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| author | Andy Roulin <aroulin@nvidia.com> | 2026-04-05 23:52:23 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-11 01:52:25 +0300 |
| commit | c4f2aab121cdc8400dcd5ec3cc0aa0fb3c06694f (patch) | |
| tree | d5268fc5dccb4a91d52e4cbe12f5cc4028047ef7 | |
| parent | 54fc83a1728535831df0f251e155d05574918115 (diff) | |
| download | linux-c4f2aab121cdc8400dcd5ec3cc0aa0fb3c06694f.tar.xz | |
docs: net: bridge: document stp_mode attribute
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.
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Andy Roulin <aroulin@nvidia.com>
Link: https://patch.msgid.link/20260405205224.3163000-3-aroulin@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | Documentation/networking/bridge.rst | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/networking/bridge.rst b/Documentation/networking/bridge.rst index ef8b73e157b2..c1e6ea52c9e5 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 ==== |