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