58 lines
1.3 KiB
C
58 lines
1.3 KiB
C
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/*
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* ratelimit.c - Do something with rate limit.
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*
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* Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com>
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*
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* 2008-05-01 rewrite the function and use a ratelimit_state data struct as
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* parameter. Now every user can use their own standalone ratelimit_state.
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*
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* This file is released under the GPLv2.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/jiffies.h>
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#include <linux/module.h>
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static DEFINE_SPINLOCK(ratelimit_lock);
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/*
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* __ratelimit - rate limiting
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* @rs: ratelimit_state data
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*
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* This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
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* in every @rs->ratelimit_jiffies
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*/
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int __ratelimit(struct ratelimit_state *rs)
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{
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unsigned long flags;
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if (!rs->interval)
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return 1;
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spin_lock_irqsave(&ratelimit_lock, flags);
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if (!rs->begin)
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rs->begin = jiffies;
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if (time_is_before_jiffies(rs->begin + rs->interval)) {
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if (rs->missed)
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printk(KERN_WARNING "%s: %d callbacks suppressed\n",
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__func__, rs->missed);
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rs->begin = 0;
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rs->printed = 0;
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rs->missed = 0;
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}
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if (rs->burst && rs->burst > rs->printed)
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goto print;
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rs->missed++;
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spin_unlock_irqrestore(&ratelimit_lock, flags);
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return 0;
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print:
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rs->printed++;
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spin_unlock_irqrestore(&ratelimit_lock, flags);
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return 1;
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}
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EXPORT_SYMBOL(__ratelimit);
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