From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit 372022830b06d9980c7e8b41fa0a4081cff883b0 upstream.
There are some cases where rtt_us derives from deltas of jiffies,
instead of using usec timestamps.
Since we want to track minimal rtt, better to assume a delta of 0 jiffie
might be in fact be very close to 1 jiffie.
It is kind of sad jiffies_to_usecs(1) calls a function instead of simply
using a constant.
Fixes: f672258391b42 ("tcp: track min RTT using windowed min-filter")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Neal Cardwell <ncardwell@xxxxxxxxxx>
Cc: Yuchung Cheng <ycheng@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_input.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2926,7 +2926,10 @@ static void tcp_update_rtt_min(struct so
{
const u32 now = tcp_time_stamp, wlen = sysctl_tcp_min_rtt_wlen * HZ;
struct rtt_meas *m = tcp_sk(sk)->rtt_min;
- struct rtt_meas rttm = { .rtt = (rtt_us ? : 1), .ts = now };
+ struct rtt_meas rttm = {
+ .rtt = likely(rtt_us) ? rtt_us : jiffies_to_usecs(1),
+ .ts = now,
+ };
u32 elapsed;
/* Check if the new measurement updates the 1st, 2nd, or 3rd choices */
