kernel/trace/trace_events_trigger.c

   1 /*
   2  * trace_events_trigger - trace event triggers
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/ctype.h>
  23 #include <linux/mutex.h>
  24 #include <linux/slab.h>
  25 #include <linux/rculist.h>
  26
  27 #include "trace.h"
  28
  29 static LIST_HEAD(trigger_commands);
  30 static DEFINE_MUTEX(trigger_cmd_mutex);
  31
  32 void trigger_data_free(struct event_trigger_data *data)
  33 {
  34         if (data->cmd_ops->set_filter)
  35                 data->cmd_ops->set_filter(NULL, data, NULL);
  36
  37         synchronize_sched(); /* make sure current triggers exit before free */
  38         kfree(data);
  39 }
  40
  41 /**
  42  * event_triggers_call - Call triggers associated with a trace event
  43  * @file: The trace_event_file associated with the event
  44  * @rec: The trace entry for the event, NULL for unconditional invocation
  45  *
  46  * For each trigger associated with an event, invoke the trigger
  47  * function registered with the associated trigger command.  If rec is
  48  * non-NULL, it means that the trigger requires further processing and
  49  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
  50  * trigger has a filter associated with it, rec will checked against
  51  * the filter and if the record matches the trigger will be invoked.
  52  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
  53  * in any case until the current event is written, the trigger
  54  * function isn't invoked but the bit associated with the deferred
  55  * trigger is set in the return value.
  56  *
  57  * Returns an enum event_trigger_type value containing a set bit for
  58  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  59  *
  60  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  61  *
  62  * Return: an enum event_trigger_type value containing a set bit for
  63  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  64  */
  65 enum event_trigger_type
  66 event_triggers_call(struct trace_event_file *file, void *rec,
  67                     struct ring_buffer_event *event)
  68 {
  69         struct event_trigger_data *data;
  70         enum event_trigger_type tt = ETT_NONE;
  71         struct event_filter *filter;
  72
  73         if (list_empty(&file->triggers))
  74                 return tt;
  75
  76         list_for_each_entry_rcu(data, &file->triggers, list) {
  77                 if (data->paused)
  78                         continue;
  79                 if (!rec) {
  80                         data->ops->func(data, rec, event);
  81                         continue;
  82                 }
  83                 filter = rcu_dereference_sched(data->filter);
  84                 if (filter && !filter_match_preds(filter, rec))
  85                         continue;
  86                 if (event_command_post_trigger(data->cmd_ops)) {
  87                         tt |= data->cmd_ops->trigger_type;
  88                         continue;
  89                 }
  90                 data->ops->func(data, rec, event);
  91         }
  92         return tt;
  93 }
  94 EXPORT_SYMBOL_GPL(event_triggers_call);
  95
  96 /**
  97  * event_triggers_post_call - Call 'post_triggers' for a trace event
  98  * @file: The trace_event_file associated with the event
  99  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
 100  * @rec: The trace entry for the event
 101  *
 102  * For each trigger associated with an event, invoke the trigger
 103  * function registered with the associated trigger command, if the
 104  * corresponding bit is set in the tt enum passed into this function.
 105  * See @event_triggers_call for details on how those bits are set.
 106  *
 107  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 108  */
 109 void
 110 event_triggers_post_call(struct trace_event_file *file,
 111                          enum event_trigger_type tt,
 112                          void *rec, struct ring_buffer_event *event)
 113 {
 114         struct event_trigger_data *data;
 115
 116         list_for_each_entry_rcu(data, &file->triggers, list) {
 117                 if (data->paused)
 118                         continue;
 119                 if (data->cmd_ops->trigger_type & tt)
 120                         data->ops->func(data, rec, event);
 121         }
 122 }
 123 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 124
 125 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 126
 127 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 128 {
 129         struct trace_event_file *event_file = event_file_data(m->private);
 130
 131         if (t == SHOW_AVAILABLE_TRIGGERS)
 132                 return NULL;
 133
 134         return seq_list_next(t, &event_file->triggers, pos);
 135 }
 136
 137 static void *trigger_start(struct seq_file *m, loff_t *pos)
 138 {
 139         struct trace_event_file *event_file;
 140
 141         /* ->stop() is called even if ->start() fails */
 142         mutex_lock(&event_mutex);
 143         event_file = event_file_data(m->private);
 144         if (unlikely(!event_file))
 145                 return ERR_PTR(-ENODEV);
 146
 147         if (list_empty(&event_file->triggers))
 148                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 149
 150         return seq_list_start(&event_file->triggers, *pos);
 151 }
 152
 153 static void trigger_stop(struct seq_file *m, void *t)
 154 {
 155         mutex_unlock(&event_mutex);
 156 }
 157
 158 static int trigger_show(struct seq_file *m, void *v)
 159 {
 160         struct event_trigger_data *data;
 161         struct event_command *p;
 162
 163         if (v == SHOW_AVAILABLE_TRIGGERS) {
 164                 seq_puts(m, "# Available triggers:\n");
 165                 seq_putc(m, '#');
 166                 mutex_lock(&trigger_cmd_mutex);
 167                 list_for_each_entry_reverse(p, &trigger_commands, list)
 168                         seq_printf(m, " %s", p->name);
 169                 seq_putc(m, '\n');
 170                 mutex_unlock(&trigger_cmd_mutex);
 171                 return 0;
 172         }
 173
 174         data = list_entry(v, struct event_trigger_data, list);
 175         data->ops->print(m, data->ops, data);
 176
 177         return 0;
 178 }
 179
 180 static const struct seq_operations event_triggers_seq_ops = {
 181         .start = trigger_start,
 182         .next = trigger_next,
 183         .stop = trigger_stop,
 184         .show = trigger_show,
 185 };
 186
 187 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 188 {
 189         int ret = 0;
 190
 191         mutex_lock(&event_mutex);
 192
 193         if (unlikely(!event_file_data(file))) {
 194                 mutex_unlock(&event_mutex);
 195                 return -ENODEV;
 196         }
