- struct blk_ioprio *blkioprio_blkg;
- struct rq_qos *rqos;
- int ret;
-
- blkioprio_blkg = kzalloc(sizeof(*blkioprio_blkg), GFP_KERNEL);
- if (!blkioprio_blkg)
- return -ENOMEM;
-
- ret = blkcg_activate_policy(q, &ioprio_policy);
- if (ret) {
- kfree(blkioprio_blkg);
- return ret;
- }
-
- rqos = &blkioprio_blkg->rqos;
- rqos->id = RQ_QOS_IOPRIO;
- rqos->ops = &blkcg_ioprio_ops;
- rqos->q = q;
-
- /*
- * Registering the rq-qos policy after activating the blk-cgroup
- * policy guarantees that ioprio_blkcg_from_bio(bio) != NULL in the
- * rq-qos callbacks.
- */
- rq_qos_add(q, rqos);
-
- return 0;