1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef RQ_QOS_H
  3#define RQ_QOS_H
  4
  5#include <linux/kernel.h>
  6#include <linux/blkdev.h>
  7#include <linux/blk_types.h>
  8#include <linux/atomic.h>
  9#include <linux/wait.h>
 10#include <linux/blk-mq.h>
 11
 12#include "blk-mq-debugfs.h"
 13
 14struct blk_mq_debugfs_attr;
 15
 16enum rq_qos_id {
 17	RQ_QOS_WBT,
 18	RQ_QOS_LATENCY,
 19	RQ_QOS_COST,
 20};
 21
 22struct rq_wait {
 23	wait_queue_head_t wait;
 24	atomic_t inflight;
 25};
 26
 27struct rq_qos {
 28	struct rq_qos_ops *ops;
 29	struct request_queue *q;
 30	enum rq_qos_id id;
 31	struct rq_qos *next;
 32#ifdef CONFIG_BLK_DEBUG_FS
 33	struct dentry *debugfs_dir;
 34#endif
 35};
 36
 37struct rq_qos_ops {
 38	void (*throttle)(struct rq_qos *, struct bio *);
 39	void (*track)(struct rq_qos *, struct request *, struct bio *);
 40	void (*merge)(struct rq_qos *, struct request *, struct bio *);
 41	void (*issue)(struct rq_qos *, struct request *);
 42	void (*requeue)(struct rq_qos *, struct request *);
 43	void (*done)(struct rq_qos *, struct request *);
 44	void (*done_bio)(struct rq_qos *, struct bio *);
 45	void (*cleanup)(struct rq_qos *, struct bio *);
 46	void (*queue_depth_changed)(struct rq_qos *);
 47	void (*exit)(struct rq_qos *);
 48	const struct blk_mq_debugfs_attr *debugfs_attrs;
 49};
 50
 51struct rq_depth {
 52	unsigned int max_depth;
 53
 54	int scale_step;
 55	bool scaled_max;
 56
 57	unsigned int queue_depth;
 58	unsigned int default_depth;
 59};
 60
 61static inline struct rq_qos *rq_qos_id(struct request_queue *q,
 62				       enum rq_qos_id id)
 63{
 64	struct rq_qos *rqos;
 65	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
 66		if (rqos->id == id)
 67			break;
 68	}
 69	return rqos;
 70}
 71
 72static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
 73{
 74	return rq_qos_id(q, RQ_QOS_WBT);
 75}
 76
 77static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
 78{
 79	return rq_qos_id(q, RQ_QOS_LATENCY);
 80}
 81
 82static inline void rq_wait_init(struct rq_wait *rq_wait)
 83{
 84	atomic_set(&rq_wait->inflight, 0);
 85	init_waitqueue_head(&rq_wait->wait);
 86}
 87
 88static inline int rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
 89{
 90	/*
 91	 * No IO can be in-flight when adding rqos, so freeze queue, which
 92	 * is fine since we only support rq_qos for blk-mq queue.
 93	 *
 94	 * Reuse ->queue_lock for protecting against other concurrent
 95	 * rq_qos adding/deleting
 96	 */
 97	blk_mq_freeze_queue(q);
 98
 99	spin_lock_irq(&q->queue_lock);
100	if (rq_qos_id(q, rqos->id))
101		goto ebusy;
102	rqos->next = q->rq_qos;
103	q->rq_qos = rqos;
104	spin_unlock_irq(&q->queue_lock);
105
106	blk_mq_unfreeze_queue(q);
107
108	if (rqos->ops->debugfs_attrs) {
109		mutex_lock(&q->debugfs_mutex);
110		blk_mq_debugfs_register_rqos(rqos);
111		mutex_unlock(&q->debugfs_mutex);
112	}
113
114	return 0;
115ebusy:
116	spin_unlock_irq(&q->queue_lock);
117	blk_mq_unfreeze_queue(q);
118	return -EBUSY;
119
120}
121
122static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
123{
124	struct rq_qos **cur;
125
126	/*
127	 * See comment in rq_qos_add() about freezing queue & using
128	 * ->queue_lock.
129	 */
130	blk_mq_freeze_queue(q);
131
132	spin_lock_irq(&q->queue_lock);
133	for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
134		if (*cur == rqos) {
135			*cur = rqos->next;
136			break;
137		}
138	}
139	spin_unlock_irq(&q->queue_lock);
140
141	blk_mq_unfreeze_queue(q);
142
143	mutex_lock(&q->debugfs_mutex);
144	blk_mq_debugfs_unregister_rqos(rqos);
145	mutex_unlock(&q->debugfs_mutex);
146}
147
148typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
149typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
150
151void rq_qos_wait(struct rq_wait *rqw, void *private_data,
152		 acquire_inflight_cb_t *acquire_inflight_cb,
153		 cleanup_cb_t *cleanup_cb);
154bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
155bool rq_depth_scale_up(struct rq_depth *rqd);
156bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
157bool rq_depth_calc_max_depth(struct rq_depth *rqd);
158
159void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
160void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
161void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
162void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
163void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
164void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
165void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
166void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
167void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
168
169static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
170{
171	if (q->rq_qos)
172		__rq_qos_cleanup(q->rq_qos, bio);
173}
174
175static inline void rq_qos_done(struct request_queue *q, struct request *rq)
176{
177	if (q->rq_qos)
178		__rq_qos_done(q->rq_qos, rq);
179}
180
181static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
182{
183	if (q->rq_qos)
184		__rq_qos_issue(q->rq_qos, rq);
185}
186
187static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
188{
189	if (q->rq_qos)
190		__rq_qos_requeue(q->rq_qos, rq);
191}
192
193static inline void rq_qos_done_bio(struct bio *bio)
194{
195	if (bio->bi_bdev && (bio_flagged(bio, BIO_QOS_THROTTLED) ||
196			     bio_flagged(bio, BIO_QOS_MERGED))) {
197		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
198		if (q->rq_qos)
199			__rq_qos_done_bio(q->rq_qos, bio);
200	}
201}
202
203static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
204{
205	if (q->rq_qos) {
206		bio_set_flag(bio, BIO_QOS_THROTTLED);
207		__rq_qos_throttle(q->rq_qos, bio);
208	}
209}
210
211static inline void rq_qos_track(struct request_queue *q, struct request *rq,
212				struct bio *bio)
213{
214	if (q->rq_qos)
215		__rq_qos_track(q->rq_qos, rq, bio);
216}
217
218static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
219				struct bio *bio)
220{
221	if (q->rq_qos) {
222		bio_set_flag(bio, BIO_QOS_MERGED);
223		__rq_qos_merge(q->rq_qos, rq, bio);
224	}
225}
226
227static inline void rq_qos_queue_depth_changed(struct request_queue *q)
228{
229	if (q->rq_qos)
230		__rq_qos_queue_depth_changed(q->rq_qos);
231}
232
233void rq_qos_exit(struct request_queue *);
234
235#endif