Commit | Line | Data |
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4e3c1b9b MD |
1 | /* |
2 | * ltt-events.c | |
3 | * | |
4 | * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Holds LTTng per-session event registry. | |
7 | */ | |
8 | ||
9 | #include <linux/module.h> | |
10 | #include "ltt-events.h" | |
11 | ||
12 | static LIST_HEAD(sessions); | |
13 | static DEFINE_MUTEX(sessions_mutex); | |
14 | static struct kmem_cache *event_cache; | |
15 | ||
abcca994 MD |
16 | static void synchronize_trace(void) |
17 | { | |
18 | synchronize_sched(); | |
19 | #ifdef CONFIG_PREEMPT_RT | |
20 | synchronize_rcu(); | |
21 | #endif | |
22 | } | |
23 | ||
4e3c1b9b MD |
24 | struct ltt_session *ltt_session_create(char *name) |
25 | { | |
26 | struct ltt_session *session; | |
27 | ||
28 | mutex_lock(&sessions_mutex); | |
29 | list_for_each_entry(session, &sessions, list) | |
30 | if (!strcmp(session->name, name)) | |
31 | goto exist; | |
32 | session = kmalloc(sizeof(struct ltt_session) + strlen(name) + 1); | |
33 | if (!session) | |
34 | return NULL; | |
35 | strcpy(session->name, name); | |
36 | INIT_LIST_HEAD(&session->chan); | |
37 | list_add(&session->list, &sessions); | |
38 | mutex_unlock(&sessions_mutex); | |
39 | return session; | |
40 | ||
41 | exist: | |
42 | mutex_unlock(&sessions_mutex); | |
43 | return NULL; | |
44 | } | |
45 | ||
46 | int ltt_session_destroy(struct ltt_session *session) | |
47 | { | |
48 | struct ltt_channel *chan, *tmpchan; | |
49 | struct ltt_event *event, *tmpevent; | |
50 | ||
51 | mutex_lock(&sessions_mutex); | |
abcca994 MD |
52 | session->active = 0; |
53 | synchronize_trace(); /* Wait for in-flight events to complete */ | |
4e3c1b9b MD |
54 | list_for_each_entry_safe(event, tmpevent, &session->events, list) |
55 | _ltt_event_destroy(event); | |
56 | list_for_each_entry_safe(chan, tmpchan, &session->chan, list) | |
57 | _ltt_channel_destroy(chan); | |
58 | list_del(&session->list); | |
59 | mutex_unlock(&sessions_mutex); | |
60 | kfree(session); | |
61 | } | |
62 | ||
63 | struct ltt_channel *ltt_channel_create(struct ltt_session *session, char *name, | |
64 | int overwrite, void *buf_addr, | |
65 | size_t subbuf_size, size_t num_subbuf, | |
66 | unsigned int switch_timer_interval, | |
67 | unsigned int read_timer_interval) | |
68 | { | |
69 | struct ltt_channel *chan; | |
70 | ||
71 | mutex_lock(&sessions_mutex); | |
e5382b6d MD |
72 | if (session->active) |
73 | goto active; /* Refuse to add channel to active session */ | |
4e3c1b9b MD |
74 | list_for_each_entry(chan, &session->chan, list) |
75 | if (!strcmp(chan->name, name)) | |
76 | goto exist; | |
77 | chan = kmalloc(sizeof(struct ltt_channel) + strlen(name) + 1, GFP_KERNEL); | |
78 | if (!chan) | |
79 | return NULL; | |
80 | strcpy(chan->name, name); | |
81 | chan->session = session; | |
82 | ||
83 | /* TODO: create rb channel */ | |
84 | list_add(&chan->list, &session->chan); | |
85 | mutex_unlock(&sessions_mutex); | |
86 | return chan; | |
87 | ||
88 | exist: | |
e5382b6d | 89 | active: |
4e3c1b9b MD |
90 | mutex_unlock(&sessions_mutex); |
91 | return NULL; | |
92 | } | |
93 | ||
94 | /* | |
95 | * Only used internally at session destruction. | |
96 | */ | |
97 | int _ltt_channel_destroy(struct ltt_channel *chan) | |
98 | { | |
abcca994 | 99 | /* TODO: destroy rb channel */ |
4e3c1b9b MD |
100 | list_del(&chan->list); |
101 | kfree(chan); | |
102 | } | |
103 | ||
e5382b6d MD |
104 | /* |
105 | * Supports event creation while tracing session is active. | |
106 | */ | |
4e3c1b9b MD |
107 | struct ltt_event *ltt_event_create(struct ltt_channel *chan, char *name, |
108 | void *filter) | |
109 | { | |
110 | struct ltt_event *event; | |
3d084699 | 111 | int ret; |
4e3c1b9b MD |
112 | |
113 | mutex_lock(&sessions_mutex); | |
e5382b6d MD |
114 | if (chan->free_event_id == -1UL) |
115 | goto full; | |
4e3c1b9b MD |
116 | /* |
117 | * This is O(n^2) (for each event loop called at event creation). | |
118 | * Might require a hash if we have lots of events. | |
119 | */ | |
120 | list_for_each_entry(event, &chan->session->events, list) | |
121 | if (!strcmp(event->name, name)) | |
122 | goto exist; | |
123 | event = kmem_cache_zalloc(events_cache, GFP_KERNEL); | |
124 | if (!event) | |
125 | goto cache_error; | |
126 | event->name = kmalloc(strlen(name) + 1, GFP_KERNEL); | |
127 | if (!event->name) | |
128 | goto error; | |
129 | strcpy(event->name, name); | |
130 | event->chan = chan; | |
131 | event->filter = filter; | |
e5382b6d | 132 | event->id = chan->free_event_id++; |
4e3c1b9b | 133 | mutex_unlock(&sessions_mutex); |
e5382b6d MD |
134 | /* Populate ltt_event structure before tracepoint registration. */ |
135 | smp_wmb(); | |
4e3c1b9b MD |
136 | return event; |
137 | ||
138 | error: | |
139 | kmem_cache_free(event); | |
140 | cache_error: | |
141 | exist: | |
e5382b6d | 142 | full: |
4e3c1b9b MD |
143 | mutex_unlock(&sessions_mutex); |
144 | return NULL; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Only used internally at session destruction. | |
149 | */ | |
150 | int _ltt_event_destroy(struct ltt_event *event) | |
151 | { | |
152 | /* TODO unregister from tracepoint */ | |
153 | kfree(event->name); | |
154 | kmem_cache_free(event); | |
155 | } | |
156 | ||
157 | static int __init ltt_events_init(void) | |
158 | { | |
159 | int ret; | |
160 | ||
161 | events_cache = KMEM_CACHE(ltt_event, 0); | |
162 | if (!events_cache) | |
163 | return -ENOMEM; | |
92e94819 MD |
164 | |
165 | /* TODO: show ABI to userspace */ | |
166 | ||
4e3c1b9b MD |
167 | return 0; |
168 | } | |
169 | ||
170 | static void __exit ltt_events_exit(void) | |
171 | { | |
92e94819 MD |
172 | struct ltt_session *session, *tmpsession; |
173 | ||
174 | /* TODO: hide ABI from userspace, wait for callers to release refs. */ | |
175 | ||
176 | list_for_each_entry_safe(session, tmpsession, &sessions, list) | |
177 | ltt_session_destroy(session); | |
4e3c1b9b MD |
178 | kmem_cache_destroy(events_cache); |
179 | } | |
92e94819 MD |
180 | |
181 | MODULE_LICENSE("GPL and additional rights"); | |
182 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); | |
183 | MODULE_DESCRIPTION("LTTng Events"); |