1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * mod_hash: flexible hash table implementation. 28 * 29 * This is a reasonably fast, reasonably flexible hash table implementation 30 * which features pluggable hash algorithms to support storing arbitrary keys 31 * and values. It is designed to handle small (< 100,000 items) amounts of 32 * data. The hash uses chaining to resolve collisions, and does not feature a 33 * mechanism to grow the hash. Care must be taken to pick nchains to be large 34 * enough for the application at hand, or lots of time will be wasted searching 35 * hash chains. 36 * 37 * The client of the hash is required to supply a number of items to support 38 * the various hash functions: 39 * 40 * - Destructor functions for the key and value being hashed. 41 * A destructor is responsible for freeing an object when the hash 42 * table is no longer storing it. Since keys and values can be of 43 * arbitrary type, separate destructors for keys & values are used. 44 * These may be mod_hash_null_keydtor and mod_hash_null_valdtor if no 45 * destructor is needed for either a key or value. 46 * 47 * - A hashing algorithm which returns a uint_t representing a hash index 48 * The number returned need _not_ be between 0 and nchains. The mod_hash 49 * code will take care of doing that. The second argument (after the 50 * key) to the hashing function is a void * that represents 51 * hash_alg_data-- this is provided so that the hashing algrorithm can 52 * maintain some state across calls, or keep algorithm-specific 53 * constants associated with the hash table. 54 * 55 * A pointer-hashing and a string-hashing algorithm are supplied in 56 * this file. 57 * 58 * - A key comparator (a la qsort). 59 * This is used when searching the hash chain. The key comparator 60 * determines if two keys match. It should follow the return value 61 * semantics of strcmp. 62 * 63 * string and pointer comparators are supplied in this file. 64 * 65 * mod_hash_create_strhash() and mod_hash_create_ptrhash() provide good 66 * examples of how to create a customized hash table. 67 * 68 * Basic hash operations: 69 * 70 * mod_hash_create_strhash(name, nchains, dtor), 71 * create a hash using strings as keys. 72 * NOTE: This create a hash which automatically cleans up the string 73 * values it is given for keys. 74 * 75 * mod_hash_create_ptrhash(name, nchains, dtor, key_elem_size): 76 * create a hash using pointers as keys. 77 * 78 * mod_hash_create_extended(name, nchains, kdtor, vdtor, 79 * hash_alg, hash_alg_data, 80 * keycmp, sleep) 81 * create a customized hash table. 82 * 83 * mod_hash_destroy_hash(hash): 84 * destroy the given hash table, calling the key and value destructors 85 * on each key-value pair stored in the hash. 86 * 87 * mod_hash_insert(hash, key, val): 88 * place a key, value pair into the given hash. 89 * duplicate keys are rejected. 90 * 91 * mod_hash_insert_reserve(hash, key, val, handle): 92 * place a key, value pair into the given hash, using handle to indicate 93 * the reserved storage for the pair. (no memory allocation is needed 94 * during a mod_hash_insert_reserve.) duplicate keys are rejected. 95 * 96 * mod_hash_reserve(hash, *handle): 97 * reserve storage for a key-value pair using the memory allocation 98 * policy of 'hash', returning the storage handle in 'handle'. 99 * 100 * mod_hash_reserve_nosleep(hash, *handle): reserve storage for a key-value 101 * pair ignoring the memory allocation policy of 'hash' and always without 102 * sleep, returning the storage handle in 'handle'. 