68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
/*
|
|
* 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 (!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;
|
|
}
|
|
spin_unlock_irqrestore(&rs->lock, flags);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(___ratelimit);
|