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TOMOYO Linux Cross Reference
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 
 26 #include "trace.h"
 27 
 28 static LIST_HEAD(trigger_commands);
 29 static DEFINE_MUTEX(trigger_cmd_mutex);
 30 
 31 void trigger_data_free(struct event_trigger_data *data)
 32 {
 33         if (data->cmd_ops->set_filter)
 34                 data->cmd_ops->set_filter(NULL, data, NULL);
 35 
 36         synchronize_sched(); /* make sure current triggers exit before free */
 37         kfree(data);
 38 }
 39 
 40 /**
 41  * event_triggers_call - Call triggers associated with a trace event
 42  * @file: The trace_event_file associated with the event
 43  * @rec: The trace entry for the event, NULL for unconditional invocation
 44  *
 45  * For each trigger associated with an event, invoke the trigger
 46  * function registered with the associated trigger command.  If rec is
 47  * non-NULL, it means that the trigger requires further processing and
 48  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
 49  * trigger has a filter associated with it, rec will checked against
 50  * the filter and if the record matches the trigger will be invoked.
 51  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
 52  * in any case until the current event is written, the trigger
 53  * function isn't invoked but the bit associated with the deferred
 54  * trigger is set in the return value.
 55  *
 56  * Returns an enum event_trigger_type value containing a set bit for
 57  * any trigger that should be deferred, ETT_NONE if nothing to defer.
 58  *
 59  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 60  *
 61  * Return: an enum event_trigger_type value containing a set bit for
 62  * any trigger that should be deferred, ETT_NONE if nothing to defer.
 63  */
 64 enum event_trigger_type
 65 event_triggers_call(struct trace_event_file *file, void *rec)
 66 {
 67         struct event_trigger_data *data;
 68         enum event_trigger_type tt = ETT_NONE;
 69         struct event_filter *filter;
 70 
 71         if (list_empty(&file->triggers))
 72                 return tt;
 73 
 74         list_for_each_entry_rcu(data, &file->triggers, list) {
 75                 if (data->paused)
 76                         continue;
 77                 if (!rec) {
 78                         data->ops->func(data, rec);
 79                         continue;
 80                 }
 81                 filter = rcu_dereference_sched(data->filter);
 82                 if (filter && !filter_match_preds(filter, rec))
 83                         continue;
 84                 if (event_command_post_trigger(data->cmd_ops)) {
 85                         tt |= data->cmd_ops->trigger_type;
 86                         continue;
 87                 }
 88                 data->ops->func(data, rec);
 89         }
 90         return tt;
 91 }
 92 EXPORT_SYMBOL_GPL(event_triggers_call);
 93 
 94 /**
 95  * event_triggers_post_call - Call 'post_triggers' for a trace event
 96  * @file: The trace_event_file associated with the event
 97  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
 98  * @rec: The trace entry for the event
 99  *
100  * For each trigger associated with an event, invoke the trigger
101  * function registered with the associated trigger command, if the
102  * corresponding bit is set in the tt enum passed into this function.
103  * See @event_triggers_call for details on how those bits are set.
104  *
105  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
106  */
107 void
108 event_triggers_post_call(struct trace_event_file *file,
109                          enum event_trigger_type tt,
110                          void *rec)
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, rec);
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;
485                 list_for_each_entry_rcu(data, &file->triggers, list) {
486                         trace_event_trigger_enable_disable(file, 0);
487                         if (data->ops->free)
488                                 data->ops->free(data->ops, data);
489                 }
490         }
491 }
492 
493 /**
494  * update_cond_flag - Set or reset the TRIGGER_COND bit
495  * @file: The trace_event_file associated with the event
496  *
497  * If an event has triggers and any of those triggers has a filter or
498  * a post_trigger, trigger invocation needs to be deferred until after
499  * the current event has logged its data, and the event should have
500  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
501  * cleared.
502  */
503 void update_cond_flag(struct trace_event_file *file)
504 {
505         struct event_trigger_data *data;
506         bool set_cond = false;
507 
508         list_for_each_entry_rcu(data, &file->triggers, list) {
509                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
510                     event_command_needs_rec(data->cmd_ops)) {
511                         set_cond = true;
512                         break;
513                 }
514         }
515 
516         if (set_cond)
517                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
518         else
519                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
520 }
521 
522 /**
523  * register_trigger - Generic event_command @reg implementation
524  * @glob: The raw string used to register the trigger
525  * @ops: The trigger ops associated with the trigger
526  * @data: Trigger-specific data to associate with the trigger
527  * @file: The trace_event_file associated with the event
528  *
529  * Common implementation for event trigger registration.
530  *
531  * Usually used directly as the @reg method in event command
532  * implementations.
