kernel/trace/trace_events_trigger.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_trigger - trace event triggers
   4  *
   5  * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/ctype.h>
  10 #include <linux/mutex.h>
  11 #include <linux/slab.h>
  12 #include <linux/rculist.h>
  13
  14 #include "trace.h"
  15
  16 static LIST_HEAD(trigger_commands);
  17 static DEFINE_MUTEX(trigger_cmd_mutex);
  18
  19 void trigger_data_free(struct event_trigger_data *data)
  20 {
  21         if (data->cmd_ops->set_filter)
  22                 data->cmd_ops->set_filter(NULL, data, NULL);
  23
  24         /* make sure current triggers exit before free */
  25         tracepoint_synchronize_unregister();
  26
  27         kfree(data);
  28 }
  29
  30 /**
  31  * event_triggers_call - Call triggers associated with a trace event
  32  * @file: The trace_event_file associated with the event
  33  * @rec: The trace entry for the event, NULL for unconditional invocation
  34  *
  35  * For each trigger associated with an event, invoke the trigger
  36  * function registered with the associated trigger command.  If rec is
  37  * non-NULL, it means that the trigger requires further processing and
  38  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
  39  * trigger has a filter associated with it, rec will checked against
  40  * the filter and if the record matches the trigger will be invoked.
  41  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
  42  * in any case until the current event is written, the trigger
  43  * function isn't invoked but the bit associated with the deferred
  44  * trigger is set in the return value.
  45  *
  46  * Returns an enum event_trigger_type value containing a set bit for
  47  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  48  *
  49  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  50  *
  51  * Return: an enum event_trigger_type value containing a set bit for
  52  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  53  */
  54 enum event_trigger_type
  55 event_triggers_call(struct trace_event_file *file, void *rec,
  56                     struct ring_buffer_event *event)
  57 {
  58         struct event_trigger_data *data;
  59         enum event_trigger_type tt = ETT_NONE;
  60         struct event_filter *filter;
  61
  62         if (list_empty(&file->triggers))
  63                 return tt;
  64
  65         list_for_each_entry_rcu(data, &file->triggers, list) {
  66                 if (data->paused)
  67                         continue;
  68                 if (!rec) {
  69                         data->ops->func(data, rec, event);
  70                         continue;
  71                 }
  72                 filter = rcu_dereference_sched(data->filter);
  73                 if (filter && !filter_match_preds(filter, rec))
  74                         continue;
  75                 if (event_command_post_trigger(data->cmd_ops)) {
  76                         tt |= data->cmd_ops->trigger_type;
  77                         continue;
  78                 }
  79                 data->ops->func(data, rec, event);
  80         }
  81         return tt;
  82 }
  83 EXPORT_SYMBOL_GPL(event_triggers_call);
  84
  85 /**
  86  * event_triggers_post_call - Call 'post_triggers' for a trace event
  87  * @file: The trace_event_file associated with the event
  88  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
  89  *
  90  * For each trigger associated with an event, invoke the trigger
  91  * function registered with the associated trigger command, if the
  92  * corresponding bit is set in the tt enum passed into this function.
  93  * See @event_triggers_call for details on how those bits are set.
  94  *
  95  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  96  */
  97 void
  98 event_triggers_post_call(struct trace_event_file *file,
  99                          enum event_trigger_type tt)
 100 {
 101         struct event_trigger_data *data;
 102
 103         list_for_each_entry_rcu(data, &file->triggers, list) {
 104                 if (data->paused)
 105                         continue;
 106                 if (data->cmd_ops->trigger_type & tt)
 107                         data->ops->func(data, NULL, NULL);
 108         }
 109 }
 110 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 111
 112 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 113
 114 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 115 {
 116         struct trace_event_file *event_file = event_file_data(m->private);
 117
 118         if (t == SHOW_AVAILABLE_TRIGGERS)
 119                 return NULL;
 120
 121         return seq_list_next(t, &event_file->triggers, pos);
 122 }
 123
 124 static void *trigger_start(struct seq_file *m, loff_t *pos)
 125 {
 126         struct trace_event_file *event_file;
 127
 128         /* ->stop() is called even if ->start() fails */
 129         mutex_lock(&event_mutex);
 130         event_file = event_file_data(m->private);
 131         if (unlikely(!event_file))
 132                 return ERR_PTR(-ENODEV);
 133
 134         if (list_empty(&event_file->triggers))
 135                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 136
 137         return seq_list_start(&event_file->triggers, *pos);
 138 }
 139
 140 static void trigger_stop(struct seq_file *m, void *t)
 141 {
 142         mutex_unlock(&event_mutex);
 143 }
 144
 145 static int trigger_show(struct seq_file *m, void *v)
 146 {
 147         struct event_trigger_data *data;
 148         struct event_command *p;
 149
 150         if (v == SHOW_AVAILABLE_TRIGGERS) {
 151                 seq_puts(m, "# Available triggers:\n");
 152                 seq_putc(m, '#');
 153                 mutex_lock(&trigger_cmd_mutex);
 154                 list_for_each_entry_reverse(p, &trigger_commands, list)
 155                         seq_printf(m, " %s", p->name);
 156                 seq_putc(m, '\n');
 157                 mutex_unlock(&trigger_cmd_mutex);
 158                 return 0;
 159         }
 160
 161         data = list_entry(v, struct event_trigger_data, list);
 162         data->ops->print(m, data->ops, data);
 163
 164         return 0;
 165 }
 166
 167 static const struct seq_operations event_triggers_seq_ops = {
 168         .start = trigger_start,
 169         .next = trigger_next,
 170         .stop = trigger_stop,
 171         .show = trigger_show,
 172 };
 173
 174 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 175 {
 176         int ret = 0;
 177
 178         mutex_lock(&event_mutex);
 179
 180         if (unlikely(!event_file_data(file))) {
 181                 mutex_unlock(&event_mutex);
 182                 return -ENODEV;
 183         }
 184
 185         if ((file->f_mode & FMODE_WRITE) &&
 186             (file->f_flags & O_TRUNC)) {
 187                 struct trace_event_file *event_file;
 188                 struct event_command *p;
 189
 190                 event_file = event_file_data(file);
 191
