sys/sys/kobj.h

   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/sys/kobj.h,v 1.8 2003/09/22 21:32:49 peter Exp $
  27  * $DragonFly: src/sys/sys/kobj.h,v 1.11 2007/10/03 18:58:20 dillon Exp $
  28  */
  29
  30 #ifndef _SYS_KOBJ_H_
  31 #define _SYS_KOBJ_H_
  32
  33 #ifndef _SYS_TYPES_H_
  34 #include <sys/types.h>
  35 #endif
  36
  37 #if !defined(_KERNEL) && !defined(_KERNEL_STRUCTURES)
  38 #error "This file should not be included by userland programs."
  39 #endif
  40
  41 /*
  42  * Forward declarations
  43  */
  44 typedef struct kobj             *kobj_t;
  45 typedef struct kobj_class       *kobj_class_t;
  46 typedef struct kobj_method      kobj_method_t;
  47 typedef int                     (*kobjop_t)(void);
  48 typedef struct kobj_ops         *kobj_ops_t;
  49 typedef struct kobjop_desc      *kobjop_desc_t;
  50 struct malloc_type;
  51
  52 struct kobj_method {
  53         kobjop_desc_t   desc;
  54         kobjop_t        func;
  55 };
  56
  57 /*
  58  * A class is simply a method table and a sizeof value. When the first
  59  * instance of the class is created, the method table will be compiled
  60  * into a form more suited to efficient method dispatch. This compiled
  61  * method table is always the first field of the object.
  62  */
  63 #define KOBJ_CLASS_FIELDS                                               \
  64         const char      *name;          /* class name */                \
  65         kobj_method_t   *methods;       /* method table */              \
  66         size_t          size;           /* object size */               \
  67         kobj_class_t    *baseclasses;   /* base classes */              \
  68         u_int           refs;           /* reference count */           \
  69         kobj_ops_t      ops             /* compiled method table */
  70
  71 struct kobj_class {
  72         KOBJ_CLASS_FIELDS;
  73 };
  74
  75 /*
  76  * Implementation of kobj.
  77  */
  78 #define KOBJ_FIELDS                             \
  79         kobj_ops_t      ops
  80
  81 struct kobj {
  82         KOBJ_FIELDS;
  83 };
  84
  85 /*
  86  * The ops table is used as a cache of results from kobj_lookup_method().
  87  */
  88
  89 #define KOBJ_CACHE_SIZE 256
  90
  91 struct kobj_ops {
  92         kobj_method_t   *cache[KOBJ_CACHE_SIZE];
  93         kobj_class_t    cls;
  94 };
  95
  96 struct kobjop_desc {
  97         unsigned int    id;     /* unique ID */
  98         kobj_method_t   *deflt; /* default implementation */
  99 };
 100
 101 /*
 102  * Shorthand for constructing method tables.
 103  */
 104 #define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC }
 105
 106 /*
 107  * Declare a class (which should be defined in another file.
 108  */
 109 #define DECLARE_CLASS(name) extern struct kobj_class name
 110
 111 /*
 112  * Define a class with no base classes (api backward-compatible. with
 113  * FreeBSD-5.1 and earlier).
 114  */
 115 #define DEFINE_CLASS(name, methods, size)               \
 116 DEFINE_CLASS_0(name, name ## _class, methods, size)
 117
 118 /*
 119  * Define a class with no base classes. Use like this:
 120  *
 121  * DEFINE_CLASS_0(foo, foo_class, foo_methods, sizeof(foo_softc));
 122  */
 123 #define DEFINE_CLASS_0(name, classvar, methods, size)   \
 124                                                         \
 125 struct kobj_class classvar = {                          \
 126         #name, methods, size, NULL, 0, NULL             \
 127 }
 128
 129 /*
 130  * Define a class with no base classes using the named structure
 131  * as an extension of the kobj_class structure.
