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Commit | Line | Data |
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5f97a5a8 DY |
1 | /* |
2 | * ratelimit.c - Do something with rate limit. | |
3 | * | |
4 | * Isolated from kernel/printk.c by Dave Young <hidave.darkstar@gmail.com> | |
5 | * | |
717115e1 DY |
6 | * 2008-05-01 rewrite the function and use a ratelimit_state data struct as |
7 | * parameter. Now every user can use their own standalone ratelimit_state. | |
8 | * | |
5f97a5a8 | 9 | * This file is released under the GPLv2. |
5f97a5a8 DY |
10 | */ |
11 | ||
3fff4c42 | 12 | #include <linux/ratelimit.h> |
5f97a5a8 DY |
13 | #include <linux/jiffies.h> |
14 | #include <linux/module.h> | |
15 | ||
16 | /* | |
17 | * __ratelimit - rate limiting | |
717115e1 | 18 | * @rs: ratelimit_state data |
5f97a5a8 | 19 | * |
717115e1 DY |
20 | * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks |
21 | * in every @rs->ratelimit_jiffies | |
5f97a5a8 | 22 | */ |
5c828713 | 23 | int ___ratelimit(struct ratelimit_state *rs, const char *func) |
5f97a5a8 | 24 | { |
4d9c377c | 25 | unsigned long flags; |
979f693d | 26 | int ret; |
4d9c377c | 27 | |
717115e1 DY |
28 | if (!rs->interval) |
29 | return 1; | |
5f97a5a8 | 30 | |
edaac8e3 IM |
31 | /* |
32 | * If we contend on this state's lock then almost | |
33 | * by definition we are too busy to print a message, | |
34 | * in addition to the one that will be printed by | |
35 | * the entity that is holding the lock already: | |
36 | */ | |
37 | if (!spin_trylock_irqsave(&rs->lock, flags)) | |
38 | return 1; | |
39 | ||
717115e1 DY |
40 | if (!rs->begin) |
41 | rs->begin = jiffies; | |
5f97a5a8 | 42 | |
717115e1 DY |
43 | if (time_is_before_jiffies(rs->begin + rs->interval)) { |
44 | if (rs->missed) | |
45 | printk(KERN_WARNING "%s: %d callbacks suppressed\n", | |
5c828713 | 46 | func, rs->missed); |
979f693d | 47 | rs->begin = 0; |
717115e1 | 48 | rs->printed = 0; |
979f693d | 49 | rs->missed = 0; |
5f97a5a8 | 50 | } |
979f693d IM |
51 | if (rs->burst && rs->burst > rs->printed) { |
52 | rs->printed++; | |
53 | ret = 1; | |
54 | } else { | |
55 | rs->missed++; | |
56 | ret = 0; | |
57 | } | |
58 | spin_unlock_irqrestore(&rs->lock, flags); | |
717115e1 | 59 | |
979f693d | 60 | return ret; |
5f97a5a8 | 61 | } |
5c828713 | 62 | EXPORT_SYMBOL(___ratelimit); |