[PATCH v2 net-next 1/3] tcp: inline __tcp_v4_send_check()
From: Eric Dumazet <edumazet@google.com>
Date: 2026-02-23 10:07:33
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
Inline __tcp_v4_send_check(), like __tcp_v6_send_check(). Move tcp_v4_send_check() to tcp_output.c close to its fast path caller (__tcp_transmit_skb()). Note __tcp_v4_send_check() is still out-of-line for tcp4_gso_segment() because it is called in an unlikely() section. $ scripts/bloat-o-meter -t vmlinux.0 vmlinux.1 add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-9 (-9) Function old new delta __tcp_v4_send_check 130 121 -9 Total: Before=25143100, After=25143091, chg -0.00% Signed-off-by: Eric Dumazet <edumazet@google.com> --- include/net/tcp.h | 10 +++++++++- net/ipv4/tcp_ipv4.c | 18 ------------------ net/ipv4/tcp_output.c | 10 +++++++++- 3 files changed, 18 insertions(+), 20 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 40e72b9cb85f08714d3f458c0bd1402a5fb1eb4e..3c84433f3d57b1bb29b10f41a5d9981145134237 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h@@ -2382,7 +2382,15 @@ void tcp_gro_complete(struct sk_buff *skb); static inline void tcp_gro_complete(struct sk_buff *skb) { } #endif -void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); +static inline void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, + __be32 daddr) +{ + struct tcphdr *th = tcp_hdr(skb); + + th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = offsetof(struct tcphdr, check); +} static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) {
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 6264fc0b2be53854598d7c37ce1c7928d2e0b507..da708aff06230615bdc9cc19fcd8b2bd91462eff 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -661,24 +661,6 @@ int tcp_v4_err(struct sk_buff *skb, u32 info) return 0; } -void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) -{ - struct tcphdr *th = tcp_hdr(skb); - - th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); - skb->csum_start = skb_transport_header(skb) - skb->head; - skb->csum_offset = offsetof(struct tcphdr, check); -} - -/* This routine computes an IPv4 TCP checksum. */ -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); - #define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32)) static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 326b58ff1118d02fc396753d56f210f9d3007c7f..29056d6fc787ec4ad4e3126634e5d52dacf6d700 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c@@ -1496,7 +1496,15 @@ static void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb) INDIRECT_CALLABLE_DECLARE(int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)); INDIRECT_CALLABLE_DECLARE(int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)); -INDIRECT_CALLABLE_DECLARE(void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)); + +/* This routine computes an IPv4 TCP checksum. */ +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); /* This routine actually transmits TCP packets queued in by * tcp_do_sendmsg(). This is used by both the initial
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2.53.0.345.g96ddfc5eaa-goog