Garbage collect the lock

gns3server/web/route.py

@@ -163,9 +163,16 @@ class Route(object):
                     vm_id = request.match_info.get("vm_id")
                     if vm_id is None:
                         vm_id = request.match_info["device_id"]
-                    cls._vm_locks.setdefault(vm_id, asyncio.Lock())
-                    with (yield from cls._vm_locks[vm_id]):
+                    cls._vm_locks.setdefault(vm_id, {"lock": asyncio.Lock(), "concurrency": 0})
+                    cls._vm_locks[vm_id]["concurrency"] += 1
+
+                    with (yield from cls._vm_locks[vm_id]["lock"]):
                         response = yield from control_schema(request)
+                    cls._vm_locks[vm_id]["concurrency"] -= 1
+
+                    # No more waiting requests, garbage collect the lock
+                    if cls._vm_locks[vm_id]["concurrency"] <= 0:
+                        del cls._vm_locks[vm_id]
                 else:
                     response = yield from control_schema(request)
                 return response