 197
 198         if ((file->f_mode & FMODE_WRITE) &&
 199             (file->f_flags & O_TRUNC)) {
 200                 struct trace_event_file *event_file;
 201                 struct event_command *p;
 202
 203                 event_file = event_file_data(file);
 204
 205                 list_for_each_entry(p, &trigger_commands, list) {
 206                         if (p->unreg_all)
 207                                 p->unreg_all(event_file);
 208                 }
 209         }
 210
 211         if (file->f_mode & FMODE_READ) {
 212                 ret = seq_open(file, &event_triggers_seq_ops);
 213                 if (!ret) {
 214                         struct seq_file *m = file->private_data;
 215                         m->private = file;
 216                 }
 217         }
 218
 219         mutex_unlock(&event_mutex);
 220
 221         return ret;
 222 }
 223
 224 static int trigger_process_regex(struct trace_event_file *file, char *buff)
 225 {
 226         char *command, *next = buff;
 227         struct event_command *p;
 228         int ret = -EINVAL;
 229
 230         command = strsep(&next, ": \t");
 231         command = (command[0] != '!') ? command : command + 1;
 232
 233         mutex_lock(&trigger_cmd_mutex);
 234         list_for_each_entry(p, &trigger_commands, list) {
 235                 if (strcmp(p->name, command) == 0) {
 236                         ret = p->func(p, file, buff, command, next);
 237                         goto out_unlock;
 238                 }
 239         }
 240  out_unlock:
 241         mutex_unlock(&trigger_cmd_mutex);
 242
 243         return ret;
 244 }
 245
 246 static ssize_t event_trigger_regex_write(struct file *file,
 247                                          const char __user *ubuf,
 248                                          size_t cnt, loff_t *ppos)
 249 {
 250         struct trace_event_file *event_file;
 251         ssize_t ret;
 252         char *buf;
 253
 254         if (!cnt)
 255                 return 0;
 256
 257         if (cnt >= PAGE_SIZE)
 258                 return -EINVAL;
 259
 260         buf = memdup_user_nul(ubuf, cnt);
 261         if (IS_ERR(buf))
 262                 return PTR_ERR(buf);
 263
 264         strim(buf);
 265
 266         mutex_lock(&event_mutex);
 267         event_file = event_file_data(file);
 268         if (unlikely(!event_file)) {
 269                 mutex_unlock(&event_mutex);
 270                 kfree(buf);
 271                 return -ENODEV;
 272         }
 273         ret = trigger_process_regex(event_file, buf);
 274         mutex_unlock(&event_mutex);
 275
 276         kfree(buf);
 277         if (ret < 0)
 278                 goto out;
 279
 280         *ppos += cnt;
 281         ret = cnt;
 282  out:
 283         return ret;
 284 }
 285
 286 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 287 {
 288         mutex_lock(&event_mutex);
 289
 290         if (file->f_mode & FMODE_READ)
 291                 seq_release(inode, file);
 292
 293         mutex_unlock(&event_mutex);
 294
 295         return 0;
 296 }
 297
 298 static ssize_t
 299 event_trigger_write(struct file *filp, const char __user *ubuf,
 300                     size_t cnt, loff_t *ppos)
 301 {
 302         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 303 }
 304
 305 static int
 306 event_trigger_open(struct inode *inode, struct file *filp)
 307 {
 308         return event_trigger_regex_open(inode, filp);
 309 }
 310
 311 static int
 312 event_trigger_release(struct inode *inode, struct file *file)
 313 {
 314         return event_trigger_regex_release(inode, file);
 315 }
 316
 317 const struct file_operations event_trigger_fops = {
 318         .open = event_trigger_open,
 319         .read = seq_read,
 320         .write = event_trigger_write,
 321         .llseek = tracing_lseek,
 322         .release = event_trigger_release,
 323 };
 324
 325 /*
 326  * Currently we only register event commands from __init, so mark this
 327  * __init too.
 328  */
 329 __init int register_event_command(struct event_command *cmd)
 330 {
 331         struct event_command *p;
 332         int ret = 0;
 333
 334         mutex_lock(&trigger_cmd_mutex);
 335         list_for_each_entry(p, &trigger_commands, list) {
 336                 if (strcmp(cmd->name, p->name) == 0) {
 337                         ret = -EBUSY;
 338                         goto out_unlock;
 339                 }
 340         }
 341         list_add(&cmd->list, &trigger_commands);
 342  out_unlock:
 343         mutex_unlock(&trigger_cmd_mutex);
 344
 345         return ret;
 346 }
 347
 348 /*
 349  * Currently we only unregister event commands from __init, so mark
 350  * this __init too.
 351  */
 352 __init int unregister_event_command(struct event_command *cmd)
 353 {
 354         struct event_command *p, *n;
 355         int ret = -ENODEV;
 356
 357         mutex_lock(&trigger_cmd_mutex);
 358         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 359                 if (strcmp(cmd->name, p->name) == 0) {
 360                         ret = 0;
 361                         list_del_init(&p->list);
 362                         goto out_unlock;
 363                 }
 364         }
 365  out_unlock:
 366         mutex_unlock(&trigger_cmd_mutex);
 367
 368         return ret;
 369 }
 370
 371 /**
 372  * event_trigger_print - Generic event_trigger_ops @print implementation
 373  * @name: The name of the event trigger
 374  * @m: The seq_file being printed to
 375  * @data: Trigger-specific data
 376  * @filter_str: filter_str to print, if present
 377  *
 378  * Common implementation for event triggers to print themselves.
 379  *
 380  * Usually wrapped by a function that simply sets the @name of the
 381  * trigger command and then invokes this.
 382  *
 383  * Return: 0 on success, errno otherwise
 384  */
 385 static int
 386 event_trigger_print(const char *name, struct seq_file *m,
 387                     void *data, char *filter_str)
 388 {
 389         long count = (long)data;
 390
 391         seq_puts(m, name);
 392
 393         if (count == -1)
 394                 seq_puts(m, ":unlimited");
 395         else
 396                 seq_printf(m, ":count=%ld", count);
 397
 398         if (filter_str)
 399                 seq_printf(m, " if %s\n", filter_str);
 400         else
 401                 seq_putc(m, '\n');
 402
 403         return 0;
 404 }
 405
 406 /**
 407  * event_trigger_init - Generic event_trigger_ops @init implementation
 408  * @ops: The trigger ops associated with the trigger
 409  * @data: Trigger-specific data
 410  *
 411  * Common implementation of event trigger initialization.
 412  *
 413  * Usually used directly as the @init method in event trigger
 414  * implementations.
