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12#include <linux/list.h>
13#include <linux/rbtree.h>
14#include <linux/debugfs.h>
15#include "trace_stat.h"
16#include "trace.h"
17
18
19
20
21
22
23
24struct stat_node {
25 struct rb_node node;
26 void *stat;
27};
28
29
30struct stat_session {
31 struct list_head session_list;
32 struct tracer_stat *ts;
33 struct rb_root stat_root;
34 struct mutex stat_mutex;
35 struct dentry *file;
36};
37
38
39static LIST_HEAD(all_stat_sessions);
40static DEFINE_MUTEX(all_stat_sessions_mutex);
41
42
43static struct dentry *stat_dir;
44
45
46
47
48
49
50
51
52static struct rb_node *release_next(struct tracer_stat *ts,
53 struct rb_node *node)
54{
55 struct stat_node *snode;
56 struct rb_node *parent = rb_parent(node);
57
58 if (node->rb_left)
59 return node->rb_left;
60 else if (node->rb_right)
61 return node->rb_right;
62 else {
63 if (!parent)
64 ;
65 else if (parent->rb_left == node)
66 parent->rb_left = NULL;
67 else
68 parent->rb_right = NULL;
69
70 snode = container_of(node, struct stat_node, node);
71 if (ts->stat_release)
72 ts->stat_release(snode->stat);
73 kfree(snode);
74
75 return parent;
76 }
77}
78
79static void __reset_stat_session(struct stat_session *session)
80{
81 struct rb_node *node = session->stat_root.rb_node;
82
83 while (node)
84 node = release_next(session->ts, node);
85
86 session->stat_root = RB_ROOT;
87}
88
89static void reset_stat_session(struct stat_session *session)
90{
91 mutex_lock(&session->stat_mutex);
92 __reset_stat_session(session);
93 mutex_unlock(&session->stat_mutex);
94}
95
96static void destroy_session(struct stat_session *session)
97{
98 debugfs_remove(session->file);
99 __reset_stat_session(session);
100 mutex_destroy(&session->stat_mutex);
101 kfree(session);
102}
103
104typedef int (*cmp_stat_t)(void *, void *);
105
106static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
107{
108 struct rb_node **new = &(root->rb_node), *parent = NULL;
109 struct stat_node *data;
110
111 data = kzalloc(sizeof(*data), GFP_KERNEL);
112 if (!data)
113 return -ENOMEM;
114 data->stat = stat;
115
116
117
118
119
120 while (*new) {
121 struct stat_node *this;
122 int result;
123
124 this = container_of(*new, struct stat_node, node);
125 result = cmp(data->stat, this->stat);
126
127 parent = *new;
128 if (result >= 0)
129 new = &((*new)->rb_left);
130 else
131 new = &((*new)->rb_right);
132 }
133
134 rb_link_node(&data->node, parent, new);
135 rb_insert_color(&data->node, root);
136 return 0;
137}
138
139
140
141
142
143
144static int dummy_cmp(void *p1, void *p2)
145{
146 return -1;
147}
148
149
150
151
152
153
154static int stat_seq_init(struct stat_session *session)
155{
156 struct tracer_stat *ts = session->ts;
157 struct rb_root *root = &session->stat_root;
158 void *stat;
159 int ret = 0;
160 int i;
161
162 mutex_lock(&session->stat_mutex);
163 __reset_stat_session(session);
164
165 if (!ts->stat_cmp)
166 ts->stat_cmp = dummy_cmp;
167
168 stat = ts->stat_start(ts);
169 if (!stat)
170 goto exit;
171
172 ret = insert_stat(root, stat, ts->stat_cmp);
173 if (ret)
174 goto exit;
175
176
177
178
179 for (i = 1; ; i++) {
180 stat = ts->stat_next(stat, i);
181
182
183 if (!stat)
184 break;
185
186 ret = insert_stat(root, stat, ts->stat_cmp);
187 if (ret)
188 goto exit_free_rbtree;
189 }
190
191exit:
192 mutex_unlock(&session->stat_mutex);
193 return ret;
194
195exit_free_rbtree:
196 __reset_stat_session(session);
197 mutex_unlock(&session->stat_mutex);
198 return ret;
199}
200
201
202static void *stat_seq_start(struct seq_file *s, loff_t *pos)
203{
204 struct stat_session *session = s->private;
205 struct rb_node *node;
206 int n = *pos;
207 int i;
208
209
210 mutex_lock(&session->stat_mutex);
211
212
213 if (session->ts->stat_headers) {
214 if (n == 0)
215 return SEQ_START_TOKEN;
216 n--;
217 }
218
219 node = rb_first(&session->stat_root);