533  *
534  * Return: 0 on success, errno otherwise
535  */
536 static int register_trigger(char *glob, struct event_trigger_ops *ops,
537                             struct event_trigger_data *data,
538                             struct trace_event_file *file)
539 {
540         struct event_trigger_data *test;
541         int ret = 0;
542 
543         list_for_each_entry_rcu(test, &file->triggers, list) {
544                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
545                         ret = -EEXIST;
546                         goto out;
547                 }
548         }
549 
550         if (data->ops->init) {
551                 ret = data->ops->init(data->ops, data);
552                 if (ret < 0)
553                         goto out;
554         }
555 
556         list_add_rcu(&data->list, &file->triggers);
557         ret++;
558 
559         update_cond_flag(file);
560         if (trace_event_trigger_enable_disable(file, 1) < 0) {
561                 list_del_rcu(&data->list);
562                 update_cond_flag(file);
563                 ret--;
564         }
565 out:
566         return ret;
567 }
568 
569 /**
570  * unregister_trigger - Generic event_command @unreg implementation
571  * @glob: The raw string used to register the trigger
572  * @ops: The trigger ops associated with the trigger
573  * @test: Trigger-specific data used to find the trigger to remove
574  * @file: The trace_event_file associated with the event
575  *
576  * Common implementation for event trigger unregistration.
577  *
578  * Usually used directly as the @unreg method in event command
579  * implementations.
580  */
581 void unregister_trigger(char *glob, struct event_trigger_ops *ops,
582                         struct event_trigger_data *test,
583                         struct trace_event_file *file)
584 {
585         struct event_trigger_data *data;
586         bool unregistered = false;
587 
588         list_for_each_entry_rcu(data, &file->triggers, list) {
589                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
590                         unregistered = true;
591                         list_del_rcu(&data->list);
592                         trace_event_trigger_enable_disable(file, 0);
593                         update_cond_flag(file);
594                         break;
595                 }
596         }
597 
598         if (unregistered && data->ops->free)
599                 data->ops->free(data->ops, data);
600 }
601 
602 /**
603  * event_trigger_callback - Generic event_command @func implementation
604  * @cmd_ops: The command ops, used for trigger registration
605  * @file: The trace_event_file associated with the event
606  * @glob: The raw string used to register the trigger
607  * @cmd: The cmd portion of the string used to register the trigger
608  * @param: The params portion of the string used to register the trigger
609  *
610  * Common implementation for event command parsing and trigger
611  * instantiation.
612  *
613  * Usually used directly as the @func method in event command
614  * implementations.
615  *
616  * Return: 0 on success, errno otherwise
617  */
618 static int
619 event_trigger_callback(struct event_command *cmd_ops,
620                        struct trace_event_file *file,
621                        char *glob, char *cmd, char *param)
622 {
623         struct event_trigger_data *trigger_data;
624         struct event_trigger_ops *trigger_ops;
625         char *trigger = NULL;
626         char *number;
627         int ret;
628 
629         /* separate the trigger from the filter (t:n [if filter]) */
630         if (param && isdigit(param[0]))
631                 trigger = strsep(&param, " \t");
632 
633         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
634 
635         ret = -ENOMEM;
636         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
637         if (!trigger_data)
638                 goto out;
639 
640         trigger_data->count = -1;
641         trigger_data->ops = trigger_ops;
642         trigger_data->cmd_ops = cmd_ops;
643         INIT_LIST_HEAD(&trigger_data->list);
644         INIT_LIST_HEAD(&trigger_data->named_list);
645 
646         if (glob[0] == '!') {
647                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
648                 kfree(trigger_data);
649                 ret = 0;
650                 goto out;
651         }
652 
653         if (trigger) {
654                 number = strsep(&trigger, ":");
655 
656                 ret = -EINVAL;
657                 if (!strlen(number))
658                         goto out_free;
659 
660                 /*
661                  * We use the callback data field (which is a pointer)
662                  * as our counter.
663                  */
664                 ret = kstrtoul(number, 0, &trigger_data->count);
665                 if (ret)
666                         goto out_free;
667         }
668 
669         if (!param) /* if param is non-empty, it's supposed to be a filter */
670                 goto out_reg;
671 
672         if (!cmd_ops->set_filter)
673                 goto out_reg;
674 
675         ret = cmd_ops->set_filter(param, trigger_data, file);
676         if (ret < 0)
677                 goto out_free;
678 
679  out_reg:
680         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
681         /*
682          * The above returns on success the # of functions enabled,
683          * but if it didn't find any functions it returns zero.
684          * Consider no functions a failure too.