 415  *
 416  * Return: 0 on success, errno otherwise
 417  */
 418 int event_trigger_init(struct event_trigger_ops *ops,
 419                        struct event_trigger_data *data)
 420 {
 421         data->ref++;
 422         return 0;
 423 }
 424
 425 /**
 426  * event_trigger_free - Generic event_trigger_ops @free implementation
 427  * @ops: The trigger ops associated with the trigger
 428  * @data: Trigger-specific data
 429  *
 430  * Common implementation of event trigger de-initialization.
 431  *
 432  * Usually used directly as the @free method in event trigger
 433  * implementations.
 434  */
 435 static void
 436 event_trigger_free(struct event_trigger_ops *ops,
 437                    struct event_trigger_data *data)
 438 {
 439         if (WARN_ON_ONCE(data->ref <= 0))
 440                 return;
 441
 442         data->ref--;
 443         if (!data->ref)
 444                 trigger_data_free(data);
 445 }
 446
 447 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 448                                        int trigger_enable)
 449 {
 450         int ret = 0;
 451
 452         if (trigger_enable) {
 453                 if (atomic_inc_return(&file->tm_ref) > 1)
 454                         return ret;
 455                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 456                 ret = trace_event_enable_disable(file, 1, 1);
 457         } else {
 458                 if (atomic_dec_return(&file->tm_ref) > 0)
 459                         return ret;
 460                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 461                 ret = trace_event_enable_disable(file, 0, 1);
 462         }
 463
 464         return ret;
 465 }
 466
 467 /**
 468  * clear_event_triggers - Clear all triggers associated with a trace array
 469  * @tr: The trace array to clear
 470  *
 471  * For each trigger, the triggering event has its tm_ref decremented
 472  * via trace_event_trigger_enable_disable(), and any associated event
 473  * (in the case of enable/disable_event triggers) will have its sm_ref
 474  * decremented via free()->trace_event_enable_disable().  That
 475  * combination effectively reverses the soft-mode/trigger state added
 476  * by trigger registration.
 477  *
 478  * Must be called with event_mutex held.
 479  */
 480 void
 481 clear_event_triggers(struct trace_array *tr)
 482 {
 483         struct trace_event_file *file;
 484
 485         list_for_each_entry(file, &tr->events, list) {
 486                 struct event_trigger_data *data, *n;
 487                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 488                         trace_event_trigger_enable_disable(file, 0);
 489                         list_del_rcu(&data->list);
 490                         if (data->ops->free)
 491                                 data->ops->free(data->ops, data);
 492                 }
 493         }
 494 }
 495
 496 /**
 497  * update_cond_flag - Set or reset the TRIGGER_COND bit
 498  * @file: The trace_event_file associated with the event
 499  *
 500  * If an event has triggers and any of those triggers has a filter or
 501  * a post_trigger, trigger invocation needs to be deferred until after
 502  * the current event has logged its data, and the event should have
 503  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 504  * cleared.
 505  */
 506 void update_cond_flag(struct trace_event_file *file)
 507 {
 508         struct event_trigger_data *data;
 509         bool set_cond = false;
 510
 511         list_for_each_entry_rcu(data, &file->triggers, list) {
 512                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 513                     event_command_needs_rec(data->cmd_ops)) {
 514                         set_cond = true;
 515                         break;
 516                 }
 517         }
 518
 519         if (set_cond)
 520                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 521         else
 522                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 523 }
 524
 525 /**
 526  * register_trigger - Generic event_command @reg implementation
 527  * @glob: The raw string used to register the trigger
 528  * @ops: The trigger ops associated with the trigger
 529  * @data: Trigger-specific data to associate with the trigger
 530  * @file: The trace_event_file associated with the event
 531  *
 532  * Common implementation for event trigger registration.
 533  *
 534  * Usually used directly as the @reg method in event command
 535  * implementations.
 536  *
 537  * Return: 0 on success, errno otherwise
 538  */
 539 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 540                             struct event_trigger_data *data,
 541                             struct trace_event_file *file)
 542 {
 543         struct event_trigger_data *test;
 544         int ret = 0;
 545
 546         list_for_each_entry_rcu(test, &file->triggers, list) {
 547                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 548                         ret = -EEXIST;
 549                         goto out;
 550                 }
 551         }
 552
 553         if (data->ops->init) {
 554                 ret = data->ops->init(data->ops, data);
 555                 if (ret < 0)
 556                         goto out;
 557         }
 558
 559         list_add_rcu(&data->list, &file->triggers);
 560         ret++;
 561
 562         update_cond_flag(file);
 563         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 564                 list_del_rcu(&data->list);
 565                 update_cond_flag(file);
 566                 ret--;
 567         }
 568 out:
 569         return ret;
 570 }
 571
 572 /**
 573  * unregister_trigger - Generic event_command @unreg implementation
 574  * @glob: The raw string used to register the trigger
 575  * @ops: The trigger ops associated with the trigger
 576  * @test: Trigger-specific data used to find the trigger to remove
 577  * @file: The trace_event_file associated with the event
 578  *
 579  * Common implementation for event trigger unregistration.
 580  *
 581  * Usually used directly as the @unreg method in event command
 582  * implementations.
 583  */
 584 void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 585                         struct event_trigger_data *test,
 586                         struct trace_event_file *file)
 587 {
 588         struct event_trigger_data *data;
 589         bool unregistered = false;
 590
 591         list_for_each_entry_rcu(data, &file->triggers, list) {
 592                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 593                         unregistered = true;
 594                         list_del_rcu(&data->list);
 595                         trace_event_trigger_enable_disable(file, 0);
 596                         update_cond_flag(file);
 597                         break;
 598                 }
 599         }
 600
 601         if (unregistered && data->ops->free)
 602                 data->ops->free(data->ops, data);
 603 }
 604
 605 /**
 606  * event_trigger_callback - Generic event_command @func implementation
 607  * @cmd_ops: The command ops, used for trigger registration
 608  * @file: The trace_event_file associated with the event
 609  * @glob: The raw string used to register the trigger
 610  * @cmd: The cmd portion of the string used to register the trigger
 611  * @param: The params portion of the string used to register the trigger
 612  *
 613  * Common implementation for event command parsing and trigger
 614  * instantiation.
 615  *
 616  * Usually used directly as the @func method in event command
 617  * implementations.
