Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/* CacheFiles statistics
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */
 
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include "internal.h"
 
atomic_t cachefiles_lookup_histogram[HZ];
atomic_t cachefiles_mkdir_histogram[HZ];
atomic_t cachefiles_create_histogram[HZ];
 
/*
 * display the latency histogram
 */
static int cachefiles_histogram_show(struct seq_file *m, void *v)
{
<------>unsigned long index;
<------>unsigned x, y, z, t;
 
<------>switch ((unsigned long) v) {
<------>case 1:
<------><------>seq_puts(m, "JIFS  SECS  LOOKUPS   MKDIRS    CREATES\n");
<------><------>return 0;
<------>case 2:
<------><------>seq_puts(m, "===== ===== ========= ========= =========\n");
<------><------>return 0;
<------>default:
<------><------>index = (unsigned long) v - 3;
<------><------>x = atomic_read(&cachefiles_lookup_histogram[index]);
<------><------>y = atomic_read(&cachefiles_mkdir_histogram[index]);
<------><------>z = atomic_read(&cachefiles_create_histogram[index]);
<------><------>if (x == 0 && y == 0 && z == 0)
<------><------><------>return 0;
 
<------><------>t = (index * 1000) / HZ;
 
<------><------>seq_printf(m, "%4lu  0.%03u %9u %9u %9u\n", index, t, x, y, z);
<------><------>return 0;
<------>}
}
 
/*
 * set up the iterator to start reading from the first line
 */
static void *cachefiles_histogram_start(struct seq_file *m, loff_t *_pos)
{
<------>if ((unsigned long long)*_pos >= HZ + 2)
<------><------>return NULL;
<------>if (*_pos == 0)
<------><------>*_pos = 1;
<------>return (void *)(unsigned long) *_pos;
}
 
/*
 * move to the next line
 */
static void *cachefiles_histogram_next(struct seq_file *m, void *v, loff_t *pos)
{
<------>(*pos)++;
<------>return (unsigned long long)*pos > HZ + 2 ?
<------><------>NULL : (void *)(unsigned long) *pos;
}
 
/*
 * clean up after reading
 */
static void cachefiles_histogram_stop(struct seq_file *m, void *v)
{
}
 
static const struct seq_operations cachefiles_histogram_ops = {
<------>.start		= cachefiles_histogram_start,
<------>.stop		= cachefiles_histogram_stop,
<------>.next		= cachefiles_histogram_next,
<------>.show		= cachefiles_histogram_show,
};
 
/*
 * initialise the /proc/fs/cachefiles/ directory
 */
int __init cachefiles_proc_init(void)
{
<------>_enter("");
 
<------>if (!proc_mkdir("fs/cachefiles", NULL))
<------><------>goto error_dir;
 
<------>if (!proc_create_seq("fs/cachefiles/histogram", S_IFREG | 0444, NULL,
<------><------><------> &cachefiles_histogram_ops))
<------><------>goto error_histogram;
 
<------>_leave(" = 0");
<------>return 0;
 
error_histogram:
<------>remove_proc_entry("fs/cachefiles", NULL);
error_dir:
<------>_leave(" = -ENOMEM");
<------>return -ENOMEM;
}
 
/*
 * clean up the /proc/fs/cachefiles/ directory
 */
void cachefiles_proc_cleanup(void)
{
<------>remove_proc_entry("fs/cachefiles/histogram", NULL);
<------>remove_proc_entry("fs/cachefiles", NULL);
}