Subject: [PATCH net-next v2 11/13] doc/netlink: Describe nested structs in netlink raw docs

From: Donald Hunter <[email-masked]>
Date: Mon, 29 Jan 2024 22:34:56 +0000

Add a description and example of nested struct definitions
to the netlink raw documentation.

Signed-off-by: Donald Hunter <[email-masked]>
---
 .../userspace-api/netlink/netlink-raw.rst     | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/Documentation/userspace-api/netlink/netlink-raw.rst b/Documentation/userspace-api/netlink/netlink-raw.rst
index 32197f3cb40e..1990eea772d0 100644
--- a/Documentation/userspace-api/netlink/netlink-raw.rst
+++ b/Documentation/userspace-api/netlink/netlink-raw.rst
@@ -158,3 +158,37 @@ alongside a sub-message selector and also in a top level ``attribute-set``, then
 the selector will be resolved using the value 'closest' to the selector. If the
 value is not present in the message at the same level as defined in the spec
 then this is an error.
+
+Nested struct definitions
+-------------------------
+
+Many raw netlink families such as :doc:`tc<../../networking/netlink_spec/tc>`
+make use of nested struct definitions. The ``netlink-raw`` schema makes it
+possible to embed a struct within a struct definition using the ``struct``
+property. For example, the following struct definition embeds the
+``tc-ratespec`` struct definition for both the ``rate`` and the ``peakrate``
+members of ``struct tc-tbf-qopt``.
+
+.. code-block:: yaml
+
+  -
+    name: tc-tbf-qopt
+    type: struct
+    members:
+      -
+        name: rate
+        type: binary
+        struct: tc-ratespec
+      -
+        name: peakrate
+        type: binary
+        struct: tc-ratespec
+      -
+        name: limit
+        type: u32
+      -
+        name: buffer
+        type: u32
+      -
+        name: mtu
+        type: u32
-- 
2.42.0