subr_specificdata.c revision 1.13.44.1
1 /* $NetBSD: subr_specificdata.c,v 1.13.44.1 2017/12/03 11:38:45 jdolecek Exp $ */ 2 3 /*- 4 * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 2006 YAMAMOTO Takashi. 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 45 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 48 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 55 * SUCH DAMAGE. 56 */ 57 58 #include <sys/cdefs.h> 59 __KERNEL_RCSID(0, "$NetBSD: subr_specificdata.c,v 1.13.44.1 2017/12/03 11:38:45 jdolecek Exp $"); 60 61 #include <sys/param.h> 62 #include <sys/kmem.h> 63 #include <sys/specificdata.h> 64 #include <sys/queue.h> 65 #include <sys/mutex.h> 66 67 /* 68 * Locking notes: 69 * 70 * The specdataref_container pointer in the specificdata_reference 71 * is volatile. To read it, you must hold EITHER the domain lock 72 * or the ref lock. To write it, you must hold BOTH the domain lock 73 * and the ref lock. The locks must be acquired in the following 74 * order: 75 * domain -> ref 76 */ 77 78 typedef struct { 79 specificdata_dtor_t ski_dtor; 80 } specificdata_key_impl; 81 82 struct specificdata_container { 83 size_t sc_nkey; 84 LIST_ENTRY(specificdata_container) sc_list; 85 void * sc_data[]; /* variable length */ 86 }; 87 88 #define SPECIFICDATA_CONTAINER_BYTESIZE(n) \ 89 (sizeof(struct specificdata_container) + ((n) * sizeof(void *))) 90 91 struct specificdata_domain { 92 kmutex_t sd_lock; 93 unsigned int sd_nkey; 94 LIST_HEAD(, specificdata_container) sd_list; 95 specificdata_key_impl *sd_keys; 96 }; 97 98 static void 99 specificdata_container_link(specificdata_domain_t sd, 100 specificdata_container_t sc) 101 { 102 103 LIST_INSERT_HEAD(&sd->sd_list, sc, sc_list); 104 } 105 106 static void 107 specificdata_container_unlink(specificdata_domain_t sd, 108 specificdata_container_t sc) 109 { 110 111 LIST_REMOVE(sc, sc_list); 112 } 113 114 static void 115 specificdata_destroy_datum(specificdata_domain_t sd, 116 specificdata_container_t sc, specificdata_key_t key) 117 { 118 specificdata_dtor_t dtor; 119 void *data; 120 121 if (key >= sc->sc_nkey) 122 return; 123 124 KASSERT(key < sd->sd_nkey); 125 126 data = sc->sc_data[key]; 127 dtor = sd->sd_keys[key].ski_dtor; 128 129 if (dtor != NULL) { 130 if (data != NULL) { 131 sc->sc_data[key] = NULL; 132 (*dtor)(data); 133 } 134 } else { 135 KASSERT(data == NULL); 136 } 137 } 138 139 static void 140 specificdata_noop_dtor(void *data) 141 { 142 143 /* nothing */ 144 } 145 146 /* 147 * specificdata_domain_create -- 148 * Create a specificdata domain. 149 */ 150 specificdata_domain_t 151 specificdata_domain_create(void) 152 { 153 specificdata_domain_t sd; 154 155 sd = kmem_zalloc(sizeof(*sd), KM_SLEEP); 156 mutex_init(&sd->sd_lock, MUTEX_DEFAULT, IPL_NONE); 157 LIST_INIT(&sd->sd_list); 158 159 return (sd); 160 } 161 162 /* 163 * specificdata_domain_delete -- 164 * Destroy a specificdata domain. 165 */ 166 void 167 specificdata_domain_delete(specificdata_domain_t sd) 168 { 169 170 panic("specificdata_domain_delete: not implemented"); 171 } 172 173 /* 174 * specificdata_key_create -- 175 * Create a specificdata key for a domain. 