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Date:   Tue, 2 Feb 2021 08:29:09 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Leon Romanovsky <leon@kernel.org>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Leon Romanovsky <leonro@nvidia.com>, coreteam@netfilter.org,
        Eric Dumazet <edumazet@google.com>,
        Florian Westphal <fw@strlen.de>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Jozsef Kadlecsik <kadlec@netfilter.org>,
        Julian Anastasov <ja@ssi.bg>, linux-kernel@vger.kernel.org,
        lvs-devel@vger.kernel.org, Matteo Croce <mcroce@redhat.com>,
        netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
        Simon Horman <horms@verge.net.au>
Subject: Re: [PATCH net 1/4] ipv6: silence compilation warning for non-IPV6
 builds
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In-Reply-To: <20210202135544.3262383-2-leon@kernel.org>
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        <20210202135544.3262383-2-leon@kernel.org>
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On Tue,  2 Feb 2021 15:55:41 +0200 Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> The W=1 compilation of allmodconfig generates the following warning:
> 
> net/ipv6/icmp.c:448:6: warning: no previous prototype for 'icmp6_send' [-Wmissing-prototypes]
>   448 | void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
>       |      ^~~~~~~~~~
> 
> In such configuration, the icmp6_send() is not used outside of icmp.c, so close
> its EXPORT_SYMBOL and add "static" word to limit the scope.
> 
> Fixes: cc7a21b6fbd9 ("ipv6: icmp6: avoid indirect call for icmpv6_send()")
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

That's a little much ifdefinery, why not move the declaration from
under the ifdef in the header instead?

If you repost please target net-next, admittedly these fixes are pretty
"obviously correct" but they are not urgent either.

> diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
> index f3d05866692e..5d4232b492dc 100644
> --- a/net/ipv6/icmp.c
> +++ b/net/ipv6/icmp.c
> @@ -445,6 +445,9 @@ static int icmp6_iif(const struct sk_buff *skb)
>  /*
>   *	Send an ICMP message in response to a packet in error
>   */
> +#if !IS_BUILTIN(CONFIG_IPV6)
> +static
> +#endif
>  void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
>  		const struct in6_addr *force_saddr)
>  {
> @@ -634,7 +637,10 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info,
>  out_bh_enable:
>  	local_bh_enable();
>  }
> +
> +#if IS_BUILTIN(CONFIG_IPV6)
>  EXPORT_SYMBOL(icmp6_send);
> +#endif
> 
>  /* Slightly more convenient version of icmp6_send.
>   */
> --
> 2.29.2
>