kernel/trace/trace_events_trigger.c

   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 /*
1127  * Skip 3:
1128  *   stacktrace_trigger()
1129  *   event_triggers_post_call()
1130  *   trace_event_raw_event_xxx()
1131  */
1132 #define STACK_SKIP 3
1133
1134 static void
1135 stacktrace_trigger(struct event_trigger_data *data, void *rec)
1136 {
1137         trace_dump_stack(STACK_SKIP);
1138 }
1139
1140 static void
1141 stacktrace_count_trigger(struct event_trigger_data *data, void *rec)
1142 {
1143         if (!data->count)
1144                 return;
1145
1146         if (data->count != -1)
1147                 (data->count)--;
1148
1149         stacktrace_trigger(data, rec);
1150 }
1151
1152 static int
1153 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1154                          struct event_trigger_data *data)
1155 {
1156         return event_trigger_print("stacktrace", m, (void *)data->count,
1157                                    data->filter_str);
1158 }
1159
1160 static struct event_trigger_ops stacktrace_trigger_ops = {
1161         .func                   = stacktrace_trigger,
1162         .print                  = stacktrace_trigger_print,
1163         .init                   = event_trigger_init,
1164         .free                   = event_trigger_free,
1165 };
1166
1167 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1168         .func                   = stacktrace_count_trigger,
1169         .print                  = stacktrace_trigger_print,
1170         .init                   = event_trigger_init,
1171         .free                   = event_trigger_free,
1172 };
1173
1174 static struct event_trigger_ops *
1175 stacktrace_get_trigger_ops(char *cmd, char *param)
1176 {
1177         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1178 }
1179
1180 static struct event_command trigger_stacktrace_cmd = {
1181         .name                   = "stacktrace",
1182         .trigger_type           = ETT_STACKTRACE,
1183         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1184         .func                   = event_trigger_callback,
1185         .reg                    = register_trigger,
1186         .unreg                  = unregister_trigger,
1187         .get_trigger_ops        = stacktrace_get_trigger_ops,
1188         .set_filter             = set_trigger_filter,
1189 };
1190
1191 static __init int register_trigger_stacktrace_cmd(void)
1192 {
1193         int ret;
1194
1195         ret = register_event_command(&trigger_stacktrace_cmd);
1196         WARN_ON(ret < 0);
1197
1198         return ret;
1199 }
1200 #else
1201 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1202 #endif /* CONFIG_STACKTRACE */
1203
1204 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1205 {
1206         unregister_event_command(&trigger_traceon_cmd);
1207         unregister_event_command(&trigger_traceoff_cmd);
1208 }
1209
1210 static void
1211 event_enable_trigger(struct event_trigger_data *data, void *rec)
1212 {
1213         struct enable_trigger_data *enable_data = data->private_data;
1214
1215         if (enable_data->enable)
1216                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1217         else
1218                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1219 }
1220
1221 static void
1222 event_enable_count_trigger(struct event_trigger_data *data, void *rec)
1223 {
1224         struct enable_trigger_data *enable_data = data->private_data;
1225
1226         if (!data->count)
1227                 return;
1228
1229         /* Skip if the event is in a state we want to switch to */
1230         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1231                 return;
1232
1233         if (data->count != -1)
1234                 (data->count)--;
1235
1236         event_enable_trigger(data, rec);
1237 }
1238
1239 int event_enable_trigger_print(struct seq_file *m,
1240                                struct event_trigger_ops *ops,
1241                                struct event_trigger_data *data)
1242 {
1243         struct enable_trigger_data *enable_data = data->private_data;
1244
1245         seq_printf(m, "%s:%s:%s",
1246                    enable_data->hist ?
