Use explicit select condition in SQL query in "_port_filter_hook"

Instead of executing a subquery inside a select, use a proper filter
condition instead.

Closes-Bug: #1936675
Change-Id: I97e9ca244c0716510fcd4ec81d54046be9c5f8f8

neutron/db/db_base_plugin_v2.py

@@ -42,6 +42,7 @@ from oslo_db import exception as os_db_exc
 from oslo_log import log as logging
 from oslo_utils import excutils
 from oslo_utils import uuidutils
+from sqlalchemy import and_
 from sqlalchemy import exc as sql_exc
 from sqlalchemy import func
 from sqlalchemy import not_
@@ -111,10 +112,9 @@ def _update_subnetpool_dict(orig_pool, new_pool):
 def _port_filter_hook(context, original_model, conditions):
     # Apply the port filter only in non-admin and non-advsvc context
     if ndb_utils.model_query_scope_is_project(context, original_model):
-        conditions |= (models_v2.Port.network_id.in_(
-            context.session.query(models_v2.Network.id).
-            filter(context.project_id == models_v2.Network.project_id).
-            subquery()))
+        conditions |= and_(
+            models_v2.Port.network_id == models_v2.Network.id,
+            models_v2.Network.project_id == context.project_id)
     return conditions
 
 
@@ -1576,6 +1576,7 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
                 Port.fixed_ips.any(IPAllocation.subnet_id.in_(subnet_ids)))
         if limit:
             query = query.limit(limit)
+        query = query.distinct()
         return query
 
     @db_api.retry_if_session_inactive()