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/kern/subr_kobj.c,v 1.4.2.1 2001/02/02 19:49:13 cg Exp $
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 #include <sys/thread.h>
36 #include <sys/thread2.h>
37 #ifndef TEST
38 #include <sys/systm.h>
39 #endif
40 #include <sys/kobj.h>
41
42 #ifdef TEST
43 #include "usertest.h"
44 #endif
45
46 static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
47
48 static struct lwkt_token kobj_token;
49 static int kobj_next_id = 1;
50
51 static void
kobj_init_token(void * arg)52 kobj_init_token(void *arg)
53 {
54 lwkt_token_init(&kobj_token, "kobj");
55 }
56
57 SYSINIT(kobj, SI_BOOT1_LOCK, SI_ORDER_ANY, kobj_init_token, NULL);
58
59 /*
60 * This method structure is used to initialise new caches. Since the
61 * desc pointer is NULL, it is guaranteed never to match any real
62 * descriptors.
63 */
64 static const struct kobj_method null_method = {
65 0, 0,
66 };
67
68 int
kobj_error_method(void)69 kobj_error_method(void)
70 {
71 return ENXIO;
72 }
73
74 static void
kobj_register_method(struct kobjop_desc * desc)75 kobj_register_method(struct kobjop_desc *desc)
76 {
77 if (desc->id == 0)
78 desc->id = kobj_next_id++;
79 }
80
81 static void
kobj_unregister_method(struct kobjop_desc * desc)82 kobj_unregister_method(struct kobjop_desc *desc)
83 {
84 }
85
86 static void
kobj_class_compile(kobj_class_t cls)87 kobj_class_compile(kobj_class_t cls)
88 {
89 kobj_method_t *m;
90 kobj_ops_t ops;
91 int i;
92
93 /*
94 * Don't do anything if we are already compiled.
95 */
96 if (cls->ops)
97 return;
98
99 /*
100 * Allocate space for the compiled ops table.
101 */
102 ops = kmalloc(sizeof(struct kobj_ops), M_KOBJ, M_INTWAIT);
103 for (i = 0; i < KOBJ_CACHE_SIZE; i++)
104 ops->cache[i] = &null_method;
105 if (cls->ops) {
106 /*
107 * In case of preemption, another thread might have been faster,
108 * but that's fine for us.
109 */
110 kfree(ops, M_KOBJ);
111 return;
112 }
113
114 ops->cls = cls;
115 cls->ops = ops;
116
117 /*
118 * Afterwards register any methods which need it.
119 */
120 for (m = cls->methods; m->desc; m++)
121 kobj_register_method(m->desc);
122 }
123
124 static kobj_method_t *
kobj_lookup_method_class(kobj_class_t cls,kobjop_desc_t desc)125 kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc)
126 {
127 kobj_method_t *methods = cls->methods;
128 kobj_method_t *ce;
129
130 for (ce = methods; ce && ce->desc; ce++)
131 if (ce->desc == desc)
132 return(ce);
133
134 return(0);
135 }
136
137 static kobj_method_t *
kobj_lookup_method_mi(kobj_class_t cls,kobjop_desc_t desc)138 kobj_lookup_method_mi(kobj_class_t cls, kobjop_desc_t desc)
139 {
140 kobj_method_t *ce;
141 kobj_class_t *basep;
142
143 ce = kobj_lookup_method_class(cls, desc);
144 if (ce)
145 return(ce);
146
147 basep = cls->baseclasses;
148 if (basep) {
149 for (; *basep; basep++) {
150 ce = kobj_lookup_method_mi(*basep, desc);
151 if (ce)
152 return(ce);
153 }
154 }
155
156 return(0);
157 }
158
159 kobj_method_t*
kobj_lookup_method(kobj_class_t cls,kobj_method_t ** cep,kobjop_desc_t desc)160 kobj_lookup_method(kobj_class_t cls,
161 kobj_method_t **cep,
162 kobjop_desc_t desc)
163 {
164 kobj_method_t *ce;
165
166 ce = kobj_lookup_method_mi(cls, desc);
167 if (!ce)
168 ce = &desc->deflt;
169 *cep = ce;
170 return(ce);
171 }
172
173 /*
174 * This is called from the KOBJOPLOOKUP() macro in sys/kobj.h and
175 * replaces the original large body of the macro with a single
176 * procedure call.
177 */
178 kobjop_t
kobj_lookup_method_cache(kobj_class_t cls,kobj_method_t ** cep,kobjop_desc_t desc)179 kobj_lookup_method_cache(kobj_class_t cls, kobj_method_t **cep,
180 kobjop_desc_t desc)
181 {
182 kobj_method_t *ce;
183
184 cep = &cep[desc->id & (KOBJ_CACHE_SIZE-1)];
185 ce = *cep;
186 if (ce->desc != desc)
187 ce = kobj_lookup_method(cls, cep, desc);
188 return(ce->func);
189 }
190
191 static void
kobj_class_free(kobj_class_t cls)192 kobj_class_free(kobj_class_t cls)
193 {
194 int i;
195 kobj_method_t *m;
196
197 /*
198 * Unregister any methods which are no longer used.
199 */
200 for (i = 0, m = cls->methods; m->desc; i++, m++)
201 kobj_unregister_method(m->desc);
202
203 /*
204 * Free memory and clean up.
205 */
206 kfree(cls->ops, M_KOBJ);
207 cls->ops = 0;
208 }
209
210 void
kobj_class_instantiate(kobj_class_t cls)211 kobj_class_instantiate(kobj_class_t cls)
212 {
213 lwkt_gettoken(&kobj_token);
214 crit_enter();
215
216 if (!cls->ops)
217 kobj_class_compile(cls);
218 cls->refs++;
219
220 crit_exit();
221 lwkt_reltoken(&kobj_token);
222 }
223
224 void
kobj_class_uninstantiate(kobj_class_t cls)225 kobj_class_uninstantiate(kobj_class_t cls)
226 {
227 lwkt_gettoken(&kobj_token);
228 crit_enter();
229
230 cls->refs--;
231 if (cls->refs == 0)
232 kobj_class_free(cls);
233
234 crit_exit();
235 lwkt_reltoken(&kobj_token);
236 }
237
238 kobj_t
kobj_create(kobj_class_t cls,struct malloc_type * mtype,int mflags)239 kobj_create(kobj_class_t cls,
240 struct malloc_type *mtype,
241 int mflags)
242 {
243 kobj_t obj;
244
245 /*
246 * Allocate and initialise the new object.
247 */
248 obj = kmalloc(cls->size, mtype, mflags | M_ZERO);
249 if (!obj)
250 return 0;
251 kobj_init(obj, cls);
252
253 return obj;
254 }
255
256 void
kobj_init(kobj_t obj,kobj_class_t cls)257 kobj_init(kobj_t obj, kobj_class_t cls)
258 {
259 kobj_class_instantiate(cls);
260 obj->ops = cls->ops;
261 }
262
263 void
kobj_delete(kobj_t obj,struct malloc_type * mtype)264 kobj_delete(kobj_t obj, struct malloc_type *mtype)
265 {
266 kobj_class_t cls = obj->ops->cls;
267
268 kobj_class_uninstantiate(cls);
269
270 obj->ops = 0;
271 if (mtype)
272 kfree(obj, mtype);
273 }
274