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Linux/kernel/trace/trace_events_trigger.c

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  1 /*
  2  * trace_events_trigger - trace event triggers
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License as published by
  6  * the Free Software Foundation; either version 2 of the License, or
  7  * (at your option) any later version.
  8  *
  9  * This program is distributed in the hope that it will be useful,
 10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  *
 14  * You should have received a copy of the GNU General Public License
 15  * along with this program; if not, write to the Free Software
 16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 17  *
 18  * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
 19  */
 20 
 21 #include <linux/module.h>
 22 #include <linux/ctype.h>
 23 #include <linux/mutex.h>
 24 #include <linux/slab.h>
 25 #include <linux/rculist.h>
 26 
 27 #include "trace.h"
 28 
 29 static LIST_HEAD(trigger_commands);
 30 static DEFINE_MUTEX(trigger_cmd_mutex);
 31 
 32 void trigger_data_free(struct event_trigger_data *data)
 33 {
 34         if (data->cmd_ops->set_filter)
 35                 data->cmd_ops->set_filter(NULL, data, NULL);
 36 
 37         synchronize_sched(); /* make sure current triggers exit before free */
 38         kfree(data);
 39 }
 40 
 41 /**
 42  * event_triggers_call - Call triggers associated with a trace event
 43  * @file: The trace_event_file associated with the event
 44  * @rec: The trace entry for the event, NULL for unconditional invocation
 45  *
 46  * For each trigger associated with an event, invoke the trigger
 47  * function registered with the associated trigger command.  If rec is
 48  * non-NULL, it means that the trigger requires further processing and
 49  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
 50  * trigger has a filter associated with it, rec will checked against
 51  * the filter and if the record matches the trigger will be invoked.
 52  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
 53  * in any case until the current event is written, the trigger
 54  * function isn't invoked but the bit associated with the deferred
 55  * trigger is set in the return value.
 56  *
 57  * Returns an enum event_trigger_type value containing a set bit for
 58  * any trigger that should be deferred, ETT_NONE if nothing to defer.
 59  *
 60  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 61  *
 62  * Return: an enum event_trigger_type value containing a set bit for
 63  * any trigger that should be deferred, ETT_NONE if nothing to defer.
 64  */
 65 enum event_trigger_type
 66 event_triggers_call(struct trace_event_file *file, void *rec,
 67                     struct ring_buffer_event *event)
 68 {
 69         struct event_trigger_data *data;
 70         enum event_trigger_type tt = ETT_NONE;
 71         struct event_filter *filter;
 72 
 73         if (list_empty(&file->triggers))
 74                 return tt;
 75 
 76         list_for_each_entry_rcu(data, &file->triggers, list) {
 77                 if (data->paused)
 78                         continue;
 79                 if (!rec) {
 80                         data->ops->func(data, rec, event);
 81                         continue;
 82                 }
 83                 filter = rcu_dereference_sched(data->filter);
 84                 if (filter && !filter_match_preds(filter, rec))
 85                         continue;
 86                 if (event_command_post_trigger(data->cmd_ops)) {
 87                         tt |= data->cmd_ops->trigger_type;
 88                         continue;
 89                 }
 90                 data->ops->func(data, rec, event);
 91         }
 92         return tt;
 93 }
 94 EXPORT_SYMBOL_GPL(event_triggers_call);
 95 
 96 /**
 97  * event_triggers_post_call - Call 'post_triggers' for a trace event
 98  * @file: The trace_event_file associated with the event
 99  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
100  *
101  * For each trigger associated with an event, invoke the trigger
102  * function registered with the associated trigger command, if the
103  * corresponding bit is set in the tt enum passed into this function.
104  * See @event_triggers_call for details on how those bits are set.
105  *
106  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
107  */
108 void
109 event_triggers_post_call(struct trace_event_file *file,
110                          enum event_trigger_type tt)
111 {
112         struct event_trigger_data *data;
113 
114         list_for_each_entry_rcu(data, &file->triggers, list) {
115                 if (data->paused)
116                         continue;
117                 if (data->cmd_ops->trigger_type & tt)
118                         data->ops->func(data, NULL, NULL);
119         }
120 }
121 EXPORT_SYMBOL_GPL(event_triggers_post_call);
122 
123 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
124 
125 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
126 {
127         struct trace_event_file *event_file = event_file_data(m->private);
128 
129         if (t == SHOW_AVAILABLE_TRIGGERS)
130                 return NULL;
131 
132         return seq_list_next(t, &event_file->triggers, pos);
133 }
134 
135 static void *trigger_start(struct seq_file *m, loff_t *pos)
136 {
137         struct trace_event_file *event_file;
138 
139         /* ->stop() is called even if ->start() fails */
140         mutex_lock(&event_mutex);
141         event_file = event_file_data(m->private);
142         if (unlikely(!event_file))
143                 return ERR_PTR(-ENODEV);
144 
145         if (list_empty(&event_file->triggers))
146                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
147 
148         return seq_list_start(&event_file->triggers, *pos);
149 }
150 
151 static void trigger_stop(struct seq_file *m, void *t)
152 {
153         mutex_unlock(&event_mutex);
154 }
155 
156 static int trigger_show(struct seq_file *m, void *v)
157 {
158         struct event_trigger_data *data;
159         struct event_command *p;
160 
161         if (v == SHOW_AVAILABLE_TRIGGERS) {
162                 seq_puts(m, "# Available triggers:\n");
163                 seq_putc(m, '#');
164                 mutex_lock(&trigger_cmd_mutex);
165                 list_for_each_entry_reverse(p, &trigger_commands, list)
166                         seq_printf(m, " %s", p->name);
167                 seq_putc(m, '\n');
168                 mutex_unlock(&trigger_cmd_mutex);
169                 return 0;
170         }
171 
172         data = list_entry(v, struct event_trigger_data, list);
173         data->ops->print(m, data->ops, data);
174 
175         return 0;
176 }
177 
178 static const struct seq_operations event_triggers_seq_ops = {
179         .start = trigger_start,
180         .next = trigger_next,
181         .stop = trigger_stop,
182         .show = trigger_show,