 618  *
 619  * Return: 0 on success, errno otherwise
 620  */
 621 static int
 622 event_trigger_callback(struct event_command *cmd_ops,
 623                        struct trace_event_file *file,
 624                        char *glob, char *cmd, char *param)
 625 {
 626         struct event_trigger_data *trigger_data;
 627         struct event_trigger_ops *trigger_ops;
 628         char *trigger = NULL;
 629         char *number;
 630         int ret;
 631
 632         /* separate the trigger from the filter (t:n [if filter]) */
 633         if (param && isdigit(param[0]))
 634                 trigger = strsep(&param, " \t");
 635
 636         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 637
 638         ret = -ENOMEM;
 639         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 640         if (!trigger_data)
 641                 goto out;
 642
 643         trigger_data->count = -1;
 644         trigger_data->ops = trigger_ops;
 645         trigger_data->cmd_ops = cmd_ops;
 646         trigger_data->private_data = file;
 647         INIT_LIST_HEAD(&trigger_data->list);
 648         INIT_LIST_HEAD(&trigger_data->named_list);
 649
 650         if (glob[0] == '!') {
 651                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 652                 kfree(trigger_data);
 653                 ret = 0;
 654                 goto out;
 655         }
 656
 657         if (trigger) {
 658                 number = strsep(&trigger, ":");
 659
 660                 ret = -EINVAL;
 661                 if (!strlen(number))
 662                         goto out_free;
 663
 664                 /*
 665                  * We use the callback data field (which is a pointer)
 666                  * as our counter.
 667                  */
 668                 ret = kstrtoul(number, 0, &trigger_data->count);
 669                 if (ret)
 670                         goto out_free;
 671         }
 672
 673         if (!param) /* if param is non-empty, it's supposed to be a filter */
 674                 goto out_reg;
 675
 676         if (!cmd_ops->set_filter)
 677                 goto out_reg;
 678
 679         ret = cmd_ops->set_filter(param, trigger_data, file);
 680         if (ret < 0)
 681                 goto out_free;
 682
 683  out_reg:
 684         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 685         /*
 686          * The above returns on success the # of functions enabled,
 687          * but if it didn't find any functions it returns zero.
 688          * Consider no functions a failure too.
 689          */
 690         if (!ret) {
 691                 ret = -ENOENT;
 692                 goto out_free;
 693         } else if (ret < 0)
 694                 goto out_free;
 695         ret = 0;
 696  out:
 697         return ret;
 698
 699  out_free:
 700         if (cmd_ops->set_filter)
 701                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 702         kfree(trigger_data);
 703         goto out;
 704 }
 705
 706 /**
 707  * set_trigger_filter - Generic event_command @set_filter implementation
 708  * @filter_str: The filter string for the trigger, NULL to remove filter
 709  * @trigger_data: Trigger-specific data
 710  * @file: The trace_event_file associated with the event
 711  *
 712  * Common implementation for event command filter parsing and filter
 713  * instantiation.
 714  *
 715  * Usually used directly as the @set_filter method in event command
 716  * implementations.
 717  *
 718  * Also used to remove a filter (if filter_str = NULL).
 719  *
 720  * Return: 0 on success, errno otherwise
 721  */
 722 int set_trigger_filter(char *filter_str,
 723                        struct event_trigger_data *trigger_data,
 724                        struct trace_event_file *file)
 725 {
 726         struct event_trigger_data *data = trigger_data;
 727         struct event_filter *filter = NULL, *tmp;
 728         int ret = -EINVAL;
 729         char *s;
 730
 731         if (!filter_str) /* clear the current filter */
 732                 goto assign;
 733
 734         s = strsep(&filter_str, " \t");
 735
 736         if (!strlen(s) || strcmp(s, "if") != 0)
 737                 goto out;
 738
 739         if (!filter_str)
 740                 goto out;
 741
 742         /* The filter is for the 'trigger' event, not the triggered event */
 743         ret = create_event_filter(file->event_call, filter_str, false, &filter);
 744         if (ret)
 745                 goto out;
 746  assign:
 747         tmp = rcu_access_pointer(data->filter);
 748
 749         rcu_assign_pointer(data->filter, filter);
 750
 751         if (tmp) {
 752                 /* Make sure the call is done with the filter */
 753                 synchronize_sched();
 754                 free_event_filter(tmp);
 755         }
 756
 757         kfree(data->filter_str);
 758         data->filter_str = NULL;
 759
 760         if (filter_str) {
 761                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 762                 if (!data->filter_str) {
 763                         free_event_filter(rcu_access_pointer(data->filter));
 764                         data->filter = NULL;
 765                         ret = -ENOMEM;
 766                 }
 767         }
 768  out:
 769         return ret;
 770 }
 771
 772 static LIST_HEAD(named_triggers);
 773
 774 /**
 775  * find_named_trigger - Find the common named trigger associated with @name
 776  * @name: The name of the set of named triggers to find the common data for
 777  *
 778  * Named triggers are sets of triggers that share a common set of
 779  * trigger data.  The first named trigger registered with a given name
 780  * owns the common trigger data that the others subsequently
 781  * registered with the same name will reference.  This function
 782  * returns the common trigger data associated with that first
 783  * registered instance.
 784  *
 785  * Return: the common trigger data for the given named trigger on
 786  * success, NULL otherwise.
 787  */
 788 struct event_trigger_data *find_named_trigger(const char *name)
 789 {
 790         struct event_trigger_data *data;
 791
 792         if (!name)
 793                 return NULL;
 794
 795         list_for_each_entry(data, &named_triggers, named_list) {
 796                 if (data->named_data)
 797                         continue;
 798                 if (strcmp(data->name, name) == 0)
 799                         return data;
 800         }
 801
 802         return NULL;
 803 }
 804
 805 /**
 806  * is_named_trigger - determine if a given trigger is a named trigger
 807  * @test: The trigger data to test
 808  *
 809  * Return: true if 'test' is a named trigger, false otherwise.
 810  */
 811 bool is_named_trigger(struct event_trigger_data *test)
 812 {
 813         struct event_trigger_data *data;
 814
 815         list_for_each_entry(data, &named_triggers, named_list) {
 816                 if (test == data)
 817                         return true;
 818         }
 819
 820         return false;
 821 }
 822
 823 /**
 824  * save_named_trigger - save the trigger in the named trigger list
 825  * @name: The name of the named trigger set
 826  * @data: The trigger data to save
 827  *
 828  * Return: 0 if successful, negative error otherwise.
