FreeBSD/Linux Kernel Cross Reference
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 * $FreeBSD$
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 #ifndef TEST
36 #include <sys/systm.h>
37 #endif
38 #include <sys/kobj.h>
39
40 #ifdef TEST
41 #include "usertest.h"
42 #endif
43
44 static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
45
46 #ifdef KOBJ_STATS
47
48 #include <sys/sysctl.h>
49
50 int kobj_lookup_hits;
51 int kobj_lookup_misses;
52
53 SYSCTL_INT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD,
54 &kobj_lookup_hits, 0, "")
55 SYSCTL_INT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD,
56 &kobj_lookup_misses, 0, "")
57
58 #endif
59
60 static int kobj_next_id = 1;
61
62 static int
63 kobj_error_method(void)
64 {
65 return ENXIO;
66 }
67
68 static void
69 kobj_register_method(struct kobjop_desc *desc)
70 {
71 if (desc->id == 0)
72 desc->id = kobj_next_id++;
73 }
74
75 static void
76 kobj_unregister_method(struct kobjop_desc *desc)
77 {
78 }
79
80 static void
81 kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops)
82 {
83 kobj_method_t *m;
84 int i;
85
86 /*
87 * Don't do anything if we are already compiled.
88 */
89 if (cls->ops)
90 return;
91
92 /*
93 * First register any methods which need it.
94 */
95 for (i = 0, m = cls->methods; m->desc; i++, m++)
96 kobj_register_method(m->desc);
97
98 /*
99 * Then initialise the ops table.
100 */
101 bzero(ops, sizeof(struct kobj_ops));
102 ops->cls = cls;
103 cls->ops = ops;
104 }
105
106 void
107 kobj_class_compile(kobj_class_t cls)
108 {
109 kobj_ops_t ops;
110
111 /*
112 * Allocate space for the compiled ops table.
113 */
114 ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT);
115 if (!ops)
116 panic("kobj_compile_methods: out of memory");
117 kobj_class_compile_common(cls, ops);
118 }
119
120 void
121 kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops)
122 {
123 /*
124 * Increment refs to make sure that the ops table is not freed.
125 */
126 cls->refs++;
127 kobj_class_compile_common(cls, ops);
128 }
129
130 void
131 kobj_lookup_method(kobj_method_t *methods,
132 kobj_method_t *ce,
133 kobjop_desc_t desc)
134 {
135 ce->desc = desc;
136 for (; methods && methods->desc; methods++) {
137 if (methods->desc == desc) {
138 ce->func = methods->func;
139 return;
140 }
141 }
142 if (desc->deflt)
143 ce->func = desc->deflt;
144 else
145 ce->func = kobj_error_method;
146 return;
147 }
148
149 void
150 kobj_class_free(kobj_class_t cls)
151 {
152 int i;
153 kobj_method_t *m;
154
155 /*
156 * Unregister any methods which are no longer used.
157 */
158 for (i = 0, m = cls->methods; m->desc; i++, m++)
159 kobj_unregister_method(m->desc);
160
161 /*
162 * Free memory and clean up.
163 */
164 free(cls->ops, M_KOBJ);
165 cls->ops = 0;
166 }
167
168 kobj_t
169 kobj_create(kobj_class_t cls,
170 struct malloc_type *mtype,
171 int mflags)
172 {
173 kobj_t obj;
174
175 /*
176 * Allocate and initialise the new object.
177 */
178 obj = malloc(cls->size, mtype, mflags | M_ZERO);
179 if (!obj)
180 return 0;
181 kobj_init(obj, cls);
182
183 return obj;
184 }
185
186 void
187 kobj_init(kobj_t obj, kobj_class_t cls)
188 {
189 /*
190 * Consider compiling the class' method table.
191 */
192 if (!cls->ops)
193 kobj_class_compile(cls);
194
195 obj->ops = cls->ops;
196 cls->refs++;
197 }
198
199 void
200 kobj_delete(kobj_t obj, struct malloc_type *mtype)
201 {
202 kobj_class_t cls = obj->ops->cls;
203
204 /*
205 * Consider freeing the compiled method table for the class
206 * after its last instance is deleted. As an optimisation, we
207 * should defer this for a short while to avoid thrashing.
208 */
209 cls->refs--;
210 if (!cls->refs)
211 kobj_class_free(cls);
212
213 obj->ops = 0;
214 if (mtype)
215 free(obj, mtype);
216 }
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