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kernel/linux-rt-4.4.41/fs/cachefiles/main.c 2.42 KB
5113f6f70   김현기   kernel add
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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 (dhowells@redhat.com)
   *
   * 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) {
  		pr_notice("Failed to allocate an object jar
  ");
  		goto error_object_jar;
  	}
  
  	ret = cachefiles_proc_init();
  	if (ret < 0)
  		goto error_proc;
  
  	pr_info("Loaded
  ");
  	return 0;
  
  error_proc:
  	kmem_cache_destroy(cachefiles_object_jar);
  error_object_jar:
  	misc_deregister(&cachefiles_dev);
  error_dev:
  	pr_err("failed to register: %d
  ", ret);
  	return ret;
  }
  
  fs_initcall(cachefiles_init);
  
  /*
   * clean up on module removal
   */
  static void __exit cachefiles_exit(void)
  {
  	pr_info("Unloading
  ");
  
  	cachefiles_proc_cleanup();
  	kmem_cache_destroy(cachefiles_object_jar);
  	misc_deregister(&cachefiles_dev);
  }
  
  module_exit(cachefiles_exit);