 192                 list_for_each_entry(p, &trigger_commands, list) {
 193                         if (p->unreg_all)
 194                                 p->unreg_all(event_file);
 195                 }
 196         }
 197
 198         if (file->f_mode & FMODE_READ) {
 199                 ret = seq_open(file, &event_triggers_seq_ops);
 200                 if (!ret) {
 201                         struct seq_file *m = file->private_data;
 202                         m->private = file;
 203                 }
 204         }
 205
 206         mutex_unlock(&event_mutex);
 207
 208         return ret;
 209 }
 210
 211 static int trigger_process_regex(struct trace_event_file *file, char *buff)
 212 {
 213         char *command, *next = buff;
 214         struct event_command *p;
 215         int ret = -EINVAL;
 216
 217         command = strsep(&next, ": \t");
 218         command = (command[0] != '!') ? command : command + 1;
 219
 220         mutex_lock(&trigger_cmd_mutex);
 221         list_for_each_entry(p, &trigger_commands, list) {
 222                 if (strcmp(p->name, command) == 0) {
 223                         ret = p->func(p, file, buff, command, next);
 224                         goto out_unlock;
 225                 }
 226         }
 227  out_unlock:
 228         mutex_unlock(&trigger_cmd_mutex);
 229
 230         return ret;
 231 }
 232
 233 static ssize_t event_trigger_regex_write(struct file *file,
 234                                          const char __user *ubuf,
 235                                          size_t cnt, loff_t *ppos)
 236 {
 237         struct trace_event_file *event_file;
 238         ssize_t ret;
 239         char *buf;
 240
 241         if (!cnt)
 242                 return 0;
 243
 244         if (cnt >= PAGE_SIZE)
 245                 return -EINVAL;
 246
 247         buf = memdup_user_nul(ubuf, cnt);
 248         if (IS_ERR(buf))
 249                 return PTR_ERR(buf);
 250
 251         strim(buf);
 252
 253         mutex_lock(&event_mutex);
 254         event_file = event_file_data(file);
 255         if (unlikely(!event_file)) {
 256                 mutex_unlock(&event_mutex);
 257                 kfree(buf);
 258                 return -ENODEV;
 259         }
 260         ret = trigger_process_regex(event_file, buf);
 261         mutex_unlock(&event_mutex);
 262
 263         kfree(buf);
 264         if (ret < 0)
 265                 goto out;
 266
 267         *ppos += cnt;
 268         ret = cnt;
 269  out:
 270         return ret;
 271 }
 272
 273 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 274 {
 275         mutex_lock(&event_mutex);
 276
 277         if (file->f_mode & FMODE_READ)
 278                 seq_release(inode, file);
 279
 280         mutex_unlock(&event_mutex);
 281
 282         return 0;
 283 }
 284
 285 static ssize_t
 286 event_trigger_write(struct file *filp, const char __user *ubuf,
 287                     size_t cnt, loff_t *ppos)
 288 {
 289         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 290 }
 291
 292 static int
 293 event_trigger_open(struct inode *inode, struct file *filp)
 294 {
 295         return event_trigger_regex_open(inode, filp);
 296 }
 297
 298 static int
 299 event_trigger_release(struct inode *inode, struct file *file)
 300 {
 301         return event_trigger_regex_release(inode, file);
 302 }
 303
 304 const struct file_operations event_trigger_fops = {
 305         .open = event_trigger_open,
 306         .read = seq_read,
 307         .write = event_trigger_write,
 308         .llseek = tracing_lseek,
 309         .release = event_trigger_release,
 310 };
 311
 312 /*
 313  * Currently we only register event commands from __init, so mark this
 314  * __init too.
 315  */
 316 __init int register_event_command(struct event_command *cmd)
 317 {
 318         struct event_command *p;
 319         int ret = 0;
 320
 321         mutex_lock(&trigger_cmd_mutex);
 322         list_for_each_entry(p, &trigger_commands, list) {
 323                 if (strcmp(cmd->name, p->name) == 0) {
 324                         ret = -EBUSY;
 325                         goto out_unlock;
 326                 }
 327         }
 328         list_add(&cmd->list, &trigger_commands);
 329  out_unlock:
 330         mutex_unlock(&trigger_cmd_mutex);
 331
 332         return ret;
 333 }
 334
 335 /*
 336  * Currently we only unregister event commands from __init, so mark
 337  * this __init too.
 338  */
 339 __init int unregister_event_command(struct event_command *cmd)
 340 {
 341         struct event_command *p, *n;
 342         int ret = -ENODEV;
 343
 344         mutex_lock(&trigger_cmd_mutex);
 345         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 346                 if (strcmp(cmd->name, p->name) == 0) {
 347                         ret = 0;
 348                         list_del_init(&p->list);
 349                         goto out_unlock;
 350                 }
 351         }
 352  out_unlock:
 353         mutex_unlock(&trigger_cmd_mutex);
 354
 355         return ret;
 356 }
 357
 358 /**
 359  * event_trigger_print - Generic event_trigger_ops @print implementation
 360  * @name: The name of the event trigger
 361  * @m: The seq_file being printed to
 362  * @data: Trigger-specific data
 363  * @filter_str: filter_str to print, if present
 364  *
 365  * Common implementation for event triggers to print themselves.
 366  *
 367  * Usually wrapped by a function that simply sets the @name of the
 368  * trigger command and then invokes this.
 369  *
 370  * Return: 0 on success, errno otherwise
 371  */
 372 static int
 373 event_trigger_print(const char *name, struct seq_file *m,
 374                     void *data, char *filter_str)
 375 {
 376         long count = (long)data;
 377
 378         seq_puts(m, name);
 379
 380         if (count == -1)
 381                 seq_puts(m, ":unlimited");
 382         else
 383                 seq_printf(m, ":count=%ld", count);
 384
 385         if (filter_str)
 386                 seq_printf(m, " if %s\n", filter_str);
 387         else
 388                 seq_putc(m, '\n');
 389
 390         return 0;
 391 }
 392
 393 /**
 394  * event_trigger_init - Generic event_trigger_ops @init implementation
 395  * @ops: The trigger ops associated with the trigger
 396  * @data: Trigger-specific data
 397  *
 398  * Common implementation of event trigger initialization.
 399  *
 400  * Usually used directly as the @init method in event trigger
 401  * implementations.
 402  *
 403  * Return: 0 on success, errno otherwise
 404  */
 405 int event_trigger_init(struct event_trigger_ops *ops,
 406                        struct event_trigger_data *data)
 407 {
 408         data->ref++;
 409         return 0;
 410 }
 411
 412 /**
 413  * event_trigger_free - Generic event_trigger_ops @free implementation
 414  * @ops: The trigger ops associated with the trigger
 415  * @data: Trigger-specific data
 416  *
 417  * Common implementation of event trigger de-initialization.