176 * 177 * Note: This is a rare operation. 178 */ 179 int 180 specificdata_key_create(specificdata_domain_t sd, specificdata_key_t *keyp, 181 specificdata_dtor_t dtor) 182 { 183 specificdata_key_impl *newkeys; 184 specificdata_key_t key = 0; 185 size_t nsz; 186 187 ASSERT_SLEEPABLE(); 188 189 if (dtor == NULL) 190 dtor = specificdata_noop_dtor; 191 192 mutex_enter(&sd->sd_lock); 193 194 if (sd->sd_keys == NULL) 195 goto needalloc; 196 197 for (; key < sd->sd_nkey; key++) { 198 if (sd->sd_keys[key].ski_dtor == NULL) 199 goto gotit; 200 } 201 202 needalloc: 203 nsz = (sd->sd_nkey + 1) * sizeof(*newkeys); 204 /* XXXSMP allocating memory while holding a lock. */ 205 newkeys = kmem_zalloc(nsz, KM_SLEEP); 206 if (sd->sd_keys != NULL) { 207 size_t osz = sd->sd_nkey * sizeof(*newkeys); 208 memcpy(newkeys, sd->sd_keys, osz); 209 kmem_free(sd->sd_keys, osz); 210 } 211 sd->sd_keys = newkeys; 212 sd->sd_nkey++; 213 gotit: 214 sd->sd_keys[key].ski_dtor = dtor; 215 216 mutex_exit(&sd->sd_lock); 217 218 *keyp = key; 219 return (0); 220 } 221 222 /* 223 * specificdata_key_delete -- 224 * Destroy a specificdata key for a domain. 225 * 226 * Note: This is a rare operation. 227 */ 228 void 229 specificdata_key_delete(specificdata_domain_t sd, specificdata_key_t key) 230 { 231 specificdata_container_t sc; 232 233 mutex_enter(&sd->sd_lock); 234 235 if (key >= sd->sd_nkey) 236 goto out; 237 238 /* 239 * Traverse all of the specificdata containers in the domain 240 * and the destroy the datum for the dying key. 241 */ 242 LIST_FOREACH(sc, &sd->sd_list, sc_list) { 243 specificdata_destroy_datum(sd, sc, key); 244 } 245 246 sd->sd_keys[key].ski_dtor = NULL; 247 248 out: 249 mutex_exit(&sd->sd_lock); 250 } 251 252 /* 253 * specificdata_init -- 254 * Initialize a specificdata container for operation in the 255 * specified domain. 256 */ 257 int 258 specificdata_init(specificdata_domain_t sd, specificdata_reference *ref) 259 { 260 261 /* 262 * Just NULL-out the container pointer; we'll allocate the 263 * container the first time specificdata is put into it. 264 */ 265 ref->specdataref_container = NULL; 266 mutex_init(&ref->specdataref_lock, MUTEX_DEFAULT, IPL_NONE); 267 268 return (0); 269 } 270 271 /* 272 * specificdata_fini -- 273 * Destroy a specificdata container. We destroy all of the datums 274 * stuffed into the container just as if the key were destroyed. 275 */ 276 void 277 specificdata_fini(specificdata_domain_t sd, specificdata_reference *ref) 278 { 279 specificdata_container_t sc; 280 specificdata_key_t key; 281 282 ASSERT_SLEEPABLE(); 283 284 mutex_destroy(&ref->specdataref_lock); 285 286 sc = ref->specdataref_container; 287 if (sc == NULL) 288 return; 289 ref->specdataref_container = NULL; 290 291 mutex_enter(&sd->sd_lock); 292 293 specificdata_container_unlink(sd, sc); 294 for (key = 0; key < sc->sc_nkey; key++) { 295 specificdata_destroy_datum(sd, sc, key); 296 } 297 298 mutex_exit(&sd->sd_lock); 299 300 kmem_free(sc, SPECIFICDATA_CONTAINER_BYTESIZE(sc->sc_nkey)); 301 } 302 303 /* 304 * specificdata_getspecific -- 305 * Get a datum from a container. 