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