Re: [PATCH v5 bpf-next 05/11] tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues.

[Martin KaFai Lau]

On Mon, May 10, 2021 at 12:44:27PM +0900, Kuniyuki Iwashima wrote:
> diff --git a/net/core/request_sock.c b/net/core/request_sock.c
> index f35c2e998406..7879a3660c52 100644
> --- a/net/core/request_sock.c
> +++ b/net/core/request_sock.c
> @@ -130,3 +130,42 @@ void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
>  out:
>  	spin_unlock_bh(&fastopenq->lock);
>  }
> +
> +struct request_sock *reqsk_clone(struct request_sock *req, struct sock *sk)
> +{
> +	struct sock *req_sk, *nreq_sk;
> +	struct request_sock *nreq;
> +
> +	nreq = kmem_cache_alloc(req->rsk_ops->slab, GFP_ATOMIC | __GFP_NOWARN);
> +	if (!nreq) {
> +		/* paired with refcount_inc_not_zero() in reuseport_migrate_sock() */
> +		sock_put(sk);
> +		return NULL;
> +	}
> +
> +	req_sk = req_to_sk(req);
> +	nreq_sk = req_to_sk(nreq);
> +
> +	memcpy(nreq_sk, req_sk,
> +	       offsetof(struct sock, sk_dontcopy_begin));
> +	memcpy(&nreq_sk->sk_dontcopy_end, &req_sk->sk_dontcopy_end,
> +	       req->rsk_ops->obj_size - offsetof(struct sock, sk_dontcopy_end));
> +
> +	sk_node_init(&nreq_sk->sk_node);
> +	nreq_sk->sk_tx_queue_mapping = req_sk->sk_tx_queue_mapping;
> +#ifdef CONFIG_XPS
> +	nreq_sk->sk_rx_queue_mapping = req_sk->sk_rx_queue_mapping;
> +#endif
> +	nreq_sk->sk_incoming_cpu = req_sk->sk_incoming_cpu;
> +	refcount_set(&nreq_sk->sk_refcnt, 0);
> +
> +	nreq->rsk_listener = sk;
> +
> +	/* We need not acquire fastopenq->lock
> +	 * because the child socket is locked in inet_csk_listen_stop().
> +	 */
> +	if (tcp_rsk(nreq)->tfo_listener)
Should IPPROTO_TCP be tested first like other similar situations
in inet_connection_sock.c?

Also, reqsk_clone() is only used in inet_connection_sock.c.
Can it be moved to inet_connection_sock.c instead and renamed to
inet_reqsk_clone()?