net/9p/mod.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  9P entry point
   4  *
   5  *  Copyright (C) 2007 by Latchesar Ionkov <[email protected]>
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <[email protected]>
   7  *  Copyright (C) 2002 by Ron Minnich <[email protected]>
   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(&v9fs_trans_lock);
  68         list_add_tail(&m->list, &v9fs_trans_list);
  69         spin_unlock(&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(&v9fs_trans_lock);
  81         list_del_init(&m->list);
  82         spin_unlock(&v9fs_trans_lock);
  83 }
  84 EXPORT_SYMBOL(v9fs_unregister_trans);
  85
  86 static struct p9_trans_module *_p9_get_trans_by_name(char *s)
  87 {
  88         struct p9_trans_module *t, *found = NULL;
  89
  90         spin_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(t->owner)) {
  95                         found = t;
  96                         break;
  97                 }
  98
  99         spin_unlock(&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(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 /**
 127  * v9fs_get_default_trans - get the default transport
 128  *
 129  */
 130
 131 struct p9_trans_module *v9fs_get_default_trans(void)
 132 {
 133         struct p9_trans_module *t, *found = NULL;
 134
 135         spin_lock(&v9fs_trans_lock);
 136
 137         list_for_each_entry(t, &v9fs_trans_list, list)
 138                 if (t->def && try_module_get(t->owner)) {
 139                         found = t;
 140                         break;
 141                 }
 142
 143         if (!found)
 144                 list_for_each_entry(t, &v9fs_trans_list, list)
 145                         if (try_module_get(t->owner)) {
 146                                 found = t;
 147                                 break;
 148                         }
 149
 150         spin_unlock(&v9fs_trans_lock);
 151         return found;
 152 }
 153 EXPORT_SYMBOL(v9fs_get_default_trans);
 154
 155 /**
 156  * v9fs_put_trans - put trans
 157  * @m: transport to put
 158  *
 159  */
 160 void v9fs_put_trans(struct p9_trans_module *m)
 161 {
 162         if (m)
 163                 module_put(m->owner);
 164 }
 165
 166 /**
 167  * init_p9 - Initialize module
 168  *
 169  */
 170 static int __init init_p9(void)
 171 {
 172         int ret;
 173
 174         ret = p9_client_init();
 175         if (ret)
 176                 return ret;
 177
 178         p9_error_init();
 179         pr_info("Installing 9P2000 support\n");
 180         p9_trans_fd_init();
 181
 182         return ret;
 183 }
 184
 185 /**
 186  * exit_p9 - shutdown module
 187  *
 188  */
 189
 190 static void __exit exit_p9(void)
 191 {
 192         pr_info("Unloading 9P2000 support\n");
 193
 194         p9_trans_fd_exit();
 195         p9_client_exit();
 196 }
 197
 198 module_init(init_p9)
 199 module_exit(exit_p9)
 200
 201 MODULE_AUTHOR("Latchesar Ionkov <[email protected]>");
 202 MODULE_AUTHOR("Eric Van Hensbergen <[email protected]>");
 203 MODULE_AUTHOR("Ron Minnich <[email protected]>");
 204 MODULE_LICENSE("GPL");
 205 MODULE_DESCRIPTION("Plan 9 Resource Sharing Support (9P2000)");