183 };
184 
185 static int event_trigger_regex_open(struct inode *inode, struct file *file)
186 {
187         int ret = 0;
188 
189         mutex_lock(&event_mutex);
190 
191         if (unlikely(!event_file_data(file))) {
192                 mutex_unlock(&event_mutex);
193                 return -ENODEV;
194         }
195 
196         if ((file->f_mode & FMODE_WRITE) &&
197             (file->f_flags & O_TRUNC)) {
198                 struct trace_event_file *event_file;
199                 struct event_command *p;
200 
201                 event_file = event_file_data(file);
202 
203                 list_for_each_entry(p, &trigger_commands, list) {
204                         if (p->unreg_all)
205                                 p->unreg_all(event_file);
206                 }
207         }
208 
209         if (file->f_mode & FMODE_READ) {
210                 ret = seq_open(file, &event_triggers_seq_ops);
211                 if (!ret) {
212                         struct seq_file *m = file->private_data;
213                         m->private = file;
214                 }
215         }
216 
217         mutex_unlock(&event_mutex);
218 
219         return ret;
220 }
221 
222 static int trigger_process_regex(struct trace_event_file *file, char *buff)
223 {
224         char *command, *next = buff;
225         struct event_command *p;
226         int ret = -EINVAL;
227 
228         command = strsep(&next, ": \t");
229         command = (command[0] != '!') ? command : command + 1;
230 
231         mutex_lock(&trigger_cmd_mutex);
232         list_for_each_entry(p, &trigger_commands, list) {
233                 if (strcmp(p->name, command) == 0) {
234                         ret = p->func(p, file, buff, command, next);
235                         goto out_unlock;
236                 }
237         }
238  out_unlock:
239         mutex_unlock(&trigger_cmd_mutex);
240 
241         return ret;
242 }
243 
244 static ssize_t event_trigger_regex_write(struct file *file,
245                                          const char __user *ubuf,
246                                          size_t cnt, loff_t *ppos)
247 {
248         struct trace_event_file *event_file;
249         ssize_t ret;
250         char *buf;
251 
252         if (!cnt)
253                 return 0;
254 
255         if (cnt >= PAGE_SIZE)
256                 return -EINVAL;
257 
258         buf = memdup_user_nul(ubuf, cnt);
259         if (IS_ERR(buf))
260                 return PTR_ERR(buf);
261 
262         strim(buf);
263 
264         mutex_lock(&event_mutex);
265         event_file = event_file_data(file);
266         if (unlikely(!event_file)) {
267                 mutex_unlock(&event_mutex);
268                 kfree(buf);
269                 return -ENODEV;
270         }
271         ret = trigger_process_regex(event_file, buf);
272         mutex_unlock(&event_mutex);
273 
274         kfree(buf);
275         if (ret < 0)
276                 goto out;
277 
278         *ppos += cnt;
279         ret = cnt;
280  out:
281         return ret;
282 }
283 
284 static int event_trigger_regex_release(struct inode *inode, struct file *file)
285 {
286         mutex_lock(&event_mutex);
287 
288         if (file->f_mode & FMODE_READ)
289                 seq_release(inode, file);
290 
291         mutex_unlock(&event_mutex);
292 
293         return 0;
294 }
295 
296 static ssize_t
297 event_trigger_write(struct file *filp, const char __user *ubuf,
298                     size_t cnt, loff_t *ppos)
299 {
300         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
301 }
302 
303 static int
304 event_trigger_open(struct inode *inode, struct file *filp)
305 {
306         return event_trigger_regex_open(inode, filp);
307 }
308 
309 static int
310 event_trigger_release(struct inode *inode, struct file *file)
311 {
312         return event_trigger_regex_release(inode, file);
313 }
314 
315 const struct file_operations event_trigger_fops = {
316         .open = event_trigger_open,
317         .read = seq_read,
318         .write = event_trigger_write,
319         .llseek = tracing_lseek,
320         .release = event_trigger_release,
321 };
322 
323 /*
324  * Currently we only register event commands from __init, so mark this
325  * __init too.
326  */
327 __init int register_event_command(struct event_command *cmd)
328 {
329         struct event_command *p;
330         int ret = 0;
331 
332         mutex_lock(&trigger_cmd_mutex);
333         list_for_each_entry(p, &trigger_commands, list) {
334                 if (strcmp(cmd->name, p->name) == 0) {
335                         ret = -EBUSY;
336                         goto out_unlock;
337                 }
338         }
339         list_add(&cmd->list, &trigger_commands);
340  out_unlock:
341         mutex_unlock(&trigger_cmd_mutex);
342 
343         return ret;
344 }
345 
346 /*
347  * Currently we only unregister event commands from __init, so mark
348  * this __init too.
349  */
350 __init int unregister_event_command(struct event_command *cmd)
351 {
352         struct event_command *p, *n;
353         int ret = -ENODEV;
354 
355         mutex_lock(&trigger_cmd_mutex);
356         list_for_each_entry_safe(p, n, &trigger_commands, list) {
357                 if (strcmp(cmd->name, p->name) == 0) {
358                         ret = 0;
359                         list_del_init(&p->list);
360                         goto out_unlock;
361                 }
362         }
363  out_unlock:
364         mutex_unlock(&trigger_cmd_mutex);
365 
366         return ret;
367 }
368 
369 /**
370  * event_trigger_print - Generic event_trigger_ops @print implementation
371  * @name: The name of the event trigger
372  * @m: The seq_file being printed to
373  * @data: Trigger-specific data
374  * @filter_str: filter_str to print, if present
375  *
376  * Common implementation for event triggers to print themselves.
377  *
378  * Usually wrapped by a function that simply sets the @name of the
379  * trigger command and then invokes this.
380  *
381  * Return: 0 on success, errno otherwise
382  */
383 static int
384 event_trigger_print(const char *name, struct seq_file *m,
385                     void *data, char *filter_str)
386 {
387         long count = (long)data;
388 
389         seq_puts(m, name);
390 
391         if (count == -1)
392                 seq_puts(m, ":unlimited");
393         else
394                 seq_printf(m, ":count=%ld", count);
395 
396         if (filter_str)
397                 seq_printf(m, " if %s\n", filter_str);
398         else
399                 seq_putc(m, '\n');
400 
401         return 0;
402 }
403 
404 /**
405  * event_trigger_init - Generic event_trigger_ops @init implementation
406  * @ops: The trigger ops associated with the trigger
407  * @data: Trigger-specific data
408  *
409  * Common implementation of event trigger initialization.
410  *
411  * Usually used directly as the @init method in event trigger
412  * implementations.
