1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * 9P entry point
4 *
5 * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
6 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
7 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8 */
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/module.h>
13#include <linux/kmod.h>
14#include <linux/errno.h>
15#include <linux/sched.h>
16#include <linux/moduleparam.h>
17#include <net/9p/9p.h>
18#include <linux/fs.h>
19#include <net/9p/client.h>
20#include <net/9p/transport.h>
21#include <linux/list.h>
22#include <linux/spinlock.h>
23
24#ifdef CONFIG_NET_9P_DEBUG
25unsigned int p9_debug_level; /* feature-rific global debug level */
26EXPORT_SYMBOL(p9_debug_level);
27module_param_named(debug, p9_debug_level, uint, 0);
28MODULE_PARM_DESC(debug, "9P debugging level");
29
30void _p9_debug(enum p9_debug_flags level, const char *func,
31 const char *fmt, ...)
32{
33 struct va_format vaf;
34 va_list args;
35
36 if ((p9_debug_level & level) != level)
37 return;
38
39 va_start(args, fmt);
40
41 vaf.fmt = fmt;
42 vaf.va = &args;
43
44 if (level == P9_DEBUG_9P)
45 pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
46 else
47 pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
48
49 va_end(args);
50}
51EXPORT_SYMBOL(_p9_debug);
52#endif
53
54/* Dynamic Transport Registration Routines */
55
56static DEFINE_SPINLOCK(v9fs_trans_lock);
57static LIST_HEAD(v9fs_trans_list);
58
59/**
60 * v9fs_register_trans - register a new transport with 9p
61 * @m: structure describing the transport module and entry points
62 *
63 */
64void v9fs_register_trans(struct p9_trans_module *m)
65{
66 spin_lock(lock: &v9fs_trans_lock);
67 list_add_tail(new: &m->list, head: &v9fs_trans_list);
68 spin_unlock(lock: &v9fs_trans_lock);
69}
70EXPORT_SYMBOL(v9fs_register_trans);
71
72/**
73 * v9fs_unregister_trans - unregister a 9p transport
74 * @m: the transport to remove
75 *
76 */
77void v9fs_unregister_trans(struct p9_trans_module *m)
78{
79 spin_lock(lock: &v9fs_trans_lock);
80 list_del_init(entry: &m->list);
81 spin_unlock(lock: &v9fs_trans_lock);
82}
83EXPORT_SYMBOL(v9fs_unregister_trans);
84
85static struct p9_trans_module *_p9_get_trans_by_name(const char *s)
86{
87 struct p9_trans_module *t, *found = NULL;
88
89 spin_lock(lock: &v9fs_trans_lock);
90
91 list_for_each_entry(t, &v9fs_trans_list, list)
92 if (strcmp(t->name, s) == 0 &&
93 try_module_get(module: t->owner)) {
94 found = t;
95 break;
96 }
97
98 spin_unlock(lock: &v9fs_trans_lock);
99
100 return found;
101}
102
103/**
104 * v9fs_get_trans_by_name - get transport with the matching name
105 * @s: string identifying transport
106 *
107 */
108struct p9_trans_module *v9fs_get_trans_by_name(const char *s)
109{
110 struct p9_trans_module *found = NULL;
111
112 found = _p9_get_trans_by_name(s);
113
114#ifdef CONFIG_MODULES
115 if (!found) {
116 request_module("9p-%s", s);
117 found = _p9_get_trans_by_name(s);
118 }
119#endif
120
121 return found;
122}
123EXPORT_SYMBOL(v9fs_get_trans_by_name);
124
125static const char * const v9fs_default_transports[] = {
126 "virtio", "tcp", "fd", "unix", "xen", "rdma",
127};
128
129/**
130 * v9fs_get_default_trans - get the default transport
131 *
132 */
133
134struct p9_trans_module *v9fs_get_default_trans(void)
135{
136 struct p9_trans_module *t, *found = NULL;
137 int i;
138
139 spin_lock(lock: &v9fs_trans_lock);
140
141 list_for_each_entry(t, &v9fs_trans_list, list)
142 if (t->def && try_module_get(module: t->owner)) {
143 found = t;
144 break;
145 }
146
147 if (!found)
148 list_for_each_entry(t, &v9fs_trans_list, list)
149 if (try_module_get(module: t->owner)) {
150 found = t;
151 break;
152 }
153
154 spin_unlock(lock: &v9fs_trans_lock);
155
156 for (i = 0; !found && i < ARRAY_SIZE(v9fs_default_transports); i++)
157 found = v9fs_get_trans_by_name(v9fs_default_transports[i]);
158
159 return found;
160}
161EXPORT_SYMBOL(v9fs_get_default_trans);
162
163/**
164 * v9fs_put_trans - put trans
165 * @m: transport to put
166 *
167 */
168void v9fs_put_trans(struct p9_trans_module *m)
169{
170 if (m)
171 module_put(module: m->owner);
172}
173EXPORT_SYMBOL(v9fs_put_trans);
174
175/**
176 * init_p9 - Initialize module
177 *
178 */
179static int __init init_p9(void)
180{
181 int ret;
182
183 ret = p9_client_init();
184 if (ret)
185 return ret;
186
187 p9_error_init();
188 pr_info("Installing 9P2000 support\n");
189
190 return ret;
191}
192
193/**
194 * exit_p9 - shutdown module
195 *
196 */
197
198static void __exit exit_p9(void)
199{
200 pr_info("Unloading 9P2000 support\n");
201
202 p9_client_exit();
203}
204
205module_init(init_p9)
206module_exit(exit_p9)
207
208MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
209MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
210MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
211MODULE_LICENSE("GPL");
212MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");
213

source code of linux/net/9p/mod.c