What do you mean?

There is already a function for each "atomically" block in MutexState.

The names of those functions aren't that great, but I'm not sure how to do better.

Perhaps they should be called something like if_queue_size_non_null_and_lockers_is_one_then_decrement_queue_size_and_return_true_otherwise_decrement_lockers_and_return_false, but I'm not quite sure that it's a good idea.