| 1 | /* $NetBSD: subr_specificdata.c,v 1.13 2008/04/28 20:24:04 martin 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 2008/04/28 20:24:04 martin 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 | KASSERT(sd != NULL); |
| 157 | mutex_init(&sd->sd_lock, MUTEX_DEFAULT, IPL_NONE); |
| 158 | LIST_INIT(&sd->sd_list); |
| 159 | |
| 160 | return (sd); |
| 161 | } |
| 162 | |
| 163 | /* |
| 164 | * specificdata_domain_delete -- |
| 165 | * Destroy a specificdata domain. |
| 166 | */ |
| 167 | void |
| 168 | specificdata_domain_delete(specificdata_domain_t sd) |
| 169 | { |
| 170 | |
| 171 | panic("specificdata_domain_delete: not implemented" ); |
| 172 | } |
| 173 | |
| 174 | /* |
| 175 | * specificdata_key_create -- |
| 176 | * Create a specificdata key for a domain. |
| 177 | * |
| 178 | * Note: This is a rare operation. |
| 179 | */ |
| 180 | int |
| 181 | specificdata_key_create(specificdata_domain_t sd, specificdata_key_t *keyp, |
| 182 | specificdata_dtor_t dtor) |
| 183 | { |
| 184 | specificdata_key_impl *newkeys; |
| 185 | specificdata_key_t key = 0; |
| 186 | size_t nsz; |
| 187 | |
| 188 | ASSERT_SLEEPABLE(); |
| 189 | |
| 190 | if (dtor == NULL) |
| 191 | dtor = specificdata_noop_dtor; |
| 192 | |
| 193 | mutex_enter(&sd->sd_lock); |
| 194 | |
| 195 | if (sd->sd_keys == NULL) |
| 196 | goto needalloc; |
| 197 | |
| 198 | for (; key < sd->sd_nkey; key++) { |
| 199 | if (sd->sd_keys[key].ski_dtor == NULL) |
| 200 | goto gotit; |
| 201 | } |
| 202 | |
| 203 | needalloc: |
| 204 | nsz = (sd->sd_nkey + 1) * sizeof(*newkeys); |
| 205 | /* XXXSMP allocating memory while holding a lock. */ |
| 206 | newkeys = kmem_zalloc(nsz, KM_SLEEP); |
| 207 | KASSERT(newkeys != NULL); |
| 208 | if (sd->sd_keys != NULL) { |
| 209 | size_t osz = sd->sd_nkey * sizeof(*newkeys); |
| 210 | memcpy(newkeys, sd->sd_keys, osz); |
| 211 | kmem_free(sd->sd_keys, osz); |
| 212 | } |
| 213 | sd->sd_keys = newkeys; |
| 214 | sd->sd_nkey++; |
| 215 | gotit: |
| 216 | sd->sd_keys[key].ski_dtor = dtor; |
| 217 | |
| 218 | mutex_exit(&sd->sd_lock); |
| 219 | |
| 220 | *keyp = key; |
| 221 | return (0); |
| 222 | } |
| 223 | |
| 224 | /* |
| 225 | * specificdata_key_delete -- |
| 226 | * Destroy a specificdata key for a domain. |
| 227 | * |
| 228 | * Note: This is a rare operation. |
| 229 | */ |
| 230 | void |
| 231 | specificdata_key_delete(specificdata_domain_t sd, specificdata_key_t key) |
| 232 | { |
| 233 | specificdata_container_t sc; |
| 234 | |
| 235 | mutex_enter(&sd->sd_lock); |
| 236 | |
| 237 | if (key >= sd->sd_nkey) |
| 238 | goto out; |
| 239 | |
| 240 | /* |
| 241 | * Traverse all of the specificdata containers in the domain |
| 242 | * and the destroy the datum for the dying key. |
| 243 | */ |
| 244 | LIST_FOREACH(sc, &sd->sd_list, sc_list) { |
| 245 | specificdata_destroy_datum(sd, sc, key); |
| 246 | } |
| 247 | |
| 248 | sd->sd_keys[key].ski_dtor = NULL; |
| 249 | |
| 250 | out: |
| 251 | mutex_exit(&sd->sd_lock); |
| 252 | } |
| 253 | |
| 254 | /* |
| 255 | * specificdata_init -- |
| 256 | * Initialize a specificdata container for operation in the |
| 257 | * specified domain. |
| 258 | */ |
| 259 | int |
| 260 | specificdata_init(specificdata_domain_t sd, specificdata_reference *ref) |
| 261 | { |
| 262 | |
| 263 | /* |
| 264 | * Just NULL-out the container pointer; we'll allocate the |
| 265 | * container the first time specificdata is put into it. |
| 266 | */ |
| 267 | ref->specdataref_container = NULL; |
| 268 | mutex_init(&ref->specdataref_lock, MUTEX_DEFAULT, IPL_NONE); |
| 269 | |
| 270 | return (0); |
| 271 | } |
| 272 | |
| 273 | /* |
| 274 | * specificdata_fini -- |
| 275 | * Destroy a specificdata container. We destroy all of the datums |
| 276 | * stuffed into the container just as if the key were destroyed. |
| 277 | */ |
| 278 | void |
| 279 | specificdata_fini(specificdata_domain_t sd, specificdata_reference *ref) |
| 280 | { |
| 281 | specificdata_container_t sc; |
| 282 | specificdata_key_t key; |
| 283 | |
| 284 | ASSERT_SLEEPABLE(); |
| 285 | |
| 286 | mutex_destroy(&ref->specdataref_lock); |
| 287 | |
| 288 | sc = ref->specdataref_container; |
