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32b0b89533
When an 802.3ad (LACP) bonding interface has no slaves in the
collecting/distributing state, the bonding master still reports
carrier as up as long as at least 'min_links' slaves have carrier.
In this situation, only one slave is effectively used for TX/RX,
while traffic received on other slaves is dropped. Upper-layer
daemons therefore consider the interface operational, even though
traffic may be blackholed if the lack of LACP negotiation means
the partner is not ready to deal with traffic.
Introduce a configuration knob to control this behavior. It allows
the bonding master to assert carrier only when at least 'min_links'
slaves are in Collecting_Distributing state.
The default mode preserves the existing behavior. This patch only
introduces the knob; its behavior is implemented in the subsequent
commit.
Fixes: 655f8919d5 ("bonding: add min links parameter to 802.3ad")
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
Acked-by: Jay Vosburgh <jv@jvosburgh.net>
Link: https://patch.msgid.link/20260603150331.1919611-4-louis.scalbert@6wind.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Why we want a copy of kernel headers in tools?
==============================================
There used to be no copies, with tools/ code using kernel headers
directly. From time to time tools/perf/ broke due to legitimate kernel
hacking. At some point Linus complained about such direct usage. Then we
adopted the current model.
The way these headers are used in perf are not restricted to just
including them to compile something.
There are sometimes used in scripts that convert defines into string
tables, etc, so some change may break one of these scripts, or new MSRs
may use some different #define pattern, etc.
E.g.:
$ ls -1 tools/perf/trace/beauty/*.sh | head -5
tools/perf/trace/beauty/arch_errno_names.sh
tools/perf/trace/beauty/drm_ioctl.sh
tools/perf/trace/beauty/fadvise.sh
tools/perf/trace/beauty/fsconfig.sh
tools/perf/trace/beauty/fsmount.sh
$
$ tools/perf/trace/beauty/fadvise.sh
static const char *fadvise_advices[] = {
[0] = "NORMAL",
[1] = "RANDOM",
[2] = "SEQUENTIAL",
[3] = "WILLNEED",
[4] = "DONTNEED",
[5] = "NOREUSE",
};
$
The tools/perf/check-headers.sh script, part of the tools/ build
process, points out changes in the original files.
So its important not to touch the copies in tools/ when doing changes in
the original kernel headers, that will be done later, when
check-headers.sh inform about the change to the perf tools hackers.
Another explanation from Ingo Molnar:
It's better than all the alternatives we tried so far:
- Symbolic links and direct #includes: this was the original approach but
was pushed back on from the kernel side, when tooling modified the
headers and broke them accidentally for kernel builds.
- Duplicate self-defined ABI headers like glibc: double the maintenance
burden, double the chance for mistakes, plus there's no tech-driven
notification mechanism to look at new kernel side changes.
What we are doing now is a third option:
- A software-enforced copy-on-write mechanism of kernel headers to
tooling, driven by non-fatal warnings on the tooling side build when
kernel headers get modified:
Warning: Kernel ABI header differences:
diff -u tools/include/uapi/drm/i915_drm.h include/uapi/drm/i915_drm.h
diff -u tools/include/uapi/linux/fs.h include/uapi/linux/fs.h
diff -u tools/include/uapi/linux/kvm.h include/uapi/linux/kvm.h
...
The tooling policy is to always pick up the kernel side headers as-is,
and integate them into the tooling build. The warnings above serve as a
notification to tooling maintainers that there's changes on the kernel
side.
We've been using this for many years now, and it might seem hacky, but
works surprisingly well.