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tcp: fix RFS vs lockless listeners

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Before recent TCP listener patches, we were updating listener
sk->sk_rxhash before the cloning of master socket.

children sk_rxhash was therefore correct after the normal 3WHS.

But with lockless listener, we no longer dirty/change listener sk_rxhash
as it would be racy.

We need to correctly update the child sk_rxhash, otherwise first data
packet wont hit correct cpu if RFS is used.

Fixes: 079096f103 ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Willem de Bruijn <willemb@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-10-08 11:16:48 -07:00 committed by David S. Miller
parent 5010ea59e1
commit 6bcfd7f8c2
2 changed files with 2 additions and 0 deletions
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1
net/ipv4/syncookies.c
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@ -225,6 +225,7 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
child = icsk->icsk_af_ops->syn_recv_sock(sk, skb, req, dst); child = icsk->icsk_af_ops->syn_recv_sock(sk, skb, req, dst);
if (child) { if (child) {
atomic_set(&req->rsk_refcnt, 1); atomic_set(&req->rsk_refcnt, 1);
sock_rps_save_rxhash(child, skb);
inet_csk_reqsk_queue_add(sk, req, child); inet_csk_reqsk_queue_add(sk, req, child);
} else { } else {
reqsk_free(req); reqsk_free(req);

1
net/ipv4/tcp_minisocks.c
View File

@ -768,6 +768,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
if (!child) if (!child)
goto listen_overflow; goto listen_overflow;
sock_rps_save_rxhash(child, skb);
tcp_synack_rtt_meas(child, req); tcp_synack_rtt_meas(child, req);
inet_csk_reqsk_queue_drop(sk, req); inet_csk_reqsk_queue_drop(sk, req);
inet_csk_reqsk_queue_add(sk, req, child); inet_csk_reqsk_queue_add(sk, req, child);