net/9p/mod.c

   1 /*
   2  *  net/9p/9p.c
   3  *
   4  *  9P entry point
   5  *
   6  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
   7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2
  12  *  as published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to:
  21  *  Free Software Foundation
  22  *  51 Franklin Street, Fifth Floor
  23  *  Boston, MA  02111-1301  USA
  24  *
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/moduleparam.h>
  29 #include <net/9p/9p.h>
  30 #include <linux/fs.h>
  31 #include <linux/parser.h>
  32 #include <net/9p/transport.h>
  33 #include <linux/list.h>
  34 #include <linux/spinlock.h>
  35
  36 #ifdef CONFIG_NET_9P_DEBUG
  37 unsigned int p9_debug_level = 0;        /* feature-rific global debug level  */
  38 EXPORT_SYMBOL(p9_debug_level);
  39 module_param_named(debug, p9_debug_level, uint, 0);
  40 MODULE_PARM_DESC(debug, "9P debugging level");
  41 #endif
  42
  43 /*
  44  * Dynamic Transport Registration Routines
  45  *
  46  */
  47
  48 static DEFINE_SPINLOCK(v9fs_trans_lock);
  49 static LIST_HEAD(v9fs_trans_list);
  50
  51 /**
  52  * v9fs_register_trans - register a new transport with 9p
  53  * @m: structure describing the transport module and entry points
  54  *
  55  */
  56 void v9fs_register_trans(struct p9_trans_module *m)
  57 {
  58         spin_lock(&v9fs_trans_lock);
  59         list_add_tail(&m->list, &v9fs_trans_list);
  60         spin_unlock(&v9fs_trans_lock);
  61 }
  62 EXPORT_SYMBOL(v9fs_register_trans);
  63
  64 /**
  65  * v9fs_unregister_trans - unregister a 9p transport
  66  * @m: the transport to remove
  67  *
  68  */
  69 void v9fs_unregister_trans(struct p9_trans_module *m)
  70 {
  71         spin_lock(&v9fs_trans_lock);
  72         list_del_init(&m->list);
  73         spin_unlock(&v9fs_trans_lock);
  74 }
  75 EXPORT_SYMBOL(v9fs_unregister_trans);
  76
  77 /**
  78  * v9fs_get_trans_by_name - get transport with the matching name
  79  * @name: string identifying transport
  80  *
  81  */
  82 struct p9_trans_module *v9fs_get_trans_by_name(const substring_t *name)
  83 {
  84         struct p9_trans_module *t, *found = NULL;
  85
  86         spin_lock(&v9fs_trans_lock);
  87
  88         list_for_each_entry(t, &v9fs_trans_list, list)
  89                 if (strncmp(t->name, name->from, name->to-name->from) == 0 &&
  90                     try_module_get(t->owner)) {
  91                         found = t;
  92                         break;
  93                 }
  94
  95         spin_unlock(&v9fs_trans_lock);
  96         return found;
  97 }
  98 EXPORT_SYMBOL(v9fs_get_trans_by_name);
  99
 100 /**
 101  * v9fs_get_default_trans - get the default transport
 102  *
 103  */
 104
 105 struct p9_trans_module *v9fs_get_default_trans(void)
 106 {
 107         struct p9_trans_module *t, *found = NULL;
 108
 109         spin_lock(&v9fs_trans_lock);
 110
 111         list_for_each_entry(t, &v9fs_trans_list, list)
 112                 if (t->def && try_module_get(t->owner)) {
 113                         found = t;
 114                         break;
 115                 }
 116
 117         if (!found)
 118                 list_for_each_entry(t, &v9fs_trans_list, list)
 119                         if (try_module_get(t->owner)) {
 120                                 found = t;
 121                                 break;
 122                         }
 123
 124         spin_unlock(&v9fs_trans_lock);
 125         return found;
 126 }
 127 EXPORT_SYMBOL(v9fs_get_default_trans);
 128
 129 /**
 130  * v9fs_put_trans - put trans
 131  * @m: transport to put
 132  *
 133  */
 134 void v9fs_put_trans(struct p9_trans_module *m)
 135 {
 136         if (m)
 137                 module_put(m->owner);
 138 }
 139
 140 /**
 141  * v9fs_init - Initialize module
 142  *
 143  */
 144 static int __init init_p9(void)
 145 {
 146         int ret = 0;
 147
 148         p9_error_init();
 149         printk(KERN_INFO "Installing 9P2000 support\n");
 150         p9_trans_fd_init();
 151
 152         return ret;
 153 }
 154
 155 /**
 156  * v9fs_init - shutdown module
 157  *
 158  */
 159
 160 static void __exit exit_p9(void)
 161 {
 162         printk(KERN_INFO "Unloading 9P2000 support\n");
 163
 164         p9_trans_fd_exit();
 165 }
 166
 167 module_init(init_p9)
 168 module_exit(exit_p9)
 169
 170 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 171 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 172 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 173 MODULE_LICENSE("GPL");