trace_events_trigger.c 34.6 KB
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/*
 * trace_events_trigger - trace event triggers
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
 */

#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/mutex.h>
#include <linux/slab.h>

#include "trace.h"

static LIST_HEAD(trigger_commands);
static DEFINE_MUTEX(trigger_cmd_mutex);

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static void
trigger_data_free(struct event_trigger_data *data)
{
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	if (data->cmd_ops->set_filter)
		data->cmd_ops->set_filter(NULL, data, NULL);

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	synchronize_sched(); /* make sure current triggers exit before free */
	kfree(data);
}

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/**
 * event_triggers_call - Call triggers associated with a trace event
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 * @file: The trace_event_file associated with the event
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 * @rec: The trace entry for the event, NULL for unconditional invocation
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 *
 * For each trigger associated with an event, invoke the trigger
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 * function registered with the associated trigger command.  If rec is
 * non-NULL, it means that the trigger requires further processing and
 * shouldn't be unconditionally invoked.  If rec is non-NULL and the
 * trigger has a filter associated with it, rec will checked against
 * the filter and if the record matches the trigger will be invoked.
 * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
 * in any case until the current event is written, the trigger
 * function isn't invoked but the bit associated with the deferred
 * trigger is set in the return value.
 *
 * Returns an enum event_trigger_type value containing a set bit for
 * any trigger that should be deferred, ETT_NONE if nothing to defer.
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 *
 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 *
 * Return: an enum event_trigger_type value containing a set bit for
 * any trigger that should be deferred, ETT_NONE if nothing to defer.
 */
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enum event_trigger_type
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event_triggers_call(struct trace_event_file *file, void *rec)
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{
	struct event_trigger_data *data;
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	enum event_trigger_type tt = ETT_NONE;
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	struct event_filter *filter;
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	if (list_empty(&file->triggers))
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		return tt;
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	list_for_each_entry_rcu(data, &file->triggers, list) {
		if (!rec) {
			data->ops->func(data);
			continue;
		}
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		filter = rcu_dereference_sched(data->filter);
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		if (filter && !filter_match_preds(filter, rec))
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			continue;
		if (data->cmd_ops->post_trigger) {
			tt |= data->cmd_ops->trigger_type;
			continue;
		}
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		data->ops->func(data);
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	}
	return tt;
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}
EXPORT_SYMBOL_GPL(event_triggers_call);

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/**
 * event_triggers_post_call - Call 'post_triggers' for a trace event
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 * @file: The trace_event_file associated with the event
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 * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
 *
 * For each trigger associated with an event, invoke the trigger
 * function registered with the associated trigger command, if the
 * corresponding bit is set in the tt enum passed into this function.
 * See @event_triggers_call for details on how those bits are set.
 *
 * Called from tracepoint handlers (with rcu_read_lock_sched() held).
 */
void
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event_triggers_post_call(struct trace_event_file *file,
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			 enum event_trigger_type tt)
{
	struct event_trigger_data *data;

	list_for_each_entry_rcu(data, &file->triggers, list) {
		if (data->cmd_ops->trigger_type & tt)
			data->ops->func(data);
	}
}
EXPORT_SYMBOL_GPL(event_triggers_post_call);

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#define SHOW_AVAILABLE_TRIGGERS	(void *)(1UL)

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static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
{
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	struct trace_event_file *event_file = event_file_data(m->private);
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	if (t == SHOW_AVAILABLE_TRIGGERS)
		return NULL;

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	return seq_list_next(t, &event_file->triggers, pos);
}

static void *trigger_start(struct seq_file *m, loff_t *pos)
{
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	struct trace_event_file *event_file;
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	/* ->stop() is called even if ->start() fails */
	mutex_lock(&event_mutex);
	event_file = event_file_data(m->private);
	if (unlikely(!event_file))
		return ERR_PTR(-ENODEV);

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	if (list_empty(&event_file->triggers))
		return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;

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	return seq_list_start(&event_file->triggers, *pos);
}

static void trigger_stop(struct seq_file *m, void *t)
{
	mutex_unlock(&event_mutex);
}

static int trigger_show(struct seq_file *m, void *v)
{
	struct event_trigger_data *data;
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	struct event_command *p;

	if (v == SHOW_AVAILABLE_TRIGGERS) {
		seq_puts(m, "# Available triggers:\n");
		seq_putc(m, '#');
		mutex_lock(&trigger_cmd_mutex);
		list_for_each_entry_reverse(p, &trigger_commands, list)
			seq_printf(m, " %s", p->name);
		seq_putc(m, '\n');
		mutex_unlock(&trigger_cmd_mutex);
		return 0;
	}
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	data = list_entry(v, struct event_trigger_data, list);
	data->ops->print(m, data->ops, data);