 829  */
 830 int save_named_trigger(const char *name, struct event_trigger_data *data)
 831 {
 832         data->name = kstrdup(name, GFP_KERNEL);
 833         if (!data->name)
 834                 return -ENOMEM;
 835
 836         list_add(&data->named_list, &named_triggers);
 837
 838         return 0;
 839 }
 840
 841 /**
 842  * del_named_trigger - delete a trigger from the named trigger list
 843  * @data: The trigger data to delete
 844  */
 845 void del_named_trigger(struct event_trigger_data *data)
 846 {
 847         kfree(data->name);
 848         data->name = NULL;
 849
 850         list_del(&data->named_list);
 851 }
 852
 853 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 854 {
 855         struct event_trigger_data *test;
 856
 857         list_for_each_entry(test, &named_triggers, named_list) {
 858                 if (strcmp(test->name, data->name) == 0) {
 859                         if (pause) {
 860                                 test->paused_tmp = test->paused;
 861                                 test->paused = true;
 862                         } else {
 863                                 test->paused = test->paused_tmp;
 864                         }
 865                 }
 866         }
 867 }
 868
 869 /**
 870  * pause_named_trigger - Pause all named triggers with the same name
 871  * @data: The trigger data of a named trigger to pause
 872  *
 873  * Pauses a named trigger along with all other triggers having the
 874  * same name.  Because named triggers share a common set of data,
 875  * pausing only one is meaningless, so pausing one named trigger needs
 876  * to pause all triggers with the same name.
 877  */
 878 void pause_named_trigger(struct event_trigger_data *data)
 879 {
 880         __pause_named_trigger(data, true);
 881 }
 882
 883 /**
 884  * unpause_named_trigger - Un-pause all named triggers with the same name
 885  * @data: The trigger data of a named trigger to unpause
 886  *
 887  * Un-pauses a named trigger along with all other triggers having the
 888  * same name.  Because named triggers share a common set of data,
 889  * unpausing only one is meaningless, so unpausing one named trigger
 890  * needs to unpause all triggers with the same name.
 891  */
 892 void unpause_named_trigger(struct event_trigger_data *data)
 893 {
 894         __pause_named_trigger(data, false);
 895 }
 896
 897 /**
 898  * set_named_trigger_data - Associate common named trigger data
 899  * @data: The trigger data of a named trigger to unpause
 900  *
 901  * Named triggers are sets of triggers that share a common set of
 902  * trigger data.  The first named trigger registered with a given name
 903  * owns the common trigger data that the others subsequently
 904  * registered with the same name will reference.  This function
 905  * associates the common trigger data from the first trigger with the
 906  * given trigger.
 907  */
 908 void set_named_trigger_data(struct event_trigger_data *data,
 909                             struct event_trigger_data *named_data)
 910 {
 911         data->named_data = named_data;
 912 }
 913
 914 struct event_trigger_data *
 915 get_named_trigger_data(struct event_trigger_data *data)
 916 {
 917         return data->named_data;
 918 }
 919
 920 static void
 921 traceon_trigger(struct event_trigger_data *data, void *rec,
 922                 struct ring_buffer_event *event)
 923 {
 924         if (tracing_is_on())
 925                 return;
 926
 927         tracing_on();
 928 }
 929
 930 static void
 931 traceon_count_trigger(struct event_trigger_data *data, void *rec,
 932                       struct ring_buffer_event *event)
 933 {
 934         if (tracing_is_on())
 935                 return;
 936
 937         if (!data->count)
 938                 return;
 939
 940         if (data->count != -1)
 941                 (data->count)--;
 942
 943         tracing_on();
 944 }
 945
 946 static void
 947 traceoff_trigger(struct event_trigger_data *data, void *rec,
 948                  struct ring_buffer_event *event)
 949 {
 950         if (!tracing_is_on())
 951                 return;
 952
 953         tracing_off();
 954 }
 955
 956 static void
 957 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
 958                        struct ring_buffer_event *event)
 959 {
 960         if (!tracing_is_on())
 961                 return;
 962
 963         if (!data->count)
 964                 return;
 965
 966         if (data->count != -1)
 967                 (data->count)--;
 968
 969         tracing_off();
 970 }
 971
 972 static int
 973 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 974                       struct event_trigger_data *data)
 975 {
 976         return event_trigger_print("traceon", m, (void *)data->count,
 977                                    data->filter_str);
 978 }
 979
 980 static int
 981 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 982                        struct event_trigger_data *data)
 983 {
 984         return event_trigger_print("traceoff", m, (void *)data->count,
 985                                    data->filter_str);
 986 }
 987
 988 static struct event_trigger_ops traceon_trigger_ops = {
 989         .func                   = traceon_trigger,
 990         .print                  = traceon_trigger_print,
 991         .init                   = event_trigger_init,
 992         .free                   = event_trigger_free,
 993 };
 994
 995 static struct event_trigger_ops traceon_count_trigger_ops = {
 996         .func                   = traceon_count_trigger,
 997         .print                  = traceon_trigger_print,
 998         .init                   = event_trigger_init,
 999         .free                   = event_trigger_free,
1000 };
1001
1002 static struct event_trigger_ops traceoff_trigger_ops = {
1003         .func                   = traceoff_trigger,
1004         .print                  = traceoff_trigger_print,
1005         .init                   = event_trigger_init,
1006         .free                   = event_trigger_free,
1007 };
1008
1009 static struct event_trigger_ops traceoff_count_trigger_ops = {
1010         .func                   = traceoff_count_trigger,
1011         .print                  = traceoff_trigger_print,
1012         .init                   = event_trigger_init,
1013         .free                   = event_trigger_free,
1014 };
1015
1016 static struct event_trigger_ops *
1017 onoff_get_trigger_ops(char *cmd, char *param)
1018 {
1019         struct event_trigger_ops *ops;
1020
1021         /* we register both traceon and traceoff to this callback */
1022         if (strcmp(cmd, "traceon") == 0)
1023                 ops = param ? &traceon_count_trigger_ops :
1024                         &traceon_trigger_ops;
1025         else
1026                 ops = param ? &traceoff_count_trigger_ops :
1027                         &traceoff_trigger_ops;
1028
1029         return ops;
1030 }
1031
1032 static struct event_command trigger_traceon_cmd = {
1033         .name                   = "traceon",
1034         .trigger_type           = ETT_TRACE_ONOFF,
1035         .func                   = event_trigger_callback,
1036         .reg                    = register_trigger,
1037         .unreg                  = unregister_trigger,
1038         .get_trigger_ops        = onoff_get_trigger_ops,
1039         .set_filter             = set_trigger_filter,
1040 };
1041
1042 static struct event_command trigger_traceoff_cmd = {
1043         .name                   = "traceoff",
1044         .trigger_type           = ETT_TRACE_ONOFF,
1045         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1046         .func                   = event_trigger_callback,
1047         .reg                    = register_trigger,
1048         .unreg                  = unregister_trigger,
