Commit 97d7ae6e authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: inet6_csk_xmit() optimization 



After prior patches, inet6_csk_xmit() can reuse inet->cork.fl.u.ip6
if __sk_dst_check() returns a valid dst.

Otherwise call inet6_csk_route_socket() to refresh inet->cork.fl.u.ip6
content and get a new dst.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260206173426.1638518-8-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a6eee39c

net/ipv6/inet6_connection_sock.c

+15 −15
Original line number Diff line number Diff line
@@ -81,13 +81,11 @@ static struct dst_entry *inet6_csk_route_socket(struct sock *sk, 
	final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &np->final);

	rcu_read_unlock();



	dst = __sk_dst_check(sk, np->dst_cookie);

	if (!dst) {

	dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p);



	if (!IS_ERR(dst))

		ip6_dst_store(sk, dst, false, false);

	}



	return dst;

}
@@ -98,6 +96,8 @@ int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused 
	struct dst_entry *dst;

	int res;



	dst = __sk_dst_check(sk, np->dst_cookie);

	if (unlikely(!dst)) {

		dst = inet6_csk_route_socket(sk, fl6);

		if (IS_ERR(dst)) {

			WRITE_ONCE(sk->sk_err_soft, -PTR_ERR(dst));
@@ -105,13 +105,13 @@ int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused 
			kfree_skb(skb);

			return PTR_ERR(dst);

		}

		/* Restore final destination back after routing done */

		fl6->daddr = sk->sk_v6_daddr;

	}



	rcu_read_lock();

	skb_dst_set_noref(skb, dst);



	/* Restore final destination back after routing done */

	fl6->daddr = sk->sk_v6_daddr;



	res = ip6_xmit(sk, skb, fl6, sk->sk_mark, rcu_dereference(np->opt),

		       np->tclass, READ_ONCE(sk->sk_priority));

	rcu_read_unlock();