1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_RATELIMIT_H
3#define _LINUX_RATELIMIT_H
4
5#include <linux/param.h>
6#include <linux/sched.h>
7#include <linux/spinlock.h>
8
9#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
10#define DEFAULT_RATELIMIT_BURST 10
11
12/* issue num suppressed message on exit */
13#define RATELIMIT_MSG_ON_RELEASE BIT(0)
14
15struct ratelimit_state {
16 raw_spinlock_t lock; /* protect the state */
17
18 int interval;
19 int burst;
20 int printed;
21 int missed;
22 unsigned long begin;
23 unsigned long flags;
24};
25
26#define RATELIMIT_STATE_INIT(name, interval_init, burst_init) { \
27 .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
28 .interval = interval_init, \
29 .burst = burst_init, \
30 }
31
32#define RATELIMIT_STATE_INIT_DISABLED \
33 RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
34
35#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init) \
36 \
37 struct ratelimit_state name = \
38 RATELIMIT_STATE_INIT(name, interval_init, burst_init) \
39
40static inline void ratelimit_state_init(struct ratelimit_state *rs,
41 int interval, int burst)
42{
43 memset(rs, 0, sizeof(*rs));
44
45 raw_spin_lock_init(&rs->lock);
46 rs->interval = interval;
47 rs->burst = burst;
48}
49
50static inline void ratelimit_default_init(struct ratelimit_state *rs)
51{
52 return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
53 DEFAULT_RATELIMIT_BURST);
54}
55
56static inline void ratelimit_state_exit(struct ratelimit_state *rs)
57{
58 if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
59 return;
60
61 if (rs->missed) {
62 pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
63 current->comm, rs->missed);
64 rs->missed = 0;
65 }
66}
67
68static inline void
69ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
70{
71 rs->flags = flags;
72}
73
74extern struct ratelimit_state printk_ratelimit_state;
75
76extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
77#define __ratelimit(state) ___ratelimit(state, __func__)
78
79#ifdef CONFIG_PRINTK
80
81#define WARN_ON_RATELIMIT(condition, state) ({ \
82 bool __rtn_cond = !!(condition); \
83 WARN_ON(__rtn_cond && __ratelimit(state)); \
84 __rtn_cond; \
85})
86
87#define WARN_RATELIMIT(condition, format, ...) \
88({ \
89 static DEFINE_RATELIMIT_STATE(_rs, \
90 DEFAULT_RATELIMIT_INTERVAL, \
91 DEFAULT_RATELIMIT_BURST); \
92 int rtn = !!(condition); \
93 \
94 if (unlikely(rtn && __ratelimit(&_rs))) \
95 WARN(rtn, format, ##__VA_ARGS__); \
96 \
97 rtn; \
98})
99
100#else
101
102#define WARN_ON_RATELIMIT(condition, state) \
103 WARN_ON(condition)
104
105#define WARN_RATELIMIT(condition, format, ...) \
106({ \
107 int rtn = WARN(condition, format, ##__VA_ARGS__); \
108 rtn; \
109})
110
111#endif
112
113#endif /* _LINUX_RATELIMIT_H */
114