From acb4a6bfc80ddeea4c44074dd630f916259e909e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 6 Oct 2015 14:49:58 -0700 Subject: [PATCH] tcp: ensure prior synack rtx behavior with small backlogs Some applications use a listen() backlog of 1. Prior kernels were silently enforcing a qlen_log of 4, so that we were sending up to /proc/sys/net/ipv4/tcp_synack_retries SYNACK messages. Fixes: ef547f2ac16b ("tcp: remove max_qlen_log") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/inet_connection_sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 89eedfb..514b9e9 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -579,7 +579,7 @@ static void reqsk_timer_handler(unsigned long data) * ones are about to clog our table. */ qlen = reqsk_queue_len(queue); - if ((qlen << 1) > sk_listener->sk_max_ack_backlog) { + if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) { int young = reqsk_queue_len_young(queue) << 1; while (thresh > 2) { -- 2.7.4