/* * ratelimit.c - Do something with rate limit. * * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com> * * 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/ratelimit.h>#include <linux/jiffies.h>#include <linux/module.h> /* * __ratelimit - rate limiting * @rs: ratelimit_state data * @func: name of calling function * * This enforces a rate limit: not more than @rs->burst callbacks * in every @rs->interval * * RETURNS: * 0 means callbacks will be suppressed. * 1 means go ahead and do it. */int ___ratelimit(struct ratelimit_state *rs, const char *func){	unsigned long flags;	int ret; 	if (!rs->interval)		return 1; 	/*	 * If we contend on this state's lock then almost	 * by definition we are too busy to print a message,	 * in addition to the one that will be printed by	 * the entity that is holding the lock already:	 */	if (!raw_spin_trylock_irqsave(&rs->lock, flags))		return 0; 	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) {		rs->printed++;		ret = 1;	} else {		rs->missed++;		ret = 0;	}	raw_spin_unlock_irqrestore(&rs->lock, flags); 	return ret;}EXPORT_SYMBOL(___ratelimit);