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| author | Yuchung Cheng <ycheng@google.com> | 2017-12-07 11:33:30 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-08 14:14:11 -0500 |
| commit | 0ce294d88457bccd7f9991f883fec80022a1ddbd (patch) | |
| tree | 9b4bb1c98c751b01b0f06fded0e3db0e403b5cfc /net | |
| parent | 2edbdb3159d6f6bd3a9b6e7f789f2b879699a519 (diff) | |
| download | lwn-0ce294d88457bccd7f9991f883fec80022a1ddbd.tar.gz lwn-0ce294d88457bccd7f9991f883fec80022a1ddbd.zip | |
tcp: correctly test congestion state in RACK
RACK does not test the loss recovery state correctly to compute
the reordering window. It assumes if lost_out is zero then TCP is
not in loss recovery. But it can be zero during recovery before
calling tcp_rack_detect_loss(): when an ACK acknowledges all
packets marked lost before receiving this ACK, but has not yet
to discover new ones by tcp_rack_detect_loss(). The fix is to
simply test the congestion state directly.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_recovery.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c index d3ea89020c69..3143664902e9 100644 --- a/net/ipv4/tcp_recovery.c +++ b/net/ipv4/tcp_recovery.c @@ -55,7 +55,8 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout) * to queuing or delayed ACKs. */ reo_wnd = 1000; - if ((tp->rack.reord || !tp->lost_out) && min_rtt != ~0U) { + if ((tp->rack.reord || inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery) && + min_rtt != ~0U) { reo_wnd = max((min_rtt >> 2) * tp->rack.reo_wnd_steps, reo_wnd); reo_wnd = min(reo_wnd, tp->srtt_us >> 3); } |