blk-rq-qos: make rq_qos_add and rq_qos_del more useful

Switch to passing a gendisk, and make rq_qos_add initialize all required
fields and drop the not required q argument from rq_qos_del.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Herrmann <aherrmann@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230203150400.3199230-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-iocost.c

@@ -2843,9 +2843,7 @@ static struct rq_qos_ops ioc_rqos_ops = {
 
 static int blk_iocost_init(struct gendisk *disk)
 {
-	struct request_queue *q = disk->queue;
 	struct ioc *ioc;
-	struct rq_qos *rqos;
 	int i, cpu, ret;
 
 	ioc = kzalloc(sizeof(*ioc), GFP_KERNEL);
@@ -2868,11 +2866,6 @@ static int blk_iocost_init(struct gendisk *disk)
 		local64_set(&ccs->rq_wait_ns, 0);
 	}
 
-	rqos = &ioc->rqos;
-	rqos->id = RQ_QOS_COST;
-	rqos->ops = &ioc_rqos_ops;
-	rqos->q = q;
-
 	spin_lock_init(&ioc->lock);
 	timer_setup(&ioc->timer, ioc_timer_fn, 0);
 	INIT_LIST_HEAD(&ioc->active_iocgs);
@@ -2896,17 +2889,17 @@ static int blk_iocost_init(struct gendisk *disk)
 	 * called before policy activation completion, can't assume that the
 	 * target bio has an iocg associated and need to test for NULL iocg.
 	 */
-	ret = rq_qos_add(q, rqos);
+	ret = rq_qos_add(&ioc->rqos, disk, RQ_QOS_COST, &ioc_rqos_ops);
 	if (ret)
 		goto err_free_ioc;
 
-	ret = blkcg_activate_policy(q, &blkcg_policy_iocost);
+	ret = blkcg_activate_policy(disk->queue, &blkcg_policy_iocost);
 	if (ret)
 		goto err_del_qos;
 	return 0;
 
 err_del_qos:
-	rq_qos_del(q, rqos);
+	rq_qos_del(&ioc->rqos);
 err_free_ioc:
 	free_percpu(ioc->pcpu_stat);
 	kfree(ioc);

block/blk-iolatency.c

@@ -757,24 +757,18 @@ static void blkiolatency_enable_work_fn(struct work_struct *work)
 
 int blk_iolatency_init(struct gendisk *disk)
 {
-	struct request_queue *q = disk->queue;
 	struct blk_iolatency *blkiolat;
-	struct rq_qos *rqos;
 	int ret;
 
 	blkiolat = kzalloc(sizeof(*blkiolat), GFP_KERNEL);
 	if (!blkiolat)
 		return -ENOMEM;
 
-	rqos = &blkiolat->rqos;
-	rqos->id = RQ_QOS_LATENCY;
-	rqos->ops = &blkcg_iolatency_ops;
-	rqos->q = q;
-
-	ret = rq_qos_add(q, rqos);
+	ret = rq_qos_add(&blkiolat->rqos, disk, RQ_QOS_LATENCY,
+			 &blkcg_iolatency_ops);
 	if (ret)
 		goto err_free;
-	ret = blkcg_activate_policy(q, &blkcg_policy_iolatency);
+	ret = blkcg_activate_policy(disk->queue, &blkcg_policy_iolatency);
 	if (ret)
 		goto err_qos_del;
 
@@ -784,7 +778,7 @@ int blk_iolatency_init(struct gendisk *disk)
 	return 0;
 
 err_qos_del:
-	rq_qos_del(q, rqos);
+	rq_qos_del(&blkiolat->rqos);
 err_free:
 	kfree(blkiolat);
 	return ret;

block/blk-rq-qos.c

@@ -295,8 +295,15 @@ void rq_qos_exit(struct request_queue *q)
 	}
 }
 
-int rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
+int rq_qos_add(struct rq_qos *rqos, struct gendisk *disk, enum rq_qos_id id,
+		struct rq_qos_ops *ops)
 {
+	struct request_queue *q = disk->queue;
+
+	rqos->q = q;
+	rqos->id = id;
+	rqos->ops = ops;
+
 	/*
 	 * No IO can be in-flight when adding rqos, so freeze queue, which
 	 * is fine since we only support rq_qos for blk-mq queue.
@@ -326,11 +333,11 @@ int rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
 	spin_unlock_irq(&q->queue_lock);
 	blk_mq_unfreeze_queue(q);
 	return -EBUSY;
-
 }
 
-void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
+void rq_qos_del(struct rq_qos *rqos)
 {
+	struct request_queue *q = rqos->q;
 	struct rq_qos **cur;
 
 	/*

block/blk-rq-qos.h

@@ -85,8 +85,9 @@ static inline void rq_wait_init(struct rq_wait *rq_wait)
 	init_waitqueue_head(&rq_wait->wait);
 }
 
-int rq_qos_add(struct request_queue *q, struct rq_qos *rqos);
-void rq_qos_del(struct request_queue *q, struct rq_qos *rqos);
+int rq_qos_add(struct rq_qos *rqos, struct gendisk *disk, enum rq_qos_id id,
+		struct rq_qos_ops *ops);
+void rq_qos_del(struct rq_qos *rqos);
 
 typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
 typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);

block/blk-wbt.c

@@ -932,9 +932,6 @@ int wbt_init(struct gendisk *disk)
 	for (i = 0; i < WBT_NUM_RWQ; i++)
 		rq_wait_init(&rwb->rq_wait[i]);
 
-	rwb->rqos.id = RQ_QOS_WBT;
-	rwb->rqos.ops = &wbt_rqos_ops;
-	rwb->rqos.q = q;
 	rwb->last_comp = rwb->last_issue = jiffies;
 	rwb->win_nsec = RWB_WINDOW_NSEC;
 	rwb->enable_state = WBT_STATE_ON_DEFAULT;
@@ -947,7 +944,7 @@ int wbt_init(struct gendisk *disk)
 	/*
 	 * Assign rwb and add the stats callback.
 	 */
-	ret = rq_qos_add(q, &rwb->rqos);
+	ret = rq_qos_add(&rwb->rqos, disk, RQ_QOS_WBT, &wbt_rqos_ops);
 	if (ret)
 		goto err_free;