 418  *
 419  * Usually used directly as the @free method in event trigger
 420  * implementations.
 421  */
 422 static void
 423 event_trigger_free(struct event_trigger_ops *ops,
 424                    struct event_trigger_data *data)
 425 {
 426         if (WARN_ON_ONCE(data->ref <= 0))
 427                 return;
 428
 429         data->ref--;
 430         if (!data->ref)
 431                 trigger_data_free(data);
 432 }
 433
 434 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 435                                        int trigger_enable)
 436 {
 437         int ret = 0;
 438
 439         if (trigger_enable) {
 440                 if (atomic_inc_return(&file->tm_ref) > 1)
 441                         return ret;
 442                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 443                 ret = trace_event_enable_disable(file, 1, 1);
 444         } else {
 445                 if (atomic_dec_return(&file->tm_ref) > 0)
 446                         return ret;
 447                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 448                 ret = trace_event_enable_disable(file, 0, 1);
 449         }
 450
 451         return ret;
 452 }
 453
 454 /**
 455  * clear_event_triggers - Clear all triggers associated with a trace array
 456  * @tr: The trace array to clear
 457  *
 458  * For each trigger, the triggering event has its tm_ref decremented
 459  * via trace_event_trigger_enable_disable(), and any associated event
 460  * (in the case of enable/disable_event triggers) will have its sm_ref
 461  * decremented via free()->trace_event_enable_disable().  That
 462  * combination effectively reverses the soft-mode/trigger state added
 463  * by trigger registration.
 464  *
 465  * Must be called with event_mutex held.
 466  */
 467 void
 468 clear_event_triggers(struct trace_array *tr)
 469 {
 470         struct trace_event_file *file;
 471
 472         list_for_each_entry(file, &tr->events, list) {
 473                 struct event_trigger_data *data, *n;
 474                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 475                         trace_event_trigger_enable_disable(file, 0);
 476                         list_del_rcu(&data->list);
 477                         if (data->ops->free)
 478                                 data->ops->free(data->ops, data);
 479                 }
 480         }
 481 }
 482
 483 /**
 484  * update_cond_flag - Set or reset the TRIGGER_COND bit
 485  * @file: The trace_event_file associated with the event
 486  *
 487  * If an event has triggers and any of those triggers has a filter or
 488  * a post_trigger, trigger invocation needs to be deferred until after
 489  * the current event has logged its data, and the event should have
 490  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 491  * cleared.
 492  */
 493 void update_cond_flag(struct trace_event_file *file)
 494 {
 495         struct event_trigger_data *data;
 496         bool set_cond = false;
 497
 498         list_for_each_entry_rcu(data, &file->triggers, list) {
 499                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 500                     event_command_needs_rec(data->cmd_ops)) {
 501                         set_cond = true;
 502                         break;
 503                 }
 504         }
 505
 506         if (set_cond)
 507                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 508         else
 509                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 510 }
 511
 512 /**
 513  * register_trigger - Generic event_command @reg implementation
 514  * @glob: The raw string used to register the trigger
 515  * @ops: The trigger ops associated with the trigger
 516  * @data: Trigger-specific data to associate with the trigger
 517  * @file: The trace_event_file associated with the event
 518  *
 519  * Common implementation for event trigger registration.
 520  *
 521  * Usually used directly as the @reg method in event command
 522  * implementations.
 523  *
 524  * Return: 0 on success, errno otherwise
 525  */
 526 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 527                             struct event_trigger_data *data,
 528                             struct trace_event_file *file)
 529 {
 530         struct event_trigger_data *test;
 531         int ret = 0;
 532
 533         list_for_each_entry_rcu(test, &file->triggers, list) {
 534                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 535                         ret = -EEXIST;
 536                         goto out;
 537                 }
 538         }
 539
 540         if (data->ops->init) {
 541                 ret = data->ops->init(data->ops, data);
 542                 if (ret < 0)
 543                         goto out;
 544         }
 545
 546         list_add_rcu(&data->list, &file->triggers);
 547         ret++;
 548
 549         update_cond_flag(file);
 550         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 551                 list_del_rcu(&data->list);
 552                 update_cond_flag(file);
 553                 ret--;
 554         }
 555 out:
 556         return ret;
 557 }
 558
 559 /**
 560  * unregister_trigger - Generic event_command @unreg implementation
 561  * @glob: The raw string used to register the trigger
 562  * @ops: The trigger ops associated with the trigger
 563  * @test: Trigger-specific data used to find the trigger to remove
 564  * @file: The trace_event_file associated with the event
 565  *
 566  * Common implementation for event trigger unregistration.
 567  *
 568  * Usually used directly as the @unreg method in event command
 569  * implementations.
 570  */
 571 static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 572                                struct event_trigger_data *test,
 573                                struct trace_event_file *file)
 574 {
 575         struct event_trigger_data *data;
 576         bool unregistered = false;
 577
 578         list_for_each_entry_rcu(data, &file->triggers, list) {
 579                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 580                         unregistered = true;
 581                         list_del_rcu(&data->list);
 582                         trace_event_trigger_enable_disable(file, 0);
 583                         update_cond_flag(file);
 584                         break;
 585                 }
 586         }
 587
 588         if (unregistered && data->ops->free)
 589                 data->ops->free(data->ops, data);
 590 }
 591
 592 /**
 593  * event_trigger_callback - Generic event_command @func implementation
 594  * @cmd_ops: The command ops, used for trigger registration
 595  * @file: The trace_event_file associated with the event
 596  * @glob: The raw string used to register the trigger
 597  * @cmd: The cmd portion of the string used to register the trigger
 598  * @param: The params portion of the string used to register the trigger
 599  *
 600  * Common implementation for event command parsing and trigger
 601  * instantiation.
 602  *
 603  * Usually used directly as the @func method in event command
 604  * implementations.
