1 // SPDX-License-Identifier: GPL-2.0-only
3 * ratelimit.c - Do something with rate limit.
5 * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com>
7 * 2008-05-01 rewrite the function and use a ratelimit_state data struct as
8 * parameter. Now every user can use their own standalone ratelimit_state.
11 #include <linux/ratelimit.h>
12 #include <linux/jiffies.h>
13 #include <linux/export.h>
16 * __ratelimit - rate limiting
17 * @rs: ratelimit_state data
18 * @func: name of calling function
20 * This enforces a rate limit: not more than @rs->burst callbacks
21 * in every @rs->interval
24 * 0 means callbacks will be suppressed.
25 * 1 means go ahead and do it.
27 int ___ratelimit(struct ratelimit_state *rs, const char *func)
35 * If we contend on this state's lock then almost
36 * by definition we are too busy to print a message,
37 * in addition to the one that will be printed by
38 * the entity that is holding the lock already:
40 if (!raw_spin_trylock(&rs->lock))
46 if (time_is_before_jiffies(rs->begin + rs->interval)) {
48 if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) {
50 "%s: %d callbacks suppressed\n",
58 if (rs->burst && rs->burst > rs->printed) {
65 raw_spin_unlock(&rs->lock);
69 EXPORT_SYMBOL(___ratelimit);