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tcp: make TCP_INFO more consistent 

tcp_get_info() has to lock the socket, so lets lock it
for an extended critical section, so that various fields
have consistent values.

This solves an annoying issue that some applications
reported when multiple counters are updated during one
particular rx/rx event, and TCP_INFO was called from
another cpu.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Eric Dumazet 2017-01-09 10:29:27 -08:00 committed by David S. Miller
parent c22e5c125b
commit b369e7fd41
1 changed files with 4 additions and 4 deletions
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8
net/ipv4/tcp.c
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@ -2766,6 +2766,9 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
info->tcpi_sacked = sk->sk_max_ack_backlog;
return;
}
slow = lock_sock_fast(sk);
info->tcpi_ca_state = icsk->icsk_ca_state;
info->tcpi_retransmits = icsk->icsk_retransmits;
info->tcpi_probes = icsk->icsk_probes_out;
@ -2816,15 +2819,11 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
info->tcpi_total_retrans = tp->total_retrans;
slow = lock_sock_fast(sk);
info->tcpi_bytes_acked = tp->bytes_acked;
info->tcpi_bytes_received = tp->bytes_received;
info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
tcp_get_info_chrono_stats(tp, info);
unlock_sock_fast(sk, slow);
info->tcpi_segs_out = tp->segs_out;
info->tcpi_segs_in = tp->segs_in;
@ -2840,6 +2839,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
do_div(rate64, intv);
info->tcpi_delivery_rate = rate64;
}
unlock_sock_fast(sk, slow);
}
EXPORT_SYMBOL_GPL(tcp_get_info);