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