1 /*- 2 * Copyright (c) 2000,2003 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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/kernel.h> 32 #include <sys/kobj.h> 33 #include <sys/lock.h> 34 #include <sys/malloc.h> 35 #include <sys/mutex.h> 36 #include <sys/sysctl.h> 37 #ifndef TEST 38 #include <sys/systm.h> 39 #endif 40 41 #ifdef TEST 42 #include "usertest.h" 43 #endif 44 45 static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures"); 46 47 #ifdef KOBJ_STATS 48 49 u_int kobj_lookup_hits; 50 u_int kobj_lookup_misses; 51 52 SYSCTL_UINT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD, 53 &kobj_lookup_hits, 0, ""); 54 SYSCTL_UINT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD, 55 &kobj_lookup_misses, 0, ""); 56 57 #endif 58 59 static struct mtx kobj_mtx; 60 static int kobj_mutex_inited; 61 static int kobj_next_id = 1; 62 63 #define KOBJ_LOCK() mtx_lock(&kobj_mtx) 64 #define KOBJ_UNLOCK() mtx_unlock(&kobj_mtx) 65 #define KOBJ_ASSERT(what) mtx_assert(&kobj_mtx, what); 66 67 SYSCTL_INT(_kern, OID_AUTO, kobj_methodcount, CTLFLAG_RD, 68 &kobj_next_id, 0, ""); 69 70 static void 71 kobj_init_mutex(void *arg) 72 { 73 if (!kobj_mutex_inited) { 74 mtx_init(&kobj_mtx, "kobj", NULL, MTX_DEF); 75 kobj_mutex_inited = 1; 76 } 77 } 78 79 SYSINIT(kobj, SI_SUB_LOCK, SI_ORDER_ANY, kobj_init_mutex, NULL); 80 81 /* 82 * This method structure is used to initialise new caches. Since the 83 * desc pointer is NULL, it is guaranteed never to match any read 84 * descriptors. 85 */ 86 static const struct kobj_method null_method = { 87 0, 0, 88 }; 89 90 int 91 kobj_error_method(void) 92 { 93 94 return ENXIO; 95 } 96 97 static void 98 kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops) 99 { 100 kobj_method_t *m; 101 int i; 102 103 /* 104 * Don't do anything if we are already compiled. 105 */ 106 if (cls->ops) 107 return; 108 109 /* 110 * First register any methods which need it. 111 */ 112 for (i = 0, m = cls->methods; m->desc; i++, m++) { 113 if (m->desc->id == 0) 114 m->desc->id = kobj_next_id++; 115 } 116 117 /* 118 * Then initialise the ops table. 119 */ 120 for (i = 0; i < KOBJ_CACHE_SIZE; i++) 121 ops->cache[i] = &null_method; 122 ops->cls = cls; 123 cls->ops = ops; 124 } 125 126 void 127 kobj_class_compile(kobj_class_t cls) 128 { 129 kobj_ops_t ops; 130 131 KOBJ_ASSERT(MA_NOTOWNED); 132 133 /* 134 * Allocate space for the compiled ops table. 135 */ 136 ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT); 137 if (!ops) 138 panic("%s: out of memory", __func__); 139 140 KOBJ_LOCK(); 141 142 /* 143 * We may have lost a race for kobj_class_compile here - check 144 * to make sure someone else hasn't already compiled this 145 * class. 146 */ 147 if (cls->ops) { 148 KOBJ_UNLOCK(); 149 free(ops, M_KOBJ); 150 return; 151 } 152 153 kobj_class_compile_common(cls, ops); 154 KOBJ_UNLOCK(); 155 } 156 157 void 158 kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops) 159 { 160 161 KASSERT(kobj_mutex_inited == 0, 162 ("%s: only supported during early cycles", __func__)); 163 164 /* 165 * Increment refs to make sure that the ops table is not freed. 