| /* |
| * 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/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) |
| { |
| 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); |