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
_p9_debug(enum p9_debug_flags level,const char * func,const char * fmt,...)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 */
v9fs_register_trans(struct p9_trans_module * m)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 */
v9fs_unregister_trans(struct p9_trans_module * m)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 */
v9fs_get_trans_by_name(char * s)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
v9fs_get_default_trans(void)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 */
v9fs_put_trans(struct p9_trans_module * m)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 */
init_p9(void)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
exit_p9(void)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");
192
