tcp: Replace min_tso_segs() with tso_segs() CC callback

Browse source

This patch replaces the existing min_tso_segs() callback with a new
tso_segs() callback, allowing congestion control algorithms to provide
an explicit TSO segment count for each data burst and bypass
tcp_tso_autosize(). The resulting tso_segs value is clamped to
[1, sk->sk_gso_max_segs], preventing congestion-control implementations
from returning an invalid zero-segment value.

This change has the following impacts on BPF struct_ops users:
- The callback is renamed from min_tso_segs() to tso_segs()
- The signature gains an extra u32 mss_now argument
- The return value semantics is changed from "floor value passed into
  tcp_tso_autosize()" to "final tso_segs value", bypassing autosizing

As a result, existing BPF programs must be updated, because returning a
small constant will now directly limit the final tso_segs value instead
of specifying the minimum value passed to tcp_tso_autosize().

Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Signed-off-by: Ilpo Järvinen <ij@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Chia-Yu Chang 2026-08-31 18:52:29 +02:00 • committed by Jakub Kicinski

parent 9eab111e76

commit cb145191e9

5 changed files with 38 additions and 20 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

15

include/net/tcp.h

View file

4

net/ipv4/bpf_tcp_ca.c

View file

13

net/ipv4/tcp_bbr.c

View file

18

net/ipv4/tcp_output.c

View file

8

tools/testing/selftests/bpf/progs/tcp_ca_kfunc.c

View file