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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /lib/ratelimit.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/ratelimit.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/lib/ratelimit.c b/lib/ratelimit.c new file mode 100644 index 0000000000..ce945c1798 --- /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 <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. + */ + +#include <linux/ratelimit.h> +#include <linux/jiffies.h> +#include <linux/export.h> + +/* + * __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); |