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
_p9_debug(enum p9_debug_flags level,const char * func,const char * fmt,...)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 */
v9fs_register_trans(struct p9_trans_module * m)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 */
v9fs_unregister_trans(struct p9_trans_module * m)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
_p9_get_trans_by_name(char * s)86 static struct p9_trans_module *_p9_get_trans_by_name(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 */
v9fs_get_trans_by_name(char * s)109 struct p9_trans_module *v9fs_get_trans_by_name(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 /**
127 * v9fs_get_default_trans - get the default transport
128 *
129 */
130
v9fs_get_default_trans(void)131 struct p9_trans_module *v9fs_get_default_trans(void)
132 {
133 struct p9_trans_module *t, *found = NULL;
134
135 spin_lock(&v9fs_trans_lock);
136
137 list_for_each_entry(t, &v9fs_trans_list, list)
138 if (t->def && try_module_get(t->owner)) {
139 found = t;
140 break;
141 }
142
143 if (!found)
144 list_for_each_entry(t, &v9fs_trans_list, list)
145 if (try_module_get(t->owner)) {
146 found = t;
147 break;
148 }
149
150 spin_unlock(&v9fs_trans_lock);
151 return found;
152 }
153 EXPORT_SYMBOL(v9fs_get_default_trans);
154
155 /**
156 * v9fs_put_trans - put trans
157 * @m: transport to put
158 *
159 */
v9fs_put_trans(struct p9_trans_module * m)160 void v9fs_put_trans(struct p9_trans_module *m)
161 {
162 if (m)
163 module_put(m->owner);
164 }
165
166 /**
167 * init_p9 - Initialize module
168 *
169 */
init_p9(void)170 static int __init init_p9(void)
171 {
172 int ret;
173
174 ret = p9_client_init();
175 if (ret)
176 return ret;
177
178 p9_error_init();
179 pr_info("Installing 9P2000 support\n");
180 p9_trans_fd_init();
181
182 return ret;
183 }
184
185 /**
186 * exit_p9 - shutdown module
187 *
188 */
189
exit_p9(void)190 static void __exit exit_p9(void)
191 {
192 pr_info("Unloading 9P2000 support\n");
193
194 p9_trans_fd_exit();
195 p9_client_exit();
196 }
197
198 module_init(init_p9)
199 module_exit(exit_p9)
200
201 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
202 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
203 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
204 MODULE_LICENSE("GPL");
205 MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");
206