1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2021 Red Hat, Inc. All rights reserved.
4  *
5  * This file is released under the GPL.
6  */
7 
8 #ifndef DM_IO_TRACKER_H
9 #define DM_IO_TRACKER_H
10 
11 #include <linux/jiffies.h>
12 
13 struct dm_io_tracker {
14 	spinlock_t lock;
15 
16 	/*
17 	 * Sectors of in-flight IO.
18 	 */
19 	sector_t in_flight;
20 
21 	/*
22 	 * The time, in jiffies, when this device became idle
23 	 * (if it is indeed idle).
24 	 */
25 	unsigned long idle_time;
26 	unsigned long last_update_time;
27 };
28 
dm_iot_init(struct dm_io_tracker * iot)29 static inline void dm_iot_init(struct dm_io_tracker *iot)
30 {
31 	spin_lock_init(&iot->lock);
32 	iot->in_flight = 0ul;
33 	iot->idle_time = 0ul;
34 	iot->last_update_time = jiffies;
35 }
36 
dm_iot_idle_for(struct dm_io_tracker * iot,unsigned long j)37 static inline bool dm_iot_idle_for(struct dm_io_tracker *iot, unsigned long j)
38 {
39 	bool r = false;
40 
41 	spin_lock_irq(&iot->lock);
42 	if (!iot->in_flight)
43 		r = time_after(jiffies, iot->idle_time + j);
44 	spin_unlock_irq(&iot->lock);
45 
46 	return r;
47 }
48 
dm_iot_idle_time(struct dm_io_tracker * iot)49 static inline unsigned long dm_iot_idle_time(struct dm_io_tracker *iot)
50 {
51 	unsigned long r = 0;
52 
53 	spin_lock_irq(&iot->lock);
54 	if (!iot->in_flight)
55 		r = jiffies - iot->idle_time;
56 	spin_unlock_irq(&iot->lock);
57 
58 	return r;
59 }
60 
dm_iot_io_begin(struct dm_io_tracker * iot,sector_t len)61 static inline void dm_iot_io_begin(struct dm_io_tracker *iot, sector_t len)
62 {
63 	spin_lock_irq(&iot->lock);
64 	iot->in_flight += len;
65 	spin_unlock_irq(&iot->lock);
66 }
67 
dm_iot_io_end(struct dm_io_tracker * iot,sector_t len)68 static inline void dm_iot_io_end(struct dm_io_tracker *iot, sector_t len)
69 {
70 	unsigned long flags;
71 
72 	if (!len)
73 		return;
74 
75 	spin_lock_irqsave(&iot->lock, flags);
76 	iot->in_flight -= len;
77 	if (!iot->in_flight)
78 		iot->idle_time = jiffies;
79 	spin_unlock_irqrestore(&iot->lock, flags);
80 }
81 
82 #endif
83