/* * 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/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);