tcp: only initialize sockcm tsflags field

wdebruij · kuba-moo · commit aaf6532d119d · 2025-02-18T18:27:19.000-08:00
TCP only reads the tsflags field. Don't bother initializing others. Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://patch.msgid.link/20250214222720.3205500-2-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
@@ -1127,7 +1127,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
 		/* 'common' sending to sendq */
 	}
 
-	sockcm_init(&sockc, sk);
+	sockc = (struct sockcm_cookie) { .tsflags = READ_ONCE(sk->sk_tsflags)};
 	if (msg->msg_controllen) {
 		err = sock_cmsg_send(sk, msg, &sockc);
 		if (unlikely(err)) {

Original file line number	Diff line number	Diff line change
`@@ -1127,7 +1127,7 @@ int tcp_sendmsg_locked(struct sock sk, struct msghdr msg, size_t size)`
`1127`	`1127`	`/* 'common' sending to sendq */`
`1128`	`1128`	`}`
`1129`	`1129`
`1130`		`- sockcm_init(&sockc, sk);`
	`1130`	`+ sockc = (struct sockcm_cookie) { .tsflags = READ_ONCE(sk->sk_tsflags)};`
`1131`	`1131`	`if (msg->msg_controllen) {`
`1132`	`1132`	`err = sock_cmsg_send(sk, msg, &sockc);`
`1133`	`1133`	`if (unlikely(err)) {`