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Commit b369e7fd authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c22e5c12

net/ipv4/tcp.c

+4 −4
Original line number Diff line number Diff line
@@ -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);