[linux.git] / lib / ratelimit.c

/*
 * ratelimit.c - Do something with rate limit.
 *
 * Isolated from kernel/printk.c by Dave Young <[email protected]>
 *
 * 2008-05-01 rewrite the function and use a ratelimit_state data struct as
 * parameter. Now every user can use their own standalone ratelimit_state.
 *
 * This file is released under the GPLv2.
 *
 */

#include <linux/kernel.h>
#include <linux/jiffies.h>
#include <linux/module.h>

static DEFINE_SPINLOCK(ratelimit_lock);

/*
 * __ratelimit - rate limiting
 * @rs: ratelimit_state data
 *
 * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
 * in every @rs->ratelimit_jiffies
 */
int __ratelimit(struct ratelimit_state *rs)
{
	unsigned long flags;

	if (!rs->interval)
		return 1;

	spin_lock_irqsave(&ratelimit_lock, flags);
	if (!rs->begin)
		rs->begin = jiffies;

	if (time_is_before_jiffies(rs->begin + rs->interval)) {
		if (rs->missed)
			printk(KERN_WARNING "%s: %d callbacks suppressed\n",
				__func__, rs->missed);
		rs->begin = 0;
		rs->printed = 0;
		rs->missed = 0;
	}
	if (rs->burst && rs->burst > rs->printed)
		goto print;

	rs->missed++;
	spin_unlock_irqrestore(&ratelimit_lock, flags);
	return 0;

print:
	rs->printed++;
	spin_unlock_irqrestore(&ratelimit_lock, flags);
	return 1;
}
EXPORT_SYMBOL(__ratelimit);
Commit	Line	Data
5f97a5a8 DY	1	/*
	2	* ratelimit.c - Do something with rate limit.
	3	*
	4	* Isolated from kernel/printk.c by Dave Young <[email protected]>
	5	*
717115e1 DY	6	* 2008-05-01 rewrite the function and use a ratelimit_state data struct as
	7	* parameter. Now every user can use their own standalone ratelimit_state.
	8	*
5f97a5a8 DY	9	* This file is released under the GPLv2.
	10	*
	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/jiffies.h>
	15	#include <linux/module.h>
	16
717115e1	17	static DEFINE_SPINLOCK(ratelimit_lock);
717115e1	18
5f97a5a8 DY	19	/*
5f97a5a8 DY	20	* __ratelimit - rate limiting
717115e1	21	* @rs: ratelimit_state data
5f97a5a8	22	*
717115e1 DY	23	* This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
717115e1 DY	24	* in every @rs->ratelimit_jiffies
5f97a5a8	25	*/
717115e1	26	int __ratelimit(struct ratelimit_state *rs)
5f97a5a8	27	{
4d9c377c AD	28	unsigned long flags;
4d9c377c AD	29
717115e1 DY	30	if (!rs->interval)
717115e1 DY	31	return 1;
5f97a5a8 DY	32
5f97a5a8 DY	33	spin_lock_irqsave(&ratelimit_lock, flags);
717115e1 DY	34	if (!rs->begin)
717115e1 DY	35	rs->begin = jiffies;
5f97a5a8	36
717115e1 DY	37	if (time_is_before_jiffies(rs->begin + rs->interval)) {
	38	if (rs->missed)
	39	printk(KERN_WARNING "%s: %d callbacks suppressed\n",
	40	__func__, rs->missed);
	41	rs->begin = 0;
	42	rs->printed = 0;
	43	rs->missed = 0;
5f97a5a8	44	}
717115e1 DY	45	if (rs->burst && rs->burst > rs->printed)
	46	goto print;
	47
	48	rs->missed++;
5f97a5a8 DY	49	spin_unlock_irqrestore(&ratelimit_lock, flags);
5f97a5a8 DY	50	return 0;
717115e1 DY	51
	52	print:
	53	rs->printed++;
	54	spin_unlock_irqrestore(&ratelimit_lock, flags);
	55	return 1;
5f97a5a8 DY	56	}
5f97a5a8 DY	57	EXPORT_SYMBOL(__ratelimit);