103 * 104 * mod_hash_remove(hash, key, *val): 105 * remove a key-value pair with key 'key' from 'hash', destroying the 106 * stored key, and returning the value in val. 107 * 108 * mod_hash_replace(hash, key, val) 109 * atomically remove an existing key-value pair from a hash, and replace 110 * the key and value with the ones supplied. The removed key and value 111 * (if any) are destroyed. 112 * 113 * mod_hash_destroy(hash, key): 114 * remove a key-value pair with key 'key' from 'hash', destroying both 115 * stored key and stored value. 116 * 117 * mod_hash_find(hash, key, val): 118 * find a value in the hash table corresponding to the given key. 119 * 120 * mod_hash_find_cb(hash, key, val, found_callback) 121 * find a value in the hash table corresponding to the given key. 122 * If a value is found, call specified callback passing key and val to it. 123 * The callback is called with the hash lock held. 124 * It is intended to be used in situations where the act of locating the 125 * data must also modify it - such as in reference counting schemes. 126 * 127 * mod_hash_walk(hash, callback(key, elem, arg), arg) 128 * walks all the elements in the hashtable and invokes the callback 129 * function with the key/value pair for each element. the hashtable 130 * is locked for readers so the callback function should not attempt 131 * to do any updates to the hashable. the callback function should 132 * return MH_WALK_CONTINUE to continue walking the hashtable or 133 * MH_WALK_TERMINATE to abort the walk of the hashtable. 134 * 135 * mod_hash_clear(hash): 136 * clears the given hash table of entries, calling the key and value 137 * destructors for every element in the hash. 138 */ 139 140 #include <sys/bitmap.h> 141 #include <sys/debug.h> 142 #include <sys/kmem.h> 143 #include <sys/sunddi.h> 144 145 #include <sys/modhash_impl.h> 146 147 /* 148 * MH_KEY_DESTROY() 149 * Invoke the key destructor. 150 */ 151 #define MH_KEY_DESTROY(hash, key) ((hash->mh_kdtor)(key)) 152 153 /* 154 * MH_VAL_DESTROY() 155 * Invoke the value destructor. 156 */ 157 #define MH_VAL_DESTROY(hash, val) ((hash->mh_vdtor)(val)) 158 159 /* 160 * MH_KEYCMP() 161 * Call the key comparator for the given hash keys. 162 */ 163 #define MH_KEYCMP(hash, key1, key2) ((hash->mh_keycmp)(key1, key2)) 164 165 /* 166 * Cache for struct mod_hash_entry 167 */ 168 kmem_cache_t *mh_e_cache = NULL; 169 mod_hash_t *mh_head = NULL; 170 kmutex_t mh_head_lock; 171 172 /* 173 * mod_hash_null_keydtor() 174 * mod_hash_null_valdtor() 175 * no-op key and value destructors. 176 */ 177 /*ARGSUSED*/ 178 void 179 mod_hash_null_keydtor(mod_hash_key_t key) 180 { 181 } 182 183 /*ARGSUSED*/ 184 void 185 mod_hash_null_valdtor(mod_hash_val_t val) 186 { 187 } 188 189 /* 190 * mod_hash_bystr() 191 * mod_hash_strkey_cmp() 192 * mod_hash_strkey_dtor() 193 * mod_hash_strval_dtor() 194 * Hash and key comparison routines for hashes with string keys. 195 * 196 * mod_hash_create_strhash() 197 * Create a hash using strings as keys 198 * 199 * The string hashing algorithm is from the "Dragon Book" -- 200 * "Compilers: Principles, Tools & Techniques", by Aho, Sethi, Ullman 201 */ 202 203 /*ARGSUSED*/ 204 uint_t 205 mod_hash_bystr(void *hash_data, mod_hash_key_t key) 206 { 207 uint_t hash = 0; 208 uint_t g; 209 char *p, *k = (char *)key; 210 211 ASSERT(k); 212 for (p = k; *p != '\0'; p++) { 213 hash = (hash << 4) + *p; 214 