> {
> struct request_queue *q = rqos->q;
> - const char *dir_name = rq_qos_id_to_name(rqos->id);
> + const char *dir_name;
> +
> + dir_name = rqos->ops->name ? rqos->ops->name : rq_qos_id_to_name(rqos->id);
Overly long line here. And it would be much more readable if you used
a good old if/else.
> +static DEFINE_IDA(rq_qos_ida);
> +static int nr_rqos_blkcg_pols;
> +static DEFINE_MUTEX(rq_qos_mutex);
> +static LIST_HEAD(rq_qos_list);
Please use an allocating xarray instead of an IDA plus list.
> + /*
> + * queue must have been unregistered here, it is safe to iterate
> + * the list w/o lock
> + */
Please capitalize multi-line comments.
> + * After the pluggable blk-qos, rqos's life cycle become complicated,
> + * as we may modify the rqos list there. Except for the places where
> + * queue is not registered, there are following places may access rqos
> + * list concurrently:
Code comments are not the place to explain history. PLease explain the
current situation.
> +struct rq_qos *rq_qos_get(struct request_queue *q, int id)
> +{
> + struct rq_qos *rqos;
> +
> + spin_lock_irq(&q->queue_lock);
Please don't use the grab all queue_lock for new code. It badly needs
to be split and documented, and new code is the best place to start
that.
Also with all the new code please add a new config option that is
selected by all rq-pos implementations so that blk-rq-qos.c only gets
built when actually needed.
> +static inline struct rq_qos *rq_qos_by_id(struct request_queue *q, int id)
> +{
> + struct rq_qos *rqos;
> +
> + WARN_ON(!mutex_is_locked(&q->sysfs_lock) && !spin_is_locked(&q->queue_lock));
Another overly long line. And in doubt split this into two helpers
so that you cna use lockdep_assert_held instead of doing the incorrect
asserts.