	return 0;
}

static const struct seq_operations event_triggers_seq_ops = {
	.start = trigger_start,
	.next = trigger_next,
	.stop = trigger_stop,
	.show = trigger_show,
};

static int event_trigger_regex_open(struct inode *inode, struct file *file)
{
	int ret = 0;

	mutex_lock(&event_mutex);

	if (unlikely(!event_file_data(file))) {
		mutex_unlock(&event_mutex);
		return -ENODEV;
	}

	if (file->f_mode & FMODE_READ) {
		ret = seq_open(file, &event_triggers_seq_ops);
		if (!ret) {
			struct seq_file *m = file->private_data;
			m->private = file;
		}
	}

	mutex_unlock(&event_mutex);

	return ret;
}

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static int trigger_process_regex(struct trace_event_file *file, char *buff)
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{
	char *command, *next = buff;
	struct event_command *p;
	int ret = -EINVAL;

	command = strsep(&next, ": \t");
	command = (command[0] != '!') ? command : command + 1;

	mutex_lock(&trigger_cmd_mutex);
	list_for_each_entry(p, &trigger_commands, list) {
		if (strcmp(p->name, command) == 0) {
			ret = p->func(p, file, buff, command, next);
			goto out_unlock;
		}
	}
 out_unlock:
	mutex_unlock(&trigger_cmd_mutex);

	return ret;
}

static ssize_t event_trigger_regex_write(struct file *file,
					 const char __user *ubuf,
					 size_t cnt, loff_t *ppos)
{
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	struct trace_event_file *event_file;
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	ssize_t ret;
	char *buf;

	if (!cnt)
		return 0;

	if (cnt >= PAGE_SIZE)
		return -EINVAL;

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	buf = memdup_user_nul(ubuf, cnt);
	if (IS_ERR(buf))
		return PTR_ERR(buf);
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	strim(buf);

	mutex_lock(&event_mutex);
	event_file = event_file_data(file);
	if (unlikely(!event_file)) {
		mutex_unlock(&event_mutex);
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		kfree(buf);
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		return -ENODEV;
	}
	ret = trigger_process_regex(event_file, buf);
	mutex_unlock(&event_mutex);

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	kfree(buf);
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	if (ret < 0)
		goto out;

	*ppos += cnt;
	ret = cnt;
 out:
	return ret;
}

static int event_trigger_regex_release(struct inode *inode, struct file *file)
{
	mutex_lock(&event_mutex);

	if (file->f_mode & FMODE_READ)
		seq_release(inode, file);

	mutex_unlock(&event_mutex);

	return 0;
}

static ssize_t
event_trigger_write(struct file *filp, const char __user *ubuf,
		    size_t cnt, loff_t *ppos)
{
	return event_trigger_regex_write(filp, ubuf, cnt, ppos);
}

static int
event_trigger_open(struct inode *inode, struct file *filp)
{
	return event_trigger_regex_open(inode, filp);
}

static int
event_trigger_release(struct inode *inode, struct file *file)
{
	return event_trigger_regex_release(inode, file);
}

const struct file_operations event_trigger_fops = {
	.open = event_trigger_open,
	.read = seq_read,
	.write = event_trigger_write,
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	.llseek = tracing_lseek,
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	.release = event_trigger_release,
};

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/*
 * Currently we only register event commands from __init, so mark this
 * __init too.
 */
static __init int register_event_command(struct event_command *cmd)
{
	struct event_command *p;
	int ret = 0;

	mutex_lock(&trigger_cmd_mutex);
	list_for_each_entry(p, &trigger_commands, list) {
		if (strcmp(cmd->name, p->name) == 0) {
			ret = -EBUSY;
			goto out_unlock;
		}
	}
	list_add(&cmd->list, &trigger_commands);
 out_unlock:
	mutex_unlock(&trigger_cmd_mutex);

	return ret;
}

/*
 * Currently we only unregister event commands from __init, so mark
 * this __init too.
 */
static __init int unregister_event_command(struct event_command *cmd)
{
	struct event_command *p, *n;
	int ret = -ENODEV;

	mutex_lock(&trigger_cmd_mutex);
	list_for_each_entry_safe(p, n, &trigger_commands, list) {
		if (strcmp(cmd->name, p->name) == 0) {
			ret = 0;
			list_del_init(&p->list);
			goto out_unlock;
		}
	}
 out_unlock:
	mutex_unlock(&trigger_cmd_mutex);

	return ret;
}

/**
 * event_trigger_print - Generic event_trigger_ops @print implementation
 * @name: The name of the event trigger
 * @m: The seq_file being printed to
 * @data: Trigger-specific data
 * @filter_str: filter_str to print, if present
 *
 * Common implementation for event triggers to print themselves.
 *
 * Usually wrapped by a function that simply sets the @name of the
 * trigger command and then invokes this.
 *
 * Return: 0 on success, errno otherwise
 */
static int
event_trigger_print(const char *name, struct seq_file *m,
		    void *data, char *filter_str)
{
	long count = (long)data;

