main.c

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/* Network filesystem caching backend to use cache files on a premounted
 * filesystem
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/statfs.h>
#include <linux/sysctl.h>
#include <linux/miscdevice.h>
#include "internal.h"

unsigned cachefiles_debug;
module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");

MODULE_DESCRIPTION("Mounted-filesystem based cache");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");

struct kmem_cache *cachefiles_object_jar;

static struct miscdevice cachefiles_dev = {
    .minor  = MISC_DYNAMIC_MINOR,
    .name   = "cachefiles",
    .fops   = &cachefiles_daemon_fops,
};

static void cachefiles_object_init_once(void *_object)
{
    struct cachefiles_object *object = _object;

    memset(object, 0, sizeof(*object));
    spin_lock_init(&object->work_lock);
}

/*
 * initialise the fs caching module
 */
static int __init cachefiles_init(void)
{
    int ret;

    ret = misc_register(&cachefiles_dev);
    if (ret < 0)
        goto error_dev;

    /* create an object jar */
    ret = -ENOMEM;
    cachefiles_object_jar =
        kmem_cache_create("cachefiles_object_jar",
                  sizeof(struct cachefiles_object),
                  0,
                  SLAB_HWCACHE_ALIGN,
                  cachefiles_object_init_once);
    if (!cachefiles_object_jar) {
        printk(KERN_NOTICE
               "CacheFiles: Failed to allocate an object jar\n");
        goto error_object_jar;
    }

    ret = cachefiles_proc_init();
    if (ret < 0)
        goto error_proc;

    printk(KERN_INFO "CacheFiles: Loaded\n");
    return 0;

error_proc:
    kmem_cache_destroy(cachefiles_object_jar);
error_object_jar:
    misc_deregister(&cachefiles_dev);
error_dev:
    kerror("failed to register: %d", ret);
    return ret;
}

fs_initcall(cachefiles_init);

/*
 * clean up on module removal
 */
static void __exit cachefiles_exit(void)
{
    printk(KERN_INFO "CacheFiles: Unloading\n");

    cachefiles_proc_cleanup();
    kmem_cache_destroy(cachefiles_object_jar);
    misc_deregister(&cachefiles_dev);
}

module_exit(cachefiles_exit);