diff mbox series

[net-next,v3,2/3] net: tcp: allow zero-window ACK update the window

Message ID 20230808115835.2862058-3-imagedong@tencent.com
State New
Headers
Series net: tcp: support probing OOM |

Commit Message

Menglong Dong Aug. 8, 2023, 11:58 a.m. UTC 
  From: Menglong Dong <imagedong@tencent.com>

Fow now, an ACK can update the window in following case, according to
the tcp_may_update_window():

1. the ACK acknowledged new data
2. the ACK has new data
3. the ACK expand the window and the seq of it is valid

Now, we allow the ACK update the window if the window is 0, and the
seq/ack of it is valid. This is for the case that the receiver replies
an zero-window ACK when it is under memory stress and can't queue the new
data.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 net/ipv4/tcp_input.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2ac059483410..d34d52fdfdb1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3525,7 +3525,7 @@  static inline bool tcp_may_update_window(const struct tcp_sock *tp,
 {
 	return	after(ack, tp->snd_una) ||
 		after(ack_seq, tp->snd_wl1) ||
-		(ack_seq == tp->snd_wl1 && nwin > tp->snd_wnd);
+		(ack_seq == tp->snd_wl1 && (nwin > tp->snd_wnd || !nwin));
 }
 
 /* If we update tp->snd_una, also update tp->bytes_acked */