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 <linux/parser.h>
20#include <net/9p/client.h>
21#include <net/9p/transport.h>
22#include <linux/list.h>
23#include <linux/spinlock.h>
24
25#ifdef CONFIG_NET_9P_DEBUG
26unsigned int p9_debug_level; /* feature-rific global debug level */
27EXPORT_SYMBOL(p9_debug_level);
28module_param_named(debug, p9_debug_level, uint, 0);
29MODULE_PARM_DESC(debug, "9P debugging level");
30
31void _p9_debug(enum p9_debug_flags level, const char *func,
32 const char *fmt, ...)
33{
34 struct va_format vaf;
35 va_list args;
36
37 if ((p9_debug_level & level) != level)
38 return;
39
40 va_start(args, fmt);
41
42 vaf.fmt = fmt;
43 vaf.va = &args;
44
45 if (level == P9_DEBUG_9P)
46 pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
47 else
48 pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
49
50 va_end(args);
51}
52EXPORT_SYMBOL(_p9_debug);
53#endif
54
55/* Dynamic Transport Registration Routines */
56
57static DEFINE_SPINLOCK(v9fs_trans_lock);
58static LIST_HEAD(v9fs_trans_list);
59
60/**
61 * v9fs_register_trans - register a new transport with 9p
62 * @m: structure describing the transport module and entry points
63 *
64 */
65void v9fs_register_trans(struct p9_trans_module *m)
66{
67 spin_lock(lock: &v9fs_trans_lock);
68 list_add_tail(new: &m->list, head: &v9fs_trans_list);
69 spin_unlock(lock: &v9fs_trans_lock);
70}
71EXPORT_SYMBOL(v9fs_register_trans);
72
73/**
74 * v9fs_unregister_trans - unregister a 9p transport
75 * @m: the transport to remove
76 *
77 */
78void v9fs_unregister_trans(struct p9_trans_module *m)
79{
80 spin_lock(lock: &v9fs_trans_lock);
81 list_del_init(entry: &m->list);
82 spin_unlock(lock: &v9fs_trans_lock);
83}
84EXPORT_SYMBOL(v9fs_unregister_trans);
85
86static struct p9_trans_module *_p9_get_trans_by_name(const char *s)
87{
88 struct p9_trans_module *t, *found = NULL;
89
90 spin_lock(lock: &v9fs_trans_lock);
91
92 list_for_each_entry(t, &v9fs_trans_list, list)
93 if (strcmp(t->name, s) == 0 &&
94 try_module_get(module: t->owner)) {
95 found = t;
96 break;
97 }
98
99 spin_unlock(lock: &v9fs_trans_lock);
100
101 return found;
102}
103
104/**
105 * v9fs_get_trans_by_name - get transport with the matching name
106 * @s: string identifying transport
107 *
108 */
109struct p9_trans_module *v9fs_get_trans_by_name(const char *s)
110{
111 struct p9_trans_module *found = NULL;
112
113 found = _p9_get_trans_by_name(s);
114
115#ifdef CONFIG_MODULES
116 if (!found) {
117 request_module("9p-%s", s);
118 found = _p9_get_trans_by_name(s);
119 }
120#endif
121
122 return found;
123}
124EXPORT_SYMBOL(v9fs_get_trans_by_name);
125
126static const char * const v9fs_default_transports[] = {
127 "virtio", "tcp", "fd", "unix", "xen", "rdma",
128};
129
130/**
131 * v9fs_get_default_trans - get the default transport
132 *
133 */
134
135struct p9_trans_module *v9fs_get_default_trans(void)
136{
137 struct p9_trans_module *t, *found = NULL;
138 int i;
139
140 spin_lock(lock: &v9fs_trans_lock);
141
142 list_for_each_entry(t, &v9fs_trans_list, list)
143 if (t->def && try_module_get(module: t->owner)) {
144 found = t;
145 break;
146 }
147
148 if (!found)
149 list_for_each_entry(t, &v9fs_trans_list, list)
150 if (try_module_get(module: t->owner)) {
151 found = t;
152 break;
153 }
154
155 spin_unlock(lock: &v9fs_trans_lock);
156
157 for (i = 0; !found && i < ARRAY_SIZE(v9fs_default_transports); i++)
158 found = v9fs_get_trans_by_name(v9fs_default_transports[i]);
159
160 return found;
161}
162EXPORT_SYMBOL(v9fs_get_default_trans);
163
164/**
165 * v9fs_put_trans - put trans
166 * @m: transport to put
167 *
168 */
169void v9fs_put_trans(struct p9_trans_module *m)
170{
171 if (m)
172 module_put(module: m->owner);
173}
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