413  *
414  * Return: 0 on success, errno otherwise
415  */
416 int event_trigger_init(struct event_trigger_ops *ops,
417                        struct event_trigger_data *data)
418 {
419         data->ref++;
420         return 0;
421 }
422 
423 /**
424  * event_trigger_free - Generic event_trigger_ops @free implementation
425  * @ops: The trigger ops associated with the trigger
426  * @data: Trigger-specific data
427  *
428  * Common implementation of event trigger de-initialization.
429  *
430  * Usually used directly as the @free method in event trigger
431  * implementations.
432  */
433 static void
434 event_trigger_free(struct event_trigger_ops *ops,
435                    struct event_trigger_data *data)
436 {
437         if (WARN_ON_ONCE(data->ref <= 0))
438                 return;
439 
440         data->ref--;
441         if (!data->ref)
442                 trigger_data_free(data);
443 }
444 
445 int trace_event_trigger_enable_disable(struct trace_event_file *file,
446                                        int trigger_enable)
447 {
448         int ret = 0;
449 
450         if (trigger_enable) {
451                 if (atomic_inc_return(&file->tm_ref) > 1)
452                         return ret;
453                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
454                 ret = trace_event_enable_disable(file, 1, 1);
455         } else {
456                 if (atomic_dec_return(&file->tm_ref) > 0)
457                         return ret;
458                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
459                 ret = trace_event_enable_disable(file, 0, 1);
460         }
461 
462         return ret;
463 }
464 
465 /**
466  * clear_event_triggers - Clear all triggers associated with a trace array
467  * @tr: The trace array to clear
468  *
469  * For each trigger, the triggering event has its tm_ref decremented
470  * via trace_event_trigger_enable_disable(), and any associated event
471  * (in the case of enable/disable_event triggers) will have its sm_ref
472  * decremented via free()->trace_event_enable_disable().  That
473  * combination effectively reverses the soft-mode/trigger state added
474  * by trigger registration.
475  *
476  * Must be called with event_mutex held.
477  */
478 void
479 clear_event_triggers(struct trace_array *tr)
480 {
481         struct trace_event_file *file;
482 
483         list_for_each_entry(file, &tr->events, list) {
484                 struct event_trigger_data *data, *n;
485                 list_for_each_entry_safe(data, n, &file->triggers, list) {
486                         trace_event_trigger_enable_disable(file, 0);
487                         list_del_rcu(&data->list);
488                         if (data->ops->free)
489                                 data->ops->free(data->ops, data);
490                 }
491         }
492 }
493 
494 /**
495  * update_cond_flag - Set or reset the TRIGGER_COND bit
496  * @file: The trace_event_file associated with the event
497  *
498  * If an event has triggers and any of those triggers has a filter or
499  * a post_trigger, trigger invocation needs to be deferred until after
500  * the current event has logged its data, and the event should have
501  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
502  * cleared.
503  */
504 void update_cond_flag(struct trace_event_file *file)
505 {
506         struct event_trigger_data *data;
507         bool set_cond = false;
508 
509         list_for_each_entry_rcu(data, &file->triggers, list) {
510                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
511                     event_command_needs_rec(data->cmd_ops)) {
512                         set_cond = true;
513                         break;
514                 }
515         }
516 
517         if (set_cond)
518                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
519         else
520                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
521 }
522 
523 /**
524  * register_trigger - Generic event_command @reg implementation
525  * @glob: The raw string used to register the trigger
526  * @ops: The trigger ops associated with the trigger
527  * @data: Trigger-specific data to associate with the trigger
528  * @file: The trace_event_file associated with the event
529  *
530  * Common implementation for event trigger registration.
531  *
532  * Usually used directly as the @reg method in event command
533  * implementations.
534  *
535  * Return: 0 on success, errno otherwise
536  */
537 static int register_trigger(char *glob, struct event_trigger_ops *ops,
538                             struct event_trigger_data *data,
539                             struct trace_event_file *file)
540 {
541         struct event_trigger_data *test;
542         int ret = 0;
543 
544         list_for_each_entry_rcu(test, &file->triggers, list) {
545                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
546                         ret = -EEXIST;
547                         goto out;
548                 }
549         }
550 
551         if (data->ops->init) {
552                 ret = data->ops->init(data->ops, data);
553                 if (ret < 0)
554                         goto out;
555         }
556 
557         list_add_rcu(&data->list, &file->triggers);
558         ret++;
559 
560         update_cond_flag(file);
561         if (trace_event_trigger_enable_disable(file, 1) < 0) {
562                 list_del_rcu(&data->list);
563                 update_cond_flag(file);
564                 ret--;
565         }
566 out:
567         return ret;
568 }
569 
570 /**
571  * unregister_trigger - Generic event_command @unreg implementation
572  * @glob: The raw string used to register the trigger
573  * @ops: The trigger ops associated with the trigger
574  * @test: Trigger-specific data used to find the trigger to remove
575  * @file: The trace_event_file associated with the event
576  *
577  * Common implementation for event trigger unregistration.
578  *
579  * Usually used directly as the @unreg method in event command
580  * implementations.
581  */
582 void unregister_trigger(char *glob, struct event_trigger_ops *ops,
583                         struct event_trigger_data *test,
584                         struct trace_event_file *file)
585 {
586         struct event_trigger_data *data;
587         bool unregistered = false;
588 
589         list_for_each_entry_rcu(data, &file->triggers, list) {
590                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
591                         unregistered = true;
592                         list_del_rcu(&data->list);
593                         trace_event_trigger_enable_disable(file, 0);
594                         update_cond_flag(file);
595                         break;
596                 }
597         }
598 
599         if (unregistered && data->ops->free)
600                 data->ops->free(data->ops, data);
601 }
602 
603 /**
604  * event_trigger_callback - Generic event_command @func implementation
605  * @cmd_ops: The command ops, used for trigger registration
606  * @file: The trace_event_file associated with the event
607  * @glob: The raw string used to register the trigger
608  * @cmd: The cmd portion of the string used to register the trigger
609  * @param: The params portion of the string used to register the trigger
610  *
611  * Common implementation for event command parsing and trigger
612  * instantiation.
613  *
614  * Usually used directly as the @func method in event command
615  * implementations.
