ratelimit.h 2.63 KB
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_RATELIMIT_H
#define _LINUX_RATELIMIT_H
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#include <linux/param.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#define DEFAULT_RATELIMIT_INTERVAL	(5 * HZ)
#define DEFAULT_RATELIMIT_BURST		10
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/* issue num suppressed message on exit */
#define RATELIMIT_MSG_ON_RELEASE	BIT(0)

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struct ratelimit_state {
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	raw_spinlock_t	lock;		/* protect the state */
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	int		interval;
	int		burst;
	int		printed;
	int		missed;
	unsigned long	begin;
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	unsigned long	flags;
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};

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#define RATELIMIT_STATE_INIT(name, interval_init, burst_init) {		\
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		.lock		= __RAW_SPIN_LOCK_UNLOCKED(name.lock),	\
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		.interval	= interval_init,			\
		.burst		= burst_init,				\
	}
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#define RATELIMIT_STATE_INIT_DISABLED					\
	RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)

#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)		\
									\
	struct ratelimit_state name =					\
		RATELIMIT_STATE_INIT(name, interval_init, burst_init)	\

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static inline void ratelimit_state_init(struct ratelimit_state *rs,
					int interval, int burst)
{
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	memset(rs, 0, sizeof(*rs));

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	raw_spin_lock_init(&rs->lock);
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	rs->interval	= interval;
	rs->burst	= burst;
}

static inline void ratelimit_default_init(struct ratelimit_state *rs)
{
	return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
					DEFAULT_RATELIMIT_BURST);
}

static inline void ratelimit_state_exit(struct ratelimit_state *rs)
{
	if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
		return;

	if (rs->missed) {
		pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
			current->comm, rs->missed);
		rs->missed = 0;
	}
}

static inline void
ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
{
	rs->flags = flags;
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}

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extern struct ratelimit_state printk_ratelimit_state;

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

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

#else

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

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

#endif

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#endif /* _LINUX_RATELIMIT_H */