685          */
686         if (!ret) {
687                 ret = -ENOENT;
688                 goto out_free;
689         } else if (ret < 0)
690                 goto out_free;
691         ret = 0;
692  out:
693         return ret;
694 
695  out_free:
696         if (cmd_ops->set_filter)
697                 cmd_ops->set_filter(NULL, trigger_data, NULL);
698         kfree(trigger_data);
699         goto out;
700 }
701 
702 /**
703  * set_trigger_filter - Generic event_command @set_filter implementation
704  * @filter_str: The filter string for the trigger, NULL to remove filter
705  * @trigger_data: Trigger-specific data
706  * @file: The trace_event_file associated with the event
707  *
708  * Common implementation for event command filter parsing and filter
709  * instantiation.
710  *
711  * Usually used directly as the @set_filter method in event command
712  * implementations.
713  *
714  * Also used to remove a filter (if filter_str = NULL).
715  *
716  * Return: 0 on success, errno otherwise
717  */
718 int set_trigger_filter(char *filter_str,
719                        struct event_trigger_data *trigger_data,
720                        struct trace_event_file *file)
721 {
722         struct event_trigger_data *data = trigger_data;
723         struct event_filter *filter = NULL, *tmp;
724         int ret = -EINVAL;
725         char *s;
726 
727         if (!filter_str) /* clear the current filter */
728                 goto assign;
729 
730         s = strsep(&filter_str, " \t");
731 
732         if (!strlen(s) || strcmp(s, "if") != 0)
733                 goto out;
734 
735         if (!filter_str)
736                 goto out;
737 
738         /* The filter is for the 'trigger' event, not the triggered event */
739         ret = create_event_filter(file->event_call, filter_str, false, &filter);
740         if (ret)
741                 goto out;
742  assign:
743         tmp = rcu_access_pointer(data->filter);
744 
745         rcu_assign_pointer(data->filter, filter);
746 
747         if (tmp) {
748                 /* Make sure the call is done with the filter */
749                 synchronize_sched();
750                 free_event_filter(tmp);
751         }
752 
753         kfree(data->filter_str);
754         data->filter_str = NULL;
755 
756         if (filter_str) {
757                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
758                 if (!data->filter_str) {
759                         free_event_filter(rcu_access_pointer(data->filter));
760                         data->filter = NULL;
761                         ret = -ENOMEM;
762                 }
763         }
764  out:
765         return ret;
766 }
767 
768 static LIST_HEAD(named_triggers);
769 
770 /**
771  * find_named_trigger - Find the common named trigger associated with @name
772  * @name: The name of the set of named triggers to find the common data for
773  *
774  * Named triggers are sets of triggers that share a common set of
775  * trigger data.  The first named trigger registered with a given name
776  * owns the common trigger data that the others subsequently
777  * registered with the same name will reference.  This function
778  * returns the common trigger data associated with that first
779  * registered instance.
780  *
781  * Return: the common trigger data for the given named trigger on
782  * success, NULL otherwise.
783  */
784 struct event_trigger_data *find_named_trigger(const char *name)
785 {
786         struct event_trigger_data *data;
787 
788         if (!name)
789                 return NULL;
790 
791         list_for_each_entry(data, &named_triggers, named_list) {
792                 if (data->named_data)
793                         continue;
794                 if (strcmp(data->name, name) == 0)
795                         return data;
796         }
797 
798         return NULL;
799 }
800 
801 /**
802  * is_named_trigger - determine if a given trigger is a named trigger
803  * @test: The trigger data to test
804  *
805  * Return: true if 'test' is a named trigger, false otherwise.
806  */
807 bool is_named_trigger(struct event_trigger_data *test)
808 {
809         struct event_trigger_data *data;
810 
811         list_for_each_entry(data, &named_triggers, named_list) {
812                 if (test == data)
813                         return true;
814         }
815 
816         return false;
817 }
818 
819 /**
820  * save_named_trigger - save the trigger in the named trigger list
821  * @name: The name of the named trigger set
822  * @data: The trigger data to save
823  *
824  * Return: 0 if successful, negative error otherwise.
825  */
826 int save_named_trigger(const char *name, struct event_trigger_data *data)
827 {
828         data->name = kstrdup(name, GFP_KERNEL);
829         if (!data->name)
830                 return -ENOMEM;
831 
832         list_add(&data->named_list, &named_triggers);
833 
834         return 0;
835 }
836 
837 /**
838  * del_named_trigger - delete a trigger from the named trigger list
839  * @data: The trigger data to delete
840  */
841 void del_named_trigger(struct event_trigger_data *data)
842 {
843         kfree(data->name);
844         data->name = NULL;
845 
846         list_del(&data->named_list);
847 }
848 
849 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
850 {
851         struct event_trigger_data *test;
852 
853         list_for_each_entry(test, &named_triggers, named_list) {
854                 if (strcmp(test->name, data->name) == 0) {
855                         if (pause) {
856                                 test->paused_tmp = test->paused;
857                                 test->paused = true;
858                         } else {
859                                 test->paused = test->paused_tmp;
860                         }
861                 }
862         }
863 }
864 
865 /**
866  * pause_named_trigger - Pause all named triggers with the same name
867  * @data: The trigger data of a named trigger to pause
868  *
869  * Pauses a named trigger along with all other triggers having the
870  * same name.  Because named triggers share a common set of data,
871  * pausing only one is meaningless, so pausing one named trigger needs
872  * to pause all triggers with the same name.
