linux-stable/lib/ratelimit.c
Thomas Gleixner 55716d2643 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428
Based on 1 normalized pattern(s):

  this file is released under the gplv2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 68 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190114.292346262@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:16 +02:00

70 lines
1.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 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.
*/
#include <linux/ratelimit.h>
#include <linux/jiffies.h>
#include <linux/export.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) {
if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) {
printk_deferred(KERN_WARNING
"%s: %d callbacks suppressed\n",
func, rs->missed);
rs->missed = 0;
}
}
rs->begin = jiffies;
rs->printed = 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);