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
26 unsigned int p9_debug_level; /* feature-rific global debug level */
27 EXPORT_SYMBOL(p9_debug_level);
28 module_param_named(debug, p9_debug_level, uint, 0);
29 MODULE_PARM_DESC(debug, "9P debugging level");
30
31 void _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 }
52 EXPORT_SYMBOL(_p9_debug);
53 #endif
54
55 /* Dynamic Transport Registration Routines */
56
57 static DEFINE_SPINLOCK(v9fs_trans_lock);
58 static 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 */
65 void v9fs_register_trans(struct p9_trans_module *m)
66 {
67 spin_lock(&v9fs_trans_lock);
68 list_add_tail(&m->list, &v9fs_trans_list);
69 spin_unlock(&v9fs_trans_lock);
70 }
71 EXPORT_SYMBOL(v9fs_register_trans);
72
73 /**
74 * v9fs_unregister_trans - unregister a 9p transport
75 * @m: the transport to remove
76 *
77 */
78 void v9fs_unregister_trans(struct p9_trans_module *m)
79 {
80 spin_lock(&v9fs_trans_lock);
81 list_del_init(&m->list);
82 spin_unlock(&v9fs_trans_lock);
83 }
84 EXPORT_SYMBOL(v9fs_unregister_trans);
85
86 static 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(&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(t->owner)) {
95 found = t;
96 break;
97 }
98
99 spin_unlock(&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 */
109 struct 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 }
124 EXPORT_SYMBOL(v9fs_get_trans_by_name);
125
126 static 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
135 struct p9_trans_module *v9fs_get_default_trans(void)
136 {
137 struct p9_trans_module *t, *found = NULL;
138 int i;
139
140 spin_lock(&v9fs_trans_lock);
141
142 list_for_each_entry(t, &v9fs_trans_list, list)
143 if (t->def && try_module_get(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(t->owner)) {
151 found = t;
152 break;
153 }
154
155 spin_unlock(&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 }
162 EXPORT_SYMBOL(v9fs_get_default_trans);
163
164 /**
165 * v9fs_put_trans - put trans
166 * @m: transport to put
167 *
168 */
169 void v9fs_put_trans(struct p9_trans_module *m)
170 {
171 if (m)
172 module_put(m->owner);
173 }
174
175 /**
176 * init_p9 - Initialize module
177 *
178 */
179 static 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
198 static void __exit exit_p9(void)
199 {
200 pr_info("Unloading 9P2000 support\n");
201
202 p9_client_exit();
203 }
204
205 module_init(init_p9)
206 module_exit(exit_p9)
207
208 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
209 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
210 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
211 MODULE_LICENSE("GPL");
212 MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");
213
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