root/include/linux/ratelimit.h

INCLUDED FROM

DEFINITIONS

1. ratelimit_state_init

#ifndef _LINUX_RATELIMIT_H
#define _LINUX_RATELIMIT_H

#include <linux/param.h>
#include <linux/spinlock.h>

#define DEFAULT_RATELIMIT_INTERVAL      (5 * HZ)
#define DEFAULT_RATELIMIT_BURST         10

struct ratelimit_state {
        raw_spinlock_t  lock;           /* protect the state */

        int             interval;
        int             burst;
        int             printed;
        int             missed;
        unsigned long   begin;
};

#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)         \
                                                                        \
        struct ratelimit_state name = {                                 \
                .lock           = __RAW_SPIN_LOCK_UNLOCKED(name.lock),  \
                .interval       = interval_init,                        \
                .burst          = burst_init,                           \
        }

static inline void ratelimit_state_init(struct ratelimit_state *rs,
                                        int interval, int burst)
{
        raw_spin_lock_init(&rs->lock);
        rs->interval = interval;
        rs->burst = burst;
        rs->printed = 0;
        rs->missed = 0;
        rs->begin = 0;
}

extern struct ratelimit_state printk_ratelimit_state;

extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
#define __ratelimit(state) ___ratelimit(state, __func__)

#ifdef CONFIG_PRINTK

#define WARN_ON_RATELIMIT(condition, state)                     \
                WARN_ON((condition) && __ratelimit(state))

#define WARN_RATELIMIT(condition, format, ...)                  \
({                                                              \
        static DEFINE_RATELIMIT_STATE(_rs,                      \
                                      DEFAULT_RATELIMIT_INTERVAL,       \
                                      DEFAULT_RATELIMIT_BURST); \
        int rtn = !!(condition);                                \
                                                                \
        if (unlikely(rtn && __ratelimit(&_rs)))                 \
                WARN(rtn, format, ##__VA_ARGS__);               \
                                                                \
        rtn;                                                    \
})

#else

#define WARN_ON_RATELIMIT(condition, state)                     \
        WARN_ON(condition)

#define WARN_RATELIMIT(condition, format, ...)                  \
({                                                              \
        int rtn = WARN(condition, format, ##__VA_ARGS__);       \
        rtn;                                                    \
})

#endif

#endif /* _LINUX_RATELIMIT_H */