netdev - Re: [RFC] fwnode: change the return type of mac address helpers

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Message-ID: <53aadbb8-54de-fc86-29a7-818cab80e808@pensando.io>
Date:   Wed, 6 Oct 2021 11:13:13 -0700
From:   Shannon Nelson <snelson@...sando.io>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     Andrew Lunn <andrew@...n.ch>, netdev@...r.kernel.org,
        gregkh@...uxfoundation.org, rafael@...nel.org,
        saravanak@...gle.com, mw@...ihalf.com, jeremy.linton@....com
Subject: Re: [RFC] fwnode: change the return type of mac address helpers

On 10/6/21 10:49 AM, Jakub Kicinski wrote:
> On Wed, 6 Oct 2021 09:55:59 -0700 Shannon Nelson wrote:
>>>>> -	if (!device_get_ethdev_addr(dev, ndev))
>>>>> +	if (device_get_ethdev_addr(dev, ndev))
>>>>>    		eth_hw_addr_random(ndev);
>>>> That is going to be interesting for out of tree drivers.
>>> Indeed :(  But I think it's worth it - I thought it's only device tree
>>> that has the usual errno return code but inside eth.c there are also
>>> helpers for platform and nvmem mac retrieval which also return errno.
>> As the maintainer of an out-of-tree driver, this kind of change with
>> little warning really can ruin my day.
>>
>> I understand that as Linux kernel developers we really can't spend much
>> time coddling the outer fringe, but we can at least give them hints.
>> Changing the sense of the non-zero return from good to bad in several
>> functions without something else that the compiler can warn on
>> needlessly sets up time bombs for the unsuspecting.  Can we find a way
>> to break their compile rather than surprise them with a broken runtime?
> I also changed the arguments in v2, so OOT will no longer silently
> break (not that it was the main motivation ;))

That works - thanks.
sln