mod.c

  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 <net/9p/client.h>
 20#include <net/9p/transport.h>
 21#include <linux/list.h>
 22#include <linux/spinlock.h>
 23
 24#ifdef CONFIG_NET_9P_DEBUG
 25unsigned int p9_debug_level;	/* feature-rific global debug level  */
 26EXPORT_SYMBOL(p9_debug_level);
 27module_param_named(debug, p9_debug_level, uint, 0);
 28MODULE_PARM_DESC(debug, "9P debugging level");
 29
 30void _p9_debug(enum p9_debug_flags level, const char *func,
 31	       const char *fmt, ...)
 32{
 33	struct va_format vaf;
 34	va_list args;
 35
 36	if ((p9_debug_level & level) != level)
 37		return;
 38
 39	va_start(args, fmt);
 40
 41	vaf.fmt = fmt;
 42	vaf.va = &args;
 43
 44	if (level == P9_DEBUG_9P)
 45		pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
 46	else
 47		pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
 48
 49	va_end(args);
 50}
 51EXPORT_SYMBOL(_p9_debug);
 52#endif
 53
 54/* Dynamic Transport Registration Routines */
 55
 56static DEFINE_SPINLOCK(v9fs_trans_lock);
 57static LIST_HEAD(v9fs_trans_list);
 58
 59/**
 60 * v9fs_register_trans - register a new transport with 9p
 61 * @m: structure describing the transport module and entry points
 62 *
 63 */
 64void v9fs_register_trans(struct p9_trans_module *m)
 65{
 66	spin_lock(&v9fs_trans_lock);
 67	list_add_tail(&m->list, &v9fs_trans_list);
 68	spin_unlock(&v9fs_trans_lock);
 69}
 70EXPORT_SYMBOL(v9fs_register_trans);
 71
 72/**
 73 * v9fs_unregister_trans - unregister a 9p transport
 74 * @m: the transport to remove
 75 *
 76 */
 77void v9fs_unregister_trans(struct p9_trans_module *m)
 78{
 79	spin_lock(&v9fs_trans_lock);
 80	list_del_init(&m->list);
 81	spin_unlock(&v9fs_trans_lock);
 82}
 83EXPORT_SYMBOL(v9fs_unregister_trans);
 84
 85static struct p9_trans_module *_p9_get_trans_by_name(const char *s)
 86{
 87	struct p9_trans_module *t, *found = NULL;
 88
 89	spin_lock(&v9fs_trans_lock);
 90
 91	list_for_each_entry(t, &v9fs_trans_list, list)
 92		if (strcmp(t->name, s) == 0 &&
 93		    try_module_get(t->owner)) {
 94			found = t;
 95			break;
 96		}
 97
 98	spin_unlock(&v9fs_trans_lock);
 99
100	return found;
101}
102
103/**
104 * v9fs_get_trans_by_name - get transport with the matching name
105 * @s: string identifying transport
106 *
107 */
108struct p9_trans_module *v9fs_get_trans_by_name(const char *s)
109{
110	struct p9_trans_module *found = NULL;
111
112	found = _p9_get_trans_by_name(s);
113
114#ifdef CONFIG_MODULES
115	if (!found) {
116		request_module("9p-%s", s);
117		found = _p9_get_trans_by_name(s);
118	}
119#endif
120
121	return found;
122}
123EXPORT_SYMBOL(v9fs_get_trans_by_name);
124
125static const char * const v9fs_default_transports[] = {
126	"virtio", "tcp", "fd", "unix", "xen", "rdma",
127};
128
129/**
130 * v9fs_get_default_trans - get the default transport
131 *
132 */
133
134struct p9_trans_module *v9fs_get_default_trans(void)
135{
136	struct p9_trans_module *t, *found = NULL;
137	int i;
138
139	spin_lock(&v9fs_trans_lock);
140
141	list_for_each_entry(t, &v9fs_trans_list, list)
142		if (t->def && try_module_get(t->owner)) {
143			found = t;
144			break;
145		}
146
147	if (!found)
148		list_for_each_entry(t, &v9fs_trans_list, list)
149			if (try_module_get(t->owner)) {
150				found = t;
151				break;
152			}
153
154	spin_unlock(&v9fs_trans_lock);
155
156	for (i = 0; !found && i < ARRAY_SIZE(v9fs_default_transports); i++)
157		found = v9fs_get_trans_by_name(v9fs_default_transports[i]);
158
159	return found;
160}
161EXPORT_SYMBOL(v9fs_get_default_trans);
162
163/**
164 * v9fs_put_trans - put trans
165 * @m: transport to put
166 *
167 */
168void v9fs_put_trans(struct p9_trans_module *m)
169{
170	if (m)
171		module_put(m->owner);
172}
173EXPORT_SYMBOL(v9fs_put_trans);
174
175/**
176 * init_p9 - Initialize module
177 *
178 */
179static 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
198static void __exit exit_p9(void)
199{
200	pr_info("Unloading 9P2000 support\n");
201
202	p9_client_exit();
203}
204
205module_init(init_p9)
206module_exit(exit_p9)
207
208MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
209MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
210MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
211MODULE_LICENSE("GPL");
212MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");