 605  *
 606  * Return: 0 on success, errno otherwise
 607  */
 608 static int
 609 event_trigger_callback(struct event_command *cmd_ops,
 610                        struct trace_event_file *file,
 611                        char *glob, char *cmd, char *param)
 612 {
 613         struct event_trigger_data *trigger_data;
 614         struct event_trigger_ops *trigger_ops;
 615         char *trigger = NULL;
 616         char *number;
 617         int ret;
 618
 619         /* separate the trigger from the filter (t:n [if filter]) */
 620         if (param && isdigit(param[0]))
 621                 trigger = strsep(&param, " \t");
 622
 623         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 624
 625         ret = -ENOMEM;
 626         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 627         if (!trigger_data)
 628                 goto out;
 629
 630         trigger_data->count = -1;
 631         trigger_data->ops = trigger_ops;
 632         trigger_data->cmd_ops = cmd_ops;
 633         trigger_data->private_data = file;
 634         INIT_LIST_HEAD(&trigger_data->list);
 635         INIT_LIST_HEAD(&trigger_data->named_list);
 636
 637         if (glob[0] == '!') {
 638                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 639                 kfree(trigger_data);
 640                 ret = 0;
 641                 goto out;
 642         }
 643
 644         if (trigger) {
 645                 number = strsep(&trigger, ":");
 646
 647                 ret = -EINVAL;
 648                 if (!strlen(number))
 649                         goto out_free;
 650
 651                 /*
 652                  * We use the callback data field (which is a pointer)
 653                  * as our counter.
 654                  */
 655                 ret = kstrtoul(number, 0, &trigger_data->count);
 656                 if (ret)
 657                         goto out_free;
 658         }
 659
 660         if (!param) /* if param is non-empty, it's supposed to be a filter */
 661                 goto out_reg;
 662
 663         if (!cmd_ops->set_filter)
 664                 goto out_reg;
 665
 666         ret = cmd_ops->set_filter(param, trigger_data, file);
 667         if (ret < 0)
 668                 goto out_free;
 669
 670  out_reg:
 671         /* Up the trigger_data count to make sure reg doesn't free it on failure */
 672         event_trigger_init(trigger_ops, trigger_data);
 673         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 674         /*
 675          * The above returns on success the # of functions enabled,
 676          * but if it didn't find any functions it returns zero.
 677          * Consider no functions a failure too.
 678          */
 679         if (!ret) {
 680                 cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 681                 ret = -ENOENT;
 682         } else if (ret > 0)
 683                 ret = 0;
 684
 685         /* Down the counter of trigger_data or free it if not used anymore */
 686         event_trigger_free(trigger_ops, trigger_data);
 687  out:
 688         return ret;
 689
 690  out_free:
 691         if (cmd_ops->set_filter)
 692                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 693         kfree(trigger_data);
 694         goto out;
 695 }
 696
 697 /**
 698  * set_trigger_filter - Generic event_command @set_filter implementation
 699  * @filter_str: The filter string for the trigger, NULL to remove filter
 700  * @trigger_data: Trigger-specific data
 701  * @file: The trace_event_file associated with the event
 702  *
 703  * Common implementation for event command filter parsing and filter
 704  * instantiation.
 705  *
 706  * Usually used directly as the @set_filter method in event command
 707  * implementations.
 708  *
 709  * Also used to remove a filter (if filter_str = NULL).
 710  *
 711  * Return: 0 on success, errno otherwise
 712  */
 713 int set_trigger_filter(char *filter_str,
 714                        struct event_trigger_data *trigger_data,
 715                        struct trace_event_file *file)
 716 {
 717         struct event_trigger_data *data = trigger_data;
 718         struct event_filter *filter = NULL, *tmp;
 719         int ret = -EINVAL;
 720         char *s;
 721
 722         if (!filter_str) /* clear the current filter */
 723                 goto assign;
 724
 725         s = strsep(&filter_str, " \t");
 726
 727         if (!strlen(s) || strcmp(s, "if") != 0)
 728                 goto out;
 729
 730         if (!filter_str)
 731                 goto out;
 732
 733         /* The filter is for the 'trigger' event, not the triggered event */
 734         ret = create_event_filter(file->event_call, filter_str, false, &filter);
 735         if (ret)
 736                 goto out;
 737  assign:
 738         tmp = rcu_access_pointer(data->filter);
 739
 740         rcu_assign_pointer(data->filter, filter);
 741
 742         if (tmp) {
 743                 /* Make sure the call is done with the filter */
 744                 tracepoint_synchronize_unregister();
 745                 free_event_filter(tmp);
 746         }
 747
 748         kfree(data->filter_str);
 749         data->filter_str = NULL;
 750
 751         if (filter_str) {
 752                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 753                 if (!data->filter_str) {
 754                         free_event_filter(rcu_access_pointer(data->filter));
 755                         data->filter = NULL;
 756                         ret = -ENOMEM;
 757                 }
 758         }
 759  out:
 760         return ret;
 761 }
 762
 763 static LIST_HEAD(named_triggers);
 764
 765 /**
 766  * find_named_trigger - Find the common named trigger associated with @name
 767  * @name: The name of the set of named triggers to find the common data for
 768  *
 769  * Named triggers are sets of triggers that share a common set of
 770  * trigger data.  The first named trigger registered with a given name
 771  * owns the common trigger data that the others subsequently
 772  * registered with the same name will reference.  This function
 773  * returns the common trigger data associated with that first
 774  * registered instance.
 775  *
 776  * Return: the common trigger data for the given named trigger on
 777  * success, NULL otherwise.
 778  */
 779 struct event_trigger_data *find_named_trigger(const char *name)
 780 {
 781         struct event_trigger_data *data;
 782
 783         if (!name)
 784                 return NULL;
 785
 786         list_for_each_entry(data, &named_triggers, named_list) {
 787                 if (data->named_data)
 788                         continue;
 789                 if (strcmp(data->name, name) == 0)
 790                         return data;
 791         }
 792
 793         return NULL;
 794 }
 795
 796 /**
 797  * is_named_trigger - determine if a given trigger is a named trigger
 798  * @test: The trigger data to test
 799  *
 800  * Return: true if 'test' is a named trigger, false otherwise.
 801  */
 802 bool is_named_trigger(struct event_trigger_data *test)
 803 {
 804         struct event_trigger_data *data;
 805
 806         list_for_each_entry(data, &named_triggers, named_list) {
 807                 if (test == data)
 808                         return true;
 809         }
 810
 811         return false;
 812 }
 813
 814 /**
 815  * save_named_trigger - save the trigger in the named trigger list
 816  * @name: The name of the named trigger set
 817  * @data: The trigger data to save
 818  *
 819  * Return: 0 if successful, negative error otherwise.
