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Date: Sun, 17 Oct 2021 15:48:16 +0200
From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Lukas Wunner <lukas@wunner.de>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>,
	Florian Westphal <fw@strlen.de>, netfilter-devel@vger.kernel.org,
	coreteam@netfilter.org, llvm@lists.linux.dev,
	kbuild-all@lists.01.org, linux-mm@kvack.org,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: Re: [PATCH nf-next] netfilter: core: Fix clang warnings about unused
 static inlines
Message-ID: <YWwpoI7DmT31GRW+@salvia>
References: <202110160632.WzahPgao-lkp@intel.com>
 <7bc9f3ee15533d170bc412d6bcdd122632af169d.1634370995.git.lukas@wunner.de>
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In-Reply-To: <7bc9f3ee15533d170bc412d6bcdd122632af169d.1634370995.git.lukas@wunner.de>

On Sat, Oct 16, 2021 at 10:13:27AM +0200, Lukas Wunner wrote:
> Unlike gcc, clang warns about unused static inlines that are not in an
> include file:
> 
>   net/netfilter/core.c:344:20: error: unused function 'nf_ingress_hook' [-Werror,-Wunused-function]
>   static inline bool nf_ingress_hook(const struct nf_hook_ops *reg, int pf)
>                      ^
>   net/netfilter/core.c:353:20: error: unused function 'nf_egress_hook' [-Werror,-Wunused-function]
>   static inline bool nf_egress_hook(const struct nf_hook_ops *reg, int pf)
>                      ^
> 
> According to commit 6863f5643dd7 ("kbuild: allow Clang to find unused
> static inline functions for W=1 build"), the proper resolution is to
> mark the affected functions as __maybe_unused.  An alternative approach
> would be to move them to include/linux/netfilter_netdev.h, but since
> Pablo didn't do that in commit ddcfa710d40b ("netfilter: add
> nf_ingress_hook() helper function"), I'm guessing __maybe_unused is
> preferred.
> 
> This fixes both the warning introduced by Pablo in v5.10 as well as the
> one recently introduced by myself with commit 42df6e1d221d ("netfilter:
> Introduce egress hook").

Applied, thanks.