FreeBSD/Linux Kernel Cross Reference
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 */
28
29 #ifndef _SYS_KOBJ_H_
30 #define _SYS_KOBJ_H_
31
32 #ifndef _SYS_TYPES_H_
33 #include <sys/types.h>
34 #endif
35
36 #if !defined(_KERNEL) && !defined(_KERNEL_STRUCTURES)
37 #error "This file should not be included by userland programs."
38 #endif
39
40 /*
41 * Forward declarations
42 */
43 typedef struct kobj *kobj_t;
44 typedef struct kobj_class *kobj_class_t;
45 typedef const struct kobj_method kobj_method_t;
46 typedef int (*kobjop_t)(void);
47 typedef struct kobj_ops *kobj_ops_t;
48 typedef struct kobjop_desc *kobjop_desc_t;
49 struct malloc_type;
50
51 struct kobj_method {
52 kobjop_desc_t desc;
53 kobjop_t func;
54 };
55
56 /*
57 * A class is simply a method table and a sizeof value. When the first
58 * instance of the class is created, the method table will be compiled
59 * into a form more suited to efficient method dispatch. This compiled
60 * method table is always the first field of the object.
61 */
62 #define KOBJ_CLASS_FIELDS \
63 const char *name; /* class name */ \
64 kobj_method_t *methods; /* method table */ \
65 size_t size; /* object size */ \
66 kobj_class_t *baseclasses; /* base classes */ \
67 u_int refs; /* reference count */ \
68 kobj_ops_t ops /* compiled method table */
69
70 struct kobj_class {
71 KOBJ_CLASS_FIELDS;
72 };
73
74 /*
75 * Implementation of kobj.
76 */
77 #define KOBJ_FIELDS \
78 kobj_ops_t ops
79
80 struct kobj {
81 KOBJ_FIELDS;
82 };
83
84 /*
85 * The ops table is used as a cache of results from kobj_lookup_method().
86 */
87
88 #define KOBJ_CACHE_SIZE 256
89
90 struct kobj_ops {
91 kobj_method_t *cache[KOBJ_CACHE_SIZE];
92 kobj_class_t cls;
93 };
94
95 struct kobjop_desc {
96 unsigned int id; /* unique ID */
97 kobj_method_t deflt; /* default implementation */
98 };
99
100 /*
101 * Shorthand for constructing method tables.
102 */
103 #define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC }
104 #define KOBJMETHOD_END { NULL, NULL }
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 * Lookup the method in the cache and if it isn't there look it up the
221 * slow way.
222 *
223 * We do the cache inside kobj_lookup_method() now, we don't try to
224 * expand it because it's really silly. These lookups are not in the
225 * critical path.
226 */
227
228 #define KOBJOPLOOKUP(OPS,OP) do { \
229 _m = kobj_lookup_method_cache(OPS->cls, &OPS->cache[0], \
230 &OP##_##desc); \
231 } while(0)
232
233 kobj_method_t *kobj_lookup_method(kobj_class_t cls,
234 kobj_method_t **cep,
235 kobjop_desc_t desc);
236
237 kobjop_t kobj_lookup_method_cache(kobj_class_t cls,
238 kobj_method_t **cep,
239 kobjop_desc_t desc);
240
241 /*
242 * Default method implementation. Returns ENXIO.
243 */
244 int kobj_error_method(void);
245
246 #endif /* _KERNEL */
247
248 #endif /* !_SYS_KOBJ_H_ */
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