]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
tcp: fix mishandling when the sack compression is deferred.
authorfuyuanli <fuyuanli@didiglobal.com>
Wed, 31 May 2023 08:01:50 +0000 (16:01 +0800)
committerPaolo Abeni <pabeni@redhat.com>
Thu, 1 Jun 2023 11:15:12 +0000 (13:15 +0200)
commit30c6f0bf9579debce27e45fac34fdc97e46acacc
tree50ea5008b9efe2d98f6768a7cc6a1c0178b5fb16
parent4d56304e5827c8cc8cc18c75343d283af7c4825c
tcp: fix mishandling when the sack compression is deferred.

In this patch, we mainly try to handle sending a compressed ack
correctly if it's deferred.

Here are more details in the old logic:
When sack compression is triggered in the tcp_compressed_ack_kick(),
if the sock is owned by user, it will set TCP_DELACK_TIMER_DEFERRED
and then defer to the release cb phrase. Later once user releases
the sock, tcp_delack_timer_handler() should send a ack as expected,
which, however, cannot happen due to lack of ICSK_ACK_TIMER flag.
Therefore, the receiver would not sent an ack until the sender's
retransmission timeout. It definitely increases unnecessary latency.

Fixes: 5d9f4262b7ea ("tcp: add SACK compression")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: fuyuanli <fuyuanli@didiglobal.com>
Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://lore.kernel.org/netdev/20230529113804.GA20300@didi-ThinkCentre-M920t-N000/
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230531080150.GA20424@didi-ThinkCentre-M920t-N000
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
include/net/tcp.h
net/ipv4/tcp_input.c
net/ipv4/tcp_timer.c