LXR linux/include/linux/ratelimit.h

   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