IO_APOLL_OK
if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
case IO_APOLL_OK:
return IO_APOLL_OK;
return ret == IO_APOLL_OK ? -EIOCBQUEUED : -ECANCELED;