873  */
874 void pause_named_trigger(struct event_trigger_data *data)
875 {
876         __pause_named_trigger(data, true);
877 }
878 
879 /**
880  * unpause_named_trigger - Un-pause all named triggers with the same name
881  * @data: The trigger data of a named trigger to unpause
882  *
883  * Un-pauses a named trigger along with all other triggers having the
884  * same name.  Because named triggers share a common set of data,
885  * unpausing only one is meaningless, so unpausing one named trigger
886  * needs to unpause all triggers with the same name.
887  */
888 void unpause_named_trigger(struct event_trigger_data *data)
889 {
890         __pause_named_trigger(data, false);
891 }
892 
893 /**
894  * set_named_trigger_data - Associate common named trigger data
895  * @data: The trigger data of a named trigger to unpause
896  *
897  * Named triggers are sets of triggers that share a common set of
898  * trigger data.  The first named trigger registered with a given name
899  * owns the common trigger data that the others subsequently
900  * registered with the same name will reference.  This function
901  * associates the common trigger data from the first trigger with the
902  * given trigger.
903  */
904 void set_named_trigger_data(struct event_trigger_data *data,
905                             struct event_trigger_data *named_data)
906 {
907         data->named_data = named_data;
908 }
909 
910 static void
911 traceon_trigger(struct event_trigger_data *data, void *rec)
912 {
913         if (tracing_is_on())
914                 return;
915 
916         tracing_on();
917 }
918 
919 static void
920 traceon_count_trigger(struct event_trigger_data *data, void *rec)
921 {
922         if (tracing_is_on())
923                 return;
924 
925         if (!data->count)
926                 return;
927 
928         if (data->count != -1)
929                 (data->count)--;
930 
931         tracing_on();
932 }
933 
934 static void
935 traceoff_trigger(struct event_trigger_data *data, void *rec)
936 {
937         if (!tracing_is_on())
938                 return;
939 
940         tracing_off();
941 }
942 
943 static void
944 traceoff_count_trigger(struct event_trigger_data *data, void *rec)
945 {
946         if (!tracing_is_on())
947                 return;
948 
949         if (!data->count)
950                 return;
951 
952         if (data->count != -1)
953                 (data->count)--;
954 
955         tracing_off();
956 }
957 
958 static int
959 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
960                       struct event_trigger_data *data)
961 {
962         return event_trigger_print("traceon", m, (void *)data->count,
963                                    data->filter_str);
964 }
965 
966 static int
967 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
968                        struct event_trigger_data *data)
969 {
970         return event_trigger_print("traceoff", m, (void *)data->count,
971                                    data->filter_str);
972 }
973 
974 static struct event_trigger_ops traceon_trigger_ops = {
975         .func                   = traceon_trigger,
976         .print                  = traceon_trigger_print,
977         .init                   = event_trigger_init,
978         .free                   = event_trigger_free,
979 };
980 
981 static struct event_trigger_ops traceon_count_trigger_ops = {
982         .func                   = traceon_count_trigger,
983         .print                  = traceon_trigger_print,
984         .init                   = event_trigger_init,
985         .free                   = event_trigger_free,
986 };
987 
988 static struct event_trigger_ops traceoff_trigger_ops = {
989         .func                   = traceoff_trigger,
990         .print                  = traceoff_trigger_print,
991         .init                   = event_trigger_init,
992         .free                   = event_trigger_free,
993 };
994 
995 static struct event_trigger_ops traceoff_count_trigger_ops = {
996         .func                   = traceoff_count_trigger,
997         .print                  = traceoff_trigger_print,
998         .init                   = event_trigger_init,
999         .free                   = event_trigger_free,
1000 };
1001 
1002 static struct event_trigger_ops *
1003 onoff_get_trigger_ops(char *cmd, char *param)
1004 {
1005         struct event_trigger_ops *ops;
1006 
1007         /* we register both traceon and traceoff to this callback */
1008         if (strcmp(cmd, "traceon") == 0)
1009                 ops = param ? &traceon_count_trigger_ops :
1010                         &traceon_trigger_ops;
1011         else
1012                 ops = param ? &traceoff_count_trigger_ops :
1013                         &traceoff_trigger_ops;
1014 
1015         return ops;
1016 }
1017 
1018 static struct event_command trigger_traceon_cmd = {
1019         .name                   = "traceon",
1020         .trigger_type           = ETT_TRACE_ONOFF,