if ((g = (hash & 0xf0000000)) != 0) { 215 hash ^= (g >> 24); 216 hash ^= g; 217 } 218 } 219 return (hash); 220 } 221 222 int 223 mod_hash_strkey_cmp(mod_hash_key_t key1, mod_hash_key_t key2) 224 { 225 return (strcmp((char *)key1, (char *)key2)); 226 } 227 228 void 229 mod_hash_strkey_dtor(mod_hash_key_t key) 230 { 231 char *c = (char *)key; 232 kmem_free(c, strlen(c) + 1); 233 } 234 235 void 236 mod_hash_strval_dtor(mod_hash_val_t val) 237 { 238 char *c = (char *)val; 239 kmem_free(c, strlen(c) + 1); 240 } 241 242 mod_hash_t * 243 mod_hash_create_strhash(char *name, size_t nchains, 244 void (*val_dtor)(mod_hash_val_t)) 245 { 246 return mod_hash_create_extended(name, nchains, mod_hash_strkey_dtor, 247 val_dtor, mod_hash_bystr, NULL, mod_hash_strkey_cmp, KM_SLEEP); 248 } 249 250 void 251 mod_hash_destroy_strhash(mod_hash_t *strhash) 252 { 253 ASSERT(strhash); 254 mod_hash_destroy_hash(strhash); 255 } 256 257 258 /* 259 * mod_hash_byptr() 260 * mod_hash_ptrkey_cmp() 261 * Hash and key comparison routines for hashes with pointer keys. 262 * 263 * mod_hash_create_ptrhash() 264 * mod_hash_destroy_ptrhash() 265 * Create a hash that uses pointers as keys. This hash algorithm 266 * picks an appropriate set of middle bits in the address to hash on 267 * based on the size of the hash table and a hint about the size of 268 * the items pointed at. 269 */ 270 uint_t 271 mod_hash_byptr(void *hash_data, mod_hash_key_t key) 272 { 273 uintptr_t k = (uintptr_t)key; 274 k >>= (int)(uintptr_t)hash_data; 275 276 return ((uint_t)k); 277 } 278 279 int 280 mod_hash_ptrkey_cmp(mod_hash_key_t key1, mod_hash_key_t key2) 281 { 282 uintptr_t k1 = (uintptr_t)key1; 283 uintptr_t k2 = (uintptr_t)key2; 284 if (k1 > k2) 285 return (-1); 286 else if (k1 < k2) 287 return (1); 288 else 289 return (0); 290 } 291 292 mod_hash_t * 293 mod_hash_create_ptrhash(char *name, size_t nchains, 294 void (*val_dtor)(mod_hash_val_t), size_t key_elem_size) 295 { 296 size_t rshift; 297 298 /* 299 * We want to hash on the bits in the middle of the address word 300 * Bits far to the right in the word have little significance, and 301 * are likely to all look the same (for example, an array of 302 * 256-byte structures will have the bottom 8 bits of address 303 * words the same). So we want to right-shift each address to 304 * ignore the bottom bits. 305 * 306 * The high bits, which are also unused, will get taken out when 307 * mod_hash takes hashkey % nchains. 308 */ 309 rshift = highbit(key_elem_size); 310 311 return mod_hash_create_extended(name, nchains, mod_hash_null_keydtor, 312 val_dtor, mod_hash_byptr, (void *)rshift, mod_hash_ptrkey_cmp, 313 KM_SLEEP); 314 } 315 316 void 317 mod_hash_destroy_ptrhash(mod_hash_t *hash) 318 { 319 ASSERT(hash); 320 mod_hash_destroy_hash(hash); 321 } 322 323 /* 324 * mod_hash_byid() 325 * mod_hash_idkey_cmp() 326 * Hash and key comparison routines for hashes with 32-bit unsigned keys. 327 * 328 * mod_hash_create_idhash() 329 * mod_hash_destroy_idhash() 330 * mod_hash_iddata_gen() 331 * Create a hash that uses numeric keys. 332 * 333 * The hash algorithm is documented in "Introduction to Algorithms" 334 * (Cormen, Leiserson, Rivest); when the hash table is created, it 335 * attempts to find the next largest prime above the number of hash 336 * slots. The hash index is then this number times the key modulo 337 * the hash size, or (key * prime) % nchains. 