1049         .get_trigger_ops        = onoff_get_trigger_ops,
1050         .set_filter             = set_trigger_filter,
1051 };
1052
1053 #ifdef CONFIG_TRACER_SNAPSHOT
1054 static void
1055 snapshot_trigger(struct event_trigger_data *data, void *rec,
1056                  struct ring_buffer_event *event)
1057 {
1058         struct trace_event_file *file = data->private_data;
1059
1060         if (file)
1061                 tracing_snapshot_instance(file->tr);
1062         else
1063                 tracing_snapshot();
1064 }
1065
1066 static void
1067 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1068                        struct ring_buffer_event *event)
1069 {
1070         if (!data->count)
1071                 return;
1072
1073         if (data->count != -1)
1074                 (data->count)--;
1075
1076         snapshot_trigger(data, rec, event);
1077 }
1078
1079 static int
1080 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1081                           struct event_trigger_data *data,
1082                           struct trace_event_file *file)
1083 {
1084         int ret = register_trigger(glob, ops, data, file);
1085
1086         if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) {
1087                 unregister_trigger(glob, ops, data, file);
1088                 ret = 0;
1089         }
1090
1091         return ret;
1092 }
1093
1094 static int
1095 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1096                        struct event_trigger_data *data)
1097 {
1098         return event_trigger_print("snapshot", m, (void *)data->count,
1099                                    data->filter_str);
1100 }
1101
1102 static struct event_trigger_ops snapshot_trigger_ops = {
1103         .func                   = snapshot_trigger,
1104         .print                  = snapshot_trigger_print,
1105         .init                   = event_trigger_init,
1106         .free                   = event_trigger_free,
1107 };
1108
1109 static struct event_trigger_ops snapshot_count_trigger_ops = {
1110         .func                   = snapshot_count_trigger,
1111         .print                  = snapshot_trigger_print,
1112         .init                   = event_trigger_init,
1113         .free                   = event_trigger_free,
1114 };
1115
1116 static struct event_trigger_ops *
1117 snapshot_get_trigger_ops(char *cmd, char *param)
1118 {
1119         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1120 }
1121
1122 static struct event_command trigger_snapshot_cmd = {
1123         .name                   = "snapshot",
1124         .trigger_type           = ETT_SNAPSHOT,
1125         .func                   = event_trigger_callback,
1126         .reg                    = register_snapshot_trigger,
1127         .unreg                  = unregister_trigger,
1128         .get_trigger_ops        = snapshot_get_trigger_ops,
1129         .set_filter             = set_trigger_filter,
1130 };
1131
1132 static __init int register_trigger_snapshot_cmd(void)
1133 {
1134         int ret;
1135
1136         ret = register_event_command(&trigger_snapshot_cmd);
1137         WARN_ON(ret < 0);
1138
1139         return ret;
1140 }
1141 #else
1142 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1143 #endif /* CONFIG_TRACER_SNAPSHOT */
1144
1145 #ifdef CONFIG_STACKTRACE
1146 #ifdef CONFIG_UNWINDER_ORC
1147 /* Skip 2:
1148  *   event_triggers_post_call()
1149  *   trace_event_raw_event_xxx()
1150  */
1151 # define STACK_SKIP 2
1152 #else
1153 /*
1154  * Skip 4:
1155  *   stacktrace_trigger()
1156  *   event_triggers_post_call()
1157  *   trace_event_buffer_commit()
1158  *   trace_event_raw_event_xxx()
1159  */
1160 #define STACK_SKIP 4
1161 #endif
1162
1163 static void
1164 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1165                    struct ring_buffer_event *event)
1166 {
1167         trace_dump_stack(STACK_SKIP);
1168 }
1169
1170 static void
1171 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1172                          struct ring_buffer_event *event)
1173 {
1174         if (!data->count)
1175                 return;
1176
1177         if (data->count != -1)
1178                 (data->count)--;
1179
1180         stacktrace_trigger(data, rec, event);
1181 }
1182
1183 static int
1184 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1185                          struct event_trigger_data *data)
1186 {
1187         return event_trigger_print("stacktrace", m, (void *)data->count,
1188                                    data->filter_str);
1189 }
1190
1191 static struct event_trigger_ops stacktrace_trigger_ops = {
1192         .func                   = stacktrace_trigger,
1193         .print                  = stacktrace_trigger_print,
1194         .init                   = event_trigger_init,
1195         .free                   = event_trigger_free,
1196 };
1197
1198 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1199         .func                   = stacktrace_count_trigger,
1200         .print                  = stacktrace_trigger_print,
1201         .init                   = event_trigger_init,
1202         .free                   = event_trigger_free,
1203 };
1204
1205 static struct event_trigger_ops *
1206 stacktrace_get_trigger_ops(char *cmd, char *param)
1207 {
1208         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1209 }
1210
1211 static struct event_command trigger_stacktrace_cmd = {
1212         .name                   = "stacktrace",
1213         .trigger_type           = ETT_STACKTRACE,
1214         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1215         .func                   = event_trigger_callback,
1216         .reg                    = register_trigger,
1217         .unreg                  = unregister_trigger,
1218         .get_trigger_ops        = stacktrace_get_trigger_ops,
1219         .set_filter             = set_trigger_filter,
1220 };
1221
1222 static __init int register_trigger_stacktrace_cmd(void)
1223 {
1224         int ret;
1225
1226         ret = register_event_command(&trigger_stacktrace_cmd);
1227         WARN_ON(ret < 0);
1228
1229         return ret;
1230 }
1231 #else
1232 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1233 #endif /* CONFIG_STACKTRACE */
1234
1235 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1236 {
1237         unregister_event_command(&trigger_traceon_cmd);
1238         unregister_event_command(&trigger_traceoff_cmd);
1239 }
1240
1241 static void
1242 event_enable_trigger(struct event_trigger_data *data, void *rec,
1243                      struct ring_buffer_event *event)
1244 {
1245         struct enable_trigger_data *enable_data = data->private_data;
1246
1247         if (enable_data->enable)
1248                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1249         else
1250                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1251 }
1252
1253 static void
1254 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1255                            struct ring_buffer_event *event)
1256 {
1257         struct enable_trigger_data *enable_data = data->private_data;
1258
1259         if (!data->count)
1260                 return;
1261
1262         /* Skip if the event is in a state we want to switch to */
1263         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1264                 return;
1265
1266         if (data->count != -1)
1267                 (data->count)--;
1268
1269         event_enable_trigger(data, rec, event);
1270 }
1271
1272 int event_enable_trigger_print(struct seq_file *m,
1273                                struct event_trigger_ops *ops,
1274                                struct event_trigger_data *data)
1275 {
1276         struct enable_trigger_data *enable_data = data->private_data;
1277
1278         seq_printf(m, "%s:%s:%s",
1279                    enable_data->hist ?