1021         .func                   = event_trigger_callback,
1022         .reg                    = register_trigger,
1023         .unreg                  = unregister_trigger,
1024         .get_trigger_ops        = onoff_get_trigger_ops,
1025         .set_filter             = set_trigger_filter,
1026 };
1027 
1028 static struct event_command trigger_traceoff_cmd = {
1029         .name                   = "traceoff",
1030         .trigger_type           = ETT_TRACE_ONOFF,
1031         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1032         .func                   = event_trigger_callback,
1033         .reg                    = register_trigger,
1034         .unreg                  = unregister_trigger,
1035         .get_trigger_ops        = onoff_get_trigger_ops,
1036         .set_filter             = set_trigger_filter,
1037 };
1038 
1039 #ifdef CONFIG_TRACER_SNAPSHOT
1040 static void
1041 snapshot_trigger(struct event_trigger_data *data, void *rec)
1042 {
1043         tracing_snapshot();
1044 }
1045 
1046 static void
1047 snapshot_count_trigger(struct event_trigger_data *data, void *rec)
1048 {
1049         if (!data->count)
1050                 return;
1051 
1052         if (data->count != -1)
1053                 (data->count)--;
1054 
1055         snapshot_trigger(data, rec);
1056 }
1057 
1058 static int
1059 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1060                           struct event_trigger_data *data,
1061                           struct trace_event_file *file)
1062 {
1063         int ret = register_trigger(glob, ops, data, file);
1064 
1065         if (ret > 0 && tracing_alloc_snapshot() != 0) {
1066                 unregister_trigger(glob, ops, data, file);
1067                 ret = 0;
1068         }
1069 
1070         return ret;
1071 }
1072 
1073 static int
1074 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1075                        struct event_trigger_data *data)
1076 {
1077         return event_trigger_print("snapshot", m, (void *)data->count,
1078                                    data->filter_str);
1079 }
1080 
1081 static struct event_trigger_ops snapshot_trigger_ops = {
1082         .func                   = snapshot_trigger,
1083         .print                  = snapshot_trigger_print,
1084         .init                   = event_trigger_init,
1085         .free                   = event_trigger_free,
1086 };
1087 
1088 static struct event_trigger_ops snapshot_count_trigger_ops = {
1089         .func                   = snapshot_count_trigger,
1090         .print                  = snapshot_trigger_print,
1091         .init                   = event_trigger_init,
1092         .free                   = event_trigger_free,
1093 };
1094 
1095 static struct event_trigger_ops *
1096 snapshot_get_trigger_ops(char *cmd, char *param)
1097 {
1098         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1099 }
1100 
1101 static struct event_command trigger_snapshot_cmd = {
1102         .name                   = "snapshot",
1103         .trigger_type           = ETT_SNAPSHOT,
1104         .func                   = event_trigger_callback,
1105         .reg                    = register_snapshot_trigger,
1106         .unreg                  = unregister_trigger,
1107         .get_trigger_ops        = snapshot_get_trigger_ops,
1108         .set_filter             = set_trigger_filter,
1109 };
1110 
1111 static __init int register_trigger_snapshot_cmd(void)
1112 {
1113         int ret;
1114 
1115         ret = register_event_command(&trigger_snapshot_cmd);
1116         WARN_ON(ret < 0);
1117 
1118         return ret;
1119 }
1120 #else
1121 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1122 #endif /* CONFIG_TRACER_SNAPSHOT */
1123 
1124 #ifdef CONFIG_STACKTRACE
1125 /*
1126  * Skip 3:
1127  *   stacktrace_trigger()
1128  *   event_triggers_post_call()
1129  *   trace_event_raw_event_xxx()
1130  */
1131 #define STACK_SKIP 3
1132 
1133 static void
1134 stacktrace_trigger(struct event_trigger_data *data, void *rec)
1135 {
1136         trace_dump_stack(STACK_SKIP);
1137 }
1138 
1139 static void
1140 stacktrace_count_trigger(struct event_trigger_data *data, void *rec)
1141 {
1142         if (!data->count)
1143                 return;
1144 
1145         if (data->count != -1)
1146                 (data->count)--;
1147 
1148         stacktrace_trigger(data, rec);
1149 }
1150 
1151 static int
1152 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1153                          struct event_trigger_data *data)
1154 {
1155         return event_trigger_print("stacktrace", m, (void *)data->count,
1156                                    data->filter_str);
1157 }
1158 
1159 static struct event_trigger_ops stacktrace_trigger_ops = {
1160         .func                   = stacktrace_trigger,
1161         .print                  = stacktrace_trigger_print,
1162         .init                   = event_trigger_init,
1163         .free                   = event_trigger_free,