 820  */
 821 int save_named_trigger(const char *name, struct event_trigger_data *data)
 822 {
 823         data->name = kstrdup(name, GFP_KERNEL);
 824         if (!data->name)
 825                 return -ENOMEM;
 826
 827         list_add(&data->named_list, &named_triggers);
 828
 829         return 0;
 830 }
 831
 832 /**
 833  * del_named_trigger - delete a trigger from the named trigger list
 834  * @data: The trigger data to delete
 835  */
 836 void del_named_trigger(struct event_trigger_data *data)
 837 {
 838         kfree(data->name);
 839         data->name = NULL;
 840
 841         list_del(&data->named_list);
 842 }
 843
 844 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 845 {
 846         struct event_trigger_data *test;
 847
 848         list_for_each_entry(test, &named_triggers, named_list) {
 849                 if (strcmp(test->name, data->name) == 0) {
 850                         if (pause) {
 851                                 test->paused_tmp = test->paused;
 852                                 test->paused = true;
 853                         } else {
 854                                 test->paused = test->paused_tmp;
 855                         }
 856                 }
 857         }
 858 }
 859
 860 /**
 861  * pause_named_trigger - Pause all named triggers with the same name
 862  * @data: The trigger data of a named trigger to pause
 863  *
 864  * Pauses a named trigger along with all other triggers having the
 865  * same name.  Because named triggers share a common set of data,
 866  * pausing only one is meaningless, so pausing one named trigger needs
 867  * to pause all triggers with the same name.
 868  */
 869 void pause_named_trigger(struct event_trigger_data *data)
 870 {
 871         __pause_named_trigger(data, true);
 872 }
 873
 874 /**
 875  * unpause_named_trigger - Un-pause all named triggers with the same name
 876  * @data: The trigger data of a named trigger to unpause
 877  *
 878  * Un-pauses a named trigger along with all other triggers having the
 879  * same name.  Because named triggers share a common set of data,
 880  * unpausing only one is meaningless, so unpausing one named trigger
 881  * needs to unpause all triggers with the same name.
 882  */
 883 void unpause_named_trigger(struct event_trigger_data *data)
 884 {
 885         __pause_named_trigger(data, false);
 886 }
 887
 888 /**
 889  * set_named_trigger_data - Associate common named trigger data
 890  * @data: The trigger data of a named trigger to unpause
 891  *
 892  * Named triggers are sets of triggers that share a common set of
 893  * trigger data.  The first named trigger registered with a given name
 894  * owns the common trigger data that the others subsequently
 895  * registered with the same name will reference.  This function
 896  * associates the common trigger data from the first trigger with the
 897  * given trigger.
 898  */
 899 void set_named_trigger_data(struct event_trigger_data *data,
 900                             struct event_trigger_data *named_data)
 901 {
 902         data->named_data = named_data;
 903 }
 904
 905 struct event_trigger_data *
 906 get_named_trigger_data(struct event_trigger_data *data)
 907 {
 908         return data->named_data;
 909 }
 910
 911 static void
 912 traceon_trigger(struct event_trigger_data *data, void *rec,
 913                 struct ring_buffer_event *event)
 914 {
 915         if (tracing_is_on())
 916                 return;
 917
 918         tracing_on();
 919 }
 920
 921 static void
 922 traceon_count_trigger(struct event_trigger_data *data, void *rec,
 923                       struct ring_buffer_event *event)
 924 {
 925         if (tracing_is_on())
 926                 return;
 927
 928         if (!data->count)
 929                 return;
 930
 931         if (data->count != -1)
 932                 (data->count)--;
 933
 934         tracing_on();
 935 }
 936
 937 static void
 938 traceoff_trigger(struct event_trigger_data *data, void *rec,
 939                  struct ring_buffer_event *event)
 940 {
 941         if (!tracing_is_on())
 942                 return;
 943
 944         tracing_off();
 945 }
 946
 947 static void
 948 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
 949                        struct ring_buffer_event *event)
 950 {
 951         if (!tracing_is_on())
 952                 return;
 953
 954         if (!data->count)
 955                 return;
 956
 957         if (data->count != -1)
 958                 (data->count)--;
 959
 960         tracing_off();
 961 }
 962
 963 static int
 964 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 965                       struct event_trigger_data *data)
 966 {
 967         return event_trigger_print("traceon", m, (void *)data->count,
 968                                    data->filter_str);
 969 }
 970
 971 static int
 972 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 973                        struct event_trigger_data *data)
 974 {
 975         return event_trigger_print("traceoff", m, (void *)data->count,
 976                                    data->filter_str);
 977 }
 978
 979 static struct event_trigger_ops traceon_trigger_ops = {
 980         .func                   = traceon_trigger,
 981         .print                  = traceon_trigger_print,
 982         .init                   = event_trigger_init,
 983         .free                   = event_trigger_free,
 984 };
 985
 986 static struct event_trigger_ops traceon_count_trigger_ops = {
 987         .func                   = traceon_count_trigger,
 988         .print                  = traceon_trigger_print,
 989         .init                   = event_trigger_init,
 990         .free                   = event_trigger_free,
 991 };
 992
 993 static struct event_trigger_ops traceoff_trigger_ops = {
 994         .func                   = traceoff_trigger,
 995         .print                  = traceoff_trigger_print,
 996         .init                   = event_trigger_init,
 997         .free                   = event_trigger_free,
 998 };
 999
1000 static struct event_trigger_ops traceoff_count_trigger_ops = {
1001         .func                   = traceoff_count_trigger,
1002         .print                  = traceoff_trigger_print,
1003         .init                   = event_trigger_init,
1004         .free                   = event_trigger_free,
1005 };
1006
1007 static struct event_trigger_ops *
1008 onoff_get_trigger_ops(char *cmd, char *param)
1009 {
1010         struct event_trigger_ops *ops;
1011
1012         /* we register both traceon and traceoff to this callback */
1013         if (strcmp(cmd, "traceon") == 0)
1014                 ops = param ? &traceon_count_trigger_ops :
1015                         &traceon_trigger_ops;
1016         else
1017                 ops = param ? &traceoff_count_trigger_ops :
1018                         &traceoff_trigger_ops;
1019
1020         return ops;
1021 }
1022
1023 static struct event_command trigger_traceon_cmd = {
1024         .name                   = "traceon",
1025         .trigger_type           = ETT_TRACE_ONOFF,
1026         .func                   = event_trigger_callback,
1027         .reg                    = register_trigger,
1028         .unreg                  = unregister_trigger,
1029         .get_trigger_ops        = onoff_get_trigger_ops,
1030         .set_filter             = set_trigger_filter,
1031 };
1032
1033 static struct event_command trigger_traceoff_cmd = {
1034         .name                   = "traceoff",
1035         .trigger_type           = ETT_TRACE_ONOFF,
1036         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1037         .func                   = event_trigger_callback,
1038         .reg                    = register_trigger,
1039         .unreg                  = unregister_trigger,