616  *
617  * Return: 0 on success, errno otherwise
618  */
619 static int
620 event_trigger_callback(struct event_command *cmd_ops,
621                        struct trace_event_file *file,
622                        char *glob, char *cmd, char *param)
623 {
624         struct event_trigger_data *trigger_data;
625         struct event_trigger_ops *trigger_ops;
626         char *trigger = NULL;
627         char *number;
628         int ret;
629 
630         /* separate the trigger from the filter (t:n [if filter]) */
631         if (param && isdigit(param[0]))
632                 trigger = strsep(&param, " \t");
633 
634         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
635 
636         ret = -ENOMEM;
637         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
638         if (!trigger_data)
639                 goto out;
640 
641         trigger_data->count = -1;
642         trigger_data->ops = trigger_ops;
643         trigger_data->cmd_ops = cmd_ops;
644         trigger_data->private_data = file;
645         INIT_LIST_HEAD(&trigger_data->list);
646         INIT_LIST_HEAD(&trigger_data->named_list);
647 
648         if (glob[0] == '!') {
649                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
650                 kfree(trigger_data);
651                 ret = 0;
652                 goto out;
653         }
654 
655         if (trigger) {
656                 number = strsep(&trigger, ":");
657 
658                 ret = -EINVAL;
659                 if (!strlen(number))
660                         goto out_free;
661 
662                 /*
663                  * We use the callback data field (which is a pointer)
664                  * as our counter.
665                  */
666                 ret = kstrtoul(number, 0, &trigger_data->count);
667                 if (ret)
668                         goto out_free;
669         }
670 
671         if (!param) /* if param is non-empty, it's supposed to be a filter */
672                 goto out_reg;
673 
674         if (!cmd_ops->set_filter)
675                 goto out_reg;
676 
677         ret = cmd_ops->set_filter(param, trigger_data, file);
678         if (ret < 0)
679                 goto out_free;
680 
681  out_reg:
682         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
683         /*
684          * The above returns on success the # of functions enabled,
685          * but if it didn't find any functions it returns zero.
686          * Consider no functions a failure too.
687          */
688         if (!ret) {
689                 ret = -ENOENT;
690                 goto out_free;
691         } else if (ret < 0)
692                 goto out_free;
693         ret = 0;
694  out:
695         return ret;
696 
697  out_free:
698         if (cmd_ops->set_filter)
699                 cmd_ops->set_filter(NULL, trigger_data, NULL);
700         kfree(trigger_data);
701         goto out;
702 }
703 
704 /**
705  * set_trigger_filter - Generic event_command @set_filter implementation
706  * @filter_str: The filter string for the trigger, NULL to remove filter
707  * @trigger_data: Trigger-specific data
708  * @file: The trace_event_file associated with the event
709  *
710  * Common implementation for event command filter parsing and filter
711  * instantiation.
712  *
713  * Usually used directly as the @set_filter method in event command
714  * implementations.
715  *
716  * Also used to remove a filter (if filter_str = NULL).
717  *
718  * Return: 0 on success, errno otherwise
719  */
720 int set_trigger_filter(char *filter_str,
721                        struct event_trigger_data *trigger_data,
722                        struct trace_event_file *file)
723 {
724         struct event_trigger_data *data = trigger_data;
725         struct event_filter *filter = NULL, *tmp;
726         int ret = -EINVAL;
727         char *s;
728 
729         if (!filter_str) /* clear the current filter */
730                 goto assign;
731 
732         s = strsep(&filter_str, " \t");
733 
734         if (!strlen(s) || strcmp(s, "if") != 0)
735                 goto out;
736 
737         if (!filter_str)
738                 goto out;
739 
740         /* The filter is for the 'trigger' event, not the triggered event */
741         ret = create_event_filter(file->event_call, filter_str, false, &filter);
742         if (ret)
743                 goto out;
744  assign:
745         tmp = rcu_access_pointer(data->filter);
746 
747         rcu_assign_pointer(data->filter, filter);
748 
749         if (tmp) {
750                 /* Make sure the call is done with the filter */
751                 synchronize_sched();
752                 free_event_filter(tmp);
753         }
754 
755         kfree(data->filter_str);
756         data->filter_str = NULL;
757 
758         if (filter_str) {
759                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
760                 if (!data->filter_str) {
761                         free_event_filter(rcu_access_pointer(data->filter));
762                         data->filter = NULL;
763                         ret = -ENOMEM;
764                 }
765         }
766  out:
767         return ret;
768 }
769 
770 static LIST_HEAD(named_triggers);
771 
772 /**
773  * find_named_trigger - Find the common named trigger associated with @name
774  * @name: The name of the set of named triggers to find the common data for
775  *
776  * Named triggers are sets of triggers that share a common set of
777  * trigger data.  The first named trigger registered with a given name
778  * owns the common trigger data that the others subsequently
779  * registered with the same name will reference.  This function
780  * returns the common trigger data associated with that first
781  * registered instance.
782  *
783  * Return: the common trigger data for the given named trigger on
784  * success, NULL otherwise.
785  */
786 struct event_trigger_data *find_named_trigger(const char *name)
787 {
788         struct event_trigger_data *data;
789 
790         if (!name)
791                 return NULL;
792 
793         list_for_each_entry(data, &named_triggers, named_list) {
794                 if (data->named_data)
795                         continue;
796                 if (strcmp(data->name, name) == 0)
797                         return data;
798         }
799 
800         return NULL;
801 }
802 
803 /**
804  * is_named_trigger - determine if a given trigger is a named trigger
805  * @test: The trigger data to test
806  *
807  * Return: true if 'test' is a named trigger, false otherwise.
808  */
809 bool is_named_trigger(struct event_trigger_data *test)
810 {
811         struct event_trigger_data *data;
812 
813         list_for_each_entry(data, &named_triggers, named_list) {
814                 if (test == data)
815                         return true;
816         }
817 
818         return false;
819 }
820 
821 /**
822  * save_named_trigger - save the trigger in the named trigger list
823  * @name: The name of the named trigger set
824  * @data: The trigger data to save
825  *
826  * Return: 0 if successful, negative error otherwise.