1247                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1248                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1249                    enable_data->file->event_call->class->system,
1250                    trace_event_name(enable_data->file->event_call));
1251
1252         if (data->count == -1)
1253                 seq_puts(m, ":unlimited");
1254         else
1255                 seq_printf(m, ":count=%ld", data->count);
1256
1257         if (data->filter_str)
1258                 seq_printf(m, " if %s\n", data->filter_str);
1259         else
1260                 seq_putc(m, '\n');
1261
1262         return 0;
1263 }
1264
1265 void event_enable_trigger_free(struct event_trigger_ops *ops,
1266                                struct event_trigger_data *data)
1267 {
1268         struct enable_trigger_data *enable_data = data->private_data;
1269
1270         if (WARN_ON_ONCE(data->ref <= 0))
1271                 return;
1272
1273         data->ref--;
1274         if (!data->ref) {
1275                 /* Remove the SOFT_MODE flag */
1276                 trace_event_enable_disable(enable_data->file, 0, 1);
1277                 module_put(enable_data->file->event_call->mod);
1278                 trigger_data_free(data);
1279                 kfree(enable_data);
1280         }
1281 }
1282
1283 static struct event_trigger_ops event_enable_trigger_ops = {
1284         .func                   = event_enable_trigger,
1285         .print                  = event_enable_trigger_print,
1286         .init                   = event_trigger_init,
1287         .free                   = event_enable_trigger_free,
1288 };
1289
1290 static struct event_trigger_ops event_enable_count_trigger_ops = {
1291         .func                   = event_enable_count_trigger,
1292         .print                  = event_enable_trigger_print,
1293         .init                   = event_trigger_init,
1294         .free                   = event_enable_trigger_free,
1295 };
1296
1297 static struct event_trigger_ops event_disable_trigger_ops = {
1298         .func                   = event_enable_trigger,
1299         .print                  = event_enable_trigger_print,
1300         .init                   = event_trigger_init,
1301         .free                   = event_enable_trigger_free,
1302 };
1303
1304 static struct event_trigger_ops event_disable_count_trigger_ops = {
1305         .func                   = event_enable_count_trigger,
1306         .print                  = event_enable_trigger_print,
1307         .init                   = event_trigger_init,
1308         .free                   = event_enable_trigger_free,
1309 };
1310
1311 int event_enable_trigger_func(struct event_command *cmd_ops,
1312                               struct trace_event_file *file,
1313                               char *glob, char *cmd, char *param)
1314 {
1315         struct trace_event_file *event_enable_file;
1316         struct enable_trigger_data *enable_data;
1317         struct event_trigger_data *trigger_data;
1318         struct event_trigger_ops *trigger_ops;
1319         struct trace_array *tr = file->tr;
1320         const char *system;
1321         const char *event;
1322         bool hist = false;
1323         char *trigger;
1324         char *number;
1325         bool enable;
1326         int ret;
1327
1328         if (!param)
1329                 return -EINVAL;
1330
1331         /* separate the trigger from the filter (s:e:n [if filter]) */
1332         trigger = strsep(&param, " \t");
1333         if (!trigger)
1334                 return -EINVAL;
1335
1336         system = strsep(&trigger, ":");
1337         if (!trigger)
1338                 return -EINVAL;
1339
1340         event = strsep(&trigger, ":");
1341
1342         ret = -EINVAL;
1343         event_enable_file = find_event_file(tr, system, event);
1344         if (!event_enable_file)
1345                 goto out;
1346
1347 #ifdef CONFIG_HIST_TRIGGERS
1348         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1349                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1350
1351         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1352                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1353 #else
1354         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1355 #endif
1356         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1357
1358         ret = -ENOMEM;
1359         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1360         if (!trigger_data)
1361                 goto out;
1362
1363         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1364         if (!enable_data) {
1365                 kfree(trigger_data);
1366                 goto out;
1367         }
1368
1369         trigger_data->count = -1;
1370         trigger_data->ops = trigger_ops;
1371         trigger_data->cmd_ops = cmd_ops;
1372         INIT_LIST_HEAD(&trigger_data->list);
1373         RCU_INIT_POINTER(trigger_data->filter, NULL);
1374
1375         enable_data->hist = hist;
1376         enable_data->enable = enable;
1377         enable_data->file = event_enable_file;
1378         trigger_data->private_data = enable_data;
1379
1380         if (glob[0] == '!') {
1381                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1382                 kfree(trigger_data);
1383                 kfree(enable_data);
1384                 ret = 0;
1385                 goto out;
1386         }
1387
1388         if (trigger) {
1389                 number = strsep(&trigger, ":");
1390
1391                 ret = -EINVAL;
1392                 if (!strlen(number))
1393                         goto out_free;
1394
1395                 /*
1396                  * We use the callback data field (which is a pointer)
1397                  * as our counter.