1040         .get_trigger_ops        = onoff_get_trigger_ops,
1041         .set_filter             = set_trigger_filter,
1042 };
1043
1044 #ifdef CONFIG_TRACER_SNAPSHOT
1045 static void
1046 snapshot_trigger(struct event_trigger_data *data, void *rec,
1047                  struct ring_buffer_event *event)
1048 {
1049         struct trace_event_file *file = data->private_data;
1050
1051         if (file)
1052                 tracing_snapshot_instance(file->tr);
1053         else
1054                 tracing_snapshot();
1055 }
1056
1057 static void
1058 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1059                        struct ring_buffer_event *event)
1060 {
1061         if (!data->count)
1062                 return;
1063
1064         if (data->count != -1)
1065                 (data->count)--;
1066
1067         snapshot_trigger(data, rec, event);
1068 }
1069
1070 static int
1071 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1072                           struct event_trigger_data *data,
1073                           struct trace_event_file *file)
1074 {
1075         int ret = register_trigger(glob, ops, data, file);
1076
1077         if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
1078                 unregister_trigger(glob, ops, data, file);
1079                 ret = 0;
1080         }
1081
1082         return ret;
1083 }
1084
1085 static int
1086 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1087                        struct event_trigger_data *data)
1088 {
1089         return event_trigger_print("snapshot", m, (void *)data->count,
1090                                    data->filter_str);
1091 }
1092
1093 static struct event_trigger_ops snapshot_trigger_ops = {
1094         .func                   = snapshot_trigger,
1095         .print                  = snapshot_trigger_print,
1096         .init                   = event_trigger_init,
1097         .free                   = event_trigger_free,
1098 };
1099
1100 static struct event_trigger_ops snapshot_count_trigger_ops = {
1101         .func                   = snapshot_count_trigger,
1102         .print                  = snapshot_trigger_print,
1103         .init                   = event_trigger_init,
1104         .free                   = event_trigger_free,
1105 };
1106
1107 static struct event_trigger_ops *
1108 snapshot_get_trigger_ops(char *cmd, char *param)
1109 {
1110         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1111 }
1112
1113 static struct event_command trigger_snapshot_cmd = {
1114         .name                   = "snapshot",
1115         .trigger_type           = ETT_SNAPSHOT,
1116         .func                   = event_trigger_callback,
1117         .reg                    = register_snapshot_trigger,
1118         .unreg                  = unregister_trigger,
1119         .get_trigger_ops        = snapshot_get_trigger_ops,
1120         .set_filter             = set_trigger_filter,
1121 };
1122
1123 static __init int register_trigger_snapshot_cmd(void)
1124 {
1125         int ret;
1126
1127         ret = register_event_command(&trigger_snapshot_cmd);
1128         WARN_ON(ret < 0);
1129
1130         return ret;
1131 }
1132 #else
1133 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1134 #endif /* CONFIG_TRACER_SNAPSHOT */
1135
1136 #ifdef CONFIG_STACKTRACE
1137 #ifdef CONFIG_UNWINDER_ORC
1138 /* Skip 2:
1139  *   event_triggers_post_call()
1140  *   trace_event_raw_event_xxx()
1141  */
1142 # define STACK_SKIP 2
1143 #else
1144 /*
1145  * Skip 4:
1146  *   stacktrace_trigger()
1147  *   event_triggers_post_call()
1148  *   trace_event_buffer_commit()
1149  *   trace_event_raw_event_xxx()
1150  */
1151 #define STACK_SKIP 4
1152 #endif
1153
1154 static void
1155 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1156                    struct ring_buffer_event *event)
1157 {
1158         trace_dump_stack(STACK_SKIP);
1159 }
1160
1161 static void
1162 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1163                          struct ring_buffer_event *event)
1164 {
1165         if (!data->count)
1166                 return;
1167
1168         if (data->count != -1)
1169                 (data->count)--;
1170
1171         stacktrace_trigger(data, rec, event);
1172 }
1173
1174 static int
1175 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1176                          struct event_trigger_data *data)
1177 {
1178         return event_trigger_print("stacktrace", m, (void *)data->count,
1179                                    data->filter_str);
1180 }
1181
1182 static struct event_trigger_ops stacktrace_trigger_ops = {
1183         .func                   = stacktrace_trigger,
1184         .print                  = stacktrace_trigger_print,
1185         .init                   = event_trigger_init,
1186         .free                   = event_trigger_free,
1187 };
1188
1189 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1190         .func                   = stacktrace_count_trigger,
1191         .print                  = stacktrace_trigger_print,
1192         .init                   = event_trigger_init,
1193         .free                   = event_trigger_free,
1194 };
1195
1196 static struct event_trigger_ops *
1197 stacktrace_get_trigger_ops(char *cmd, char *param)
1198 {
1199         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1200 }
1201
1202 static struct event_command trigger_stacktrace_cmd = {
1203         .name                   = "stacktrace",
1204         .trigger_type           = ETT_STACKTRACE,
1205         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1206         .func                   = event_trigger_callback,
1207         .reg                    = register_trigger,
1208         .unreg                  = unregister_trigger,
1209         .get_trigger_ops        = stacktrace_get_trigger_ops,
1210         .set_filter             = set_trigger_filter,
1211 };
1212
1213 static __init int register_trigger_stacktrace_cmd(void)
1214 {
1215         int ret;
1216
1217         ret = register_event_command(&trigger_stacktrace_cmd);
1218         WARN_ON(ret < 0);
1219
1220         return ret;
1221 }
1222 #else
1223 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1224 #endif /* CONFIG_STACKTRACE */
1225
1226 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1227 {
1228         unregister_event_command(&trigger_traceon_cmd);
1229         unregister_event_command(&trigger_traceoff_cmd);
1230 }
1231
1232 static void
1233 event_enable_trigger(struct event_trigger_data *data, void *rec,
1234                      struct ring_buffer_event *event)
1235 {
1236         struct enable_trigger_data *enable_data = data->private_data;
1237
1238         if (enable_data->enable)
1239                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1240         else
1241                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1242 }
1243
1244 static void
1245 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1246                            struct ring_buffer_event *event)
1247 {
1248         struct enable_trigger_data *enable_data = data->private_data;
1249
1250         if (!data->count)
1251                 return;
1252
1253         /* Skip if the event is in a state we want to switch to */
1254         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1255                 return;
1256
1257         if (data->count != -1)
1258                 (data->count)--;
1259
1260         event_enable_trigger(data, rec, event);
1261 }
1262
1263 int event_enable_trigger_print(struct seq_file *m,
1264                                struct event_trigger_ops *ops,
1265                                struct event_trigger_data *data)
1266 {
1267         struct enable_trigger_data *enable_data = data->private_data;
1268
1269         seq_printf(m, "%s:%s:%s",
1270                    enable_data->hist ?
