This is a note to let you know that I've just added the patch titled
Documentation: networking: Add a caveat to nexthop_compat_mode sysctl
to the 6.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
documentation-networking-add-a-caveat-to-nexthop_com.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 196deb085965fb01abbb928181eff567bcabba81
Author: Petr Machata <petrm@xxxxxxxxxx>
Date: Mon Dec 9 12:05:31 2024 +0100
Documentation: networking: Add a caveat to nexthop_compat_mode sysctl
[ Upstream commit bbe4b41259a3e255a16d795486d331c1670b4e75 ]
net.ipv4.nexthop_compat_mode was added when nexthop objects were added to
provide the view of nexthop objects through the usual lens of the route
UAPI. As nexthop objects evolved, the information provided through this
lens became incomplete. For example, details of resilient nexthop groups
are obviously omitted.
Now that 16-bit nexthop group weights are a thing, the 8-bit UAPI cannot
convey the >8-bit weight accurately. Instead of inventing workarounds for
an obsolete interface, just document the expectations of inaccuracy.
Fixes: b72a6a7ab957 ("net: nexthop: Increase weight to u16")
Signed-off-by: Petr Machata <petrm@xxxxxxxxxx>
Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Link: https://patch.msgid.link/b575e32399ccacd09079b2a218255164535123bd.1733740749.git.petrm@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index eacf8983e230..dcbb6f6caf6d 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -2170,6 +2170,12 @@ nexthop_compat_mode - BOOLEAN
understands the new API, this sysctl can be disabled to achieve full
performance benefits of the new API by disabling the nexthop expansion
and extraneous notifications.
+
+ Note that as a backward-compatible mode, dumping of modern features
+ might be incomplete or wrong. For example, resilient groups will not be
+ shown as such, but rather as just a list of next hops. Also weights that
+ do not fit into 8 bits will show incorrectly.
+
Default: true (backward compat mode)
fib_notify_on_flag_change - INTEGER
