kernel.org/core-api/printk-formats.html#physical-address-types-phys-addr-t
>>>>
>>>>
>>>>> +		return -ENODEV;
>>>>
>>>> return -EIO;
>>>
>>> I do not agree here. We did not do any I/O. If anything, this should be EINVAL.
>>> But I think that ENODEV is safer since we are in the probe context here and we
>>> do not want to see that device show up.
>> 
>> 
>> How about -ENXIO?
>> 
>> No such device or address
>> 
>> 
>> It is the only error code, except for -ENODEV
>> that is a valid error code to fail probe():
>> https://elixir.bootlin.com/linux/v7.0.1/source/drivers/base/dd.c#L653
>
>That is my point, since we want to fail probe. So I would go with this ENODEV.


ENXIO and ENODEV are handled exactly the same way in dd.c

Anyway, looking at dd.c again, any negative error code will do. The only difference seems to be that the driver core will not print an error for ENXIO and ENODEV, but will do so for any other error code.

Looking at:
https://linux.kernel.narkive.com/NI9fvCoJ/device-driver-probe-return-codes

I don't think that my original suggestion of EIO is wrong.

Anyway, considering that all error codes will fail the probe, I'm fine with any error code (except for EPROBE_DEFER :P)


Kind regards,
Niklas