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	seq_puts(m, name);
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	if (count == -1)
		seq_puts(m, ":unlimited");
	else
		seq_printf(m, ":count=%ld", count);

	if (filter_str)
		seq_printf(m, " if %s\n", filter_str);
	else
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		seq_putc(m, '\n');
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	return 0;
}

/**
 * event_trigger_init - Generic event_trigger_ops @init implementation
 * @ops: The trigger ops associated with the trigger
 * @data: Trigger-specific data
 *
 * Common implementation of event trigger initialization.
 *
 * Usually used directly as the @init method in event trigger
 * implementations.
 *
 * Return: 0 on success, errno otherwise
 */
static int
event_trigger_init(struct event_trigger_ops *ops,
		   struct event_trigger_data *data)
{
	data->ref++;
	return 0;
}

/**
 * event_trigger_free - Generic event_trigger_ops @free implementation
 * @ops: The trigger ops associated with the trigger
 * @data: Trigger-specific data
 *
 * Common implementation of event trigger de-initialization.
 *
 * Usually used directly as the @free method in event trigger
 * implementations.
 */
static void
event_trigger_free(struct event_trigger_ops *ops,
		   struct event_trigger_data *data)
{
	if (WARN_ON_ONCE(data->ref <= 0))
		return;

	data->ref--;
	if (!data->ref)
		trigger_data_free(data);
}

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static int trace_event_trigger_enable_disable(struct trace_event_file *file,
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					      int trigger_enable)
{
	int ret = 0;

	if (trigger_enable) {
		if (atomic_inc_return(&file->tm_ref) > 1)
			return ret;
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		set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
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		ret = trace_event_enable_disable(file, 1, 1);
	} else {
		if (atomic_dec_return(&file->tm_ref) > 0)
			return ret;
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		clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
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		ret = trace_event_enable_disable(file, 0, 1);
	}

	return ret;
}

/**
 * clear_event_triggers - Clear all triggers associated with a trace array
 * @tr: The trace array to clear
 *
 * For each trigger, the triggering event has its tm_ref decremented
 * via trace_event_trigger_enable_disable(), and any associated event
 * (in the case of enable/disable_event triggers) will have its sm_ref
 * decremented via free()->trace_event_enable_disable().  That
 * combination effectively reverses the soft-mode/trigger state added
 * by trigger registration.
 *
 * Must be called with event_mutex held.
 */
void
clear_event_triggers(struct trace_array *tr)
{
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	struct trace_event_file *file;
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	list_for_each_entry(file, &tr->events, list) {
		struct event_trigger_data *data;
		list_for_each_entry_rcu(data, &file->triggers, list) {
			trace_event_trigger_enable_disable(file, 0);
			if (data->ops->free)
				data->ops->free(data->ops, data);
		}
	}
}

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/**
 * update_cond_flag - Set or reset the TRIGGER_COND bit
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 * @file: The trace_event_file associated with the event
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 *
 * If an event has triggers and any of those triggers has a filter or
 * a post_trigger, trigger invocation needs to be deferred until after
 * the current event has logged its data, and the event should have
 * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 * cleared.
 */
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static void update_cond_flag(struct trace_event_file *file)
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{
	struct event_trigger_data *data;
	bool set_cond = false;

	list_for_each_entry_rcu(data, &file->triggers, list) {
		if (data->filter || data->cmd_ops->post_trigger) {
			set_cond = true;
			break;
		}
	}

	if (set_cond)
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		set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
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	else
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		clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
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}

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/**
 * register_trigger - Generic event_command @reg implementation
 * @glob: The raw string used to register the trigger
 * @ops: The trigger ops associated with the trigger
 * @data: Trigger-specific data to associate with the trigger
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 * @file: The trace_event_file associated with the event
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 *
 * Common implementation for event trigger registration.
 *
 * Usually used directly as the @reg method in event command
 * implementations.
 *
 * Return: 0 on success, errno otherwise
 */
static int register_trigger(char *glob, struct event_trigger_ops *ops,
			    struct event_trigger_data *data,
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			    struct trace_event_file *file)
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{
	struct event_trigger_data *test;
	int ret = 0;

	list_for_each_entry_rcu(test, &file->triggers, list) {
		if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
			ret = -EEXIST;
			goto out;
		}
	}

	if (data->ops->init) {
		ret = data->ops->init(data->ops, data);
		if (ret < 0)
			goto out;
	}

	list_add_rcu(&data->list, &file->triggers);
	ret++;

