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->tr, file->event_call,
 735                                   filter_str, false, &filter);
 736         /*
 737          * If create_event_filter() fails, filter still needs to be freed.
 738          * Which the calling code will do with data->filter.
 739          */
 740  assign:
 741         tmp = rcu_access_pointer(data->filter);
 742
 743         rcu_assign_pointer(data->filter, filter);
 744
 745         if (tmp) {
 746                 /* Make sure the call is done with the filter */
 747                 tracepoint_synchronize_unregister();
 748                 free_event_filter(tmp);
 749         }
 750
 751         kfree(data->filter_str);
 752         data->filter_str = NULL;
 753
 754         if (filter_str) {
 755                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 756                 if (!data->filter_str) {
 757                         free_event_filter(rcu_access_pointer(data->filter));
 758                         data->filter = NULL;
 759                         ret = -ENOMEM;
 760                 }
 761         }
 762  out:
 763         return ret;
 764 }
 765
 766 static LIST_HEAD(named_triggers);
 767
 768 /**
 769  * find_named_trigger - Find the common named trigger associated with @name
 770  * @name: The name of the set of named triggers to find the common data for
 771  *
 772  * Named triggers are sets of triggers that share a common set of
 773  * trigger data.  The first named trigger registered with a given name
 774  * owns the common trigger data that the others subsequently
 775  * registered with the same name will reference.  This function
 776  * returns the common trigger data associated with that first
 777  * registered instance.
 778  *
 779  * Return: the common trigger data for the given named trigger on
 780  * success, NULL otherwise.
 781  */
 782 struct event_trigger_data *find_named_trigger(const char *name)
 783 {
 784         struct event_trigger_data *data;
 785
 786         if (!name)
 787                 return NULL;
 788
 789         list_for_each_entry(data, &named_triggers, named_list) {
 790                 if (data->named_data)
 791                         continue;
 792                 if (strcmp(data->name, name) == 0)
 793                         return data;
 794         }
 795
 796         return NULL;
 797 }
 798
 799 /**
 800  * is_named_trigger - determine if a given trigger is a named trigger
 801  * @test: The trigger data to test
 802  *
 803  * Return: true if 'test' is a named trigger, false otherwise.
 804  */
 805 bool is_named_trigger(struct event_trigger_data *test)
 806 {
 807         struct event_trigger_data *data;
 808
 809         list_for_each_entry(data, &named_triggers, named_list) {
 810                 if (test == data)
 811                         return true;
 812         }
 813
 814         return false;
 815 }
 816
 817 /**
 818  * save_named_trigger - save the trigger in the named trigger list
 819  * @name: The name of the named trigger set
 820  * @data: The trigger data to save
 821  *
 822  * Return: 0 if successful, negative error otherwise.
 823  */
 824 int save_named_trigger(const char *name, struct event_trigger_data *data)
 825 {
 826         data->name = kstrdup(name, GFP_KERNEL);
 827         if (!data->name)
 828                 return -ENOMEM;
 829
 830         list_add(&data->named_list, &named_triggers);
 831
 832         return 0;
 833 }
 834
 835 /**
 836  * del_named_trigger - delete a trigger from the named trigger list
 837  * @data: The trigger data to delete
 838  */
 839 void del_named_trigger(struct event_trigger_data *data)
 840 {
 841         kfree(data->name);
 842         data->name = NULL;
 843
 844         list_del(&data->named_list);
 845 }
 846
 847 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 848 {
 849         struct event_trigger_data *test;
 850
 851         list_for_each_entry(test, &named_triggers, named_list) {
 852                 if (strcmp(test->name, data->name) == 0) {
 853                         if (pause) {
 854                                 test->paused_tmp = test->paused;
 855                                 test->paused = true;
 856                         } else {
 857                                 test->paused = test->paused_tmp;
 858                         }
 859                 }
 860         }
 861 }
 862
 863 /**
 864  * pause_named_trigger - Pause all named triggers with the same name
 865  * @data: The trigger data of a named trigger to pause
 866  *
 867  * Pauses a named trigger along with all other triggers having the
 868  * same name.  Because named triggers share a common set of data,
 869  * pausing only one is meaningless, so pausing one named trigger needs
 870  * to pause all triggers with the same name.
