[PATCH v2 net-next 3/3] tcp: make tcp_v{4,6}_send_check() static
From: Eric Dumazet <edumazet@google.com>
Date: 2026-02-23 10:07:36
Subsystem:
networking [general], networking [mptcp], networking [tcp], networking [tls], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthieu Baerts, Mat Martineau, Neal Cardwell, John Fastabend, Sabrina Dubroca, Linus Torvalds
tcp_v{4,6}_send_check() are only called from tcp_output.c
and should be made static so that the compiler does not need
to put an out of line copy of them.
Remove (struct inet_connection_sock_af_ops) send_check field
and use instead @net_header_len.
Move @net_header_len close to @queue_xmit for data locality
as both are used in TCP tx fast path.
$ scripts/bloat-o-meter -t vmlinux.2 vmlinux.3
add/remove: 0/2 grow/shrink: 0/3 up/down: 0/-172 (-172)
Function old new delta
__tcp_transmit_skb 3426 3423 -3
tcp_v4_send_check 136 132 -4
mptcp_subflow_init 777 763 -14
__pfx_tcp_v6_send_check 16 - -16
tcp_v6_send_check 135 - -135
Total: Before=25143196, After=25143024, chg -0.00%
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
include/net/inet_connection_sock.h | 3 +--
include/net/tcp.h | 3 ---
net/ipv4/tcp_ipv4.c | 1 -
net/ipv4/tcp_output.c | 8 +++-----
net/ipv6/tcp_ipv6.c | 2 --
net/mptcp/subflow.c | 1 -
net/tls/tls_device_fallback.c | 3 ---
7 files changed, 4 insertions(+), 17 deletions(-)
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index ecb362025c4e5183ec78aef4b45c249da87c19ea..bbc9355871c767b51e3d1a4d2436022a8556416c 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h@@ -34,7 +34,7 @@ struct tcp_congestion_ops; */ struct inet_connection_sock_af_ops { int (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl); - void (*send_check)(struct sock *sk, struct sk_buff *skb); + u16 net_header_len; int (*rebuild_header)(struct sock *sk); void (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb); int (*conn_request)(struct sock *sk, struct sk_buff *skb);
@@ -43,7 +43,6 @@ struct inet_connection_sock_af_ops { struct dst_entry *dst, struct request_sock *req_unhash, bool *own_req); - u16 net_header_len; int (*setsockopt)(struct sock *sk, int level, int optname, sockptr_t optval, unsigned int optlen); int (*getsockopt)(struct sock *sk, int level, int optname,
diff --git a/include/net/tcp.h b/include/net/tcp.h
index feaddce9d80523a9e7bd9db4c691736859c48c91..dfcd38089f113389b82d90e5f45a54a618f2d590 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h@@ -531,7 +531,6 @@ u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, * TCP v4 functions exported for the inet6 API */ -void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); void tcp_v4_mtu_reduced(struct sock *sk); void tcp_req_err(struct sock *sk, u32 seq, bool abort); void tcp_ld_RTO_revert(struct sock *sk, u32 seq);
@@ -1132,8 +1131,6 @@ static inline int tcp_v6_sdif(const struct sk_buff *skb) extern const struct inet_connection_sock_af_ops ipv6_specific; -void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb); - INDIRECT_CALLABLE_DECLARE(int tcp_v6_rcv(struct sk_buff *skb)); void tcp_v6_early_demux(struct sk_buff *skb);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index da708aff06230615bdc9cc19fcd8b2bd91462eff..bd613e401d4865dcb658409b7a54d1a77e1e065c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -2405,7 +2405,6 @@ EXPORT_IPV6_MOD(inet_sk_rx_dst_set); const struct inet_connection_sock_af_ops ipv4_specific = { .queue_xmit = ip_queue_xmit, - .send_check = tcp_v4_send_check, .rebuild_header = inet_sk_rebuild_header, .sk_rx_dst_set = inet_sk_rx_dst_set, .conn_request = tcp_v4_conn_request,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index fdddb16630a5108607496bfdc4d603baa43de621..1ef419c66a0ebad6422be73a57afaba044467148 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c@@ -1498,22 +1498,20 @@ INDIRECT_CALLABLE_DECLARE(int ip_queue_xmit(struct sock *sk, struct sk_buff *skb INDIRECT_CALLABLE_DECLARE(int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)); /* This routine computes an IPv4 TCP checksum. */ -void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) +static void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) { const struct inet_sock *inet = inet_sk(sk); __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); } -EXPORT_IPV6_MOD(tcp_v4_send_check); #if IS_ENABLED(CONFIG_IPV6) #include <net/ip6_checksum.h> -void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb) +static void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb) { __tcp_v6_send_check(skb, &sk->sk_v6_rcv_saddr, &sk->sk_v6_daddr); } -EXPORT_IPV6_MOD(tcp_v6_send_check); #endif /* This routine actually transmits TCP packets queued in by
@@ -1678,7 +1676,7 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, bpf_skops_write_hdr_opt(sk, skb, NULL, NULL, 0, &opts); #if IS_ENABLED(CONFIG_IPV6) - if (likely(icsk->icsk_af_ops->send_check == tcp_v6_send_check)) + if (likely(icsk->icsk_af_ops->net_header_len == sizeof(struct ipv6hdr))) tcp_v6_send_check(sk, skb); else #endif
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 306ca0585b4a60fcaafcbc9656a5fe36ad21d1b2..f17da56b449ef30675469e033e0173059791443f 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c@@ -2017,7 +2017,6 @@ static struct timewait_sock_ops tcp6_timewait_sock_ops = { const struct inet_connection_sock_af_ops ipv6_specific = { .queue_xmit = inet6_csk_xmit, - .send_check = tcp_v6_send_check, .rebuild_header = inet6_sk_rebuild_header, .sk_rx_dst_set = inet6_sk_rx_dst_set, .conn_request = tcp_v6_conn_request,
@@ -2049,7 +2048,6 @@ static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = { */ static const struct inet_connection_sock_af_ops ipv6_mapped = { .queue_xmit = ip_queue_xmit, - .send_check = tcp_v4_send_check, .rebuild_header = inet_sk_rebuild_header, .sk_rx_dst_set = inet_sk_rx_dst_set, .conn_request = tcp_v6_conn_request,
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index f66129f1e649248e00215d254c925f66c3fffa6a..dd79c5b37a6b62750b62443d911c9fedd67d9d17 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c@@ -2190,7 +2190,6 @@ void __init mptcp_subflow_init(void) subflow_v6m_specific = subflow_v6_specific; subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; - subflow_v6m_specific.send_check = ipv4_specific.send_check; subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; subflow_v6m_specific.rebuild_header = subflow_rebuild_header;
diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c
index 03d508a45aaee9218bb2deed542534785f2019d6..de7d86bdd7ec99df5be4215ff79dbd5e86e49934 100644
--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c@@ -149,9 +149,6 @@ static int tls_enc_records(struct aead_request *aead_req, return rc; } -/* Can't use icsk->icsk_af_ops->send_check here because the ip addresses - * might have been changed by NAT. - */ static void update_chksum(struct sk_buff *skb, int headln) { struct tcphdr *th = tcp_hdr(skb);
--
2.53.0.345.g96ddfc5eaa-goog