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	update_cond_flag(file);
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	if (trace_event_trigger_enable_disable(file, 1) < 0) {
		list_del_rcu(&data->list);
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		update_cond_flag(file);
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		ret--;
	}
out:
	return ret;
}

/**
 * unregister_trigger - Generic event_command @unreg implementation
 * @glob: The raw string used to register the trigger
 * @ops: The trigger ops associated with the trigger
 * @test: Trigger-specific data used to find the trigger to remove
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 * @file: The trace_event_file associated with the event
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 *
 * Common implementation for event trigger unregistration.
 *
 * Usually used directly as the @unreg method in event command
 * implementations.
 */
static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
			       struct event_trigger_data *test,
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			       struct trace_event_file *file)
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{
	struct event_trigger_data *data;
	bool unregistered = false;

	list_for_each_entry_rcu(data, &file->triggers, list) {
		if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
			unregistered = true;
			list_del_rcu(&data->list);
			trace_event_trigger_enable_disable(file, 0);
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			update_cond_flag(file);
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			break;
		}
	}

	if (unregistered && data->ops->free)
		data->ops->free(data->ops, data);
}

/**
 * event_trigger_callback - Generic event_command @func implementation
 * @cmd_ops: The command ops, used for trigger registration
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 * @file: The trace_event_file associated with the event
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 * @glob: The raw string used to register the trigger
 * @cmd: The cmd portion of the string used to register the trigger
 * @param: The params portion of the string used to register the trigger
 *
 * Common implementation for event command parsing and trigger
 * instantiation.
 *
 * Usually used directly as the @func method in event command
 * implementations.
 *
 * Return: 0 on success, errno otherwise
 */
static int
event_trigger_callback(struct event_command *cmd_ops,
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		       struct trace_event_file *file,
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		       char *glob, char *cmd, char *param)
{
	struct event_trigger_data *trigger_data;
	struct event_trigger_ops *trigger_ops;
	char *trigger = NULL;
	char *number;
	int ret;

	/* separate the trigger from the filter (t:n [if filter]) */
	if (param && isdigit(param[0]))
		trigger = strsep(&param, " \t");

	trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);

	ret = -ENOMEM;
	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
	if (!trigger_data)
		goto out;

	trigger_data->count = -1;
	trigger_data->ops = trigger_ops;
	trigger_data->cmd_ops = cmd_ops;
	INIT_LIST_HEAD(&trigger_data->list);

	if (glob[0] == '!') {
		cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
		kfree(trigger_data);
		ret = 0;
		goto out;
	}

	if (trigger) {
		number = strsep(&trigger, ":");

		ret = -EINVAL;
		if (!strlen(number))
			goto out_free;

		/*
		 * We use the callback data field (which is a pointer)
		 * as our counter.
		 */
		ret = kstrtoul(number, 0, &trigger_data->count);
		if (ret)
			goto out_free;
	}

	if (!param) /* if param is non-empty, it's supposed to be a filter */
		goto out_reg;

	if (!cmd_ops->set_filter)
		goto out_reg;

	ret = cmd_ops->set_filter(param, trigger_data, file);
	if (ret < 0)
		goto out_free;

 out_reg:
	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
	/*
	 * The above returns on success the # of functions enabled,
	 * but if it didn't find any functions it returns zero.
	 * Consider no functions a failure too.
	 */
	if (!ret) {
		ret = -ENOENT;
		goto out_free;
	} else if (ret < 0)
		goto out_free;
	ret = 0;
 out:
	return ret;

 out_free:
677
678
	if (cmd_ops->set_filter)
		cmd_ops->set_filter(NULL, trigger_data, NULL);
679
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	kfree(trigger_data);
	goto out;
}

683
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686
/**
 * set_trigger_filter - Generic event_command @set_filter implementation
 * @filter_str: The filter string for the trigger, NULL to remove filter
 * @trigger_data: Trigger-specific data
687
 * @file: The trace_event_file associated with the event
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699
700
 *
 * Common implementation for event command filter parsing and filter
 * instantiation.
 *
 * Usually used directly as the @set_filter method in event command
 * implementations.
 *
 * Also used to remove a filter (if filter_str = NULL).
 *
 * Return: 0 on success, errno otherwise
 */
static int set_trigger_filter(char *filter_str,
			      struct event_trigger_data *trigger_data,
701
			      struct trace_event_file *file)
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{
	struct event_trigger_data *data = trigger_data;
	struct event_filter *filter = NULL, *tmp;
	int ret = -EINVAL;
	char *s;

	if (!filter_str) /* clear the current filter */
		goto assign;

	s = strsep(&filter_str, " \t");

	if (!strlen(s) || strcmp(s, "if") != 0)
		goto out;

	if (!filter_str)
		goto out;