827  */
828 int save_named_trigger(const char *name, struct event_trigger_data *data)
829 {
830         data->name = kstrdup(name, GFP_KERNEL);
831         if (!data->name)
832                 return -ENOMEM;
833 
834         list_add(&data->named_list, &named_triggers);
835 
836         return 0;
837 }
838 
839 /**
840  * del_named_trigger - delete a trigger from the named trigger list
841  * @data: The trigger data to delete
842  */
843 void del_named_trigger(struct event_trigger_data *data)
844 {
845         kfree(data->name);
846         data->name = NULL;
847 
848         list_del(&data->named_list);
849 }
850 
851 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
852 {
853         struct event_trigger_data *test;
854 
855         list_for_each_entry(test, &named_triggers, named_list) {
856                 if (strcmp(test->name, data->name) == 0) {
857                         if (pause) {
858                                 test->paused_tmp = test->paused;
859                                 test->paused = true;
860                         } else {
861                                 test->paused = test->paused_tmp;
862                         }
863                 }
864         }
865 }
866 
867 /**
868  * pause_named_trigger - Pause all named triggers with the same name
869  * @data: The trigger data of a named trigger to pause
870  *
871  * Pauses a named trigger along with all other triggers having the
872  * same name.  Because named triggers share a common set of data,
873  * pausing only one is meaningless, so pausing one named trigger needs
874  * to pause all triggers with the same name.
875  */
876 void pause_named_trigger(struct event_trigger_data *data)
877 {
878         __pause_named_trigger(data, true);
879 }
880 
881 /**
882  * unpause_named_trigger - Un-pause all named triggers with the same name
883  * @data: The trigger data of a named trigger to unpause
884  *
885  * Un-pauses a named trigger along with all other triggers having the
886  * same name.  Because named triggers share a common set of data,
887  * unpausing only one is meaningless, so unpausing one named trigger
888  * needs to unpause all triggers with the same name.
889  */
890 void unpause_named_trigger(struct event_trigger_data *data)
891 {
892         __pause_named_trigger(data, false);
893 }
894 
895 /**
896  * set_named_trigger_data - Associate common named trigger data
897  * @data: The trigger data of a named trigger to unpause
898  *
899  * Named triggers are sets of triggers that share a common set of
900  * trigger data.  The first named trigger registered with a given name
901  * owns the common trigger data that the others subsequently
902  * registered with the same name will reference.  This function
903  * associates the common trigger data from the first trigger with the
904  * given trigger.
905  */
906 void set_named_trigger_data(struct event_trigger_data *data,
907                             struct event_trigger_data *named_data)
908 {
909         data->named_data = named_data;
910 }
911 
912 struct event_trigger_data *
913 get_named_trigger_data(struct event_trigger_data *data)
914 {
915         return data->named_data;
916 }
917 
918 static void
919 traceon_trigger(struct event_trigger_data *data, void *rec,
920                 struct ring_buffer_event *event)
921 {
922         if (tracing_is_on())
923                 return;
924 
925         tracing_on();
926 }
927 
928 static void
929 traceon_count_trigger(struct event_trigger_data *data, void *rec,
930                       struct ring_buffer_event *event)
931 {
932         if (tracing_is_on())
933                 return;
934 
935         if (!data->count)
936                 return;
937 
938         if (data->count != -1)
939                 (data->count)--;
940 
941         tracing_on();
942 }
943 
944 static void
945 traceoff_trigger(struct event_trigger_data *data, void *rec,
946                  struct ring_buffer_event *event)
947 {
948         if (!tracing_is_on())
949                 return;
950 
951         tracing_off();
952 }
953 
954 static void
955 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
956                        struct ring_buffer_event *event)
957 {
958         if (!tracing_is_on())
959                 return;
960 
961         if (!data->count)
962                 return;
963 
964         if (data->count != -1)
965                 (data->count)--;
966 
967         tracing_off();
968 }
969 
970 static int
971 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
972                       struct event_trigger_data *data)
973 {
974         return event_trigger_print("traceon", m, (void *)data->count,
975                                    data->filter_str);
976 }
977 
978 static int
979 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
980                        struct event_trigger_data *data)
981 {
982         return event_trigger_print("traceoff", m, (void *)data->count,
983                                    data->filter_str);
984 }
985 
986 static struct event_trigger_ops traceon_trigger_ops = {
987         .func                   = traceon_trigger,
988         .print                  = traceon_trigger_print,
989         .init                   = event_trigger_init,
990         .free                   = event_trigger_free,
991 };
992 
993 static struct event_trigger_ops traceon_count_trigger_ops = {
994         .func                   = traceon_count_trigger,
995         .print                  = traceon_trigger_print,
996         .init                   = event_trigger_init,
997         .free                   = event_trigger_free,
998 };
999 
1000 static struct event_trigger_ops traceoff_trigger_ops = {
1001         .func                   = traceoff_trigger,
1002         .print                  = traceoff_trigger_print,
1003         .init                   = event_trigger_init,
1004         .free                   = event_trigger_free,
1005 };
1006 
1007 static struct event_trigger_ops traceoff_count_trigger_ops = {
1008         .func                   = traceoff_count_trigger,
1009         .print                  = traceoff_trigger_print,
1010         .init                   = event_trigger_init,
1011         .free                   = event_trigger_free,
1012 };
1013 
1014 static struct event_trigger_ops *
1015 onoff_get_trigger_ops(char *cmd, char *param)
1016 {
1017         struct event_trigger_ops *ops;
1018 
1019         /* we register both traceon and traceoff to this callback */
1020         if (strcmp(cmd, "traceon") == 0)
1021                 ops = param ? &traceon_count_trigger_ops :
1022                         &traceon_trigger_ops;
1023         else
1024                 ops = param ? &traceoff_count_trigger_ops :
1025                         &traceoff_trigger_ops;
1026 
1027         return ops;
1028 }
1029 
1030 static struct event_command trigger_traceon_cmd = {
1031         .name                   = "traceon",
1032         .trigger_type           = ETT_TRACE_ONOFF,
1033         .func                   = event_trigger_callback,
1034         .reg                    = register_trigger,
1035         .unreg                  = unregister_trigger,
1036         .get_trigger_ops        = onoff_get_trigger_ops,
1037         .set_filter             = set_trigger_filter,
1038 };
1039 
1040 static struct event_command trigger_traceoff_cmd = {
1041         .name                   = "traceoff",
1042         .trigger_type           = ETT_TRACE_ONOFF,
1043         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1044         .func                   = event_trigger_callback,
1045         .reg                    = register_trigger,
1046         .unreg                  = unregister_trigger,
1047         .get_trigger_ops        = onoff_get_trigger_ops,
1048         .set_filter             = set_trigger_filter,
