Merge tag '9p-for-5.3' of git://github.com/martinetd/linux
[sfrench/cifs-2.6.git] / net / 9p / mod.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  net/9p/9p.c
4  *
5  *  9P entry point
6  *
7  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
8  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
9  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
10  */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/sched.h>
17 #include <linux/moduleparam.h>
18 #include <net/9p/9p.h>
19 #include <linux/fs.h>
20 #include <linux/parser.h>
21 #include <net/9p/client.h>
22 #include <net/9p/transport.h>
23 #include <linux/list.h>
24 #include <linux/spinlock.h>
25
26 #ifdef CONFIG_NET_9P_DEBUG
27 unsigned int p9_debug_level = 0;        /* feature-rific global debug level  */
28 EXPORT_SYMBOL(p9_debug_level);
29 module_param_named(debug, p9_debug_level, uint, 0);
30 MODULE_PARM_DESC(debug, "9P debugging level");
31
32 void _p9_debug(enum p9_debug_flags level, const char *func,
33                 const char *fmt, ...)
34 {
35         struct va_format vaf;
36         va_list args;
37
38         if ((p9_debug_level & level) != level)
39                 return;
40
41         va_start(args, fmt);
42
43         vaf.fmt = fmt;
44         vaf.va = &args;
45
46         if (level == P9_DEBUG_9P)
47                 pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
48         else
49                 pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
50
51         va_end(args);
52 }
53 EXPORT_SYMBOL(_p9_debug);
54 #endif
55
56 /*
57  * Dynamic Transport Registration Routines
58  *
59  */
60
61 static DEFINE_SPINLOCK(v9fs_trans_lock);
62 static LIST_HEAD(v9fs_trans_list);
63
64 /**
65  * v9fs_register_trans - register a new transport with 9p
66  * @m: structure describing the transport module and entry points
67  *
68  */
69 void v9fs_register_trans(struct p9_trans_module *m)
70 {
71         spin_lock(&v9fs_trans_lock);
72         list_add_tail(&m->list, &v9fs_trans_list);
73         spin_unlock(&v9fs_trans_lock);
74 }
75 EXPORT_SYMBOL(v9fs_register_trans);
76
77 /**
78  * v9fs_unregister_trans - unregister a 9p transport
79  * @m: the transport to remove
80  *
81  */
82 void v9fs_unregister_trans(struct p9_trans_module *m)
83 {
84         spin_lock(&v9fs_trans_lock);
85         list_del_init(&m->list);
86         spin_unlock(&v9fs_trans_lock);
87 }
88 EXPORT_SYMBOL(v9fs_unregister_trans);
89
90 /**
91  * v9fs_get_trans_by_name - get transport with the matching name
92  * @s: string identifying transport
93  *
94  */
95 struct p9_trans_module *v9fs_get_trans_by_name(char *s)
96 {
97         struct p9_trans_module *t, *found = NULL;
98
99         spin_lock(&v9fs_trans_lock);
100
101         list_for_each_entry(t, &v9fs_trans_list, list)
102                 if (strcmp(t->name, s) == 0 &&
103                     try_module_get(t->owner)) {
104                         found = t;
105                         break;
106                 }
107
108         spin_unlock(&v9fs_trans_lock);
109         return found;
110 }
111 EXPORT_SYMBOL(v9fs_get_trans_by_name);
112
113 /**
114  * v9fs_get_default_trans - get the default transport
115  *
116  */
117
118 struct p9_trans_module *v9fs_get_default_trans(void)
119 {
120         struct p9_trans_module *t, *found = NULL;
121
122         spin_lock(&v9fs_trans_lock);
123
124         list_for_each_entry(t, &v9fs_trans_list, list)
125                 if (t->def && try_module_get(t->owner)) {
126                         found = t;
127                         break;
128                 }
129
130         if (!found)
131                 list_for_each_entry(t, &v9fs_trans_list, list)
132                         if (try_module_get(t->owner)) {
133                                 found = t;
134                                 break;
135                         }
136
137         spin_unlock(&v9fs_trans_lock);
138         return found;
139 }
140 EXPORT_SYMBOL(v9fs_get_default_trans);
141
142 /**
143  * v9fs_put_trans - put trans
144  * @m: transport to put
145  *
146  */
147 void v9fs_put_trans(struct p9_trans_module *m)
148 {
149         if (m)
150                 module_put(m->owner);
151 }
152
153 /**
154  * init_p9 - Initialize module
155  *
156  */
157 static int __init init_p9(void)
158 {
159         int ret;
160
161         ret = p9_client_init();
162         if (ret)
163                 return ret;
164
165         p9_error_init();
166         pr_info("Installing 9P2000 support\n");
167         p9_trans_fd_init();
168
169         return ret;
170 }
171
172 /**
173  * exit_p9 - shutdown module
174  *
175  */
176
177 static void __exit exit_p9(void)
178 {
179         pr_info("Unloading 9P2000 support\n");
180
181         p9_trans_fd_exit();
182         p9_client_exit();
183 }
184
185 module_init(init_p9)
186 module_exit(exit_p9)
187
188 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
189 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
190 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
191 MODULE_LICENSE("GPL");