	/* The filter is for the 'trigger' event, not the triggered event */
	ret = create_event_filter(file->event_call, filter_str, false, &filter);
	if (ret)
		goto out;
 assign:
724
	tmp = rcu_access_pointer(data->filter);
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	rcu_assign_pointer(data->filter, filter);

	if (tmp) {
		/* Make sure the call is done with the filter */
		synchronize_sched();
		free_event_filter(tmp);
	}

	kfree(data->filter_str);
	data->filter_str = NULL;

	if (filter_str) {
		data->filter_str = kstrdup(filter_str, GFP_KERNEL);
		if (!data->filter_str) {
740
			free_event_filter(rcu_access_pointer(data->filter));
741
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748
			data->filter = NULL;
			ret = -ENOMEM;
		}
	}
 out:
	return ret;
}

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760
static void
traceon_trigger(struct event_trigger_data *data)
{
	if (tracing_is_on())
		return;

	tracing_on();
}

static void
traceon_count_trigger(struct event_trigger_data *data)
{
761
762
763
	if (tracing_is_on())
		return;

764
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769
	if (!data->count)
		return;

	if (data->count != -1)
		(data->count)--;

770
	tracing_on();
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784
}

static void
traceoff_trigger(struct event_trigger_data *data)
{
	if (!tracing_is_on())
		return;

	tracing_off();
}

static void
traceoff_count_trigger(struct event_trigger_data *data)
{
785
786
787
	if (!tracing_is_on())
		return;

788
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792
793
	if (!data->count)
		return;

	if (data->count != -1)
		(data->count)--;

794
	tracing_off();
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}

static int
traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
		      struct event_trigger_data *data)
{
	return event_trigger_print("traceon", m, (void *)data->count,
				   data->filter_str);
}

static int
traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
		       struct event_trigger_data *data)
{
	return event_trigger_print("traceoff", m, (void *)data->count,
				   data->filter_str);
}

static struct event_trigger_ops traceon_trigger_ops = {
	.func			= traceon_trigger,
	.print			= traceon_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops traceon_count_trigger_ops = {
	.func			= traceon_count_trigger,
	.print			= traceon_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops traceoff_trigger_ops = {
	.func			= traceoff_trigger,
	.print			= traceoff_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops traceoff_count_trigger_ops = {
	.func			= traceoff_count_trigger,
	.print			= traceoff_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops *
onoff_get_trigger_ops(char *cmd, char *param)
{
	struct event_trigger_ops *ops;

	/* we register both traceon and traceoff to this callback */
	if (strcmp(cmd, "traceon") == 0)
		ops = param ? &traceon_count_trigger_ops :
			&traceon_trigger_ops;
	else
		ops = param ? &traceoff_count_trigger_ops :
			&traceoff_trigger_ops;

	return ops;
}

static struct event_command trigger_traceon_cmd = {
	.name			= "traceon",
	.trigger_type		= ETT_TRACE_ONOFF,
	.func			= event_trigger_callback,
	.reg			= register_trigger,
	.unreg			= unregister_trigger,
	.get_trigger_ops	= onoff_get_trigger_ops,
864
	.set_filter		= set_trigger_filter,
865
866
867
868
869
870
871
872
873
};

static struct event_command trigger_traceoff_cmd = {
	.name			= "traceoff",
	.trigger_type		= ETT_TRACE_ONOFF,
	.func			= event_trigger_callback,
	.reg			= register_trigger,
	.unreg			= unregister_trigger,
	.get_trigger_ops	= onoff_get_trigger_ops,
874
	.set_filter		= set_trigger_filter,
875
876
};

877
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890
891
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893
894
895
896
897
898
#ifdef CONFIG_TRACER_SNAPSHOT
static void
snapshot_trigger(struct event_trigger_data *data)
{
	tracing_snapshot();
}

static void
snapshot_count_trigger(struct event_trigger_data *data)
{
	if (!data->count)
		return;

	if (data->count != -1)
		(data->count)--;

	snapshot_trigger(data);
}

static int
register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
			  struct event_trigger_data *data,
899
			  struct trace_event_file *file)
900
901
902
903
904
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913
914
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918
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931
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933
934
935
936
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938
939
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941
942
943
944
945
{
	int ret = register_trigger(glob, ops, data, file);

	if (ret > 0 && tracing_alloc_snapshot() != 0) {
		unregister_trigger(glob, ops, data, file);
		ret = 0;
	}

