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Message-ID: <55764773-bf9a-94c9-ad2b-1c6e63879798@linux.ibm.com>
Date:   Thu, 22 Jun 2023 14:33:03 +0200
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Subject: Re: [PATCH] s390/net: lcs: fix build errors when FDDI is a loadable
 module
To:     Alexandra Winter <wintera@linux.ibm.com>,
        Simon Horman <simon.horman@corigine.com>
Cc:     Randy Dunlap <rdunlap@infradead.org>, linux-kernel@vger.kernel.org,
        kernel test robot <lkp@intel.com>,
        Wenjia Zhang <wenjia@linux.ibm.com>,
        linux-s390@vger.kernel.org, netdev@vger.kernel.org,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Sven Schnelle <svens@linux.ibm.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
References: <20230621213742.8245-1-rdunlap@infradead.org>
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 <3da03251-21ac-b41f-593d-cbc9ac9f86f6@linux.ibm.com>
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From:   Christian Borntraeger <borntraeger@linux.ibm.com>
In-Reply-To: <3da03251-21ac-b41f-593d-cbc9ac9f86f6@linux.ibm.com>
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Am 22.06.23 um 14:16 schrieb Alexandra Winter:
> 
> 
> On 22.06.23 09:53, Simon Horman wrote:
>> On Thu, Jun 22, 2023 at 09:15:24AM +0200, Alexandra Winter wrote:
>>>
>>>
>>> On 21.06.23 23:37, Randy Dunlap wrote:
>>>> Require FDDI to be built-in if it is used. LCS needs FDDI to be
>>>> built-in to build without errors.
>>>>
>>>> Prevents these build errors:
>>>> s390-linux-ld: drivers/s390/net/lcs.o: in function `lcs_new_device':
>>>> drivers/s390/net/lcs.c:2150: undefined reference to `fddi_type_trans'
>>>> s390-linux-ld: drivers/s390/net/lcs.c:2151: undefined reference to `alloc_fddidev'
>>>>
>>>> This FDDI requirement effectively restores the previous condition
>>>> before the blamed patch, when #ifdef CONFIG_FDDI was used, without
>>>> testing for CONFIG_FDDI_MODULE.
>>>>
>>>> Fixes: 128272336120 ("s390/net: lcs: use IS_ENABLED() for kconfig detection")
> [...]
>>
>>> 2) I wonder whether
>>>
>>>    	depends on CCW && NETDEVICES && (ETHERNET || FDDI)
>>>   +	depends on FDDI || FDDI=n
>>>
>>> would do what we want here:
>>> When FDDI is a loadable module, LCS mustn't be built-in.
>>>
>>> I will do some experiments and let you know.
>>
>> It does seem to on my side.
>> But checking would be much appreciated.
>   
> 
> Here are my experiments:

Another suggestion. Why not remove the FDDI part of the lcs driver? This seems unused
without hardware for years now.Longterm we could even remove the whole lcs driver.