[PATCH net-next v2 2/3] docs: net: bridge: document stp_mode attribute
From: Andy Roulin <hidden>
Date: 2026-03-29 02:59:09
Also in:
bridge, linux-doc, linux-kselftest, lkml
Subsystem:
documentation, networking [general], the rest · Maintainers:
Jonathan Corbet, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Add documentation for the IFLA_BR_STP_MODE bridge attribute in the "User space STP helper" section of the bridge documentation. Reference the BR_STP_MODE_* values via kernel-doc and describe the use case for network namespace environments. Signed-off-by: Andy Roulin <redacted> --- Documentation/networking/bridge.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)
diff --git a/Documentation/networking/bridge.rst b/Documentation/networking/bridge.rst
index ef8b73e157b26..c1e6ea52c9e59 100644
--- a/Documentation/networking/bridge.rst
+++ b/Documentation/networking/bridge.rst@@ -148,6 +148,28 @@ called by the kernel when STP is enabled/disabled on a bridge stp_state <0|1>``). The kernel enables user_stp mode if that command returns 0, or enables kernel_stp mode if that command returns any other value. +STP mode selection +------------------ + +The ``IFLA_BR_STP_MODE`` bridge attribute allows explicit control over how +STP operates when enabled, bypassing the ``/sbin/bridge-stp`` helper +entirely for the ``user`` and ``kernel`` modes. + +.. kernel-doc:: include/uapi/linux/if_link.h + :doc: Bridge STP mode values + +The default mode is ``BR_STP_MODE_AUTO``, which preserves the traditional +behavior of invoking the ``/sbin/bridge-stp`` helper. The ``user`` and +``kernel`` modes are particularly useful in network namespace environments +where the helper mechanism is not available, as ``call_usermodehelper()`` +is restricted to the initial network namespace. + +Example:: + + ip link set dev br0 type bridge stp_mode user stp_state 1 + +The mode can only be changed while STP is disabled. + VLAN ====
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2.43.0