	return ret;
}

static int
snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
		       struct event_trigger_data *data)
{
	return event_trigger_print("snapshot", m, (void *)data->count,
				   data->filter_str);
}

static struct event_trigger_ops snapshot_trigger_ops = {
	.func			= snapshot_trigger,
	.print			= snapshot_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops snapshot_count_trigger_ops = {
	.func			= snapshot_count_trigger,
	.print			= snapshot_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops *
snapshot_get_trigger_ops(char *cmd, char *param)
{
	return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
}

static struct event_command trigger_snapshot_cmd = {
	.name			= "snapshot",
	.trigger_type		= ETT_SNAPSHOT,
	.func			= event_trigger_callback,
	.reg			= register_snapshot_trigger,
	.unreg			= unregister_trigger,
	.get_trigger_ops	= snapshot_get_trigger_ops,
946
	.set_filter		= set_trigger_filter,
947
948
949
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952
953
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956
957
958
959
960
961
};

static __init int register_trigger_snapshot_cmd(void)
{
	int ret;

	ret = register_event_command(&trigger_snapshot_cmd);
	WARN_ON(ret < 0);

	return ret;
}
#else
static __init int register_trigger_snapshot_cmd(void) { return 0; }
#endif /* CONFIG_TRACER_SNAPSHOT */

962
963
964
965
966
#ifdef CONFIG_STACKTRACE
/*
 * Skip 3:
 *   stacktrace_trigger()
 *   event_triggers_post_call()
967
 *   trace_event_raw_event_xxx()
968
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1003
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1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
 */
#define STACK_SKIP 3

static void
stacktrace_trigger(struct event_trigger_data *data)
{
	trace_dump_stack(STACK_SKIP);
}

static void
stacktrace_count_trigger(struct event_trigger_data *data)
{
	if (!data->count)
		return;

	if (data->count != -1)
		(data->count)--;

	stacktrace_trigger(data);
}

static int
stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
			 struct event_trigger_data *data)
{
	return event_trigger_print("stacktrace", m, (void *)data->count,
				   data->filter_str);
}

static struct event_trigger_ops stacktrace_trigger_ops = {
	.func			= stacktrace_trigger,
	.print			= stacktrace_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops stacktrace_count_trigger_ops = {
	.func			= stacktrace_count_trigger,
	.print			= stacktrace_trigger_print,
	.init			= event_trigger_init,
	.free			= event_trigger_free,
};

static struct event_trigger_ops *
stacktrace_get_trigger_ops(char *cmd, char *param)
{
	return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
}

static struct event_command trigger_stacktrace_cmd = {
	.name			= "stacktrace",
	.trigger_type		= ETT_STACKTRACE,
	.post_trigger		= true,
	.func			= event_trigger_callback,
	.reg			= register_trigger,
	.unreg			= unregister_trigger,
	.get_trigger_ops	= stacktrace_get_trigger_ops,
1025
	.set_filter		= set_trigger_filter,
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
};

static __init int register_trigger_stacktrace_cmd(void)
{
	int ret;

	ret = register_event_command(&trigger_stacktrace_cmd);
	WARN_ON(ret < 0);

	return ret;
}
#else
static __init int register_trigger_stacktrace_cmd(void) { return 0; }
#endif /* CONFIG_STACKTRACE */

1041
1042
1043
1044
1045
1046
static __init void unregister_trigger_traceon_traceoff_cmds(void)
{
	unregister_event_command(&trigger_traceon_cmd);
	unregister_event_command(&trigger_traceoff_cmd);
}

1047
1048
1049
1050
1051
/* Avoid typos */
#define ENABLE_EVENT_STR	"enable_event"
#define DISABLE_EVENT_STR	"disable_event"

struct enable_trigger_data {
1052
	struct trace_event_file		*file;
1053
1054
1055
1056
1057
1058
1059
1060
1061
	bool				enable;
};

static void
event_enable_trigger(struct event_trigger_data *data)
{
	struct enable_trigger_data *enable_data = data->private_data;

	if (enable_data->enable)
1062
		clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1063
	else
1064
		set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
}

static void
event_enable_count_trigger(struct event_trigger_data *data)
{
	struct enable_trigger_data *enable_data = data->private_data;

	if (!data->count)
		return;

