4de41b5974991f05b6a1fc4f07fe40ac746770d8
[linux-2.6.git] / fs / fscache / main.c
1 /* General filesystem local caching manager
2  *
3  * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11
12 #define FSCACHE_DEBUG_LEVEL CACHE
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 "internal.h"
19
20 MODULE_DESCRIPTION("FS Cache Manager");
21 MODULE_AUTHOR("Red Hat, Inc.");
22 MODULE_LICENSE("GPL");
23
24 unsigned fscache_defer_lookup = 1;
25 module_param_named(defer_lookup, fscache_defer_lookup, uint,
26                    S_IWUSR | S_IRUGO);
27 MODULE_PARM_DESC(fscache_defer_lookup,
28                  "Defer cookie lookup to background thread");
29
30 unsigned fscache_defer_create = 1;
31 module_param_named(defer_create, fscache_defer_create, uint,
32                    S_IWUSR | S_IRUGO);
33 MODULE_PARM_DESC(fscache_defer_create,
34                  "Defer cookie creation to background thread");
35
36 unsigned fscache_debug;
37 module_param_named(debug, fscache_debug, uint,
38                    S_IWUSR | S_IRUGO);
39 MODULE_PARM_DESC(fscache_debug,
40                  "FS-Cache debugging mask");
41
42 struct kobject *fscache_root;
43
44 /*
45  * initialise the fs caching module
46  */
47 static int __init fscache_init(void)
48 {
49         int ret;
50
51         ret = slow_work_register_user();
52         if (ret < 0)
53                 goto error_slow_work;
54
55         ret = fscache_proc_init();
56         if (ret < 0)
57                 goto error_proc;
58
59         fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
60                                                sizeof(struct fscache_cookie),
61                                                0,
62                                                0,
63                                                fscache_cookie_init_once);
64         if (!fscache_cookie_jar) {
65                 printk(KERN_NOTICE
66                        "FS-Cache: Failed to allocate a cookie jar\n");
67                 ret = -ENOMEM;
68                 goto error_cookie_jar;
69         }
70
71         fscache_root = kobject_create_and_add("fscache", kernel_kobj);
72         if (!fscache_root)
73                 goto error_kobj;
74
75         printk(KERN_NOTICE "FS-Cache: Loaded\n");
76         return 0;
77
78 error_kobj:
79         kmem_cache_destroy(fscache_cookie_jar);
80 error_cookie_jar:
81         fscache_proc_cleanup();
82 error_proc:
83         slow_work_unregister_user();
84 error_slow_work:
85         return ret;
86 }
87
88 fs_initcall(fscache_init);
89
90 /*
91  * clean up on module removal
92  */
93 static void __exit fscache_exit(void)
94 {
95         _enter("");
96
97         kobject_put(fscache_root);
98         kmem_cache_destroy(fscache_cookie_jar);
99         fscache_proc_cleanup();
100         slow_work_unregister_user();
101         printk(KERN_NOTICE "FS-Cache: Unloaded\n");
102 }
103
104 module_exit(fscache_exit);
105
106 /*
107  * wait_on_bit() sleep function for uninterruptible waiting
108  */
109 int fscache_wait_bit(void *flags)
110 {
111         schedule();
112         return 0;
113 }
114 EXPORT_SYMBOL(fscache_wait_bit);
115
116 /*
117  * wait_on_bit() sleep function for interruptible waiting
118  */
119 int fscache_wait_bit_interruptible(void *flags)
120 {
121         schedule();
122         return signal_pending(current);
123 }
124 EXPORT_SYMBOL(fscache_wait_bit_interruptible);