1049 };
1050 
1051 #ifdef CONFIG_TRACER_SNAPSHOT
1052 static void
1053 snapshot_trigger(struct event_trigger_data *data, void *rec,
1054                  struct ring_buffer_event *event)
1055 {
1056         struct trace_event_file *file = data->private_data;
1057 
1058         if (file)
1059                 tracing_snapshot_instance(file->tr);
1060         else
1061                 tracing_snapshot();
1062 }
1063 
1064 static void
1065 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1066                        struct ring_buffer_event *event)
1067 {
1068         if (!data->count)
1069                 return;
1070 
1071         if (data->count != -1)
1072                 (data->count)--;
1073 
1074         snapshot_trigger(data, rec, event);
1075 }
1076 
1077 static int
1078 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1079                           struct event_trigger_data *data,
1080                           struct trace_event_file *file)
1081 {
1082         int ret = register_trigger(glob, ops, data, file);
1083 
1084         if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
1085                 unregister_trigger(glob, ops, data, file);
1086                 ret = 0;
1087         }
1088 
1089         return ret;
1090 }
1091 
1092 static int
1093 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1094                        struct event_trigger_data *data)
1095 {
1096         return event_trigger_print("snapshot", m, (void *)data->count,
1097                                    data->filter_str);
1098 }
1099 
1100 static struct event_trigger_ops snapshot_trigger_ops = {
1101         .func                   = snapshot_trigger,
1102         .print                  = snapshot_trigger_print,
1103         .init                   = event_trigger_init,
1104         .free                   = event_trigger_free,
1105 };
1106 
1107 static struct event_trigger_ops snapshot_count_trigger_ops = {
1108         .func                   = snapshot_count_trigger,
1109         .print                  = snapshot_trigger_print,
1110         .init                   = event_trigger_init,
1111         .free                   = event_trigger_free,
1112 };
1113 
1114 static struct event_trigger_ops *
1115 snapshot_get_trigger_ops(char *cmd, char *param)
1116 {
1117         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1118 }
1119 
1120 static struct event_command trigger_snapshot_cmd = {
1121         .name                   = "snapshot",
1122         .trigger_type           = ETT_SNAPSHOT,
1123         .func                   = event_trigger_callback,
1124         .reg                    = register_snapshot_trigger,
1125         .unreg                  = unregister_trigger,
1126         .get_trigger_ops        = snapshot_get_trigger_ops,
1127         .set_filter             = set_trigger_filter,
1128 };
1129 
1130 static __init int register_trigger_snapshot_cmd(void)
1131 {
1132         int ret;
1133 
1134         ret = register_event_command(&trigger_snapshot_cmd);
1135         WARN_ON(ret < 0);
1136 
1137         return ret;
1138 }
1139 #else
1140 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1141 #endif /* CONFIG_TRACER_SNAPSHOT */
1142 
1143 #ifdef CONFIG_STACKTRACE
1144 #ifdef CONFIG_UNWINDER_ORC
1145 /* Skip 2:
1146  *   event_triggers_post_call()
1147  *   trace_event_raw_event_xxx()
1148  */
1149 # define STACK_SKIP 2
1150 #else
1151 /*
1152  * Skip 4:
1153  *   stacktrace_trigger()
1154  *   event_triggers_post_call()
1155  *   trace_event_buffer_commit()
1156  *   trace_event_raw_event_xxx()
1157  */
1158 #define STACK_SKIP 4
1159 #endif
1160 
1161 static void
1162 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1163                    struct ring_buffer_event *event)
1164 {
1165         trace_dump_stack(STACK_SKIP);
1166 }
1167 
1168 static void
1169 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1170                          struct ring_buffer_event *event)
1171 {
1172         if (!data->count)
1173                 return;
1174 
1175         if (data->count != -1)
1176                 (data->count)--;
1177 
1178         stacktrace_trigger(data, rec, event);
1179 }
1180 
1181 static int
1182 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1183                          struct event_trigger_data *data)
1184 {
1185         return event_trigger_print("stacktrace", m, (void *)data->count,
1186                                    data->filter_str);
1187 }
1188 
1189 static struct event_trigger_ops stacktrace_trigger_ops = {
1190         .func                   = stacktrace_trigger,
1191         .print                  = stacktrace_trigger_print,
1192         .init                   = event_trigger_init,
1193         .free                   = event_trigger_free,
1194 };
1195 
1196 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1197         .func                   = stacktrace_count_trigger,
1198         .print                  = stacktrace_trigger_print,
1199         .init                   = event_trigger_init,
1200         .free                   = event_trigger_free,
1201 };
1202 
1203 static struct event_trigger_ops *
1204 stacktrace_get_trigger_ops(char *cmd, char *param)
1205 {
1206         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1207 }
1208 
1209 static struct event_command trigger_stacktrace_cmd = {
1210         .name                   = "stacktrace",
1211         .trigger_type           = ETT_STACKTRACE,
1212         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1213         .func                   = event_trigger_callback,
1214         .reg                    = register_trigger,
1215         .unreg                  = unregister_trigger,
1216         .get_trigger_ops        = stacktrace_get_trigger_ops,
1217         .set_filter             = set_trigger_filter,
1218 };
1219 
1220 static __init int register_trigger_stacktrace_cmd(void)
1221 {
1222         int ret;
1223 
1224         ret = register_event_command(&trigger_stacktrace_cmd);
1225         WARN_ON(ret < 0);
1226 
1227         return ret;
1228 }
1229 #else
1230 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1231 #endif /* CONFIG_STACKTRACE */
1232 
1233 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1234 {
1235         unregister_event_command(&trigger_traceon_cmd);
1236         unregister_event_command(&trigger_traceoff_cmd);
1237 }
1238 
1239 static void
1240 event_enable_trigger(struct event_trigger_data *data, void *rec,
1241                      struct ring_buffer_event *event)
1242 {
1243         struct enable_trigger_data *enable_data = data->private_data;
1244 
1245         if (enable_data->enable)
1246                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1247         else
1248                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1249 }
1250 
1251 static void
1252 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1253                            struct ring_buffer_event *event)
1254 {
1255         struct enable_trigger_data *enable_data = data->private_data;
1256 
1257         if (!data->count)
1258                 return;
1259 
1260         /* Skip if the event is in a state we want to switch to */
1261         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1262                 return;
1263 
1264         if (data->count != -1)
1265                 (data->count)--;
1266 
1267         event_enable_trigger(data, rec, event);
1268 }
1269 
1270 int event_enable_trigger_print(struct seq_file *m,
1271                                struct event_trigger_ops *ops,
1272                                struct event_trigger_data *data)
1273 {
1274         struct enable_trigger_data *enable_data = data->private_data;
1275 
1276         seq_printf(m, "%s:%s:%s",
1277                    enable_data->hist ?
