netdev - [PATCH net-next] netfilter: nft_payload: Use csum

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Message-ID: <e98467a942d65d2dc45dcf8ff809b43d4a3769eb.1754992552.git.christophe.leroy@csgroup.eu>
Date: Tue, 12 Aug 2025 11:58:43 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Pablo Neira Ayuso <pablo@...filter.org>,
	Jozsef Kadlecsik <kadlec@...filter.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
	netfilter-devel@...r.kernel.org,
	coreteam@...filter.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH net-next] netfilter: nft_payload: Use csum_replace4() instead of opencoding

Open coded calculation can be avoided and replaced by the
equivalent csum_replace4() in nft_csum_replace().

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 net/netfilter/nft_payload.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 7dfc5343dae46..e279b54ed7116 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -684,7 +684,7 @@ static const struct nft_expr_ops nft_payload_inner_ops = {
 
 static inline void nft_csum_replace(__sum16 *sum, __wsum fsum, __wsum tsum)
 {
-	*sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), fsum), tsum));
+	csum_replace4(sum, fsum, tsum);
 	if (*sum == 0)
 		*sum = CSUM_MANGLED_0;
 }
-- 
2.49.0