tcp: fix rate_app_limited to default to 1

The initial default value of 0 for tp->rate_app_limited was incorrect,
since a flow is indeed application-limited until it first sends
data. Fixing the default to be 1 is generally correct but also
specifically will help user-space applications avoid using the initial
tcpi_delivery_rate value of 0 that persists until the connection has
some non-zero bandwidth sample.

Fixes: eb8329e0a04d ("tcp: export data delivery rate")
Suggested-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David Morley <morleyd@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Tested-by: David Morley <morleyd@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c567d5e8053e0c2668196d8a0c9afc6494d8f972..33f559f491c8cfd1a66a6f58c7b4a8a19ffa6b4f 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -435,6 +435,7 @@ void tcp_init_sock(struct sock *sk)
 
        /* There's a bubble in the pipe until at least the first ACK. */
        tp->app_limited = ~0U;
+       tp->rate_app_limited = 1;
 
        /* See draft-stevens-tcpca-spec-01 for discussion of the
         * initialization of these values.
@@ -3178,6 +3179,7 @@ int tcp_disconnect(struct sock *sk, int flags)
        tp->plb_rehash = 0;
        /* There's a bubble in the pipe until at least the first ACK. */
        tp->app_limited = ~0U;
+       tp->rate_app_limited = 1;
        tp->rack.mstamp = 0;
        tp->rack.advanced = 0;
        tp->rack.reo_wnd_steps = 1;