1278                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1279                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1280                    enable_data->file->event_call->class->system,
1281                    trace_event_name(enable_data->file->event_call));
1282 
1283         if (data->count == -1)
1284                 seq_puts(m, ":unlimited");
1285         else
1286                 seq_printf(m, ":count=%ld", data->count);
1287 
1288         if (data->filter_str)
1289                 seq_printf(m, " if %s\n", data->filter_str);
1290         else
1291                 seq_putc(m, '\n');
1292 
1293         return 0;
1294 }
1295 
1296 void event_enable_trigger_free(struct event_trigger_ops *ops,
1297                                struct event_trigger_data *data)
1298 {
1299         struct enable_trigger_data *enable_data = data->private_data;
1300 
1301         if (WARN_ON_ONCE(data->ref <= 0))
1302                 return;
1303 
1304         data->ref--;
1305         if (!data->ref) {
1306                 /* Remove the SOFT_MODE flag */
1307                 trace_event_enable_disable(enable_data->file, 0, 1);
1308                 module_put(enable_data->file->event_call->mod);
1309                 trigger_data_free(data);
1310                 kfree(enable_data);
1311         }
1312 }
1313 
1314 static struct event_trigger_ops event_enable_trigger_ops = {
1315         .func                   = event_enable_trigger,
1316         .print                  = event_enable_trigger_print,
1317         .init                   = event_trigger_init,
1318         .free                   = event_enable_trigger_free,
1319 };
1320 
1321 static struct event_trigger_ops event_enable_count_trigger_ops = {
1322         .func                   = event_enable_count_trigger,
1323         .print                  = event_enable_trigger_print,
1324         .init                   = event_trigger_init,
1325         .free                   = event_enable_trigger_free,
1326 };
1327 
1328 static struct event_trigger_ops event_disable_trigger_ops = {
1329         .func                   = event_enable_trigger,
1330         .print                  = event_enable_trigger_print,
1331         .init                   = event_trigger_init,
1332         .free                   = event_enable_trigger_free,
1333 };
1334 
1335 static struct event_trigger_ops event_disable_count_trigger_ops = {
1336         .func                   = event_enable_count_trigger,
1337         .print                  = event_enable_trigger_print,
1338         .init                   = event_trigger_init,
1339         .free                   = event_enable_trigger_free,
1340 };
1341 
1342 int event_enable_trigger_func(struct event_command *cmd_ops,
1343                               struct trace_event_file *file,
1344                               char *glob, char *cmd, char *param)
1345 {
1346         struct trace_event_file *event_enable_file;
1347         struct enable_trigger_data *enable_data;
1348         struct event_trigger_data *trigger_data;
1349         struct event_trigger_ops *trigger_ops;
1350         struct trace_array *tr = file->tr;
1351         const char *system;
1352         const char *event;
1353         bool hist = false;
1354         char *trigger;
1355         char *number;
1356         bool enable;
1357         int ret;
1358 
1359         if (!param)
1360                 return -EINVAL;
1361 
1362         /* separate the trigger from the filter (s:e:n [if filter]) */
1363         trigger = strsep(&param, " \t");
1364         if (!trigger)
1365                 return -EINVAL;
1366 
1367         system = strsep(&trigger, ":");
1368         if (!trigger)
1369                 return -EINVAL;
1370 
1371         event = strsep(&trigger, ":");
1372 
1373         ret = -EINVAL;
1374         event_enable_file = find_event_file(tr, system, event);
1375         if (!event_enable_file)
1376                 goto out;
1377 
1378 #ifdef CONFIG_HIST_TRIGGERS
1379         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1380                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1381 
1382         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1383                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1384 #else
1385         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1386 #endif
1387         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1388 
1389         ret = -ENOMEM;
1390         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1391         if (!trigger_data)
1392                 goto out;
1393 
1394         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1395         if (!enable_data) {
1396                 kfree(trigger_data);
1397                 goto out;
1398         }
1399 
1400         trigger_data->count = -1;
1401         trigger_data->ops = trigger_ops;
1402         trigger_data->cmd_ops = cmd_ops;
1403         INIT_LIST_HEAD(&trigger_data->list);
1404         RCU_INIT_POINTER(trigger_data->filter, NULL);
1405 
1406         enable_data->hist = hist;
1407         enable_data->enable = enable;
1408         enable_data->file = event_enable_file;
1409         trigger_data->private_data = enable_data;
1410 
1411         if (glob[0] == '!') {
1412                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1413                 kfree(trigger_data);
1414                 kfree(enable_data);
1415                 ret = 0;
1416                 goto out;
1417         }
1418 
1419         if (trigger) {
1420                 number = strsep(&trigger, ":");
1421 
1422                 ret = -EINVAL;
1423                 if (!strlen(number))
1424                         goto out_free;
1425 
1426                 /*
1427                  * We use the callback data field (which is a pointer)
1428                  * as our counter.
1429                  */
1430                 ret = kstrtoul(number, 0, &trigger_data->count);
1431                 if (ret)
1432                         goto out_free;
1433         }
1434 
1435         if (!param) /* if param is non-empty, it's supposed to be a filter */
1436                 goto out_reg;
1437 
1438         if (!cmd_ops->set_filter)
1439                 goto out_reg;
1440 
1441         ret = cmd_ops->set_filter(param, trigger_data, file);
1442         if (ret < 0)
1443                 goto out_free;
1444 
1445  out_reg:
1446         /* Don't let event modules unload while probe registered */
1447         ret = try_module_get(event_enable_file->event_call->mod);
1448         if (!ret) {
1449                 ret = -EBUSY;
1450                 goto out_free;
1451         }
1452 
1453         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1454         if (ret < 0)
1455                 goto out_put;
1456         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1457         /*
1458          * The above returns on success the # of functions enabled,
1459          * but if it didn't find any functions it returns zero.
