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 const struct rq_qos_ops *ops;
29 struct gendisk *disk;
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, id: RQ_QOS_WBT);
75}
76
77static inline struct rq_qos *iolat_rq_qos(struct request_queue *q)
78{
79 return rq_qos_id(q, id: RQ_QOS_LATENCY);
80}
81
82static inline void rq_wait_init(struct rq_wait *rq_wait)
83{
84 atomic_set(v: &rq_wait->inflight, i: 0);
85 init_waitqueue_head(&rq_wait->wait);
86}
87
88int rq_qos_add(struct rq_qos *rqos, struct gendisk *disk, enum rq_qos_id id,
89 const struct rq_qos_ops *ops);
90void rq_qos_del(struct rq_qos *rqos);
91
92typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
93typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
94
95void rq_qos_wait(struct rq_wait *rqw, void *private_data,
96 acquire_inflight_cb_t *acquire_inflight_cb,
97 cleanup_cb_t *cleanup_cb);
98bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
99bool rq_depth_scale_up(struct rq_depth *rqd);
100bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
101bool rq_depth_calc_max_depth(struct rq_depth *rqd);
102
103void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
104void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
105void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
106void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
107void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
108void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
109void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
110void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
111void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
112
113static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
114{
115 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
116 q->rq_qos)
117 __rq_qos_cleanup(rqos: q->rq_qos, bio);
118}
119
120static inline void rq_qos_done(struct request_queue *q, struct request *rq)
121{
122 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
123 q->rq_qos && !blk_rq_is_passthrough(rq))
124 __rq_qos_done(rqos: q->rq_qos, rq);
125}
126
127static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
128{
129 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
130 q->rq_qos)
131 __rq_qos_issue(rqos: q->rq_qos, rq);
132}
133
134static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
135{
136 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
137 q->rq_qos)
138 __rq_qos_requeue(rqos: q->rq_qos, rq);
139}
140
141static inline void rq_qos_done_bio(struct bio *bio)
142{
143 struct request_queue *q;
144
145 if (!bio->bi_bdev || (!bio_flagged(bio, bit: BIO_QOS_THROTTLED) &&
146 !bio_flagged(bio, bit: BIO_QOS_MERGED)))
147 return;
148
149 q = bdev_get_queue(bdev: bio->bi_bdev);
150
151 /*
152 * A BIO may carry BIO_QOS_* flags even if the associated request_queue
153 * does not have rq_qos enabled. This can happen with stacked block
154 * devices — for example, NVMe multipath, where it's possible that the
155 * bottom device has QoS enabled but the top device does not. Therefore,
156 * always verify that q->rq_qos is present and QoS is enabled before
157 * calling __rq_qos_done_bio().
158 */
159 if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
160 __rq_qos_done_bio(rqos: q->rq_qos, bio);
161}
162
163static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
164{
165 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
166 q->rq_qos) {
167 bio_set_flag(bio, bit: BIO_QOS_THROTTLED);
168 __rq_qos_throttle(rqos: q->rq_qos, bio);
169 }
170}
171
172static inline void rq_qos_track(struct request_queue *q, struct request *rq,
173 struct bio *bio)
174{
175 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
176 q->rq_qos)
177 __rq_qos_track(rqos: q->rq_qos, rq, bio);
178}
179
180static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
181 struct bio *bio)
182{
183 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
184 q->rq_qos) {
185 bio_set_flag(bio, bit: BIO_QOS_MERGED);
186 __rq_qos_merge(rqos: q->rq_qos, rq, bio);
187 }
188}
189
190static inline void rq_qos_queue_depth_changed(struct request_queue *q)
191{
192 if (unlikely(test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags)) &&
193 q->rq_qos)
194 __rq_qos_queue_depth_changed(rqos: q->rq_qos);
195}
196
197void rq_qos_exit(struct request_queue *);
198
199#endif
200