From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- lib/ratelimit.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 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..ce945c179 --- /dev/null +++ b/lib/ratelimit.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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. + */ + +#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) +{ + /* Paired with WRITE_ONCE() in .proc_handler(). + * Changing two values seperately could be inconsistent + * and some message could be lost. (See: net_ratelimit_state). + */ + int interval = READ_ONCE(rs->interval); + int burst = READ_ONCE(rs->burst); + unsigned long flags; + int ret; + + if (!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 + 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 (burst && 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