1280                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1281                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1282                    enable_data->file->event_call->class->system,
1283                    trace_event_name(enable_data->file->event_call));
1284
1285         if (data->count == -1)
1286                 seq_puts(m, ":unlimited");
1287         else
1288                 seq_printf(m, ":count=%ld", data->count);
1289
1290         if (data->filter_str)
1291                 seq_printf(m, " if %s\n", data->filter_str);
1292         else
1293                 seq_putc(m, '\n');
1294
1295         return 0;
1296 }
1297
1298 void event_enable_trigger_free(struct event_trigger_ops *ops,
1299                                struct event_trigger_data *data)
1300 {
1301         struct enable_trigger_data *enable_data = data->private_data;
1302
1303         if (WARN_ON_ONCE(data->ref <= 0))
1304                 return;
1305
1306         data->ref--;
1307         if (!data->ref) {
1308                 /* Remove the SOFT_MODE flag */
1309                 trace_event_enable_disable(enable_data->file, 0, 1);
1310                 module_put(enable_data->file->event_call->mod);
1311                 trigger_data_free(data);
1312                 kfree(enable_data);
1313         }
1314 }
1315
1316 static struct event_trigger_ops event_enable_trigger_ops = {
1317         .func                   = event_enable_trigger,
1318         .print                  = event_enable_trigger_print,
1319         .init                   = event_trigger_init,
1320         .free                   = event_enable_trigger_free,
1321 };
1322
1323 static struct event_trigger_ops event_enable_count_trigger_ops = {
1324         .func                   = event_enable_count_trigger,
1325         .print                  = event_enable_trigger_print,
1326         .init                   = event_trigger_init,
1327         .free                   = event_enable_trigger_free,
1328 };
1329
1330 static struct event_trigger_ops event_disable_trigger_ops = {
1331         .func                   = event_enable_trigger,
1332         .print                  = event_enable_trigger_print,
1333         .init                   = event_trigger_init,
1334         .free                   = event_enable_trigger_free,
1335 };
1336
1337 static struct event_trigger_ops event_disable_count_trigger_ops = {
1338         .func                   = event_enable_count_trigger,
1339         .print                  = event_enable_trigger_print,
1340         .init                   = event_trigger_init,
1341         .free                   = event_enable_trigger_free,
1342 };
1343
1344 int event_enable_trigger_func(struct event_command *cmd_ops,
1345                               struct trace_event_file *file,
1346                               char *glob, char *cmd, char *param)
1347 {
1348         struct trace_event_file *event_enable_file;
1349         struct enable_trigger_data *enable_data;
1350         struct event_trigger_data *trigger_data;
1351         struct event_trigger_ops *trigger_ops;
1352         struct trace_array *tr = file->tr;
1353         const char *system;
1354         const char *event;
1355         bool hist = false;
1356         char *trigger;
1357         char *number;
1358         bool enable;
1359         int ret;
1360
1361         if (!param)
1362                 return -EINVAL;
1363
1364         /* separate the trigger from the filter (s:e:n [if filter]) */
1365         trigger = strsep(&param, " \t");
1366         if (!trigger)
1367                 return -EINVAL;
1368
1369         system = strsep(&trigger, ":");
1370         if (!trigger)
1371                 return -EINVAL;
1372
1373         event = strsep(&trigger, ":");
1374
1375         ret = -EINVAL;
1376         event_enable_file = find_event_file(tr, system, event);
1377         if (!event_enable_file)
1378                 goto out;
1379
1380 #ifdef CONFIG_HIST_TRIGGERS
1381         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1382                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1383
1384         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1385                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1386 #else
1387         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1388 #endif
1389         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1390
1391         ret = -ENOMEM;
1392         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1393         if (!trigger_data)
1394                 goto out;
1395
1396         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1397         if (!enable_data) {
1398                 kfree(trigger_data);
1399                 goto out;
1400         }
1401
1402         trigger_data->count = -1;
1403         trigger_data->ops = trigger_ops;
1404         trigger_data->cmd_ops = cmd_ops;
1405         INIT_LIST_HEAD(&trigger_data->list);
1406         RCU_INIT_POINTER(trigger_data->filter, NULL);
1407
1408         enable_data->hist = hist;
1409         enable_data->enable = enable;
1410         enable_data->file = event_enable_file;
1411         trigger_data->private_data = enable_data;
1412
1413         if (glob[0] == '!') {
1414                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1415                 kfree(trigger_data);
1416                 kfree(enable_data);
1417                 ret = 0;
1418                 goto out;
1419         }
1420
1421         if (trigger) {
1422                 number = strsep(&trigger, ":");
1423
1424                 ret = -EINVAL;
1425                 if (!strlen(number))
1426                         goto out_free;
1427
1428                 /*
1429                  * We use the callback data field (which is a pointer)
1430                  * as our counter.
1431                  */
1432                 ret = kstrtoul(number, 0, &trigger_data->count);
1433                 if (ret)
1434                         goto out_free;
1435         }
1436
1437         if (!param) /* if param is non-empty, it's supposed to be a filter */
1438                 goto out_reg;
1439
1440         if (!cmd_ops->set_filter)
1441                 goto out_reg;
1442
1443         ret = cmd_ops->set_filter(param, trigger_data, file);
1444         if (ret < 0)
1445                 goto out_free;
1446
1447  out_reg:
1448         /* Don't let event modules unload while probe registered */
1449         ret = try_module_get(event_enable_file->event_call->mod);
1450         if (!ret) {
1451                 ret = -EBUSY;
1452                 goto out_free;
1453         }
1454
1455         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1456         if (ret < 0)
1457                 goto out_put;
1458         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1459         /*
1460          * The above returns on success the # of functions enabled,
1461          * but if it didn't find any functions it returns zero.
