Hi, We currently support matching on user_data OR file descriptor, in conjunction with the ANY/ALL matches we also have. This series starts by cleaning up the cancelation support a bit, most notably using a common match handler to avoid duplicating the matching code in a few different spots. Then it adds IORING_ASYNC_CANCEL_USERDATA, to explicitly ask for matching on user_data. This was the only original way to match, but we since added FD matching. To retain backwards compatability, we will always match on user_data IFF none of the other key matches are set (eg FD and OP). This now allows matching on any set of criteria that the application wants. It can match on user_data AND fd, for example. Finally we add support for IORING_ASYNC_CANCEL_OP, which allows applications to match on the original request opcode as well. -- Jens Axboe