 132  */
 133 #define DEFINE_CLASS_EXT(name, classvar, methods, size, extname)        \
 134                                                         \
 135 struct extname classvar = {                             \
 136         #name, methods, size, NULL, 0, NULL             \
 137 }
 138
 139 /*
 140  * Define a class inheriting a single base class. Use like this:
 141  *
 142  * DEFINE_CLASS1(foo, foo_class, foo_methods, sizeof(foo_softc),
 143  *                        bar);
 144  */
 145 #define DEFINE_CLASS_1(name, classvar, methods, size,   \
 146                        base1)                           \
 147                                                         \
 148 static kobj_class_t name ## _baseclasses[] = {          \
 149         &base1, 0                                       \
 150 };                                                      \
 151 struct kobj_class classvar = {                          \
 152         #name, methods, size, name ## _baseclasses      \
 153 }
 154
 155 /*
 156  * Define a class inheriting two base classes. Use like this:
 157  *
 158  * DEFINE_CLASS2(foo, foo_class, foo_methods, sizeof(foo_softc),
 159  *                        bar, baz);
 160  */
 161 #define DEFINE_CLASS_2(name, methods, size,             \
 162                        base1, base2)                    \
 163                                                         \
 164 static kobj_class_t name ## _baseclasses[] = {          \
 165         &base1,                                         \
 166         &base2, 0                                       \
 167 };                                                      \
 168 struct kobj_class name ## _class = {                    \
 169         #name, methods, size, name ## _baseclasses      \
 170 }
 171
 172 /*
 173  * Define a class inheriting three base classes. Use like this:
 174  *
 175  * DEFINE_CLASS3(foo, foo_class, foo_methods, sizeof(foo_softc),
 176  *                        bar, baz, foobar);
 177  */
 178 #define DEFINE_CLASS_3(name, methods, size,             \
 179                        base1, base2, base3)             \
 180                                                         \
 181 static kobj_class_t name ## _baseclasses[] = {          \
 182         &base1,                                         \
 183         &base2,                                         \
 184         &base3, 0                                       \
 185 };                                                      \
 186 struct kobj_class name ## _class = {                    \
 187         #name, methods, size, name ## _baseclasses      \
 188 }
 189
 190 #ifdef _KERNEL
 191
 192 /*
 193  * Compile class for the first instance and add a reference.
 194  */
 195 void            kobj_class_instantiate(kobj_class_t cls);
 196
 197 /*
 198  * Remove a reference and free method table with the last instance.
 199  */
 200 void            kobj_class_uninstantiate(kobj_class_t cls);
 201
 202 /*
 203  * Allocate memory for and initialise a new object.
 204  */
 205 kobj_t          kobj_create(kobj_class_t cls,
 206                             struct malloc_type *mtype,
 207                             int mflags);
 208
 209 /*
 210  * Initialise a pre-allocated object.
 211  */
 212 void            kobj_init(kobj_t obj, kobj_class_t cls);
 213
 214 /*
 215  * Delete an object. If mtype is non-zero, free the memory.
 216  */
 217 void            kobj_delete(kobj_t obj, struct malloc_type *mtype);
 218
 219 /*
 220  * Maintain stats on hits/misses in lookup caches.
 221  */
 222 #ifdef KOBJ_STATS
 223 extern u_int kobj_lookup_hits;
 224 extern u_int kobj_lookup_misses;
 225 #endif
 226
 227 /*
 228  * Lookup the method in the cache and if it isn't there look it up the
 229  * slow way.
 230  */
 231 #ifdef KOBJ_STATS
 232 #define KOBJOPLOOKUP(OPS,OP) do {                                       \
 233         kobjop_desc_t _desc = &OP##_##desc;                             \
 234         kobj_method_t **_cep =                                          \
 235             &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)];               \
 236         kobj_method_t *_ce = *_cep;                                     \
 237         kobj_lookup_hits++; /* assume hit */                            \
 238         if (_ce->desc != _desc)                                         \
 239                 _ce = kobj_lookup_method(OPS->cls,                      \
 240                                          _cep, _desc);                  \
 241         _m = _ce->func;                                                 \
 242 } while(0)
 243 #else
 244 #define KOBJOPLOOKUP(OPS,OP) do {                                       \
 245         kobjop_desc_t _desc = &OP##_##desc;                             \
 246         kobj_method_t **_cep =                                          \
 247             &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)];               \
 248         kobj_method_t *_ce = *_cep;                                     \
 249         if (_ce->desc != _desc)                                         \
 250                 _ce = kobj_lookup_method(OPS->cls,                      \
 251                                          _cep, _desc);                  \
 252         _m = _ce->func;                                                 \
 253 } while(0)
 254 #endif
 255
 256 kobj_method_t *kobj_lookup_method(kobj_class_t cls,
 257                                   kobj_method_t **cep,
 258                                   kobjop_desc_t desc);
 259
 260 /*
 261  * Default method implementation. Returns ENXIO.
 262  */
 263 int kobj_error_method(void);
 264
 265 #endif /* _KERNEL */
 266
 267 #endif /* !_SYS_KOBJ_H_ */