1462          * Consider no functions a failure too.
1463          */
1464         if (!ret) {
1465                 ret = -ENOENT;
1466                 goto out_disable;
1467         } else if (ret < 0)
1468                 goto out_disable;
1469         /* Just return zero, not the number of enabled functions */
1470         ret = 0;
1471  out:
1472         return ret;
1473
1474  out_disable:
1475         trace_event_enable_disable(event_enable_file, 0, 1);
1476  out_put:
1477         module_put(event_enable_file->event_call->mod);
1478  out_free:
1479         if (cmd_ops->set_filter)
1480                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1481         kfree(trigger_data);
1482         kfree(enable_data);
1483         goto out;
1484 }
1485
1486 int event_enable_register_trigger(char *glob,
1487                                   struct event_trigger_ops *ops,
1488                                   struct event_trigger_data *data,
1489                                   struct trace_event_file *file)
1490 {
1491         struct enable_trigger_data *enable_data = data->private_data;
1492         struct enable_trigger_data *test_enable_data;
1493         struct event_trigger_data *test;
1494         int ret = 0;
1495
1496         list_for_each_entry_rcu(test, &file->triggers, list) {
1497                 test_enable_data = test->private_data;
1498                 if (test_enable_data &&
1499                     (test->cmd_ops->trigger_type ==
1500                      data->cmd_ops->trigger_type) &&
1501                     (test_enable_data->file == enable_data->file)) {
1502                         ret = -EEXIST;
1503                         goto out;
1504                 }
1505         }
1506
1507         if (data->ops->init) {
1508                 ret = data->ops->init(data->ops, data);
1509                 if (ret < 0)
1510                         goto out;
1511         }
1512
1513         list_add_rcu(&data->list, &file->triggers);
1514         ret++;
1515
1516         update_cond_flag(file);
1517         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1518                 list_del_rcu(&data->list);
1519                 update_cond_flag(file);
1520                 ret--;
1521         }
1522 out:
1523         return ret;
1524 }
1525
1526 void event_enable_unregister_trigger(char *glob,
1527                                      struct event_trigger_ops *ops,
1528                                      struct event_trigger_data *test,
1529                                      struct trace_event_file *file)
1530 {
1531         struct enable_trigger_data *test_enable_data = test->private_data;
1532         struct enable_trigger_data *enable_data;
1533         struct event_trigger_data *data;
1534         bool unregistered = false;
1535
1536         list_for_each_entry_rcu(data, &file->triggers, list) {
1537                 enable_data = data->private_data;
1538                 if (enable_data &&
1539                     (data->cmd_ops->trigger_type ==
1540                      test->cmd_ops->trigger_type) &&
1541                     (enable_data->file == test_enable_data->file)) {
1542                         unregistered = true;
1543                         list_del_rcu(&data->list);
1544                         trace_event_trigger_enable_disable(file, 0);
1545                         update_cond_flag(file);
1546                         break;
1547                 }
1548         }
1549
1550         if (unregistered && data->ops->free)
1551                 data->ops->free(data->ops, data);
1552 }
1553
1554 static struct event_trigger_ops *
1555 event_enable_get_trigger_ops(char *cmd, char *param)
1556 {
1557         struct event_trigger_ops *ops;
1558         bool enable;
1559
1560 #ifdef CONFIG_HIST_TRIGGERS
1561         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1562                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1563 #else
1564         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1565 #endif
1566         if (enable)
1567                 ops = param ? &event_enable_count_trigger_ops :
1568                         &event_enable_trigger_ops;
1569         else
1570                 ops = param ? &event_disable_count_trigger_ops :
1571                         &event_disable_trigger_ops;
1572
1573         return ops;
1574 }
1575
1576 static struct event_command trigger_enable_cmd = {
1577         .name                   = ENABLE_EVENT_STR,
1578         .trigger_type           = ETT_EVENT_ENABLE,
1579         .func                   = event_enable_trigger_func,
1580         .reg                    = event_enable_register_trigger,
1581         .unreg                  = event_enable_unregister_trigger,
1582         .get_trigger_ops        = event_enable_get_trigger_ops,
1583         .set_filter             = set_trigger_filter,
1584 };
1585
1586 static struct event_command trigger_disable_cmd = {
1587         .name                   = DISABLE_EVENT_STR,
1588         .trigger_type           = ETT_EVENT_ENABLE,
1589         .func                   = event_enable_trigger_func,
1590         .reg                    = event_enable_register_trigger,
1591         .unreg                  = event_enable_unregister_trigger,
1592         .get_trigger_ops        = event_enable_get_trigger_ops,
1593         .set_filter             = set_trigger_filter,
1594 };
1595
1596 static __init void unregister_trigger_enable_disable_cmds(void)
1597 {
1598         unregister_event_command(&trigger_enable_cmd);
1599         unregister_event_command(&trigger_disable_cmd);
1600 }
1601
1602 static __init int register_trigger_enable_disable_cmds(void)
1603 {
1604         int ret;
1605
1606         ret = register_event_command(&trigger_enable_cmd);
1607         if (WARN_ON(ret < 0))
1608                 return ret;
1609         ret = register_event_command(&trigger_disable_cmd);
1610         if (WARN_ON(ret < 0))
1611                 unregister_trigger_enable_disable_cmds();
1612
1613         return ret;
1614 }
1615
1616 static __init int register_trigger_traceon_traceoff_cmds(void)
1617 {
1618         int ret;
1619
1620         ret = register_event_command(&trigger_traceon_cmd);
1621         if (WARN_ON(ret < 0))
1622                 return ret;
1623         ret = register_event_command(&trigger_traceoff_cmd);
1624         if (WARN_ON(ret < 0))
1625                 unregister_trigger_traceon_traceoff_cmds();
1626
1627         return ret;
1628 }
1629
1630 __init int register_trigger_cmds(void)
1631 {
1632         register_trigger_traceon_traceoff_cmds();
1633         register_trigger_snapshot_cmd();
1634         register_trigger_stacktrace_cmd();
1635         register_trigger_enable_disable_cmds();
1636         register_trigger_hist_enable_disable_cmds();
1637         register_trigger_hist_cmd();
1638
1639         return 0;
1640 }