| 289 | if (sc == NULL) |
| 290 | return; |
| 291 | ref->specdataref_container = NULL; |
| 292 | |
| 293 | mutex_enter(&sd->sd_lock); |
| 294 | |
| 295 | specificdata_container_unlink(sd, sc); |
| 296 | for (key = 0; key < sc->sc_nkey; key++) { |
| 297 | specificdata_destroy_datum(sd, sc, key); |
| 298 | } |
| 299 | |
| 300 | mutex_exit(&sd->sd_lock); |
| 301 | |
| 302 | kmem_free(sc, SPECIFICDATA_CONTAINER_BYTESIZE(sc->sc_nkey)); |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * specificdata_getspecific -- |
| 307 | * Get a datum from a container. |
| 308 | */ |
| 309 | void * |
| 310 | specificdata_getspecific(specificdata_domain_t sd, specificdata_reference *ref, |
| 311 | specificdata_key_t key) |
| 312 | { |
| 313 | specificdata_container_t sc; |
| 314 | void *data = NULL; |
| 315 | |
| 316 | mutex_enter(&ref->specdataref_lock); |
| 317 | |
| 318 | sc = ref->specdataref_container; |
| 319 | if (sc != NULL && key < sc->sc_nkey) |
| 320 | data = sc->sc_data[key]; |
| 321 | |
| 322 | mutex_exit(&ref->specdataref_lock); |
| 323 | |
| 324 | return (data); |
| 325 | } |
| 326 | |
| 327 | /* |
| 328 | * specificdata_getspecific_unlocked -- |
| 329 | * Get a datum from a container in a lockless fashion. |
| 330 | * |
| 331 | * Note: When using this routine, care must be taken to ensure |
| 332 | * that no other thread could cause the specificdata_reference |
| 333 | * to become invalid (i.e. point at the wrong container) by |
| 334 | * issuing a setspecific call or destroying the container. |
| 335 | */ |
| 336 | void * |
| 337 | specificdata_getspecific_unlocked(specificdata_domain_t sd, |
| 338 | specificdata_reference *ref, |
| 339 | specificdata_key_t key) |
| 340 | { |
| 341 | specificdata_container_t sc; |
| 342 | |
| 343 | sc = ref->specdataref_container; |
| 344 | if (sc != NULL && key < sc->sc_nkey) |
| 345 | return (sc->sc_data[key]); |
| 346 | |
| 347 | return (NULL); |
| 348 | } |
| 349 | |
| 350 | /* |
| 351 | * specificdata_setspecific -- |
| 352 | * Put a datum into a container. |
| 353 | */ |
| 354 | void |
| 355 | specificdata_setspecific(specificdata_domain_t sd, |
| 356 | specificdata_reference *ref, |
| 357 | specificdata_key_t key, void *data) |
| 358 | { |
| 359 | specificdata_container_t sc, newsc; |
| 360 | size_t newnkey, sz; |
| 361 | |
| 362 | ASSERT_SLEEPABLE(); |
| 363 | |
| 364 | mutex_enter(&ref->specdataref_lock); |
| 365 | |
| 366 | sc = ref->specdataref_container; |
| 367 | if (__predict_true(sc != NULL && key < sc->sc_nkey)) { |
| 368 | sc->sc_data[key] = data; |
| 369 | mutex_exit(&ref->specdataref_lock); |
| 370 | return; |
| 371 | } |
| 372 | |
| 373 | mutex_exit(&ref->specdataref_lock); |
| 374 | |
| 375 | /* |
| 376 | * Slow path: need to resize. |
| 377 | */ |
| 378 | |
| 379 | mutex_enter(&sd->sd_lock); |
| 380 | newnkey = sd->sd_nkey; |
| 381 | if (key >= newnkey) { |
| 382 | mutex_exit(&sd->sd_lock); |
| 383 | panic("specificdata_setspecific" ); |
| 384 | } |
| 385 | sz = SPECIFICDATA_CONTAINER_BYTESIZE(newnkey); |
| 386 | newsc = kmem_zalloc(sz, KM_SLEEP); |
| 387 | KASSERT(newsc != NULL); |
| 388 | newsc->sc_nkey = newnkey; |
| 389 | |
| 390 | mutex_enter(&ref->specdataref_lock); |
| 391 | |
| 392 | sc = ref->specdataref_container; |
| 393 | if (sc != NULL) { |
| 394 | if (key < sc->sc_nkey) { |
| 395 | /* |
| 396 | * Someone beat us to the punch. Unwind and put |
| 397 | * the object into the now large enough container. |
| 398 | */ |
| 399 | sc->sc_data[key] = data; |
| 400 | mutex_exit(&ref->specdataref_lock); |
| 401 | mutex_exit(&sd->sd_lock); |
| 402 | kmem_free(newsc, sz); |
| 403 | return; |
| 404 | } |
| 405 | specificdata_container_unlink(sd, sc); |
| 406 | memcpy(newsc->sc_data, sc->sc_data, |
| 407 | sc->sc_nkey * sizeof(void *)); |
| 408 | } |
| 409 | newsc->sc_data[key] = data; |
| 410 | specificdata_container_link(sd, newsc); |
| 411 | ref->specdataref_container = newsc; |
| 412 | |
| 413 | mutex_exit(&ref->specdataref_lock); |
| 414 | mutex_exit(&sd->sd_lock); |
| 415 | |
| 416 | if (sc != NULL) |
| 417 | kmem_free(sc, SPECIFICDATA_CONTAINER_BYTESIZE(sc->sc_nkey)); |
| 418 | } |
| 419 | |