1164 };
1165 
1166 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1167         .func                   = stacktrace_count_trigger,
1168         .print                  = stacktrace_trigger_print,
1169         .init                   = event_trigger_init,
1170         .free                   = event_trigger_free,
1171 };
1172 
1173 static struct event_trigger_ops *
1174 stacktrace_get_trigger_ops(char *cmd, char *param)
1175 {
1176         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1177 }
1178 
1179 static struct event_command trigger_stacktrace_cmd = {
1180         .name                   = "stacktrace",
1181         .trigger_type           = ETT_STACKTRACE,
1182         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1183         .func                   = event_trigger_callback,
1184         .reg                    = register_trigger,
1185         .unreg                  = unregister_trigger,
1186         .get_trigger_ops        = stacktrace_get_trigger_ops,
1187         .set_filter             = set_trigger_filter,
1188 };
1189 
1190 static __init int register_trigger_stacktrace_cmd(void)
1191 {
1192         int ret;
1193 
1194         ret = register_event_command(&trigger_stacktrace_cmd);
1195         WARN_ON(ret < 0);
1196 
1197         return ret;
1198 }
1199 #else
1200 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1201 #endif /* CONFIG_STACKTRACE */
1202 
1203 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1204 {
1205         unregister_event_command(&trigger_traceon_cmd);
1206         unregister_event_command(&trigger_traceoff_cmd);
1207 }
1208 
1209 static void
1210 event_enable_trigger(struct event_trigger_data *data, void *rec)
1211 {
1212         struct enable_trigger_data *enable_data = data->private_data;
1213 
1214         if (enable_data->enable)
1215                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1216         else
1217                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1218 }
1219 
1220 static void
1221 event_enable_count_trigger(struct event_trigger_data *data, void *rec)
1222 {
1223         struct enable_trigger_data *enable_data = data->private_data;
1224 
1225         if (!data->count)
1226                 return;
1227 
1228         /* Skip if the event is in a state we want to switch to */
1229         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1230                 return;
1231 
1232         if (data->count != -1)
1233                 (data->count)--;
1234 
1235         event_enable_trigger(data, rec);
1236 }
1237 
1238 int event_enable_trigger_print(struct seq_file *m,
1239                                struct event_trigger_ops *ops,
1240                                struct event_trigger_data *data)
1241 {
1242         struct enable_trigger_data *enable_data = data->private_data;
1243 
1244         seq_printf(m, "%s:%s:%s",
1245                    enable_data->hist ?
1246                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1247                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1248                    enable_data->file->event_call->class->system,
1249                    trace_event_name(enable_data->file->event_call));
1250 
1251         if (data->count == -1)
1252                 seq_puts(m, ":unlimited");
1253         else
1254                 seq_printf(m, ":count=%ld", data->count);
1255 
1256         if (data->filter_str)
1257                 seq_printf(m, " if %s\n", data->filter_str);
1258         else
1259                 seq_putc(m, '\n');
1260 
1261         return 0;
1262 }
1263 
1264 void event_enable_trigger_free(struct event_trigger_ops *ops,
1265                                struct event_trigger_data *data)
1266 {
1267         struct enable_trigger_data *enable_data = data->private_data;
1268 
1269         if (WARN_ON_ONCE(data->ref <= 0))
1270                 return;
1271 
1272         data->ref--;
1273         if (!data->ref) {
1274                 /* Remove the SOFT_MODE flag */
1275                 trace_event_enable_disable(enable_data->file, 0, 1);
1276                 module_put(enable_data->file->event_call->mod);
1277                 trigger_data_free(data);
1278                 kfree(enable_data);
1279         }
1280 }
1281 
1282 static struct event_trigger_ops event_enable_trigger_ops = {
1283         .func                   = event_enable_trigger,
1284         .print                  = event_enable_trigger_print,
1285         .init                   = event_trigger_init,
1286         .free                   = event_enable_trigger_free,
1287 };
1288 
1289 static struct event_trigger_ops event_enable_count_trigger_ops = {
1290         .func                   = event_enable_count_trigger,
1291         .print                  = event_enable_trigger_print,
1292         .init                   = event_trigger_init,
1293         .free                   = event_enable_trigger_free,
1294 };
1295 
1296 static struct event_trigger_ops event_disable_trigger_ops = {