1398                  */
1399                 ret = kstrtoul(number, 0, &trigger_data->count);
1400                 if (ret)
1401                         goto out_free;
1402         }
1403
1404         if (!param) /* if param is non-empty, it's supposed to be a filter */
1405                 goto out_reg;
1406
1407         if (!cmd_ops->set_filter)
1408                 goto out_reg;
1409
1410         ret = cmd_ops->set_filter(param, trigger_data, file);
1411         if (ret < 0)
1412                 goto out_free;
1413
1414  out_reg:
1415         /* Don't let event modules unload while probe registered */
1416         ret = try_module_get(event_enable_file->event_call->mod);
1417         if (!ret) {
1418                 ret = -EBUSY;
1419                 goto out_free;
1420         }
1421
1422         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1423         if (ret < 0)
1424                 goto out_put;
1425         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1426         /*
1427          * The above returns on success the # of functions enabled,
1428          * but if it didn't find any functions it returns zero.
1429          * Consider no functions a failure too.
1430          */
1431         if (!ret) {
1432                 ret = -ENOENT;
1433                 goto out_disable;
1434         } else if (ret < 0)
1435                 goto out_disable;
1436         /* Just return zero, not the number of enabled functions */
1437         ret = 0;
1438  out:
1439         return ret;
1440
1441  out_disable:
1442         trace_event_enable_disable(event_enable_file, 0, 1);
1443  out_put:
1444         module_put(event_enable_file->event_call->mod);
1445  out_free:
1446         if (cmd_ops->set_filter)
1447                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1448         kfree(trigger_data);
1449         kfree(enable_data);
1450         goto out;
1451 }
1452
1453 int event_enable_register_trigger(char *glob,
1454                                   struct event_trigger_ops *ops,
1455                                   struct event_trigger_data *data,
1456                                   struct trace_event_file *file)
1457 {
1458         struct enable_trigger_data *enable_data = data->private_data;
1459         struct enable_trigger_data *test_enable_data;
1460         struct event_trigger_data *test;
1461         int ret = 0;
1462
1463         list_for_each_entry_rcu(test, &file->triggers, list) {
1464                 test_enable_data = test->private_data;
1465                 if (test_enable_data &&
1466                     (test->cmd_ops->trigger_type ==
1467                      data->cmd_ops->trigger_type) &&
1468                     (test_enable_data->file == enable_data->file)) {
1469                         ret = -EEXIST;
1470                         goto out;
1471                 }
1472         }
1473
1474         if (data->ops->init) {
1475                 ret = data->ops->init(data->ops, data);
1476                 if (ret < 0)
1477                         goto out;
1478         }
1479
1480         list_add_rcu(&data->list, &file->triggers);
1481         ret++;
1482
1483         update_cond_flag(file);
1484         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1485                 list_del_rcu(&data->list);
1486                 update_cond_flag(file);
1487                 ret--;
1488         }
1489 out:
1490         return ret;
1491 }
1492
1493 void event_enable_unregister_trigger(char *glob,
1494                                      struct event_trigger_ops *ops,
1495                                      struct event_trigger_data *test,
1496                                      struct trace_event_file *file)
1497 {
1498         struct enable_trigger_data *test_enable_data = test->private_data;
1499         struct enable_trigger_data *enable_data;
1500         struct event_trigger_data *data;
1501         bool unregistered = false;
1502
1503         list_for_each_entry_rcu(data, &file->triggers, list) {