220 for (i = 0; node && i < n; i++)
221 node = rb_next(node);
222
223 return node;
224}
225
226static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
227{
228 struct stat_session *session = s->private;
229 struct rb_node *node = p;
230
231 (*pos)++;
232
233 if (p == SEQ_START_TOKEN)
234 return rb_first(&session->stat_root);
235
236 return rb_next(node);
237}
238
239static void stat_seq_stop(struct seq_file *s, void *p)
240{
241 struct stat_session *session = s->private;
242 mutex_unlock(&session->stat_mutex);
243}
244
245static int stat_seq_show(struct seq_file *s, void *v)
246{
247 struct stat_session *session = s->private;
248 struct stat_node *l = container_of(v, struct stat_node, node);
249
250 if (v == SEQ_START_TOKEN)
251 return session->ts->stat_headers(s);
252
253 return session->ts->stat_show(s, l->stat);
254}
255
256static const struct seq_operations trace_stat_seq_ops = {
257 .start = stat_seq_start,
258 .next = stat_seq_next,
259 .stop = stat_seq_stop,
260 .show = stat_seq_show
261};
262
263
264static int tracing_stat_open(struct inode *inode, struct file *file)
265{
266 int ret;
267 struct seq_file *m;
268 struct stat_session *session = inode->i_private;
269
270 ret = stat_seq_init(session);
271 if (ret)
272 return ret;
273
274 ret = seq_open(file, &trace_stat_seq_ops);
275 if (ret) {
276 reset_stat_session(session);
277 return ret;
278 }
279
280 m = file->private_data;
281 m->private = session;
282 return ret;
283}
284
285
286
287
288static int tracing_stat_release(struct inode *i, struct file *f)
289{
290 struct stat_session *session = i->i_private;
291
292 reset_stat_session(session);
293
294 return seq_release(i, f);
295}
296
297static const struct file_operations tracing_stat_fops = {
298 .open = tracing_stat_open,
299 .read = seq_read,
300 .llseek = seq_lseek,
301 .release = tracing_stat_release
302};
303
304static int tracing_stat_init(void)
305{
306 struct dentry *d_tracing;
307
308 d_tracing = tracing_init_dentry();
309
310 stat_dir = debugfs_create_dir("trace_stat", d_tracing);
311 if (!stat_dir)
312 pr_warning("Could not create debugfs "
313 "'trace_stat' entry\n");
314 return 0;
315}
316
317static int init_stat_file(struct stat_session *session)
318{
319 if (!stat_dir && tracing_stat_init())
320 return -ENODEV;
321
322 session->file = debugfs_create_file(session->ts->name, 0644,
323 stat_dir,
324 session, &tracing_stat_fops);
325 if (!session->file)
326 return -ENOMEM;
327 return 0;
328}
329
330int register_stat_tracer(struct tracer_stat *trace)
331{
332 struct stat_session *session, *node;
333 int ret;
334
335 if (!trace)
336 return -EINVAL;
337
338 if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
339 return -EINVAL;
340
341
342 mutex_lock(&all_stat_sessions_mutex);
343 list_for_each_entry(node, &all_stat_sessions, session_list) {
344 if (node->ts == trace) {
345 mutex_unlock(&all_stat_sessions_mutex);
346 return -EINVAL;
347 }
348 }
349 mutex_unlock(&all_stat_sessions_mutex);
350
351
352 session = kzalloc(sizeof(*session), GFP_KERNEL);
353 if (!session)
354 return -ENOMEM;
355
356 session->ts = trace;
357 INIT_LIST_HEAD(&session->session_list);
358 mutex_init(&session->stat_mutex);
359
360 ret = init_stat_file(session);
361 if (ret) {
362 destroy_session(session);
363 return ret;
364 }
365
366
367 mutex_lock(&all_stat_sessions_mutex);
368 list_add_tail(&session->session_list, &all_stat_sessions);
369 mutex_unlock(&all_stat_sessions_mutex);
370
371 return 0;
372}
373
374void unregister_stat_tracer(struct tracer_stat *trace)
375{
376 struct stat_session *node, *tmp;
377
378 mutex_lock(&all_stat_sessions_mutex);
379 list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
380 if (node->ts == trace) {
381 list_del(&node->session_list);
382 destroy_session(node);
383 break;
384 }
385 }
386 mutex_unlock(&all_stat_sessions_mutex);
387}
388