From: Eric Dumazet <edumazet@google.com>
Date: Fri, 6 Mar 2026 15:43:22 +0000 (+0000)
Subject: tcp: avoid dst->ops->check() call in tcp_v{4,6}_do_rcv()
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=82f36517a13e6339ddd9737d8a310949e057e596;p=thirdparty%2Fkernel%2Flinux.git

tcp: avoid dst->ops->check() call in tcp_v{4,6}_do_rcv()

If incoming skb dst matches the socket cached one,
there is no need to call again dst->ops->check().

Network layer already validated the skb dst for us,
usually from tcp_v{4,6}_early_demux().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260306154322.1086539-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index f27995a645619..2ea8253b737ab 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1855,7 +1855,7 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 
 		sock_rps_save_rxhash(sk, skb);
 		sk_mark_napi_id(sk, skb);
-		if (dst) {
+		if (dst && unlikely(dst != skb_dst(skb))) {
 			if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
 			    !INDIRECT_CALL_1(dst->ops->check, ipv4_dst_check,
 					     dst, 0)) {
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 164dceb842af7..074b83c9a551f 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1596,7 +1596,7 @@ int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 
 		sock_rps_save_rxhash(sk, skb);
 		sk_mark_napi_id(sk, skb);
-		if (dst) {
+		if (dst && unlikely(dst != skb_dst(skb))) {
 			if (sk->sk_rx_dst_ifindex != skb->skb_iif ||
 			    INDIRECT_CALL_1(dst->ops->check, ip6_dst_check,
 					    dst, sk->sk_rx_dst_cookie) == NULL) {