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

@@ -854,27 +854,44 @@ class Family(SpecFamily):
                 self.root_sets[op['attribute-set']]['reply'].update(rsp_attrs)
 
     def _load_nested_sets(self):
+        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)
+                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:
+                        raise Exception("Inheriting members to a space used as root not supported")
+                    inherit.update(set(spec['type-value']))
+                elif spec['type'] == 'array-nest':
+                    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:
-                    inherit = set()
                     nested = spec['nested-attributes']
-                    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
 
-                    if 'type-value' in spec:
-                        if nested in self.root_sets:
-                            raise Exception("Inheriting members to a space used as root not supported")
-                        inherit.update(set(spec['type-value']))
-                    elif spec['type'] == 'array-nest':
-                        inherit.add('idx')
-                    self.pure_nested_structs[nested].set_inherited(inherit)
-
         # Try to reorder according to dependencies
         pns_key_list = list(self.pure_nested_structs.keys())
         pns_key_seen = set()