166 */ 167 cls->refs++; 168 kobj_class_compile_common(cls, ops); 169 } 170 171 static kobj_method_t* 172 kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc) 173 { 174 kobj_method_t *methods = cls->methods; 175 kobj_method_t *ce; 176 177 for (ce = methods; ce && ce->desc; ce++) { 178 if (ce->desc == desc) { 179 return ce; 180 } 181 } 182 183 return NULL; 184 } 185 186 static kobj_method_t* 187 kobj_lookup_method_mi(kobj_class_t cls, 188 kobjop_desc_t desc) 189 { 190 kobj_method_t *ce; 191 kobj_class_t *basep; 192 193 ce = kobj_lookup_method_class(cls, desc); 194 if (ce) 195 return ce; 196 197 basep = cls->baseclasses; 198 if (basep) { 199 for (; *basep; basep++) { 200 ce = kobj_lookup_method_mi(*basep, desc); 201 if (ce) 202 return ce; 203 } 204 } 205 206 return NULL; 207 } 208 209 kobj_method_t* 210 kobj_lookup_method(kobj_class_t cls, 211 kobj_method_t **cep, 212 kobjop_desc_t desc) 213 { 214 kobj_method_t *ce; 215 216 #ifdef KOBJ_STATS 217 /* 218 * Correct for the 'hit' assumption in KOBJOPLOOKUP and record 219 * a 'miss'. 220 */ 221 kobj_lookup_hits--; 222 kobj_lookup_misses++; 223 #endif 224 225 ce = kobj_lookup_method_mi(cls, desc); 226 if (!ce) 227 ce = &desc->deflt; 228 *cep = ce; 229 return ce; 230 } 231 232 void 233 kobj_class_free(kobj_class_t cls) 234 { 235 void* ops = NULL; 236 237 KOBJ_ASSERT(MA_NOTOWNED); 238 KOBJ_LOCK(); 239 240 /* 241 * Protect against a race between kobj_create and 242 * kobj_delete. 243 */ 244 if (cls->refs == 0) { 245 /* 246 * For now we don't do anything to unregister any methods 247 * which are no longer used. 248 */ 249 250 /* 251 * Free memory and clean up. 252 */ 253 ops = cls->ops; 254 cls->ops = NULL; 255 } 256 257 KOBJ_UNLOCK(); 258 259 if (ops) 260 free(ops, M_KOBJ); 261 } 262 263 kobj_t 264 kobj_create(kobj_class_t cls, 265 struct malloc_type *mtype, 266 int mflags) 267 { 268 kobj_t obj; 269 270 /* 271 * Allocate and initialise the new object. 272 */ 273 obj = malloc(cls->size, mtype, mflags | M_ZERO); 274 if (!obj) 275 return NULL; 276 kobj_init(obj, cls); 277 278 return obj; 279 } 280 281 static void 282 kobj_init_common(kobj_t obj, kobj_class_t cls) 283 { 284 285 obj->ops = cls->ops; 286 cls->refs++; 287 } 288 289 void 290 kobj_init(kobj_t obj, kobj_class_t cls) 291 { 292 KOBJ_ASSERT(MA_NOTOWNED); 293 retry: 294 KOBJ_LOCK(); 295 296 /* 297 * Consider compiling the class' method table. 298 */ 299 if (!cls->ops) { 300 /* 301 * kobj_class_compile doesn't want the lock held 302 * because of the call to malloc - we drop the lock 303 * and re-try. 304 */ 305 KOBJ_UNLOCK(); 306 kobj_class_compile(cls); 307 goto retry; 308 } 309 310 kobj_init_common(obj, cls); 311 312 KOBJ_UNLOCK(); 313 } 314 315 void 316 kobj_init_static(kobj_t obj, kobj_class_t cls) 317 { 318 319 KASSERT(kobj_mutex_inited == 0, 320 ("%s: only supported during early cycles", __func__)); 321 322 kobj_init_common(obj, cls); 323 } 324 325 void 326 kobj_delete(kobj_t obj, struct malloc_type *mtype) 327 { 328 kobj_class_t cls = obj->ops->cls; 329 int refs; 330 331 /* 332 * Consider freeing the compiled method table for the class 333 * after its last instance is deleted. As an optimisation, we 334 * should defer this for a short while to avoid thrashing. 335 */ 336 KOBJ_ASSERT(MA_NOTOWNED); 337 KOBJ_LOCK(); 338 cls->refs--; 339 refs = cls->refs; 340 KOBJ_UNLOCK(); 341 342 if (!refs) 343 kobj_class_free(cls); 344 345 obj->ops = NULL; 346 if (mtype) 347 free(obj, mtype); 348 } 349