 871  */
 872 void pause_named_trigger(struct event_trigger_data *data)
 873 {
 874         __pause_named_trigger(data, true);
 875 }
 876
 877 /**
 878  * unpause_named_trigger - Un-pause all named triggers with the same name
 879  * @data: The trigger data of a named trigger to unpause
 880  *
 881  * Un-pauses a named trigger along with all other triggers having the
 882  * same name.  Because named triggers share a common set of data,
 883  * unpausing only one is meaningless, so unpausing one named trigger
 884  * needs to unpause all triggers with the same name.
 885  */
 886 void unpause_named_trigger(struct event_trigger_data *data)
 887 {
 888         __pause_named_trigger(data, false);
 889 }
 890
 891 /**
 892  * set_named_trigger_data - Associate common named trigger data
 893  * @data: The trigger data of a named trigger to unpause
 894  *
 895  * Named triggers are sets of triggers that share a common set of
 896  * trigger data.  The first named trigger registered with a given name
 897  * owns the common trigger data that the others subsequently
 898  * registered with the same name will reference.  This function
 899  * associates the common trigger data from the first trigger with the
 900  * given trigger.
 901  */
 902 void set_named_trigger_data(struct event_trigger_data *data,
 903                             struct event_trigger_data *named_data)
 904 {
 905         data->named_data = named_data;
 906 }
 907
 908 struct event_trigger_data *
 909 get_named_trigger_data(struct event_trigger_data *data)
 910 {
 911         return data->named_data;
 912 }
 913
 914 static void
 915 traceon_trigger(struct event_trigger_data *data, void *rec,
 916                 struct ring_buffer_event *event)
 917 {
 918         if (tracing_is_on())
 919                 return;
 920
 921         tracing_on();
 922 }
 923
 924 static void
 925 traceon_count_trigger(struct event_trigger_data *data, void *rec,
 926                       struct ring_buffer_event *event)
 927 {
 928         if (tracing_is_on())
 929                 return;
 930
 931         if (!data->count)
 932                 return;
 933
 934         if (data->count != -1)
 935                 (data->count)--;
 936
 937         tracing_on();
 938 }
 939
 940 static void
 941 traceoff_trigger(struct event_trigger_data *data, void *rec,
 942                  struct ring_buffer_event *event)
 943 {
 944         if (!tracing_is_on())
 945                 return;
 946
 947         tracing_off();
 948 }
 949
 950 static void
 951 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
 952                        struct ring_buffer_event *event)
 953 {
 954         if (!tracing_is_on())
 955                 return;
 956
 957         if (!data->count)
 958                 return;
 959
 960         if (data->count != -1)
 961                 (data->count)--;
 962
 963         tracing_off();
 964 }
 965
 966 static int
 967 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 968                       struct event_trigger_data *data)
 969 {
 970         return event_trigger_print("traceon", m, (void *)data->count,
 971                                    data->filter_str);
 972 }
 973
 974 static int
 975 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 976                        struct event_trigger_data *data)
 977 {
 978         return event_trigger_print("traceoff", m, (void *)data->count,
 979                                    data->filter_str);
 980 }
 981
 982 static struct event_trigger_ops traceon_trigger_ops = {
 983         .func                   = traceon_trigger,
 984         .print                  = traceon_trigger_print,
 985         .init                   = event_trigger_init,
 986         .free                   = event_trigger_free,
 987 };
 988
 989 static struct event_trigger_ops traceon_count_trigger_ops = {
 990         .func                   = traceon_count_trigger,
 991         .print                  = traceon_trigger_print,
 992         .init                   = event_trigger_init,
 993         .free                   = event_trigger_free,
 994 };
 995
 996 static struct event_trigger_ops traceoff_trigger_ops = {
 997         .func                   = traceoff_trigger,
 998         .print                  = traceoff_trigger_print,
 999         .init                   = event_trigger_init,
1000         .free                   = event_trigger_free,
1001 };
1002
1003 static struct event_trigger_ops traceoff_count_trigger_ops = {
1004         .func                   = traceoff_count_trigger,
1005         .print                  = traceoff_trigger_print,
1006         .init                   = event_trigger_init,
