diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 8cb3a505f..780029547 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -2149,16 +2149,20 @@ class FederationHandler(BaseHandler):
 
         return missing_events
 
-    @defer.inlineCallbacks
-    @log_function
-    def do_auth(self, origin, event, context, auth_events):
+    async def do_auth(
+        self,
+        origin: str,
+        event: EventBase,
+        context: EventContext,
+        auth_events: StateMap[EventBase],
+    ) -> EventContext:
         """
 
         Args:
-            origin (str):
-            event (synapse.events.EventBase):
-            context (synapse.events.snapshot.EventContext):
-            auth_events (dict[(str, str)->synapse.events.EventBase]):
+            origin:
+            event:
+            context:
+            auth_events:
                 Map from (event_type, state_key) to event
 
                 Normally, our calculated auth_events based on the state of the room
@@ -2168,13 +2172,13 @@ class FederationHandler(BaseHandler):
 
                 Also NB that this function adds entries to it.
         Returns:
-            defer.Deferred[EventContext]: updated context object
+            updated context object
         """
-        room_version = yield self.store.get_room_version_id(event.room_id)
+        room_version = await self.store.get_room_version_id(event.room_id)
         room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
 
         try:
-            context = yield self._update_auth_events_and_context_for_auth(
+            context = await self._update_auth_events_and_context_for_auth(
                 origin, event, context, auth_events
             )
         except Exception: