xref: /kernel/linux/linux-5.10/net/9p/mod.c (revision 8c2ecf20) 
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
27unsigned int p9_debug_level = 0;	/* feature-rific global debug level  */
28EXPORT_SYMBOL(p9_debug_level);
29module_param_named(debug, p9_debug_level, uint, 0);
30MODULE_PARM_DESC(debug, "9P debugging level");
31
32void _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}
53EXPORT_SYMBOL(_p9_debug);
54#endif
55
56/*
57 * Dynamic Transport Registration Routines
58 *
59 */
60
61static DEFINE_SPINLOCK(v9fs_trans_lock);
62static 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 */
69void 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}
75EXPORT_SYMBOL(v9fs_register_trans);
76
77/**
78 * v9fs_unregister_trans - unregister a 9p transport
79 * @m: the transport to remove
80 *
81 */
82void 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}
88EXPORT_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 */
95struct 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}
111EXPORT_SYMBOL(v9fs_get_trans_by_name);
112
113/**
114 * v9fs_get_default_trans - get the default transport
115 *
116 */
117
118struct 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}
140EXPORT_SYMBOL(v9fs_get_default_trans);
141
142/**
143 * v9fs_put_trans - put trans
144 * @m: transport to put
145 *
146 */
147void 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 */
157static 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
177static 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
185module_init(init_p9)
186module_exit(exit_p9)
187
188MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
189MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
190MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
191MODULE_LICENSE("GPL");
192MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");
193