Subject: Re: [PATCH] bridge: only provide proxy ARP when CONFIG_INET is enabled

From: David Ahern <[email-masked]>
Date: Tue, 13 Jan 2015 14:14:20 -0700

On 1/13/15 1:57 PM, David Miller wrote:
> From: Cong Wang <[email-masked]>
> Date: Tue, 13 Jan 2015 11:25:45 -0800
>
>> On Tue, Jan 13, 2015 at 6:10 AM, Arnd Bergmann <[email-masked]> wrote:
>>> When IPV4 support is disabled, we cannot call arp_send from
>>> the bridge code, which would result in a kernel link error:
>>>
>>> net/built-in.o: In function `br_handle_frame_finish':
>>> :(.text+0x59914): undefined reference to `arp_send'
>>> :(.text+0x59a50): undefined reference to `arp_tbl'
>>>
>>> This makes the newly added proxy ARP support in the bridge
>>> code depend on the CONFIG_INET symbol and lets the compiler
>>> optimize the code out to avoid the link error.
>>>
>>
>> Not sure how much sense to make CONFIG_BRIDGE depend
>> on CONFIG_INET, at least CONFIG_BONDING does.
>
> It depends upon whether we want to provide and consider
> as a valid configuration bridging without INET.  Probably
> we do.

Rather than connect CONFIG_BRIDGE to CONFIG_INET, why not make 
br_do_proxy_arp (and setting BR_PROXYARP flag) a no-op if CONFIG_INET is 
not set?

#ifdef CONFIG_INET
#else
static inline void br_do_proxy_arp(...args...)
{
}
#endif

That covers both arp_tbl and arp_send.

David