Re: [PATCH] netfilter: turn NF_HOOK into an inline function

From: Eric W. Biederman
Date: Fri Oct 09 2015 - 14:30:40 EST


Arnd Bergmann <arnd@xxxxxxxx> writes:

> On Friday 09 October 2015 21:03:57 kbuild test robot wrote:
>> ^1da177e Linus Torvalds 2005-04-16 818 cb->rt_flags &= ~DN_RT_F_IE;
>> ^1da177e Linus Torvalds 2005-04-16 819 if (rt->rt_flags & RTCF_DOREDIRECT)
>> ^1da177e Linus Torvalds 2005-04-16 820 cb->rt_flags |= DN_RT_F_IE;
>> ^1da177e Linus Torvalds 2005-04-16 821
>> 29a26a56 Eric W. Biederman 2015-09-15 822 return NF_HOOK(NFPROTO_DECNET, NF_DN_FORWARD,
>> 29a26a56 Eric W. Biederman 2015-09-15 @823 &init_net, NULL, skb, dev, skb->dev,
>> 8f40b161 David S. Miller 2011-07-17 824 dn_to_neigh_output);
>> ^1da177e Linus Torvalds 2005-04-16 825
>> ^1da177e Linus Torvalds 2005-04-16 826 drop:
>>
>
> Ah, right. The 'dev' variable here is declared as
>
> #ifdef CONFIG_NETFILTER
> struct net_device *dev = skb->dev;
> #endif
>
> Apparently because the code produced the same warning as the ipv6 code.
>
> Removing the #ifdef here would make that code nicer and let us use
> my patch. Alternatively we could put the same #ifdef into IPV6 and
> not use the inline function.

Compilers are good at removing unused variabes (SSA should guarantee
this will always happen), and #ifdefs sucks. I vote for your inline.
Especially as the case that is actively used and tested
(CONFIG_NETFILTER) has these two functions as inline functions.

Eric
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