1007         .free                   = event_trigger_free,
1008 };
1009
1010 static struct event_trigger_ops *
1011 onoff_get_trigger_ops(char *cmd, char *param)
1012 {
1013         struct event_trigger_ops *ops;
1014
1015         /* we register both traceon and traceoff to this callback */
1016         if (strcmp(cmd, "traceon") == 0)
1017                 ops = param ? &traceon_count_trigger_ops :
1018                         &traceon_trigger_ops;
1019         else
1020                 ops = param ? &traceoff_count_trigger_ops :
1021                         &traceoff_trigger_ops;
1022
1023         return ops;
1024 }
1025
1026 static struct event_command trigger_traceon_cmd = {
1027         .name                   = "traceon",
1028         .trigger_type           = ETT_TRACE_ONOFF,
1029         .func                   = event_trigger_callback,
1030         .reg                    = register_trigger,
1031         .unreg                  = unregister_trigger,
1032         .get_trigger_ops        = onoff_get_trigger_ops,
1033         .set_filter             = set_trigger_filter,
1034 };
1035
1036 static struct event_command trigger_traceoff_cmd = {
1037         .name                   = "traceoff",
1038         .trigger_type           = ETT_TRACE_ONOFF,
1039         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1040         .func                   = event_trigger_callback,
1041         .reg                    = register_trigger,
1042         .unreg                  = unregister_trigger,
1043         .get_trigger_ops        = onoff_get_trigger_ops,
1044         .set_filter             = set_trigger_filter,
1045 };
1046
1047 #ifdef CONFIG_TRACER_SNAPSHOT
1048 static void
1049 snapshot_trigger(struct event_trigger_data *data, void *rec,
1050                  struct ring_buffer_event *event)
1051 {
1052         struct trace_event_file *file = data->private_data;
1053
1054         if (file)
1055                 tracing_snapshot_instance(file->tr);
1056         else
1057                 tracing_snapshot();
1058 }
1059
1060 static void
1061 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1062                        struct ring_buffer_event *event)
1063 {
1064         if (!data->count)
1065                 return;
1066
1067         if (data->count != -1)
1068                 (data->count)--;
1069
1070         snapshot_trigger(data, rec, event);
1071 }
1072
1073 static int
1074 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1075                           struct event_trigger_data *data,
1076                           struct trace_event_file *file)
1077 {
1078         int ret = register_trigger(glob, ops, data, file);
1079
1080         if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
1081                 unregister_trigger(glob, ops, data, file);
1082                 ret = 0;
1083         }
1084
1085         return ret;
1086 }
1087
1088 static int
1089 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1090                        struct event_trigger_data *data)
1091 {
1092         return event_trigger_print("snapshot", m, (void *)data->count,
1093                                    data->filter_str);
1094 }
1095
1096 static struct event_trigger_ops snapshot_trigger_ops = {
1097         .func                   = snapshot_trigger,
1098         .print                  = snapshot_trigger_print,
1099         .init                   = event_trigger_init,
1100         .free                   = event_trigger_free,
1101 };
1102
1103 static struct event_trigger_ops snapshot_count_trigger_ops = {
1104         .func                   = snapshot_count_trigger,
1105         .print                  = snapshot_trigger_print,
1106         .init                   = event_trigger_init,
1107         .free                   = event_trigger_free,
1108 };
1109
1110 static struct event_trigger_ops *
1111 snapshot_get_trigger_ops(char *cmd, char *param)
1112 {
1113         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1114 }
1115
1116 static struct event_command trigger_snapshot_cmd = {
1117         .name                   = "snapshot",
1118         .trigger_type           = ETT_SNAPSHOT,
1119         .func                   = event_trigger_callback,
1120         .reg                    = register_snapshot_trigger,
1121         .unreg                  = unregister_trigger,
1122         .get_trigger_ops        = snapshot_get_trigger_ops,
1123         .set_filter             = set_trigger_filter,
1124 };
1125
1126 static __init int register_trigger_snapshot_cmd(void)
1127 {
1128         int ret;
1129
1130         ret = register_event_command(&trigger_snapshot_cmd);
1131         WARN_ON(ret < 0);
1132
1133         return ret;
1134 }