1297         .func                   = event_enable_trigger,
1298         .print                  = event_enable_trigger_print,
1299         .init                   = event_trigger_init,
1300         .free                   = event_enable_trigger_free,
1301 };
1302 
1303 static struct event_trigger_ops event_disable_count_trigger_ops = {
1304         .func                   = event_enable_count_trigger,
1305         .print                  = event_enable_trigger_print,
1306         .init                   = event_trigger_init,
1307         .free                   = event_enable_trigger_free,
1308 };
1309 
1310 int event_enable_trigger_func(struct event_command *cmd_ops,
1311                               struct trace_event_file *file,
1312                               char *glob, char *cmd, char *param)
1313 {
1314         struct trace_event_file *event_enable_file;
1315         struct enable_trigger_data *enable_data;
1316         struct event_trigger_data *trigger_data;
1317         struct event_trigger_ops *trigger_ops;
1318         struct trace_array *tr = file->tr;
1319         const char *system;
1320         const char *event;
1321         bool hist = false;
1322         char *trigger;
1323         char *number;
1324         bool enable;
1325         int ret;
1326 
1327         if (!param)
1328                 return -EINVAL;
1329 
1330         /* separate the trigger from the filter (s:e:n [if filter]) */
1331         trigger = strsep(&param, " \t");
1332         if (!trigger)
1333                 return -EINVAL;
1334 
1335         system = strsep(&trigger, ":");
1336         if (!trigger)
1337                 return -EINVAL;
1338 
1339         event = strsep(&trigger, ":");
1340 
1341         ret = -EINVAL;
1342         event_enable_file = find_event_file(tr, system, event);
1343         if (!event_enable_file)
1344                 goto out;
1345 
1346 #ifdef CONFIG_HIST_TRIGGERS
1347         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1348                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1349 
1350         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1351                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1352 #else
1353         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1354 #endif
1355         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1356 
1357         ret = -ENOMEM;
1358         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1359         if (!trigger_data)
1360                 goto out;
1361 
1362         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1363         if (!enable_data) {
1364                 kfree(trigger_data);
1365                 goto out;
1366         }
1367 
1368         trigger_data->count = -1;
1369         trigger_data->ops = trigger_ops;
1370         trigger_data->cmd_ops = cmd_ops;
1371         INIT_LIST_HEAD(&trigger_data->list);
1372         RCU_INIT_POINTER(trigger_data->filter, NULL);
1373 
1374         enable_data->hist = hist;
1375         enable_data->enable = enable;
1376         enable_data->file = event_enable_file;
1377         trigger_data->private_data = enable_data;
1378 
1379         if (glob[0] == '!') {
1380                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1381                 kfree(trigger_data);
1382                 kfree(enable_data);
1383                 ret = 0;
1384                 goto out;
1385         }
1386 
1387         if (trigger) {
1388                 number = strsep(&trigger, ":");
1389 
1390                 ret = -EINVAL;
1391                 if (!strlen(number))
1392                         goto out_free;
1393 
1394                 /*
1395                  * We use the callback data field (which is a pointer)
1396                  * as our counter.
1397                  */
1398                 ret = kstrtoul(number, 0, &trigger_data->count);
1399                 if (ret)
1400                         goto out_free;
1401         }
1402 
1403         if (!param) /* if param is non-empty, it's supposed to be a filter */
1404                 goto out_reg;
1405 
1406         if (!cmd_ops->set_filter)
1407                 goto out_reg;
1408 
1409         ret = cmd_ops->set_filter(param, trigger_data, file);
1410         if (ret < 0)
1411                 goto out_free;
1412 
1413  out_reg:
1414         /* Don't let event modules unload while probe registered */
1415         ret = try_module_get(event_enable_file->event_call->mod);
1416         if (!ret) {
1417                 ret = -EBUSY;
1418                 goto out_free;
1419         }
1420 
1421         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1422         if (ret < 0)
1423                 goto out_put;
1424         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1425         /*
1426          * The above returns on success the # of functions enabled,
1427          * but if it didn't find any functions it returns zero.
1428          * Consider no functions a failure too.