1460          * Consider no functions a failure too.
1461          */
1462         if (!ret) {
1463                 ret = -ENOENT;
1464                 goto out_disable;
1465         } else if (ret < 0)
1466                 goto out_disable;
1467         /* Just return zero, not the number of enabled functions */
1468         ret = 0;
1469  out:
1470         return ret;
1471 
1472  out_disable:
1473         trace_event_enable_disable(event_enable_file, 0, 1);
1474  out_put:
1475         module_put(event_enable_file->event_call->mod);
1476  out_free:
1477         if (cmd_ops->set_filter)
1478                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1479         kfree(trigger_data);
1480         kfree(enable_data);
1481         goto out;
1482 }
1483 
1484 int event_enable_register_trigger(char *glob,
1485                                   struct event_trigger_ops *ops,
1486                                   struct event_trigger_data *data,
1487                                   struct trace_event_file *file)
1488 {
1489         struct enable_trigger_data *enable_data = data->private_data;
1490         struct enable_trigger_data *test_enable_data;
1491         struct event_trigger_data *test;
1492         int ret = 0;
1493 
1494         list_for_each_entry_rcu(test, &file->triggers, list) {
1495                 test_enable_data = test->private_data;
1496                 if (test_enable_data &&
1497                     (test->cmd_ops->trigger_type ==
1498                      data->cmd_ops->trigger_type) &&
1499                     (test_enable_data->file == enable_data->file)) {
1500                         ret = -EEXIST;
1501                         goto out;
1502                 }
1503         }
1504 
1505         if (data->ops->init) {
1506                 ret = data->ops->init(data->ops, data);
1507                 if (ret < 0)
1508                         goto out;
1509         }
1510 
1511         list_add_rcu(&data->list, &file->triggers);
1512         ret++;
1513 
1514         update_cond_flag(file);
1515         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1516                 list_del_rcu(&data->list);
1517                 update_cond_flag(file);
1518                 ret--;
1519         }
1520 out:
1521         return ret;
1522 }
1523 
1524 void event_enable_unregister_trigger(char *glob,
1525                                      struct event_trigger_ops *ops,
1526                                      struct event_trigger_data *test,
1527                                      struct trace_event_file *file)
1528 {
1529         struct enable_trigger_data *test_enable_data = test->private_data;
1530         struct enable_trigger_data *enable_data;
1531         struct event_trigger_data *data;
1532         bool unregistered = false;
1533 
1534         list_for_each_entry_rcu(data, &file->triggers, list) {
1535                 enable_data = data->private_data;
1536                 if (enable_data &&
1537                     (data->cmd_ops->trigger_type ==
1538                      test->cmd_ops->trigger_type) &&
1539                     (enable_data->file == test_enable_data->file)) {
1540                         unregistered = true;
1541                         list_del_rcu(&data->list);
1542                         trace_event_trigger_enable_disable(file, 0);
1543                         update_cond_flag(file);
1544                         break;
1545                 }
1546         }
1547 
1548         if (unregistered && data->ops->free)
1549                 data->ops->free(data->ops, data);
1550 }
1551 
1552 static struct event_trigger_ops *
1553 event_enable_get_trigger_ops(char *cmd, char *param)
1554 {
1555         struct event_trigger_ops *ops;
1556         bool enable;
1557 
1558 #ifdef CONFIG_HIST_TRIGGERS
1559         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1560                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1561 #else
1562         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1563 #endif
1564         if (enable)
1565                 ops = param ? &event_enable_count_trigger_ops :
1566                         &event_enable_trigger_ops;
1567         else
1568                 ops = param ? &event_disable_count_trigger_ops :
1569                         &event_disable_trigger_ops;
1570 
1571         return ops;
1572 }
1573 
1574 static struct event_command trigger_enable_cmd = {
1575         .name                   = ENABLE_EVENT_STR,
1576         .trigger_type           = ETT_EVENT_ENABLE,
1577         .func                   = event_enable_trigger_func,
1578         .reg                    = event_enable_register_trigger,
1579         .unreg                  = event_enable_unregister_trigger,
1580         .get_trigger_ops        = event_enable_get_trigger_ops,
1581         .set_filter             = set_trigger_filter,
1582 };
1583 
1584 static struct event_command trigger_disable_cmd = {
1585         .name                   = DISABLE_EVENT_STR,
1586         .trigger_type           = ETT_EVENT_ENABLE,
1587         .func                   = event_enable_trigger_func,
1588         .reg                    = event_enable_register_trigger,
1589         .unreg                  = event_enable_unregister_trigger,
1590         .get_trigger_ops        = event_enable_get_trigger_ops,
1591         .set_filter             = set_trigger_filter,
1592 };
1593 
1594 static __init void unregister_trigger_enable_disable_cmds(void)
1595 {
1596         unregister_event_command(&trigger_enable_cmd);
1597         unregister_event_command(&trigger_disable_cmd);
1598 }
1599 
1600 static __init int register_trigger_enable_disable_cmds(void)
1601 {
1602         int ret;
1603 
1604         ret = register_event_command(&trigger_enable_cmd);
1605         if (WARN_ON(ret < 0))
1606                 return ret;
1607         ret = register_event_command(&trigger_disable_cmd);
1608         if (WARN_ON(ret < 0))
1609                 unregister_trigger_enable_disable_cmds();
1610 
1611         return ret;
1612 }
1613 
1614 static __init int register_trigger_traceon_traceoff_cmds(void)
1615 {
1616         int ret;
1617 
1618         ret = register_event_command(&trigger_traceon_cmd);
1619         if (WARN_ON(ret < 0))
1620                 return ret;
1621         ret = register_event_command(&trigger_traceoff_cmd);
1622         if (WARN_ON(ret < 0))
1623                 unregister_trigger_traceon_traceoff_cmds();
1624 
1625         return ret;
1626 }
1627 
1628 __init int register_trigger_cmds(void)
1629 {
1630         register_trigger_traceon_traceoff_cmds();
1631         register_trigger_snapshot_cmd();
1632         register_trigger_stacktrace_cmd();
1633         register_trigger_enable_disable_cmds();
1634         register_trigger_hist_enable_disable_cmds();
1635         register_trigger_hist_cmd();
1636 
1637         return 0;
1638 }
1639 

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