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authorFlorian Westphal <fw@strlen.de>2016-11-21 14:18:38 +0100
committerDavid S. Miller <davem@davemloft.net>2016-11-21 19:20:17 +0100
commite97991832a4ea4a5f47d65f068a4c966a2eb5730 (patch)
tree870e5c09c37890d286872c9ae22382d6bf336b37 /net/ipv4/tcp_input.c
parenttcp: add cwnd_undo functions to various tcp cc algorithms (diff)
downloadlinux-e97991832a4ea4a5f47d65f068a4c966a2eb5730.tar.xz
linux-e97991832a4ea4a5f47d65f068a4c966a2eb5730.zip
tcp: make undo_cwnd mandatory for congestion modules
The undo_cwnd fallback in the stack doubles cwnd based on ssthresh, which un-does reno halving behaviour. It seems more appropriate to let congctl algorithms pair .ssthresh and .undo_cwnd properly. Add a 'tcp_reno_undo_cwnd' function and wire it up for all congestion algorithms that used to rely on the fallback. Cc: Eric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a70046fea0e8..22e6a2097ff6 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2394,10 +2394,7 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss)
if (tp->prior_ssthresh) {
const struct inet_connection_sock *icsk = inet_csk(sk);
- if (icsk->icsk_ca_ops->undo_cwnd)
- tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk);
- else
- tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh << 1);
+ tp->snd_cwnd = icsk->icsk_ca_ops->undo_cwnd(sk);
if (tp->prior_ssthresh > tp->snd_ssthresh) {
tp->snd_ssthresh = tp->prior_ssthresh;