	/* Skip if the event is in a state we want to switch to */
1076
	if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
		return;

	if (data->count != -1)
		(data->count)--;

	event_enable_trigger(data);
}

static int
event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
			   struct event_trigger_data *data)
{
	struct enable_trigger_data *enable_data = data->private_data;

	seq_printf(m, "%s:%s:%s",
		   enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR,
		   enable_data->file->event_call->class->system,
1094
		   trace_event_name(enable_data->file->event_call));
1095
1096
1097
1098
1099
1100
1101
1102
1103

	if (data->count == -1)
		seq_puts(m, ":unlimited");
	else
		seq_printf(m, ":count=%ld", data->count);

	if (data->filter_str)
		seq_printf(m, " if %s\n", data->filter_str);
	else
1104
		seq_putc(m, '\n');
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157

	return 0;
}

static void
event_enable_trigger_free(struct event_trigger_ops *ops,
			  struct event_trigger_data *data)
{
	struct enable_trigger_data *enable_data = data->private_data;

	if (WARN_ON_ONCE(data->ref <= 0))
		return;

	data->ref--;
	if (!data->ref) {
		/* Remove the SOFT_MODE flag */
		trace_event_enable_disable(enable_data->file, 0, 1);
		module_put(enable_data->file->event_call->mod);
		trigger_data_free(data);
		kfree(enable_data);
	}
}

static struct event_trigger_ops event_enable_trigger_ops = {
	.func			= event_enable_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops event_enable_count_trigger_ops = {
	.func			= event_enable_count_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops event_disable_trigger_ops = {
	.func			= event_enable_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static struct event_trigger_ops event_disable_count_trigger_ops = {
	.func			= event_enable_count_trigger,
	.print			= event_enable_trigger_print,
	.init			= event_trigger_init,
	.free			= event_enable_trigger_free,
};

static int
event_enable_trigger_func(struct event_command *cmd_ops,
1158
			  struct trace_event_file *file,
1159
1160
			  char *glob, char *cmd, char *param)
{
1161
	struct trace_event_file *event_enable_file;
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
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1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
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1211
1212
1213
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1216
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1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
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1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
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1258
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1262
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1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
	struct enable_trigger_data *enable_data;
	struct event_trigger_data *trigger_data;
	struct event_trigger_ops *trigger_ops;
	struct trace_array *tr = file->tr;
	const char *system;
	const char *event;
	char *trigger;
	char *number;
	bool enable;
	int ret;

	if (!param)
		return -EINVAL;

	/* separate the trigger from the filter (s:e:n [if filter]) */
	trigger = strsep(&param, " \t");
	if (!trigger)
		return -EINVAL;

	system = strsep(&trigger, ":");
	if (!trigger)
		return -EINVAL;

	event = strsep(&trigger, ":");

	ret = -EINVAL;
	event_enable_file = find_event_file(tr, system, event);
	if (!event_enable_file)
		goto out;

	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;

	trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);

	ret = -ENOMEM;
	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
	if (!trigger_data)
		goto out;

	enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
	if (!enable_data) {
		kfree(trigger_data);
		goto out;
	}

	trigger_data->count = -1;
	trigger_data->ops = trigger_ops;
	trigger_data->cmd_ops = cmd_ops;
	INIT_LIST_HEAD(&trigger_data->list);
	RCU_INIT_POINTER(trigger_data->filter, NULL);

	enable_data->enable = enable;
	enable_data->file = event_enable_file;
	trigger_data->private_data = enable_data;

	if (glob[0] == '!') {
		cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
		kfree(trigger_data);
		kfree(enable_data);
		ret = 0;
		goto out;
	}

	if (trigger) {
		number = strsep(&trigger, ":");

		ret = -EINVAL;
		if (!strlen(number))
			goto out_free;

		/*
		 * We use the callback data field (which is a pointer)
		 * as our counter.
		 */
		ret = kstrtoul(number, 0, &trigger_data->count);
		if (ret)
			goto out_free;
	}

	if (!param) /* if param is non-empty, it's supposed to be a filter */
		goto out_reg;

	if (!cmd_ops->set_filter)
		goto out_reg;

	ret = cmd_ops->set_filter(param, trigger_data, file);
	if (ret < 0)
		goto out_free;

 out_reg:
	/* Don't let event modules unload while probe registered */
	ret = try_module_get(event_enable_file->event_call->mod);
	if (!ret) {
		ret = -EBUSY;
		goto out_free;
	}

	ret = trace_event_enable_disable(event_enable_file, 1, 1);
	if (ret < 0)
		goto out_put;
	ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
	/*
	 * The above returns on success the # of functions enabled,
	 * but if it didn't find any functions it returns zero.
	 * Consider no functions a failure too.
	 */
	if (!ret) {
		ret = -ENOENT;
		goto out_disable;
	} else if (ret < 0)
		goto out_disable;
	/* Just return zero, not the number of enabled functions */
	ret = 0;
 out:
	return ret;

 out_disable:
	trace_event_enable_disable(event_enable_file, 0, 1);
 out_put:
	module_put(event_enable_file->event_call->mod);
 out_free:
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1284
	if (cmd_ops->set_filter)
		cmd_ops->set_filter(NULL, trigger_data, NULL);
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	kfree(trigger_data);
	kfree(enable_data);
	goto out;
}

