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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  28
  29 #include <linux/module.h>
  30 #include <linux/errno.h>
  31 #include <linux/sched.h>
  32 #include <linux/moduleparam.h>
  33 #include <net/9p/9p.h>
  34 #include <linux/fs.h>
  35 #include <linux/parser.h>
  36 #include <net/9p/client.h>
  37 #include <net/9p/transport.h>
  38 #include <linux/list.h>
  39 #include <linux/spinlock.h>
  40
  41 #ifdef CONFIG_NET_9P_DEBUG
  42 unsigned int p9_debug_level = 0;        /* feature-rific global debug level  */
  43 EXPORT_SYMBOL(p9_debug_level);
  44 module_param_named(debug, p9_debug_level, uint, 0);
  45 MODULE_PARM_DESC(debug, "9P debugging level");
  46
  47 void _p9_debug(enum p9_debug_flags level, const char *func,
  48                 const char *fmt, ...)
  49 {
  50         struct va_format vaf;
  51         va_list args;
  52
  53         if ((p9_debug_level & level) != level)
  54                 return;
  55
  56         va_start(args, fmt);
  57
  58         vaf.fmt = fmt;
  59         vaf.va = &args;
  60
  61         if (level == P9_DEBUG_9P)
  62                 pr_notice("(%8.8d) %pV", task_pid_nr(current), &vaf);
  63         else
  64                 pr_notice("-- %s (%d): %pV", func, task_pid_nr(current), &vaf);
  65
  66         va_end(args);
  67 }
  68 EXPORT_SYMBOL(_p9_debug);
  69 #endif
  70
  71 /*
  72  * Dynamic Transport Registration Routines
  73  *
  74  */
  75
  76 static DEFINE_SPINLOCK(v9fs_trans_lock);
  77 static LIST_HEAD(v9fs_trans_list);
  78
  79 /**
  80  * v9fs_register_trans - register a new transport with 9p
  81  * @m: structure describing the transport module and entry points
  82  *
  83  */
  84 void v9fs_register_trans(struct p9_trans_module *m)
  85 {
  86         spin_lock(&v9fs_trans_lock);
  87         list_add_tail(&m->list, &v9fs_trans_list);
  88         spin_unlock(&v9fs_trans_lock);
  89 }
  90 EXPORT_SYMBOL(v9fs_register_trans);
  91
  92 /**
  93  * v9fs_unregister_trans - unregister a 9p transport
  94  * @m: the transport to remove
  95  *
  96  */
  97 void v9fs_unregister_trans(struct p9_trans_module *m)
  98 {
  99         spin_lock(&v9fs_trans_lock);
 100         list_del_init(&m->list);
 101         spin_unlock(&v9fs_trans_lock);
 102 }
 103 EXPORT_SYMBOL(v9fs_unregister_trans);
 104
 105 /**
 106  * v9fs_get_trans_by_name - get transport with the matching name
 107  * @s: string identifying transport
 108  *
 109  */
 110 struct p9_trans_module *v9fs_get_trans_by_name(char *s)
 111 {
 112         struct p9_trans_module *t, *found = NULL;
 113
 114         spin_lock(&v9fs_trans_lock);
 115
 116         list_for_each_entry(t, &v9fs_trans_list, list)
 117                 if (strcmp(t->name, s) == 0 &&
 118                     try_module_get(t->owner)) {
 119                         found = t;
 120                         break;
 121                 }
 122
 123         spin_unlock(&v9fs_trans_lock);
 124         return found;
 125 }
 126 EXPORT_SYMBOL(v9fs_get_trans_by_name);
 127
 128 /**
 129  * v9fs_get_default_trans - get the default transport
 130  *
 131  */
 132
 133 struct p9_trans_module *v9fs_get_default_trans(void)
 134 {
 135         struct p9_trans_module *t, *found = NULL;
 136
 137         spin_lock(&v9fs_trans_lock);
 138
 139         list_for_each_entry(t, &v9fs_trans_list, list)
 140                 if (t->def && try_module_get(t->owner)) {
 141                         found = t;
 142                         break;
 143                 }
 144
 145         if (!found)
 146                 list_for_each_entry(t, &v9fs_trans_list, list)
 147                         if (try_module_get(t->owner)) {
 148                                 found = t;
 149                                 break;
 150                         }
 151
 152         spin_unlock(&v9fs_trans_lock);
 153         return found;
 154 }
 155 EXPORT_SYMBOL(v9fs_get_default_trans);
 156
 157 /**
 158  * v9fs_put_trans - put trans
 159  * @m: transport to put
 160  *
 161  */
 162 void v9fs_put_trans(struct p9_trans_module *m)
 163 {
 164         if (m)
 165                 module_put(m->owner);
 166 }
 167
 168 /**
 169  * init_p9 - Initialize module
 170  *
 171  */
 172 static int __init init_p9(void)
 173 {
 174         int ret = 0;
 175
 176         p9_error_init();
 177         pr_info("Installing 9P2000 support\n");
 178         p9_trans_fd_init();
 179
 180         return ret;
 181 }
 182
 183 /**
 184  * exit_p9 - shutdown module
 185  *
 186  */
 187
 188 static void __exit exit_p9(void)
 189 {
 190         pr_info("Unloading 9P2000 support\n");
 191
 192         p9_trans_fd_exit();
 193 }
 194
 195 module_init(init_p9)
 196 module_exit(exit_p9)
 197
 198 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
 199 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
 200 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
 201 MODULE_LICENSE("GPL");