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(lock: &v9fs_trans_lock); |
68 | list_add_tail(new: &m->list, head: &v9fs_trans_list); |
69 | spin_unlock(lock: &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(lock: &v9fs_trans_lock); |
81 | list_del_init(entry: &m->list); |
82 | spin_unlock(lock: &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(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 | */ |
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(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 | } |
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(module: 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 | |