release/src-rt-6.x.4708/linux/linux-2.6.36/fs/cachefiles/main.c

   1 /* Network filesystem caching backend to use cache files on a premounted
   2  * filesystem
   3  *
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public Licence
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the Licence, or (at your option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/sched.h>
  16 #include <linux/completion.h>
  17 #include <linux/slab.h>
  18 #include <linux/fs.h>
  19 #include <linux/file.h>
  20 #include <linux/namei.h>
  21 #include <linux/mount.h>
  22 #include <linux/statfs.h>
  23 #include <linux/sysctl.h>
  24 #include <linux/miscdevice.h>
  25 #include "internal.h"
  26
  27 unsigned cachefiles_debug;
  28 module_param_named(debug, cachefiles_debug, uint, S_IWUSR | S_IRUGO);
  29 MODULE_PARM_DESC(cachefiles_debug, "CacheFiles debugging mask");
  30
  31 MODULE_DESCRIPTION("Mounted-filesystem based cache");
  32 MODULE_AUTHOR("Red Hat, Inc.");
  33 MODULE_LICENSE("GPL");
  34
  35 struct kmem_cache *cachefiles_object_jar;
  36
  37 static struct miscdevice cachefiles_dev = {
  38         .minor  = MISC_DYNAMIC_MINOR,
  39         .name   = "cachefiles",
  40         .fops   = &cachefiles_daemon_fops,
  41 };
  42
  43 static void cachefiles_object_init_once(void *_object)
  44 {
  45         struct cachefiles_object *object = _object;
  46
  47         memset(object, 0, sizeof(*object));
  48         spin_lock_init(&object->work_lock);
  49 }
  50
  51 /*
  52  * initialise the fs caching module
  53  */
  54 static int __init cachefiles_init(void)
  55 {
  56         int ret;
  57
  58         ret = misc_register(&cachefiles_dev);
  59         if (ret < 0)
  60                 goto error_dev;
  61
  62         /* create an object jar */
  63         ret = -ENOMEM;
  64         cachefiles_object_jar =
  65                 kmem_cache_create("cachefiles_object_jar",
  66                                   sizeof(struct cachefiles_object),
  67                                   0,
  68                                   SLAB_HWCACHE_ALIGN,
  69                                   cachefiles_object_init_once);
  70         if (!cachefiles_object_jar) {
  71                 printk(KERN_NOTICE
  72                        "CacheFiles: Failed to allocate an object jar\n");
  73                 goto error_object_jar;
  74         }
  75
  76         ret = cachefiles_proc_init();
  77         if (ret < 0)
  78                 goto error_proc;
  79
  80         printk(KERN_INFO "CacheFiles: Loaded\n");
  81         return 0;
  82
  83 error_proc:
  84         kmem_cache_destroy(cachefiles_object_jar);
  85 error_object_jar:
  86         misc_deregister(&cachefiles_dev);
  87 error_dev:
  88         kerror("failed to register: %d", ret);
  89         return ret;
  90 }
  91
  92 fs_initcall(cachefiles_init);
  93
  94 /*
  95  * clean up on module removal
  96  */
  97 static void __exit cachefiles_exit(void)
  98 {
  99         printk(KERN_INFO "CacheFiles: Unloading\n");
 100
 101         cachefiles_proc_cleanup();
 102         kmem_cache_destroy(cachefiles_object_jar);
 103         misc_deregister(&cachefiles_dev);
 104 }
 105
 106 module_exit(cachefiles_exit);