force_abort
unlikely(READ_ONCE(ubq->force_abort)))
bool force_abort;
WRITE_ONCE(ublk_get_queue(ub, i)->force_abort, true);
ubq->force_abort = true;
ublk_get_queue(ub, i)->force_abort = true;
if (unlikely(ubq->force_abort || ubq->canceling)) {
force_abort(ctx);