1271                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1272                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1273                    enable_data->file->event_call->class->system,
1274                    trace_event_name(enable_data->file->event_call));
1275
1276         if (data->count == -1)
1277                 seq_puts(m, ":unlimited");
1278         else
1279                 seq_printf(m, ":count=%ld", data->count);
1280
1281         if (data->filter_str)
1282                 seq_printf(m, " if %s\n", data->filter_str);
1283         else
1284                 seq_putc(m, '\n');
1285
1286         return 0;
1287 }
1288
1289 void event_enable_trigger_free(struct event_trigger_ops *ops,
1290                                struct event_trigger_data *data)
1291 {
1292         struct enable_trigger_data *enable_data = data->private_data;
1293
1294         if (WARN_ON_ONCE(data->ref <= 0))
1295                 return;
1296
1297         data->ref--;
1298         if (!data->ref) {
1299                 /* Remove the SOFT_MODE flag */
1300                 trace_event_enable_disable(enable_data->file, 0, 1);
1301                 module_put(enable_data->file->event_call->mod);
1302                 trigger_data_free(data);
1303                 kfree(enable_data);
1304         }
1305 }
1306
1307 static struct event_trigger_ops event_enable_trigger_ops = {
1308         .func                   = event_enable_trigger,
1309         .print                  = event_enable_trigger_print,
1310         .init                   = event_trigger_init,
1311         .free                   = event_enable_trigger_free,
1312 };
1313
1314 static struct event_trigger_ops event_enable_count_trigger_ops = {
1315         .func                   = event_enable_count_trigger,
1316         .print                  = event_enable_trigger_print,
1317         .init                   = event_trigger_init,
1318         .free                   = event_enable_trigger_free,
1319 };
1320
1321 static struct event_trigger_ops event_disable_trigger_ops = {
1322         .func                   = event_enable_trigger,
1323         .print                  = event_enable_trigger_print,
1324         .init                   = event_trigger_init,
1325         .free                   = event_enable_trigger_free,
1326 };
1327
1328 static struct event_trigger_ops event_disable_count_trigger_ops = {
1329         .func                   = event_enable_count_trigger,
1330         .print                  = event_enable_trigger_print,
1331         .init                   = event_trigger_init,
1332         .free                   = event_enable_trigger_free,
1333 };
1334
1335 int event_enable_trigger_func(struct event_command *cmd_ops,
1336                               struct trace_event_file *file,
1337                               char *glob, char *cmd, char *param)
1338 {
1339         struct trace_event_file *event_enable_file;
1340         struct enable_trigger_data *enable_data;
1341         struct event_trigger_data *trigger_data;
1342         struct event_trigger_ops *trigger_ops;
1343         struct trace_array *tr = file->tr;
1344         const char *system;
1345         const char *event;
1346         bool hist = false;
1347         char *trigger;
1348         char *number;
1349         bool enable;
1350         int ret;
1351
1352         if (!param)
1353                 return -EINVAL;
1354
1355         /* separate the trigger from the filter (s:e:n [if filter]) */
1356         trigger = strsep(&param, " \t");
1357         if (!trigger)
1358                 return -EINVAL;
1359
1360         system = strsep(&trigger, ":");
1361         if (!trigger)
1362                 return -EINVAL;
1363
1364         event = strsep(&trigger, ":");
1365
1366         ret = -EINVAL;
1367         event_enable_file = find_event_file(tr, system, event);
1368         if (!event_enable_file)
1369                 goto out;
1370
1371 #ifdef CONFIG_HIST_TRIGGERS
1372         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1373                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1374
1375         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1376                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1377 #else
1378         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1379 #endif
1380         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1381
1382         ret = -ENOMEM;
1383         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1384         if (!trigger_data)
1385                 goto out;
1386
1387         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1388         if (!enable_data) {
1389                 kfree(trigger_data);
1390                 goto out;
1391         }
1392
1393         trigger_data->count = -1;
1394         trigger_data->ops = trigger_ops;
1395         trigger_data->cmd_ops = cmd_ops;
1396         INIT_LIST_HEAD(&trigger_data->list);
1397         RCU_INIT_POINTER(trigger_data->filter, NULL);
1398
1399         enable_data->hist = hist;
1400         enable_data->enable = enable;
1401         enable_data->file = event_enable_file;
1402         trigger_data->private_data = enable_data;
1403
1404         if (glob[0] == '!') {
1405                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1406                 kfree(trigger_data);
1407                 kfree(enable_data);
1408                 ret = 0;
1409                 goto out;
1410         }
1411
1412         /* Up the trigger_data count to make sure nothing frees it on failure */
1413         event_trigger_init(trigger_ops, trigger_data);
1414
1415         if (trigger) {
1416                 number = strsep(&trigger, ":");
1417
1418                 ret = -EINVAL;
1419                 if (!strlen(number))
1420                         goto out_free;
1421
1422                 /*
1423                  * We use the callback data field (which is a pointer)
1424                  * as our counter.
1425                  */
1426                 ret = kstrtoul(number, 0, &trigger_data->count);
1427                 if (ret)
1428                         goto out_free;
1429         }
1430
1431         if (!param) /* if param is non-empty, it's supposed to be a filter */
1432                 goto out_reg;
1433
1434         if (!cmd_ops->set_filter)
1435                 goto out_reg;
1436
1437         ret = cmd_ops->set_filter(param, trigger_data, file);
1438         if (ret < 0)
1439                 goto out_free;
1440
1441  out_reg:
1442         /* Don't let event modules unload while probe registered */
1443         ret = try_module_get(event_enable_file->event_call->mod);
1444         if (!ret) {
1445                 ret = -EBUSY;
1446                 goto out_free;
1447         }
1448
1449         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1450         if (ret < 0)
1451                 goto out_put;
1452         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1453         /*
1454          * The above returns on success the # of functions enabled,
1455          * but if it didn't find any functions it returns zero.
