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From: Simon Horman <horms@kernel.org>
To: Pablo Neira Ayuso <pablo@netfilter.org>,
	 Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	 "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	 Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	 Nathan Chancellor <nathan@kernel.org>,
	 Nick Desaulniers <ndesaulniers@google.com>,
	 Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	 netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	 netdev@vger.kernel.org, llvm@lists.linux.dev
Subject: [PATCH nf-next 1/2] netfilter: conntrack: compile label helpers unconditionally
Date: Mon, 16 Sep 2024 16:14:41 +0100	[thread overview]
Message-ID: <20240916-ct-ifdef-v1-1-81ef1798143b@kernel.org> (raw)
In-Reply-To: <20240916-ct-ifdef-v1-0-81ef1798143b@kernel.org>

The condition on CONFIG_NF_CONNTRACK_LABELS being removed by
this patch guards compilation of non-trivial implementations
of ctnetlink_dump_labels() and ctnetlink_label_size().

However, this is not necessary as each of these functions
will always return 0 if CONFIG_NF_CONNTRACK_LABELS is not defined
as each function starts with the equivalent of:

	struct nf_conn_labels *labels = nf_ct_labels_find(ct);

	if (!labels)
		return 0;

And nf_ct_labels_find always returns NULL if CONFIG_NF_CONNTRACK_LABELS
is not enabled.  So I believe that the compiler optimises the code away
in such cases anyway.

Some advantages of this approach are:

1. Fewer #ifdefs, fewer headaches
2. The trivial implementations can be dropped
3. A follow-up patch, to conditionally compile ctnetlink_label_size
   only when it is used becomes simpler (see point 1)

Found by inspection.
Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
---
 net/netfilter/nf_conntrack_netlink.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 123e2e933e9b..f1f7dff08953 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -382,7 +382,6 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
 #define ctnetlink_dump_secctx(a, b) (0)
 #endif
 
-#ifdef CONFIG_NF_CONNTRACK_LABELS
 static inline int ctnetlink_label_size(const struct nf_conn *ct)
 {
 	struct nf_conn_labels *labels = nf_ct_labels_find(ct);
@@ -411,10 +410,6 @@ ctnetlink_dump_labels(struct sk_buff *skb, const struct nf_conn *ct)
 
 	return 0;
 }
-#else
-#define ctnetlink_dump_labels(a, b) (0)
-#define ctnetlink_label_size(a)	(0)
-#endif
 
 #define master_tuple(ct) &(ct->master->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
 

-- 
2.45.2


  reply	other threads:[~2024-09-16 15:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-16 15:14 [PATCH nf-next 0/2] netfilter: conntrack: label helpers conditional compilation updates Simon Horman
2024-09-16 15:14 ` Simon Horman [this message]
2024-09-16 15:14 ` [PATCH nf-next 2/2] netfilter: conntrack: conditionally compile ctnetlink_label_size Simon Horman
2024-09-16 15:29 ` [PATCH nf-next 0/2] netfilter: conntrack: label helpers conditional compilation updates Andy Shevchenko
2024-09-18 11:52 ` Pablo Neira Ayuso
2024-09-18 13:55   ` Andy Shevchenko
2024-09-18 14:29     ` Pablo Neira Ayuso
2024-09-18 17:01       ` Andy Shevchenko
2024-09-18 21:56         ` Pablo Neira Ayuso
2024-09-19  7:19           ` Simon Horman
2024-09-19  8:05             ` Pablo Neira Ayuso
2024-09-18 18:37   ` Simon Horman

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