1504                 enable_data = data->private_data;
1505                 if (enable_data &&
1506                     (data->cmd_ops->trigger_type ==
1507                      test->cmd_ops->trigger_type) &&
1508                     (enable_data->file == test_enable_data->file)) {
1509                         unregistered = true;
1510                         list_del_rcu(&data->list);
1511                         trace_event_trigger_enable_disable(file, 0);
1512                         update_cond_flag(file);
1513                         break;
1514                 }
1515         }
1516
1517         if (unregistered && data->ops->free)
1518                 data->ops->free(data->ops, data);
1519 }
1520
1521 static struct event_trigger_ops *
1522 event_enable_get_trigger_ops(char *cmd, char *param)
1523 {
1524         struct event_trigger_ops *ops;
1525         bool enable;
1526
1527 #ifdef CONFIG_HIST_TRIGGERS
1528         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1529                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1530 #else
1531         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1532 #endif
1533         if (enable)
1534                 ops = param ? &event_enable_count_trigger_ops :
1535                         &event_enable_trigger_ops;
1536         else
1537                 ops = param ? &event_disable_count_trigger_ops :
1538                         &event_disable_trigger_ops;
1539
1540         return ops;
1541 }
1542
1543 static struct event_command trigger_enable_cmd = {
1544         .name                   = ENABLE_EVENT_STR,
1545         .trigger_type           = ETT_EVENT_ENABLE,
1546         .func                   = event_enable_trigger_func,
1547         .reg                    = event_enable_register_trigger,
1548         .unreg                  = event_enable_unregister_trigger,
1549         .get_trigger_ops        = event_enable_get_trigger_ops,
1550         .set_filter             = set_trigger_filter,
1551 };
1552
1553 static struct event_command trigger_disable_cmd = {
1554         .name                   = DISABLE_EVENT_STR,
1555         .trigger_type           = ETT_EVENT_ENABLE,
1556         .func                   = event_enable_trigger_func,
1557         .reg                    = event_enable_register_trigger,
1558         .unreg                  = event_enable_unregister_trigger,
1559         .get_trigger_ops        = event_enable_get_trigger_ops,
1560         .set_filter             = set_trigger_filter,
1561 };
1562
1563 static __init void unregister_trigger_enable_disable_cmds(void)
1564 {
1565         unregister_event_command(&trigger_enable_cmd);
1566         unregister_event_command(&trigger_disable_cmd);
1567 }
1568
1569 static __init int register_trigger_enable_disable_cmds(void)
1570 {
1571         int ret;
1572
1573         ret = register_event_command(&trigger_enable_cmd);
1574         if (WARN_ON(ret < 0))
1575                 return ret;
1576         ret = register_event_command(&trigger_disable_cmd);
1577         if (WARN_ON(ret < 0))
1578                 unregister_trigger_enable_disable_cmds();
1579
1580         return ret;
1581 }
1582
1583 static __init int register_trigger_traceon_traceoff_cmds(void)
1584 {
1585         int ret;
1586
1587         ret = register_event_command(&trigger_traceon_cmd);
1588         if (WARN_ON(ret < 0))
1589                 return ret;
1590         ret = register_event_command(&trigger_traceoff_cmd);
1591         if (WARN_ON(ret < 0))
1592                 unregister_trigger_traceon_traceoff_cmds();
1593
1594         return ret;
1595 }
1596
1597 __init int register_trigger_cmds(void)
1598 {
1599         register_trigger_traceon_traceoff_cmds();
1600         register_trigger_snapshot_cmd();
1601         register_trigger_stacktrace_cmd();
1602         register_trigger_enable_disable_cmds();
1603         register_trigger_hist_enable_disable_cmds();
1604         register_trigger_hist_cmd();
1605
1606         return 0;
1607 }