Commit | Line | Data |
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02119ee5 MD |
1 | /* |
2 | * ltt-probes.c | |
3 | * | |
4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Holds LTTng probes registry. | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include <linux/list.h> | |
11 | #include <linux/mutex.h> | |
02119ee5 | 12 | |
85a9ca7f | 13 | #include "ltt-events.h" |
02119ee5 MD |
14 | |
15 | static LIST_HEAD(probe_list); | |
16 | static DEFINE_MUTEX(probe_mutex); | |
02119ee5 | 17 | |
85a9ca7f MD |
18 | static |
19 | const struct lttng_event_desc *find_event(const char *name) | |
02119ee5 | 20 | { |
85a9ca7f MD |
21 | struct lttng_probe_desc *probe_desc; |
22 | int i; | |
02119ee5 | 23 | |
85a9ca7f MD |
24 | list_for_each_entry(probe_desc, &probe_list, head) { |
25 | for (i = 0; i < probe_desc->nr_events; i++) { | |
26 | if (!strcmp(probe_desc->event_desc[i].name, name)) | |
27 | return &probe_desc->event_desc[i]; | |
28 | } | |
02119ee5 MD |
29 | } |
30 | return NULL; | |
31 | } | |
32 | ||
85a9ca7f MD |
33 | /* |
34 | * TODO: registration of probe descriptions in dynamically allocated memory (not | |
35 | * directly in a module memory) will require some care for refcounting: it's | |
36 | * currently done by just refcounting the module in event_get/put. | |
37 | */ | |
38 | int ltt_probe_register(struct lttng_probe_desc *desc) | |
02119ee5 | 39 | { |
02119ee5 | 40 | int ret = 0; |
85a9ca7f | 41 | int i; |
02119ee5 MD |
42 | |
43 | mutex_lock(&probe_mutex); | |
85a9ca7f MD |
44 | /* |
45 | * TODO: This is O(N^2). Turn into a hash table when probe registration | |
46 | * overhead becomes an issue. | |
47 | */ | |
48 | for (i = 0; i < desc->nr_events; i++) { | |
49 | if (find_event(desc->event_desc[i].name)) { | |
50 | ret = -EEXIST; | |
51 | goto end; | |
52 | } | |
02119ee5 | 53 | } |
85a9ca7f | 54 | list_add(&desc->head, &probe_list); |
02119ee5 MD |
55 | end: |
56 | mutex_unlock(&probe_mutex); | |
57 | return ret; | |
58 | } | |
59 | EXPORT_SYMBOL_GPL(ltt_probe_register); | |
60 | ||
85a9ca7f | 61 | void ltt_probe_unregister(struct lttng_probe_desc *desc) |
02119ee5 | 62 | { |
02119ee5 | 63 | mutex_lock(&probe_mutex); |
85a9ca7f | 64 | list_del(&desc->head); |
02119ee5 | 65 | mutex_unlock(&probe_mutex); |
02119ee5 MD |
66 | } |
67 | EXPORT_SYMBOL_GPL(ltt_probe_unregister); | |
68 | ||
85a9ca7f | 69 | const struct lttng_event_desc *ltt_event_get(const char *name) |
02119ee5 | 70 | { |
85a9ca7f | 71 | const struct lttng_event_desc *event; |
02119ee5 MD |
72 | int ret; |
73 | ||
74 | mutex_lock(&probe_mutex); | |
85a9ca7f | 75 | event = find_event(name); |
c099397a | 76 | mutex_unlock(&probe_mutex); |
85a9ca7f | 77 | if (!event) |
c099397a | 78 | return NULL; |
85a9ca7f | 79 | ret = try_module_get(__module_text_address((unsigned long) event)); |
02119ee5 | 80 | WARN_ON_ONCE(!ret); |
85a9ca7f | 81 | return event; |
02119ee5 | 82 | } |
85a9ca7f | 83 | EXPORT_SYMBOL_GPL(ltt_event_get); |
02119ee5 | 84 | |
85a9ca7f | 85 | void ltt_event_put(const struct lttng_event_desc *event) |
02119ee5 | 86 | { |
85a9ca7f | 87 | module_put(__module_text_address((unsigned long) event)); |
02119ee5 | 88 | } |
85a9ca7f | 89 | EXPORT_SYMBOL_GPL(ltt_event_put); |