engines/libaio: don't reap on EAGAIN and no pending events

Instead just loop on submit, since there are no events for us
to reap. This is usually a kernel bug, violating the principle
of forward progress guarantee.

If we can't submit anything in 30 seconds, error out.

Signed-off-by: Jens Axboe <axboe@fb.com>
1 file changed