1135 #else
1136 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1137 #endif /* CONFIG_TRACER_SNAPSHOT */
1138
1139 #ifdef CONFIG_STACKTRACE
1140 #ifdef CONFIG_UNWINDER_ORC
1141 /* Skip 2:
1142  *   event_triggers_post_call()
1143  *   trace_event_raw_event_xxx()
1144  */
1145 # define STACK_SKIP 2
1146 #else
1147 /*
1148  * Skip 4:
1149  *   stacktrace_trigger()
1150  *   event_triggers_post_call()
1151  *   trace_event_buffer_commit()
1152  *   trace_event_raw_event_xxx()
1153  */
1154 #define STACK_SKIP 4
1155 #endif
1156
1157 static void
1158 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1159                    struct ring_buffer_event *event)
1160 {
1161         trace_dump_stack(STACK_SKIP);
1162 }
1163
1164 static void
1165 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1166                          struct ring_buffer_event *event)
1167 {
1168         if (!data->count)
1169                 return;
1170
1171         if (data->count != -1)
1172                 (data->count)--;
1173
1174         stacktrace_trigger(data, rec, event);
1175 }
1176
1177 static int
1178 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1179                          struct event_trigger_data *data)
1180 {
1181         return event_trigger_print("stacktrace", m, (void *)data->count,
1182                                    data->filter_str);
1183 }
1184
1185 static struct event_trigger_ops stacktrace_trigger_ops = {
1186         .func                   = stacktrace_trigger,
1187         .print                  = stacktrace_trigger_print,
1188         .init                   = event_trigger_init,
1189         .free                   = event_trigger_free,
1190 };
1191
1192 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1193         .func                   = stacktrace_count_trigger,
1194         .print                  = stacktrace_trigger_print,
1195         .init                   = event_trigger_init,
1196         .free                   = event_trigger_free,
1197 };
1198
1199 static struct event_trigger_ops *
1200 stacktrace_get_trigger_ops(char *cmd, char *param)
1201 {
1202         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1203 }
1204
1205 static struct event_command trigger_stacktrace_cmd = {
1206         .name                   = "stacktrace",
1207         .trigger_type           = ETT_STACKTRACE,
1208         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1209         .func                   = event_trigger_callback,
1210         .reg                    = register_trigger,
1211         .unreg                  = unregister_trigger,
1212         .get_trigger_ops        = stacktrace_get_trigger_ops,
1213         .set_filter             = set_trigger_filter,
1214 };
1215
1216 static __init int register_trigger_stacktrace_cmd(void)
1217 {
1218         int ret;
1219
1220         ret = register_event_command(&trigger_stacktrace_cmd);
1221         WARN_ON(ret < 0);
1222
1223         return ret;
1224 }
1225 #else
1226 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1227 #endif /* CONFIG_STACKTRACE */
1228
1229 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1230 {
1231         unregister_event_command(&trigger_traceon_cmd);
1232         unregister_event_command(&trigger_traceoff_cmd);
1233 }
1234
1235 static void
1236 event_enable_trigger(struct event_trigger_data *data, void *rec,
1237                      struct ring_buffer_event *event)
1238 {
1239         struct enable_trigger_data *enable_data = data->private_data;
1240
1241         if (enable_data->enable)
1242                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1243         else
1244                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1245 }
1246
1247 static void
1248 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1249                            struct ring_buffer_event *event)
1250 {
1251         struct enable_trigger_data *enable_data = data->private_data;
1252
1253         if (!data->count)
1254                 return;
1255
1256         /* Skip if the event is in a state we want to switch to */
1257         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1258                 return;
1259
1260         if (data->count != -1)
1261                 (data->count)--;
1262
1263         event_enable_trigger(data, rec, event);
1264 }
1265
1266 int event_enable_trigger_print(struct seq_file *m,
1267                                struct event_trigger_ops *ops,
1268                                struct event_trigger_data *data)
1269 {
1270         struct enable_trigger_data *enable_data = data->private_data;
1271
1272         seq_printf(m, "%s:%s:%s",
1273                    enable_data->hist ?
