FreeBSD/Linux Kernel Cross Reference
sys/sys/kobj.h
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2000,2003 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31 #ifndef _SYS_KOBJ_H_
32 #define _SYS_KOBJ_H_
33
34 /*
35 * Forward declarations
36 */
37 typedef struct kobj *kobj_t;
38 typedef struct kobj_class *kobj_class_t;
39 typedef const struct kobj_method kobj_method_t;
40 typedef void (*kobjop_t)(void);
41 typedef struct kobj_ops *kobj_ops_t;
42 typedef struct kobjop_desc *kobjop_desc_t;
43 struct malloc_type;
44
45 struct kobj_method {
46 kobjop_desc_t desc;
47 kobjop_t func;
48 };
49
50 /*
51 * A class is simply a method table and a sizeof value. When the first
52 * instance of the class is created, the method table will be compiled
53 * into a form more suited to efficient method dispatch. This compiled
54 * method table is always the first field of the object.
55 */
56 #define KOBJ_CLASS_FIELDS \
57 const char *name; /* class name */ \
58 kobj_method_t *methods; /* method table */ \
59 size_t size; /* object size */ \
60 kobj_class_t *baseclasses; /* base classes */ \
61 u_int refs; /* reference count */ \
62 kobj_ops_t ops /* compiled method table */
63
64 struct kobj_class {
65 KOBJ_CLASS_FIELDS;
66 };
67
68 /*
69 * Implementation of kobj.
70 */
71 #define KOBJ_FIELDS \
72 kobj_ops_t ops
73
74 struct kobj {
75 KOBJ_FIELDS;
76 };
77
78 /*
79 * The ops table is used as a cache of results from kobj_lookup_method().
80 */
81
82 #define KOBJ_CACHE_SIZE 256
83
84 struct kobj_ops {
85 kobj_method_t *cache[KOBJ_CACHE_SIZE];
86 kobj_class_t cls;
87 };
88
89 struct kobjop_desc {
90 unsigned int id; /* unique ID */
91 kobj_method_t deflt; /* default implementation */
92 };
93
94 /*
95 * Shorthand for constructing method tables.
96 * The ternary operator is (ab)used to provoke a warning when FUNC
97 * has a signature that is not compatible with kobj method signature.
98 */
99 #define KOBJMETHOD(NAME, FUNC) \
100 { &NAME##_desc, (kobjop_t) (1 ? FUNC : (NAME##_t *)NULL) }
101
102 /*
103 *
104 */
105 #define KOBJMETHOD_END { NULL, NULL }
106
107 /*
108 * Declare a class (which should be defined in another file.
109 */
110 #define DECLARE_CLASS(name) extern struct kobj_class name
111
112 /*
113 * Define a class with no base classes (api backward-compatible. with
114 * FreeBSD-5.1 and earlier).
115 */
116 #define DEFINE_CLASS(name, methods, size) \
117 DEFINE_CLASS_0(name, name ## _class, methods, size)
118
119 /*
120 * Define a class with no base classes. Use like this:
121 *
122 * DEFINE_CLASS_0(foo, foo_class, foo_methods, sizeof(foo_softc));
123 */
124 #define DEFINE_CLASS_0(name, classvar, methods, size) \
125 \
126 struct kobj_class classvar = { \
127 #name, methods, size, NULL \
128 }
129
130 /*
131 * Define a class inheriting a single base class. Use like this:
132 *
133 * DEFINE_CLASS_1(foo, foo_class, foo_methods, sizeof(foo_softc),
134 * bar);
135 */
136 #define DEFINE_CLASS_1(name, classvar, methods, size, \
137 base1) \
138 \
139 static kobj_class_t name ## _baseclasses[] = \
140 { &base1, NULL }; \
141 struct kobj_class classvar = { \
142 #name, methods, size, name ## _baseclasses \
143 }
144
145 /*
146 * Define a class inheriting two base classes. Use like this:
147 *
148 * DEFINE_CLASS_2(foo, foo_class, foo_methods, sizeof(foo_softc),
149 * bar, baz);
150 */
151 #define DEFINE_CLASS_2(name, classvar, methods, size, \
152 base1, base2) \
153 \
154 static kobj_class_t name ## _baseclasses[] = \
155 { &base1, \
156 &base2, NULL }; \
157 struct kobj_class classvar = { \
158 #name, methods, size, name ## _baseclasses \
159 }
160
161 /*
162 * Define a class inheriting three base classes. Use like this:
163 *
164 * DEFINE_CLASS_3(foo, foo_class, foo_methods, sizeof(foo_softc),
165 * bar, baz, foobar);
166 */
167 #define DEFINE_CLASS_3(name, classvar, methods, size, \
168 base1, base2, base3) \
169 \
170 static kobj_class_t name ## _baseclasses[] = \
171 { &base1, \
172 &base2, \
173 &base3, NULL }; \
174 struct kobj_class classvar = { \
175 #name, methods, size, name ## _baseclasses \
176 }
177
178 /*
179 * Compile the method table in a class.
180 */
181 void kobj_class_compile(kobj_class_t cls);
182
183 /*
184 * Compile the method table, with the caller providing the space for
185 * the ops table.(for use before malloc is initialised).
186 */
187 void kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops);
188
189 /*
190 * Free the compiled method table in a class.
191 */
192 void kobj_class_free(kobj_class_t cls);
193
194 /*
195 * Allocate memory for and initialise a new object.
196 */
197 kobj_t kobj_create(kobj_class_t cls,
198 struct malloc_type *mtype,
199 int mflags);
200
201 /*
202 * Initialise a pre-allocated object.
203 */
204 void kobj_init(kobj_t obj, kobj_class_t cls);
205 void kobj_init_static(kobj_t obj, kobj_class_t cls);
206
207 /*
208 * Delete an object. If mtype is non-zero, free the memory.
209 */
210 void kobj_delete(kobj_t obj, struct malloc_type *mtype);
211
212 /*
213 * Maintain stats on hits/misses in lookup caches.
214 */
215 #ifdef KOBJ_STATS
216 extern u_int kobj_lookup_hits;
217 extern u_int kobj_lookup_misses;
218 #endif
219
220 /*
221 * Lookup the method in the cache and if it isn't there look it up the
222 * slow way.
223 */
224 #ifdef KOBJ_STATS
225 #define KOBJOPLOOKUP(OPS,OP) do { \
226 kobjop_desc_t _desc = &OP##_##desc; \
227 kobj_method_t **_cep = \
228 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \
229 kobj_method_t *_ce = *_cep; \
230 if (_ce->desc != _desc) { \
231 _ce = kobj_lookup_method(OPS->cls, \
232 _cep, _desc); \
233 kobj_lookup_misses++; \
234 } else \
235 kobj_lookup_hits++; \
236 _m = _ce->func; \
237 } while (0)
238 #else
239 #define KOBJOPLOOKUP(OPS,OP) do { \
240 kobjop_desc_t _desc = &OP##_##desc; \
241 kobj_method_t **_cep = \
242 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \
243 kobj_method_t *_ce = *_cep; \
244 if (_ce->desc != _desc) \
245 _ce = kobj_lookup_method(OPS->cls, \
246 _cep, _desc); \
247 _m = _ce->func; \
248 } while (0)
249 #endif
250
251 kobj_method_t* kobj_lookup_method(kobj_class_t cls,
252 kobj_method_t **cep,
253 kobjop_desc_t desc);
254
255 /*
256 * Default method implementation. Returns ENXIO.
257 */
258 int kobj_error_method(void);
259
260 #endif /* !_SYS_KOBJ_H_ */
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