tools: ynl-gen: walk nested types in depth

So far we had only created structures for nested types nested
directly in messages (second level of attrs so to speak).
Walk types in depth to support deeper nesting.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/net/ynl/ynl-gen-c.py

@@ -854,18 +854,26 @@ class Family(SpecFamily):
                 self.root_sets[op['attribute-set']]['reply'].update(rsp_attrs)
 
     def _load_nested_sets(self):
-        for root_set, rs_members in self.root_sets.items():
-            for attr, spec in self.attr_sets[root_set].items():
-                if 'nested-attributes' in spec:
-                    inherit = set()
+        attr_set_queue = list(self.root_sets.keys())
+        attr_set_seen = set(self.root_sets.keys())
+
+        while len(attr_set_queue):
+            a_set = attr_set_queue.pop(0)
+            for attr, spec in self.attr_sets[a_set].items():
+                if 'nested-attributes' not in spec:
+                    continue
+
                 nested = spec['nested-attributes']
+                if nested not in attr_set_seen:
+                    attr_set_queue.append(nested)
+                    attr_set_seen.add(nested)
+
+                inherit = set()
                 if nested not in self.root_sets:
                     if nested not in self.pure_nested_structs:
                         self.pure_nested_structs[nested] = Struct(self, nested, inherited=inherit)
-                    if attr in rs_members['request']:
-                        self.pure_nested_structs[nested].request = True
-                    if attr in rs_members['reply']:
-                        self.pure_nested_structs[nested].reply = True
+                else:
+                    raise Exception(f'Using attr set as root and nested not supported - {nested}')
 
                 if 'type-value' in spec:
                     if nested in self.root_sets:
@@ -875,6 +883,15 @@ class Family(SpecFamily):
                     inherit.add('idx')
                 self.pure_nested_structs[nested].set_inherited(inherit)
 
+        for root_set, rs_members in self.root_sets.items():
+            for attr, spec in self.attr_sets[root_set].items():
+                if 'nested-attributes' in spec:
+                    nested = spec['nested-attributes']
+                    if attr in rs_members['request']:
+                        self.pure_nested_structs[nested].request = True
+                    if attr in rs_members['reply']:
+                        self.pure_nested_structs[nested].reply = True
+
         # Try to reorder according to dependencies
         pns_key_list = list(self.pure_nested_structs.keys())
         pns_key_seen = set()