linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Infrastructure for statistic tracing (histogram output).

 *

 * Copyright (C) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>

 *

 * Based on the code from trace_branch.c which is

 * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>

 *

 */

​

​

#include <linux/list.h>

#include <linux/slab.h>

#include <linux/rbtree.h>

#include <linux/tracefs.h>

#include "trace_stat.h"

#include "trace.h"

​

​

/*

 * List of stat red-black nodes from a tracer

 * We use a such tree to sort quickly the stat

 * entries from the tracer.

 */

struct stat_node {

    struct rb_node      node;

    void            *stat;

};

​

/* A stat session is the stats output in one file */

struct stat_session {

    struct list_head    session_list;

    struct tracer_stat  *ts;

    struct rb_root      stat_root;

    struct mutex        stat_mutex;

    struct dentry       *file;

};

​

/* All of the sessions currently in use. Each stat file embed one session */

static LIST_HEAD(all_stat_sessions);

static DEFINE_MUTEX(all_stat_sessions_mutex);

​

/* The root directory for all stat files */

static struct dentry        *stat_dir;

​

static void __reset_stat_session(struct stat_session *session)

{

    struct stat_node *snode, *n;

​

    rbtree_postorder_for_each_entry_safe(snode, n, &session->stat_root, node) {

        if (session->ts->stat_release)

            session->ts->stat_release(snode->stat);

        kfree(snode);

    }

​

    session->stat_root = RB_ROOT;

}

​

static void reset_stat_session(struct stat_session *session)

{

    mutex_lock(&session->stat_mutex);

    __reset_stat_session(session);

    mutex_unlock(&session->stat_mutex);

}

​

static void destroy_session(struct stat_session *session)

{

    tracefs_remove(session->file);

    __reset_stat_session(session);

    mutex_destroy(&session->stat_mutex);

    kfree(session);

}

​

typedef int (*cmp_stat_t)(void *, void *);

​

static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)

{

    struct rb_node **new = &(root->rb_node), *parent = NULL;

    struct stat_node *data;

​

    data = kzalloc(sizeof(*data), GFP_KERNEL);

    if (!data)

        return -ENOMEM;

    data->stat = stat;

​

    /*

     * Figure out where to put new node

     * This is a descendent sorting

     */

    while (*new) {

        struct stat_node *this;