subr_kobj.c revision 59093 
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: head/sys/kern/subr_kobj.c 59093 2000-04-08 14:17:18Z dfr $
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
44static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
45
46#ifdef KOBJ_STATS
47
48#include <sys/sysctl.h>
49
50int kobj_lookup_hits;
51int kobj_lookup_misses;
52
53SYSCTL_INT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD,
54	   &kobj_lookup_hits, 0, "")
55SYSCTL_INT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD,
56	   &kobj_lookup_misses, 0, "")
57
58#endif
59
60static int kobj_next_id = 1;
61
62static int
63kobj_error_method(void)
64{
65	return ENXIO;
66}
67
68static void
69kobj_register_method(struct kobjop_desc *desc)
70{
71	if (desc->id == 0)
72		desc->id = kobj_next_id++;
73}
74
75static void
76kobj_unregister_method(struct kobjop_desc *desc)
77{
78}
79
80void
81kobj_class_compile(kobj_class_t cls)
82{
83	kobj_ops_t ops;
84	kobj_method_t *m;
85	int i;
86
87	/*
88	 * Don't do anything if we are already compiled.
89	 */
90	if (cls->ops)
91		return;
92
93	/*
94	 * First register any methods which need it.
95	 */
96	for (i = 0, m = cls->methods; m->desc; i++, m++)
97		kobj_register_method(m->desc);
98
99	/*
100	 * Then allocate the compiled op table.
101	 */
102	ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT);
103	if (!ops)
104		panic("kobj_compile_methods: out of memory");
105	bzero(ops, sizeof(struct kobj_ops));
106	ops->cls = cls;
107	cls->ops = ops;
108}
109
110void
111kobj_lookup_method(kobj_method_t *methods,
112		   kobj_method_t *ce,
113		   kobjop_desc_t desc)
114{
115	ce->desc = desc;
116	for (; methods && methods->desc; methods++) {
117		if (methods->desc == desc) {
118			ce->func = methods->func;
119			return;
120		}
121	}
122	if (desc->deflt)
123		ce->func = desc->deflt;
124	else
125		ce->func = kobj_error_method;
126	return;
127}
128
129void
130kobj_class_free(kobj_class_t cls)
131{
132	int i;
133	kobj_method_t *m;
134
135	/*
136	 * Unregister any methods which are no longer used.
137	 */
138	for (i = 0, m = cls->methods; m->desc; i++, m++)
139		kobj_unregister_method(m->desc);
140
141	/*
142	 * Free memory and clean up.
143	 */
144	free(cls->ops, M_KOBJ);
145	cls->ops = 0;
146}
147
148kobj_t
149kobj_create(kobj_class_t cls,
150	    struct malloc_type *mtype,
151	    int mflags)
152{
153	kobj_t obj;
154
155	/*
156	 * Allocate and initialise the new object.
157	 */
158	obj = malloc(cls->size, mtype, mflags);
159	if (!obj)
160		return 0;
161	bzero(obj, cls->size);
162	kobj_init(obj, cls);
163
164	return obj;
165}
166
167void
168kobj_init(kobj_t obj, kobj_class_t cls)
169{
170	/*
171	 * Consider compiling the class' method table.
172	 */
173	if (!cls->ops)
174		kobj_class_compile(cls);
175
176	obj->ops = cls->ops;
177	cls->instances++;
178}
179
180void
181kobj_delete(kobj_t obj, struct malloc_type *mtype)
182{
183	kobj_class_t cls = obj->ops->cls;
184
185	/*
186	 * Consider freeing the compiled method table for the class
187	 * after its last instance is deleted. As an optimisation, we
188	 * should defer this for a short while to avoid thrashing.
189	 */
190	cls->instances--;
191	if (!cls->instances)
192		kobj_class_free(cls);
193
194	obj->ops = 0;
195	if (mtype)
196		free(obj, mtype);
197}
198