1 /*
2 * Copyright (C) 2021 Red Hat, Inc. All rights reserved.
3 *
4 * This file is released under the GPL.
5 */
6
7 #ifndef DM_IO_TRACKER_H
8 #define DM_IO_TRACKER_H
9
10 #include <linux/jiffies.h>
11
12 struct dm_io_tracker {
13 spinlock_t lock;
14
15 /*
16 * Sectors of in-flight IO.
17 */
18 sector_t in_flight;
19
20 /*
21 * The time, in jiffies, when this device became idle
22 * (if it is indeed idle).
23 */
24 unsigned long idle_time;
25 unsigned long last_update_time;
26 };
27
dm_iot_init(struct dm_io_tracker * iot)28 static inline void dm_iot_init(struct dm_io_tracker *iot)
29 {
30 spin_lock_init(&iot->lock);
31 iot->in_flight = 0ul;
32 iot->idle_time = 0ul;
33 iot->last_update_time = jiffies;
34 }
35
dm_iot_idle_for(struct dm_io_tracker * iot,unsigned long j)36 static inline bool dm_iot_idle_for(struct dm_io_tracker *iot, unsigned long j)
37 {
38 bool r = false;
39
40 spin_lock_irq(&iot->lock);
41 if (!iot->in_flight)
42 r = time_after(jiffies, iot->idle_time + j);
43 spin_unlock_irq(&iot->lock);
44
45 return r;
46 }
47
dm_iot_idle_time(struct dm_io_tracker * iot)48 static inline unsigned long dm_iot_idle_time(struct dm_io_tracker *iot)
49 {
50 unsigned long r = 0;
51
52 spin_lock_irq(&iot->lock);
53 if (!iot->in_flight)
54 r = jiffies - iot->idle_time;
55 spin_unlock_irq(&iot->lock);
56
57 return r;
58 }
59
dm_iot_io_begin(struct dm_io_tracker * iot,sector_t len)60 static inline void dm_iot_io_begin(struct dm_io_tracker *iot, sector_t len)
61 {
62 spin_lock_irq(&iot->lock);
63 iot->in_flight += len;
64 spin_unlock_irq(&iot->lock);
65 }
66
dm_iot_io_end(struct dm_io_tracker * iot,sector_t len)67 static inline void dm_iot_io_end(struct dm_io_tracker *iot, sector_t len)
68 {
69 unsigned long flags;
70
71 if (!len)
72 return;
73
74 spin_lock_irqsave(&iot->lock, flags);
75 iot->in_flight -= len;
76 if (!iot->in_flight)
77 iot->idle_time = jiffies;
78 spin_unlock_irqrestore(&iot->lock, flags);
79 }
80
81 #endif
82