1274                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1275                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1276                    enable_data->file->event_call->class->system,
1277                    trace_event_name(enable_data->file->event_call));
1278
1279         if (data->count == -1)
1280                 seq_puts(m, ":unlimited");
1281         else
1282                 seq_printf(m, ":count=%ld", data->count);
1283
1284         if (data->filter_str)
1285                 seq_printf(m, " if %s\n", data->filter_str);
1286         else
1287                 seq_putc(m, '\n');
1288
1289         return 0;
1290 }
1291
1292 void event_enable_trigger_free(struct event_trigger_ops *ops,
1293                                struct event_trigger_data *data)
1294 {
1295         struct enable_trigger_data *enable_data = data->private_data;
1296
1297         if (WARN_ON_ONCE(data->ref <= 0))
1298                 return;
1299
1300         data->ref--;
1301         if (!data->ref) {
1302                 /* Remove the SOFT_MODE flag */
1303                 trace_event_enable_disable(enable_data->file, 0, 1);
1304                 module_put(enable_data->file->event_call->mod);
1305                 trigger_data_free(data);
1306                 kfree(enable_data);
1307         }
1308 }
1309
1310 static struct event_trigger_ops event_enable_trigger_ops = {
1311         .func                   = event_enable_trigger,
1312         .print                  = event_enable_trigger_print,
1313         .init                   = event_trigger_init,
1314         .free                   = event_enable_trigger_free,
1315 };
1316
1317 static struct event_trigger_ops event_enable_count_trigger_ops = {
1318         .func                   = event_enable_count_trigger,
1319         .print                  = event_enable_trigger_print,
1320         .init                   = event_trigger_init,
1321         .free                   = event_enable_trigger_free,
1322 };
1323
1324 static struct event_trigger_ops event_disable_trigger_ops = {
1325         .func                   = event_enable_trigger,
1326         .print                  = event_enable_trigger_print,
1327         .init                   = event_trigger_init,
1328         .free                   = event_enable_trigger_free,
1329 };
1330
1331 static struct event_trigger_ops event_disable_count_trigger_ops = {
1332         .func                   = event_enable_count_trigger,
1333         .print                  = event_enable_trigger_print,
1334         .init                   = event_trigger_init,
1335         .free                   = event_enable_trigger_free,
1336 };
1337
1338 int event_enable_trigger_func(struct event_command *cmd_ops,
1339                               struct trace_event_file *file,
1340                               char *glob, char *cmd, char *param)
1341 {
1342         struct trace_event_file *event_enable_file;
1343         struct enable_trigger_data *enable_data;
1344         struct event_trigger_data *trigger_data;
1345         struct event_trigger_ops *trigger_ops;
1346         struct trace_array *tr = file->tr;
1347         const char *system;
1348         const char *event;
1349         bool hist = false;
1350         char *trigger;
1351         char *number;
1352         bool enable;
1353         int ret;
1354
1355         if (!param)
1356                 return -EINVAL;
1357
1358         /* separate the trigger from the filter (s:e:n [if filter]) */
1359         trigger = strsep(&param, " \t");
1360         if (!trigger)
1361                 return -EINVAL;
1362
1363         system = strsep(&trigger, ":");
1364         if (!trigger)
1365                 return -EINVAL;
1366
1367         event = strsep(&trigger, ":");
1368
1369         ret = -EINVAL;
1370         event_enable_file = find_event_file(tr, system, event);
1371         if (!event_enable_file)
1372                 goto out;
1373
1374 #ifdef CONFIG_HIST_TRIGGERS
1375         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1376                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1377
1378         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1379                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1380 #else
1381         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1382 #endif
1383         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1384
1385         ret = -ENOMEM;
1386         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1387         if (!trigger_data)
1388                 goto out;
1389
1390         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1391         if (!enable_data) {
1392                 kfree(trigger_data);
1393                 goto out;
1394         }
1395
1396         trigger_data->count = -1;
1397         trigger_data->ops = trigger_ops;
1398         trigger_data->cmd_ops = cmd_ops;
1399         INIT_LIST_HEAD(&trigger_data->list);
1400         RCU_INIT_POINTER(trigger_data->filter, NULL);
1401
1402         enable_data->hist = hist;
1403         enable_data->enable = enable;
1404         enable_data->file = event_enable_file;
1405         trigger_data->private_data = enable_data;
1406
1407         if (glob[0] == '!') {
1408                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1409                 kfree(trigger_data);
1410                 kfree(enable_data);
1411                 ret = 0;
1412                 goto out;
1413         }
1414
1415         /* Up the trigger_data count to make sure nothing frees it on failure */
1416         event_trigger_init(trigger_ops, trigger_data);
1417
1418         if (trigger) {
1419                 number = strsep(&trigger, ":");
1420
1421                 ret = -EINVAL;
1422                 if (!strlen(number))
1423                         goto out_free;
1424
1425                 /*
1426                  * We use the callback data field (which is a pointer)
1427                  * as our counter.