1456          * Consider no functions a failure too.
1457          */
1458         if (!ret) {
1459                 ret = -ENOENT;
1460                 goto out_disable;
1461         } else if (ret < 0)
1462                 goto out_disable;
1463         /* Just return zero, not the number of enabled functions */
1464         ret = 0;
1465         event_trigger_free(trigger_ops, trigger_data);
1466  out:
1467         return ret;
1468
1469  out_disable:
1470         trace_event_enable_disable(event_enable_file, 0, 1);
1471  out_put:
1472         module_put(event_enable_file->event_call->mod);
1473  out_free:
1474         if (cmd_ops->set_filter)
1475                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1476         event_trigger_free(trigger_ops, trigger_data);
1477         kfree(enable_data);
1478         goto out;
1479 }
1480
1481 int event_enable_register_trigger(char *glob,
1482                                   struct event_trigger_ops *ops,
1483                                   struct event_trigger_data *data,
1484                                   struct trace_event_file *file)
1485 {
1486         struct enable_trigger_data *enable_data = data->private_data;
1487         struct enable_trigger_data *test_enable_data;
1488         struct event_trigger_data *test;
1489         int ret = 0;
1490
1491         list_for_each_entry_rcu(test, &file->triggers, list) {
1492                 test_enable_data = test->private_data;
1493                 if (test_enable_data &&
1494                     (test->cmd_ops->trigger_type ==
1495                      data->cmd_ops->trigger_type) &&
1496                     (test_enable_data->file == enable_data->file)) {
1497                         ret = -EEXIST;
1498                         goto out;
1499                 }
1500         }
1501
1502         if (data->ops->init) {
1503                 ret = data->ops->init(data->ops, data);
1504                 if (ret < 0)
1505                         goto out;
1506         }
1507
1508         list_add_rcu(&data->list, &file->triggers);
1509         ret++;
1510
1511         update_cond_flag(file);
1512         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1513                 list_del_rcu(&data->list);
1514                 update_cond_flag(file);
1515                 ret--;
1516         }
1517 out:
1518         return ret;
1519 }
1520
1521 void event_enable_unregister_trigger(char *glob,
1522                                      struct event_trigger_ops *ops,
1523                                      struct event_trigger_data *test,
1524                                      struct trace_event_file *file)
1525 {
1526         struct enable_trigger_data *test_enable_data = test->private_data;
1527         struct enable_trigger_data *enable_data;
1528         struct event_trigger_data *data;
1529         bool unregistered = false;
1530
1531         list_for_each_entry_rcu(data, &file->triggers, list) {
1532                 enable_data = data->private_data;
1533                 if (enable_data &&
1534                     (data->cmd_ops->trigger_type ==
1535                      test->cmd_ops->trigger_type) &&
1536                     (enable_data->file == test_enable_data->file)) {
1537                         unregistered = true;
1538                         list_del_rcu(&data->list);
1539                         trace_event_trigger_enable_disable(file, 0);
1540                         update_cond_flag(file);
1541                         break;
1542                 }
1543         }
1544
1545         if (unregistered && data->ops->free)
1546                 data->ops->free(data->ops, data);
1547 }
1548
1549 static struct event_trigger_ops *
1550 event_enable_get_trigger_ops(char *cmd, char *param)
1551 {
1552         struct event_trigger_ops *ops;
1553         bool enable;
1554
1555 #ifdef CONFIG_HIST_TRIGGERS
1556         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1557                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1558 #else
1559         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1560 #endif
1561         if (enable)
1562                 ops = param ? &event_enable_count_trigger_ops :
1563                         &event_enable_trigger_ops;
1564         else
1565                 ops = param ? &event_disable_count_trigger_ops :
1566                         &event_disable_trigger_ops;
1567
1568         return ops;
1569 }
1570
1571 static struct event_command trigger_enable_cmd = {
1572         .name                   = ENABLE_EVENT_STR,
1573         .trigger_type           = ETT_EVENT_ENABLE,
1574         .func                   = event_enable_trigger_func,
1575         .reg                    = event_enable_register_trigger,
1576         .unreg                  = event_enable_unregister_trigger,
1577         .get_trigger_ops        = event_enable_get_trigger_ops,
1578         .set_filter             = set_trigger_filter,
1579 };
1580
1581 static struct event_command trigger_disable_cmd = {
1582         .name                   = DISABLE_EVENT_STR,
1583         .trigger_type           = ETT_EVENT_ENABLE,
1584         .func                   = event_enable_trigger_func,
1585         .reg                    = event_enable_register_trigger,
1586         .unreg                  = event_enable_unregister_trigger,
1587         .get_trigger_ops        = event_enable_get_trigger_ops,
1588         .set_filter             = set_trigger_filter,
1589 };
1590
1591 static __init void unregister_trigger_enable_disable_cmds(void)
1592 {
1593         unregister_event_command(&trigger_enable_cmd);
1594         unregister_event_command(&trigger_disable_cmd);
1595 }
1596
1597 static __init int register_trigger_enable_disable_cmds(void)
1598 {
1599         int ret;
1600
1601         ret = register_event_command(&trigger_enable_cmd);
1602         if (WARN_ON(ret < 0))
1603                 return ret;
1604         ret = register_event_command(&trigger_disable_cmd);
1605         if (WARN_ON(ret < 0))
1606                 unregister_trigger_enable_disable_cmds();
1607
1608         return ret;
1609 }
1610
1611 static __init int register_trigger_traceon_traceoff_cmds(void)
1612 {
1613         int ret;
1614
1615         ret = register_event_command(&trigger_traceon_cmd);
1616         if (WARN_ON(ret < 0))
1617                 return ret;
1618         ret = register_event_command(&trigger_traceoff_cmd);
1619         if (WARN_ON(ret < 0))
1620                 unregister_trigger_traceon_traceoff_cmds();
1621
1622         return ret;
1623 }
1624
1625 __init int register_trigger_cmds(void)
1626 {
1627         register_trigger_traceon_traceoff_cmds();
1628         register_trigger_snapshot_cmd();
1629         register_trigger_stacktrace_cmd();
1630         register_trigger_enable_disable_cmds();
1631         register_trigger_hist_enable_disable_cmds();
1632         register_trigger_hist_cmd();
1633
1634         return 0;
1635 }