xref: /openbmc/linux/fs/cachefiles/main.c (revision d2999e1b)
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 		pr_notice("Failed to allocate an object jar\n");
72 		goto error_object_jar;
73 	}
74 
75 	ret = cachefiles_proc_init();
76 	if (ret < 0)
77 		goto error_proc;
78 
79 	pr_info("Loaded\n");
80 	return 0;
81 
82 error_proc:
83 	kmem_cache_destroy(cachefiles_object_jar);
84 error_object_jar:
85 	misc_deregister(&cachefiles_dev);
86 error_dev:
87 	pr_err("failed to register: %d", ret);
88 	return ret;
89 }
90 
91 fs_initcall(cachefiles_init);
92 
93 /*
94  * clean up on module removal
95  */
96 static void __exit cachefiles_exit(void)
97 {
98 	pr_info("Unloading\n");
99 
100 	cachefiles_proc_cleanup();
101 	kmem_cache_destroy(cachefiles_object_jar);
102 	misc_deregister(&cachefiles_dev);
103 }
104 
105 module_exit(cachefiles_exit);
106