From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- lib/ratelimit.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 lib/ratelimit.c (limited to 'lib/ratelimit.c') diff --git a/lib/ratelimit.c b/lib/ratelimit.c new file mode 100644 index 000000000..40e03ea2a --- /dev/null +++ b/lib/ratelimit.c @@ -0,0 +1,67 @@ +/* + * ratelimit.c - Do something with rate limit. + * + * Isolated from kernel/printk.c by Dave Young + * + * 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 +#include +#include + +/* + * __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) + 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; + } + raw_spin_unlock_irqrestore(&rs->lock, flags); + + return ret; +} +EXPORT_SYMBOL(___ratelimit); -- cgit v1.2.3-54-g00ecf