1428                  */
1429                 ret = kstrtoul(number, 0, &trigger_data->count);
1430                 if (ret)
1431                         goto out_free;
1432         }
1433
1434         if (!param) /* if param is non-empty, it's supposed to be a filter */
1435                 goto out_reg;
1436
1437         if (!cmd_ops->set_filter)
1438                 goto out_reg;
1439
1440         ret = cmd_ops->set_filter(param, trigger_data, file);
1441         if (ret < 0)
1442                 goto out_free;
1443
1444  out_reg:
1445         /* Don't let event modules unload while probe registered */
1446         ret = try_module_get(event_enable_file->event_call->mod);
1447         if (!ret) {
1448                 ret = -EBUSY;
1449                 goto out_free;
1450         }
1451
1452         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1453         if (ret < 0)
1454                 goto out_put;
1455         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1456         /*
1457          * The above returns on success the # of functions enabled,
1458          * but if it didn't find any functions it returns zero.
1459          * Consider no functions a failure too.
1460          */
1461         if (!ret) {
1462                 ret = -ENOENT;
1463                 goto out_disable;
1464         } else if (ret < 0)
1465                 goto out_disable;
1466         /* Just return zero, not the number of enabled functions */
1467         ret = 0;
1468         event_trigger_free(trigger_ops, trigger_data);
1469  out:
1470         return ret;
1471
1472  out_disable:
1473         trace_event_enable_disable(event_enable_file, 0, 1);
1474  out_put:
1475         module_put(event_enable_file->event_call->mod);
1476  out_free:
1477         if (cmd_ops->set_filter)
1478                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1479         event_trigger_free(trigger_ops, trigger_data);
1480         kfree(enable_data);
1481         goto out;
1482 }
1483
1484 int event_enable_register_trigger(char *glob,
1485                                   struct event_trigger_ops *ops,
1486                                   struct event_trigger_data *data,
1487                                   struct trace_event_file *file)
1488 {
1489         struct enable_trigger_data *enable_data = data->private_data;
1490         struct enable_trigger_data *test_enable_data;
1491         struct event_trigger_data *test;
1492         int ret = 0;
1493
1494         list_for_each_entry_rcu(test, &file->triggers, list) {
1495                 test_enable_data = test->private_data;
1496                 if (test_enable_data &&
1497                     (test->cmd_ops->trigger_type ==
1498                      data->cmd_ops->trigger_type) &&
1499                     (test_enable_data->file == enable_data->file)) {
1500                         ret = -EEXIST;
1501                         goto out;
1502                 }
1503         }
1504
1505         if (data->ops->init) {
1506                 ret = data->ops->init(data->ops, data);
1507                 if (ret < 0)
1508                         goto out;
1509         }
1510
1511         list_add_rcu(&data->list, &file->triggers);
1512         ret++;
1513
1514         update_cond_flag(file);
1515         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1516                 list_del_rcu(&data->list);
1517                 update_cond_flag(file);
1518                 ret--;
1519         }
1520 out:
1521         return ret;
1522 }
1523
1524 void event_enable_unregister_trigger(char *glob,
1525                                      struct event_trigger_ops *ops,
1526                                      struct event_trigger_data *test,
1527                                      struct trace_event_file *file)
1528 {
1529         struct enable_trigger_data *test_enable_data = test->private_data;
1530         struct enable_trigger_data *enable_data;
1531         struct event_trigger_data *data;
1532         bool unregistered = false;
1533
