tcp: use correct counters in CA_CWR state too

As CWR is stronger than CA_Disorder state, we can miscount
SACK/Reno failure into other timeouts. Not a bad problem as
it can happen only due to ECN, FRTO detecting spurious RTO
or xmit error which are the only callers of tcp_enter_cwr.
And even then losses and RTO must still follow thereafter
to actually end up into the relevant code paths.

Compile tested.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 6 deletions

diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index f3c8c6c019ae..74a6aa003657 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -367,18 +367,19 @@ void tcp_retransmit_timer(struct sock *sk)
         if (icsk->icsk_retransmits == 0) {
                 int mib_idx;
 
-                if (icsk->icsk_ca_state == TCP_CA_Disorder) {
-                        if (tcp_is_sack(tp))
-                                mib_idx = LINUX_MIB_TCPSACKFAILURES;
-                        else
-                                mib_idx = LINUX_MIB_TCPRENOFAILURES;
-                } else if (icsk->icsk_ca_state == TCP_CA_Recovery) {
+                if (icsk->icsk_ca_state == TCP_CA_Recovery) {
                         if (tcp_is_sack(tp))
                                 mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL;
                         else
                                 mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL;
                 } else if (icsk->icsk_ca_state == TCP_CA_Loss) {
                         mib_idx = LINUX_MIB_TCPLOSSFAILURES;
+                } else if ((icsk->icsk_ca_state == TCP_CA_Disorder) ||
+                           tp->sacked_out) {
+                        if (tcp_is_sack(tp))
+                                mib_idx = LINUX_MIB_TCPSACKFAILURES;
+                        else
+                                mib_idx = LINUX_MIB_TCPRENOFAILURES;
                 } else {
                         mib_idx = LINUX_MIB_TCPTIMEOUTS;
                 }