306 */ 307 void * 308 specificdata_getspecific(specificdata_domain_t sd, specificdata_reference *ref, 309 specificdata_key_t key) 310 { 311 specificdata_container_t sc; 312 void *data = NULL; 313 314 mutex_enter(&ref->specdataref_lock); 315 316 sc = ref->specdataref_container; 317 if (sc != NULL && key < sc->sc_nkey) 318 data = sc->sc_data[key]; 319 320 mutex_exit(&ref->specdataref_lock); 321 322 return (data); 323 } 324 325 /* 326 * specificdata_getspecific_unlocked -- 327 * Get a datum from a container in a lockless fashion. 328 * 329 * Note: When using this routine, care must be taken to ensure 330 * that no other thread could cause the specificdata_reference 331 * to become invalid (i.e. point at the wrong container) by 332 * issuing a setspecific call or destroying the container. 333 */ 334 void * 335 specificdata_getspecific_unlocked(specificdata_domain_t sd, 336 specificdata_reference *ref, 337 specificdata_key_t key) 338 { 339 specificdata_container_t sc; 340 341 sc = ref->specdataref_container; 342 if (sc != NULL && key < sc->sc_nkey) 343 return (sc->sc_data[key]); 344 345 return (NULL); 346 } 347 348 /* 349 * specificdata_setspecific -- 350 * Put a datum into a container. 351 */ 352 void 353 specificdata_setspecific(specificdata_domain_t sd, 354 specificdata_reference *ref, 355 specificdata_key_t key, void *data) 356 { 357 specificdata_container_t sc, newsc; 358 size_t newnkey, sz; 359 360 ASSERT_SLEEPABLE(); 361 362 mutex_enter(&ref->specdataref_lock); 363 364 sc = ref->specdataref_container; 365 if (__predict_true(sc != NULL && key < sc->sc_nkey)) { 366 sc->sc_data[key] = data; 367 mutex_exit(&ref->specdataref_lock); 368 return; 369 } 370 371 mutex_exit(&ref->specdataref_lock); 372 373 /* 374 * Slow path: need to resize. 375 */ 376 377 mutex_enter(&sd->sd_lock); 378 newnkey = sd->sd_nkey; 379 if (key >= newnkey) { 380 mutex_exit(&sd->sd_lock); 381 panic("specificdata_setspecific"); 382 } 383 sz = SPECIFICDATA_CONTAINER_BYTESIZE(newnkey); 384 newsc = kmem_zalloc(sz, KM_SLEEP); 385 newsc->sc_nkey = newnkey; 386 387 mutex_enter(&ref->specdataref_lock); 388 389 sc = ref->specdataref_container; 390 if (sc != NULL) { 391 if (key < sc->sc_nkey) { 392 /* 393 * Someone beat us to the punch. Unwind and put 394 * the object into the now large enough container. 395 */ 396 sc->sc_data[key] = data; 397 mutex_exit(&ref->specdataref_lock); 398 mutex_exit(&sd->sd_lock); 399 kmem_free(newsc, sz); 400 return; 401 } 402 specificdata_container_unlink(sd, sc); 403 memcpy(newsc->sc_data, sc->sc_data, 404 sc->sc_nkey * sizeof(void *)); 405 } 406 newsc->sc_data[key] = data; 407 specificdata_container_link(sd, newsc); 408 ref->specdataref_container = newsc; 409 410 mutex_exit(&ref->specdataref_lock); 411 mutex_exit(&sd->sd_lock); 412 413 if (sc != NULL) 414 kmem_free(sc, SPECIFICDATA_CONTAINER_BYTESIZE(sc->sc_nkey)); 415 } 416
Indexes created Sun Sep 21 16:09:51 GMT 2025