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

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