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| author | Daniel Zahka <daniel.zahka@gmail.com> | 2025-11-18 18:50:33 -0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-11-20 19:01:22 -0800 |
| commit | 2a367002ed321e884276c3d7232a362ddd1bf7d6 (patch) | |
| tree | 250b3bafea4e03e916f7c5b7c725b5b6e179c8f2 /Documentation/networking | |
| parent | 17a42aa465c000fccdcf581950d2c6f4e0c343ca (diff) | |
devlink: support default values for param-get and param-set
Support querying and resetting to default param values.
Introduce two new devlink netlink attrs:
DEVLINK_ATTR_PARAM_VALUE_DEFAULT and
DEVLINK_ATTR_PARAM_RESET_DEFAULT. The former is used to contain an
optional parameter value inside of the param_value nested
attribute. The latter is used in param-set requests from userspace to
indicate that the driver should reset the param to its default value.
To implement this, two new functions are added to the devlink driver
api: devlink_param::get_default() and
devlink_param::reset_default(). These callbacks allow drivers to
implement default param actions for runtime and permanent cmodes. For
driverinit params, the core latches the last value set by a driver via
devl_param_driverinit_value_set(), and uses that as the default value
for a param.
Because default parameter values are optional, it would be impossible
to discern whether or not a param of type bool has default value of
false or not provided if the default value is encoded using a netlink
flag type. For this reason, when a DEVLINK_PARAM_TYPE_BOOL has an
associated default value, the default value is encoded using a u8
type.
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20251119025038.651131-4-daniel.zahka@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/devlink/devlink-params.rst | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/networking/devlink/devlink-params.rst b/Documentation/networking/devlink/devlink-params.rst index c0597d456641..ea17756dcda6 100644 --- a/Documentation/networking/devlink/devlink-params.rst +++ b/Documentation/networking/devlink/devlink-params.rst @@ -41,6 +41,16 @@ In order for ``driverinit`` parameters to take effect, the driver must support reloading via the ``devlink-reload`` command. This command will request a reload of the device driver. +Default parameter values +========================= + +Drivers may optionally export default values for parameters of cmode +``runtime`` and ``permanent``. For ``driverinit`` parameters, the last +value set by the driver will be used as the default value. Drivers can +also support resetting params with cmode ``runtime`` and ``permanent`` +to their default values. Resetting ``driverinit`` params is supported +by devlink core without additional driver support needed. + .. _devlink_params_generic: Generic configuration parameters |