static int event_enable_register_trigger(char *glob,
					 struct event_trigger_ops *ops,
					 struct event_trigger_data *data,
1293
					 struct trace_event_file *file)
1294
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{
	struct enable_trigger_data *enable_data = data->private_data;
	struct enable_trigger_data *test_enable_data;
	struct event_trigger_data *test;
	int ret = 0;

	list_for_each_entry_rcu(test, &file->triggers, list) {
		test_enable_data = test->private_data;
		if (test_enable_data &&
		    (test_enable_data->file == enable_data->file)) {
			ret = -EEXIST;
			goto out;
		}
	}

	if (data->ops->init) {
		ret = data->ops->init(data->ops, data);
		if (ret < 0)
			goto out;
	}

	list_add_rcu(&data->list, &file->triggers);
	ret++;

1318
	update_cond_flag(file);
1319
1320
	if (trace_event_trigger_enable_disable(file, 1) < 0) {
		list_del_rcu(&data->list);
1321
		update_cond_flag(file);
1322
1323
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1330
		ret--;
	}
out:
	return ret;
}

static void event_enable_unregister_trigger(char *glob,
					    struct event_trigger_ops *ops,
					    struct event_trigger_data *test,
1331
					    struct trace_event_file *file)
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
{
	struct enable_trigger_data *test_enable_data = test->private_data;
	struct enable_trigger_data *enable_data;
	struct event_trigger_data *data;
	bool unregistered = false;

	list_for_each_entry_rcu(data, &file->triggers, list) {
		enable_data = data->private_data;
		if (enable_data &&
		    (enable_data->file == test_enable_data->file)) {
			unregistered = true;
			list_del_rcu(&data->list);
			trace_event_trigger_enable_disable(file, 0);
1345
			update_cond_flag(file);
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
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1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
			break;
		}
	}

	if (unregistered && data->ops->free)
		data->ops->free(data->ops, data);
}

static struct event_trigger_ops *
event_enable_get_trigger_ops(char *cmd, char *param)
{
	struct event_trigger_ops *ops;
	bool enable;

	enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;

	if (enable)
		ops = param ? &event_enable_count_trigger_ops :
			&event_enable_trigger_ops;
	else
		ops = param ? &event_disable_count_trigger_ops :
			&event_disable_trigger_ops;

	return ops;
}

static struct event_command trigger_enable_cmd = {
	.name			= ENABLE_EVENT_STR,
	.trigger_type		= ETT_EVENT_ENABLE,
	.func			= event_enable_trigger_func,
	.reg			= event_enable_register_trigger,
	.unreg			= event_enable_unregister_trigger,
	.get_trigger_ops	= event_enable_get_trigger_ops,
1379
	.set_filter		= set_trigger_filter,
1380
1381
1382
1383
1384
1385
1386
1387
1388
};

static struct event_command trigger_disable_cmd = {
	.name			= DISABLE_EVENT_STR,
	.trigger_type		= ETT_EVENT_ENABLE,
	.func			= event_enable_trigger_func,
	.reg			= event_enable_register_trigger,
	.unreg			= event_enable_unregister_trigger,
	.get_trigger_ops	= event_enable_get_trigger_ops,
1389
	.set_filter		= set_trigger_filter,
1390
1391
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1393
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1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
};

static __init void unregister_trigger_enable_disable_cmds(void)
{
	unregister_event_command(&trigger_enable_cmd);
	unregister_event_command(&trigger_disable_cmd);
}

static __init int register_trigger_enable_disable_cmds(void)
{
	int ret;

	ret = register_event_command(&trigger_enable_cmd);
	if (WARN_ON(ret < 0))
		return ret;
	ret = register_event_command(&trigger_disable_cmd);
	if (WARN_ON(ret < 0))
		unregister_trigger_enable_disable_cmds();

	return ret;
}

1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
static __init int register_trigger_traceon_traceoff_cmds(void)
{
	int ret;

	ret = register_event_command(&trigger_traceon_cmd);
	if (WARN_ON(ret < 0))
		return ret;
	ret = register_event_command(&trigger_traceoff_cmd);
	if (WARN_ON(ret < 0))
		unregister_trigger_traceon_traceoff_cmds();

	return ret;
}

1426
1427
__init int register_trigger_cmds(void)
{
1428
	register_trigger_traceon_traceoff_cmds();
1429
	register_trigger_snapshot_cmd();
1430
	register_trigger_stacktrace_cmd();
1431
	register_trigger_enable_disable_cmds();
1432

1433
1434
	return 0;
}