sys/kern/subr_kobj.c

   1 /*-
   2  * Copyright (c) 2000 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/kern/subr_kobj.c,v 1.4.2.1 2001/02/02 19:49:13 cg Exp $
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/queue.h>
  31 #include <sys/malloc.h>
  32 #include <sys/kernel.h>
  33 #include <sys/module.h>
  34 #include <sys/errno.h>
  35 #include <sys/thread.h>
  36 #include <sys/thread2.h>
  37 #ifndef TEST
  38 #include <sys/systm.h>
  39 #endif
  40 #include <sys/kobj.h>
  41
  42 #ifdef TEST
  43 #include "usertest.h"
  44 #endif
  45
  46 static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
  47
  48 static struct lwkt_token kobj_token;
  49 static int kobj_next_id = 1;
  50
  51 static void
  52 kobj_init_token(void *arg)
  53 {
  54         lwkt_token_init(&kobj_token, "kobj");
  55 }
  56
  57 SYSINIT(kobj, SI_BOOT1_LOCK, SI_ORDER_ANY, kobj_init_token, NULL);
  58
  59 /*
  60  * This method structure is used to initialise new caches. Since the
  61  * desc pointer is NULL, it is guaranteed never to match any real
  62  * descriptors.
  63  */
  64 static const struct kobj_method null_method = {
  65         0, 0,
  66 };
  67
  68 int
  69 kobj_error_method(void)
  70 {
  71         return ENXIO;
  72 }
  73
  74 static void
  75 kobj_register_method(struct kobjop_desc *desc)
  76 {
  77         if (desc->id == 0)
  78                 desc->id = kobj_next_id++;
  79 }
  80
  81 static void
  82 kobj_unregister_method(struct kobjop_desc *desc)
  83 {
  84 }
  85
  86 static void
  87 kobj_class_compile(kobj_class_t cls)
  88 {
  89         kobj_method_t *m;
  90         kobj_ops_t ops;
  91         int i;
  92
  93         /*
  94          * Don't do anything if we are already compiled.
  95          */
  96         if (cls->ops)
  97                 return;
  98
  99         /*
 100          * Allocate space for the compiled ops table.
 101          */
 102         ops = kmalloc(sizeof(struct kobj_ops), M_KOBJ, M_INTWAIT);
 103         for (i = 0; i < KOBJ_CACHE_SIZE; i++)
 104                 ops->cache[i] = &null_method;
 105         if (cls->ops) {
 106                 /*
 107                  * In case of preemption, another thread might have been faster,
 108                  * but that's fine for us.
 109                  */
 110                 kfree(ops, M_KOBJ);
 111                 return;
 112         }
 113
 114         ops->cls = cls;
 115         cls->ops = ops;
 116
 117         /*
 118          * Afterwards register any methods which need it.
 119          */
 120         for (m = cls->methods; m->desc; m++)
 121                 kobj_register_method(m->desc);
 122 }
 123
 124 static kobj_method_t *
 125 kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc)
 126 {
 127         kobj_method_t *methods = cls->methods;
 128         kobj_method_t *ce;
 129
 130         for (ce = methods; ce && ce->desc; ce++)
 131                 if (ce->desc == desc)
 132                         return(ce);
 133
 134         return(0);
 135 }
 136
 137 static kobj_method_t *
 138 kobj_lookup_method_mi(kobj_class_t cls, kobjop_desc_t desc)
 139 {
 140         kobj_method_t *ce;
 141         kobj_class_t *basep;
 142
 143         ce = kobj_lookup_method_class(cls, desc);
 144         if (ce)
 145                 return(ce);
 146
 147         basep = cls->baseclasses;
 148         if (basep) {
 149                 for (; *basep; basep++) {
 150                         ce = kobj_lookup_method_mi(*basep, desc);
 151                         if (ce)
 152                                 return(ce);
 153                 }
 154         }
 155
 156         return(0);
 157 }
 158
 159 kobj_method_t*
 160 kobj_lookup_method(kobj_class_t cls,
 161                    kobj_method_t **cep,
 162                    kobjop_desc_t desc)
 163 {
 164         kobj_method_t *ce;
 165
 166         ce = kobj_lookup_method_mi(cls, desc);
 167         if (!ce)
 168                 ce = &desc->deflt;
 169         *cep = ce;
 170         return(ce);
 171 }
 172
 173 /*
 174  * This is called from the KOBJOPLOOKUP() macro in sys/kobj.h and
 175  * replaces the original large body of the macro with a single
 176  * procedure call.
 177  */
 178 kobjop_t
 179 kobj_lookup_method_cache(kobj_class_t cls, kobj_method_t **cep,
 180                          kobjop_desc_t desc)
 181 {
 182         kobj_method_t *ce;
 183
 184         cep = &cep[desc->id & (KOBJ_CACHE_SIZE-1)];
 185         ce = *cep;
 186         if (ce->desc != desc)
 187                 ce = kobj_lookup_method(cls, cep, desc);
 188         return(ce->func);
 189 }
 190
 191 static void
 192 kobj_class_free(kobj_class_t cls)
 193 {
 194         int i;
 195         kobj_method_t *m;
 196
 197         /*
 198          * Unregister any methods which are no longer used.
 199          */
 200         for (i = 0, m = cls->methods; m->desc; i++, m++)
 201                 kobj_unregister_method(m->desc);
 202
 203         /*
 204          * Free memory and clean up.
 205          */
 206         kfree(cls->ops, M_KOBJ);
 207         cls->ops = 0;
 208 }
 209
 210 void
 211 kobj_class_instantiate(kobj_class_t cls)
 212 {
 213         lwkt_gettoken(&kobj_token);
 214         crit_enter();
 215
 216         if (!cls->ops)
 217                 kobj_class_compile(cls);
 218         cls->refs++;
 219
 220         crit_exit();
 221         lwkt_reltoken(&kobj_token);
 222 }
 223
 224 void
 225 kobj_class_uninstantiate(kobj_class_t cls)
 226 {
 227         lwkt_gettoken(&kobj_token);
 228         crit_enter();
 229
 230         cls->refs--;
 231         if (cls->refs == 0)
 232                 kobj_class_free(cls);
 233
 234         crit_exit();
 235         lwkt_reltoken(&kobj_token);
 236 }
 237
 238 kobj_t
 239 kobj_create(kobj_class_t cls,
 240             struct malloc_type *mtype,
 241             int mflags)
 242 {
 243         kobj_t obj;
 244
 245         /*
 246          * Allocate and initialise the new object.
 247          */
 248         obj = kmalloc(cls->size, mtype, mflags | M_ZERO);
 249         if (!obj)
 250                 return 0;
 251         kobj_init(obj, cls);
 252
 253         return obj;
 254 }
 255
 256 void
 257 kobj_init(kobj_t obj, kobj_class_t cls)
 258 {
 259         kobj_class_instantiate(cls);
 260         obj->ops = cls->ops;
 261 }
 262
 263 void
 264 kobj_delete(kobj_t obj, struct malloc_type *mtype)
 265 {
 266         kobj_class_t cls = obj->ops->cls;
 267
 268         kobj_class_uninstantiate(cls);
 269
 270         obj->ops = 0;
 271         if (mtype)
 272                 kfree(obj, mtype);
 273 }