1429          */
1430         if (!ret) {
1431                 ret = -ENOENT;
1432                 goto out_disable;
1433         } else if (ret < 0)
1434                 goto out_disable;
1435         /* Just return zero, not the number of enabled functions */
1436         ret = 0;
1437  out:
1438         return ret;
1439 
1440  out_disable:
1441         trace_event_enable_disable(event_enable_file, 0, 1);
1442  out_put:
1443         module_put(event_enable_file->event_call->mod);
1444  out_free:
1445         if (cmd_ops->set_filter)
1446                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1447         kfree(trigger_data);
1448         kfree(enable_data);
1449         goto out;
1450 }
1451 
1452 int event_enable_register_trigger(char *glob,
1453                                   struct event_trigger_ops *ops,
1454                                   struct event_trigger_data *data,
1455                                   struct trace_event_file *file)
1456 {
1457         struct enable_trigger_data *enable_data = data->private_data;
1458         struct enable_trigger_data *test_enable_data;
1459         struct event_trigger_data *test;
1460         int ret = 0;
1461 
1462         list_for_each_entry_rcu(test, &file->triggers, list) {
1463                 test_enable_data = test->private_data;
1464                 if (test_enable_data &&
1465                     (test->cmd_ops->trigger_type ==
1466                      data->cmd_ops->trigger_type) &&
1467                     (test_enable_data->file == enable_data->file)) {
1468                         ret = -EEXIST;
1469                         goto out;
1470                 }
1471         }
1472 
1473         if (data->ops->init) {
1474                 ret = data->ops->init(data->ops, data);
1475                 if (ret < 0)
1476                         goto out;
1477         }
1478 
1479         list_add_rcu(&data->list, &file->triggers);
1480         ret++;
1481 
1482         update_cond_flag(file);
1483         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1484                 list_del_rcu(&data->list);
1485                 update_cond_flag(file);
1486                 ret--;
1487         }
1488 out:
1489         return ret;
1490 }
1491 
1492 void event_enable_unregister_trigger(char *glob,
1493                                      struct event_trigger_ops *ops,
1494                                      struct event_trigger_data *test,
1495                                      struct trace_event_file *file)
1496 {
1497         struct enable_trigger_data *test_enable_data = test->private_data;
1498         struct enable_trigger_data *enable_data;
1499         struct event_trigger_data *data;
1500         bool unregistered = false;
1501 
1502         list_for_each_entry_rcu(data, &file->triggers, list) {
1503                 enable_data = data->private_data;
1504                 if (enable_data &&
1505                     (data->cmd_ops->trigger_type ==
1506                      test->cmd_ops->trigger_type) &&
1507                     (enable_data->file == test_enable_data->file)) {
1508                         unregistered = true;
1509                         list_del_rcu(&data->list);
1510                         trace_event_trigger_enable_disable(file, 0);
1511                         update_cond_flag(file);
1512                         break;
1513                 }
1514         }
1515 
1516         if (unregistered && data->ops->free)
1517                 data->ops->free(data->ops, data);
1518 }
1519 
1520 static struct event_trigger_ops *
1521 event_enable_get_trigger_ops(char *cmd, char *param)
1522 {
1523         struct event_trigger_ops *ops;
1524         bool enable;
1525 
1526 #ifdef CONFIG_HIST_TRIGGERS
1527         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1528                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1529 #else
1530         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1531 #endif
1532         if (enable)
1533                 ops = param ? &event_enable_count_trigger_ops :
1534                         &event_enable_trigger_ops;
1535         else
1536                 ops = param ? &event_disable_count_trigger_ops :
1537                         &event_disable_trigger_ops;
1538 
1539         return ops;
1540 }
1541 
1542 static struct event_command trigger_enable_cmd = {
1543         .name                   = ENABLE_EVENT_STR,
1544         .trigger_type           = ETT_EVENT_ENABLE,
1545         .func                   = event_enable_trigger_func,
1546         .reg                    = event_enable_register_trigger,
1547         .unreg                  = event_enable_unregister_trigger,
1548         .get_trigger_ops        = event_enable_get_trigger_ops,
1549         .set_filter             = set_trigger_filter,
1550 };
1551 
1552 static struct event_command trigger_disable_cmd = {
1553         .name                   = DISABLE_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 __init void unregister_trigger_enable_disable_cmds(void)
1563 {
1564         unregister_event_command(&trigger_enable_cmd);
1565         unregister_event_command(&trigger_disable_cmd);
1566 }
1567 
1568 static __init int register_trigger_enable_disable_cmds(void)
1569 {
1570         int ret;
1571 
1572         ret = register_event_command(&trigger_enable_cmd);
1573         if (WARN_ON(ret < 0))
1574                 return ret;
1575         ret = register_event_command(&trigger_disable_cmd);
1576         if (WARN_ON(ret < 0))
1577                 unregister_trigger_enable_disable_cmds();
1578 
1579         return ret;
1580 }
1581 
1582 static __init int register_trigger_traceon_traceoff_cmds(void)
1583 {
1584         int ret;
1585 
1586         ret = register_event_command(&trigger_traceon_cmd);
1587         if (WARN_ON(ret < 0))
1588                 return ret;
1589         ret = register_event_command(&trigger_traceoff_cmd);
1590         if (WARN_ON(ret < 0))
1591                 unregister_trigger_traceon_traceoff_cmds();
1592 
1593         return ret;
1594 }
1595 
1596 __init int register_trigger_cmds(void)
1597 {
1598         register_trigger_traceon_traceoff_cmds();
1599         register_trigger_snapshot_cmd();
1600         register_trigger_stacktrace_cmd();
1601         register_trigger_enable_disable_cmds();
1602         register_trigger_hist_enable_disable_cmds();
1603         register_trigger_hist_cmd();
1604 
1605         return 0;
1606 }
1607 

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