1534         list_for_each_entry_rcu(data, &file->triggers, list) {
1535                 enable_data = data->private_data;
1536                 if (enable_data &&
1537                     (data->cmd_ops->trigger_type ==
1538                      test->cmd_ops->trigger_type) &&
1539                     (enable_data->file == test_enable_data->file)) {
1540                         unregistered = true;
1541                         list_del_rcu(&data->list);
1542                         trace_event_trigger_enable_disable(file, 0);
1543                         update_cond_flag(file);
1544                         break;
1545                 }
1546         }
1547
1548         if (unregistered && data->ops->free)
1549                 data->ops->free(data->ops, data);
1550 }
1551
1552 static struct event_trigger_ops *
1553 event_enable_get_trigger_ops(char *cmd, char *param)
1554 {
1555         struct event_trigger_ops *ops;
1556         bool enable;
1557
1558 #ifdef CONFIG_HIST_TRIGGERS
1559         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1560                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1561 #else
1562         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1563 #endif
1564         if (enable)
1565                 ops = param ? &event_enable_count_trigger_ops :
1566                         &event_enable_trigger_ops;
1567         else
1568                 ops = param ? &event_disable_count_trigger_ops :
1569                         &event_disable_trigger_ops;
1570
1571         return ops;
1572 }
1573
1574 static struct event_command trigger_enable_cmd = {
1575         .name                   = ENABLE_EVENT_STR,
1576         .trigger_type           = ETT_EVENT_ENABLE,
1577         .func                   = event_enable_trigger_func,
1578         .reg                    = event_enable_register_trigger,
1579         .unreg                  = event_enable_unregister_trigger,
1580         .get_trigger_ops        = event_enable_get_trigger_ops,
1581         .set_filter             = set_trigger_filter,
1582 };
1583
1584 static struct event_command trigger_disable_cmd = {
1585         .name                   = DISABLE_EVENT_STR,
1586         .trigger_type           = ETT_EVENT_ENABLE,
1587         .func                   = event_enable_trigger_func,
1588         .reg                    = event_enable_register_trigger,
1589         .unreg                  = event_enable_unregister_trigger,
1590         .get_trigger_ops        = event_enable_get_trigger_ops,
1591         .set_filter             = set_trigger_filter,
1592 };
1593
1594 static __init void unregister_trigger_enable_disable_cmds(void)
1595 {
1596         unregister_event_command(&trigger_enable_cmd);
1597         unregister_event_command(&trigger_disable_cmd);
1598 }
1599
1600 static __init int register_trigger_enable_disable_cmds(void)
1601 {
1602         int ret;
1603
1604         ret = register_event_command(&trigger_enable_cmd);
1605         if (WARN_ON(ret < 0))
1606                 return ret;
1607         ret = register_event_command(&trigger_disable_cmd);
1608         if (WARN_ON(ret < 0))
1609                 unregister_trigger_enable_disable_cmds();
1610
1611         return ret;
1612 }
1613
1614 static __init int register_trigger_traceon_traceoff_cmds(void)
1615 {
1616         int ret;
1617
1618         ret = register_event_command(&trigger_traceon_cmd);
1619         if (WARN_ON(ret < 0))
1620                 return ret;
1621         ret = register_event_command(&trigger_traceoff_cmd);
1622         if (WARN_ON(ret < 0))
1623                 unregister_trigger_traceon_traceoff_cmds();
1624
1625         return ret;
1626 }
1627
1628 __init int register_trigger_cmds(void)
1629 {
1630         register_trigger_traceon_traceoff_cmds();
1631         register_trigger_snapshot_cmd();
1632         register_trigger_stacktrace_cmd();
1633         register_trigger_enable_disable_cmds();
1634         register_trigger_hist_enable_disable_cmds();
1635         register_trigger_hist_cmd();
1636
1637         return 0;
1638 }