338 */ 339 uint_t 340 mod_hash_byid(void *hash_data, mod_hash_key_t key) 341 { 342 uint_t kval = (uint_t)(uintptr_t)hash_data; 343 return ((uint_t)(uintptr_t)key * (uint_t)kval); 344 } 345 346 int 347 mod_hash_idkey_cmp(mod_hash_key_t key1, mod_hash_key_t key2) 348 { 349 return ((uint_t)(uintptr_t)key1 - (uint_t)(uintptr_t)key2); 350 } 351 352 /* 353 * Generate the next largest prime number greater than nchains; this value 354 * is intended to be later passed in to mod_hash_create_extended() as the 355 * hash_data. 356 */ 357 uint_t 358 mod_hash_iddata_gen(size_t nchains) 359 { 360 uint_t kval, i, prime; 361 362 /* 363 * Pick the first (odd) prime greater than nchains. Make sure kval is 364 * odd (so start with nchains +1 or +2 as appropriate). 365 */ 366 kval = (nchains % 2 == 0) ? nchains + 1 : nchains + 2; 367 368 for (;;) { 369 prime = 1; 370 for (i = 3; i * i <= kval; i += 2) { 371 if (kval % i == 0) 372 prime = 0; 373 } 374 if (prime == 1) 375 break; 376 kval += 2; 377 } 378 return (kval); 379 } 380 381 mod_hash_t * 382 mod_hash_create_idhash(char *name, size_t nchains, 383 void (*val_dtor)(mod_hash_val_t)) 384 { 385 uint_t kval = mod_hash_iddata_gen(nchains); 386 387 return (mod_hash_create_extended(name, nchains, mod_hash_null_keydtor, 388 val_dtor, mod_hash_byid, (void *)(uintptr_t)kval, 389 mod_hash_idkey_cmp, KM_SLEEP)); 390 } 391 392 void 393 mod_hash_destroy_idhash(mod_hash_t *hash) 394 { 395 ASSERT(hash); 396 mod_hash_destroy_hash(hash); 397 } 398 399 /* 400 * mod_hash_init() 401 * sets up globals, etc for mod_hash_* 402 */ 403 void 404 mod_hash_init(void) 405 { 406 ASSERT(mh_e_cache == NULL); 407 mh_e_cache = kmem_cache_create("mod_hash_entries", 408 sizeof (struct mod_hash_entry), 0, NULL, NULL, NULL, NULL, 409 NULL, 0); 410 } 411 412 /* 413 * mod_hash_create_extended() 414 * The full-blown hash creation function. 415 * 416 * notes: 417 * nchains - how many hash slots to create. More hash slots will 418 * result in shorter hash chains, but will consume 419 * slightly more memory up front. 420 * sleep - should be KM_SLEEP or KM_NOSLEEP, to indicate whether 421 * to sleep for memory, or fail in low-memory conditions. 422 * 423 * Fails only if KM_NOSLEEP was specified, and no memory was available. 424 */ 425 mod_hash_t * 426 mod_hash_create_extended( 427 char *hname, /* descriptive name for hash */ 428 size_t nchains, /* number of hash slots */ 429 void (*kdtor)(mod_hash_key_t), /* key destructor */ 430 void (*vdtor)(mod_hash_val_t), /* value destructor */ 431 uint_t (*hash_alg)(void *, mod_hash_key_t), /* hash algorithm */ 432 void *hash_alg_data, /* pass-thru arg for hash_alg */ 433 int (*keycmp)(mod_hash_key_t, mod_hash_key_t), /* key comparator */ 434 int sleep) /* whether to sleep for mem */ 435 { 436 mod_hash_t *mod_hash; 437 ASSERT(hname && keycmp && hash_alg && vdtor && kdtor); 438 439 if ((mod_hash = kmem_zalloc(MH_SIZE(nchains), sleep)) == NULL) 440 return (NULL); 441 442 mod_hash->mh_name = kmem_alloc(strlen(hname) + 1, sleep); 443 if (mod_hash->mh_name == NULL) { 444 kmem_free(mod_hash, MH_SIZE(nchains)); 445 return (NULL); 446 } 447 (void) strcpy(mod_hash->mh_name, hname); 448 449 mod_hash->mh_sleep = sleep; 450 mod_hash->mh_nchains = nchains; 451 mod_hash->mh_kdtor = kdtor; 452 mod_hash->mh_vdtor = vdtor; 453 mod_hash->mh_hashalg = hash_alg; 454 mod_hash->mh_hashalg_data = hash_alg_data; 455 mod_hash->mh_keycmp = keycmp; 456 457 /* 458 * Link the hash up on the list of hashes 459 */ 460 mutex_enter(&mh_head_lock); 461 mod_hash->mh_next = mh_head; 462 mh_head = mod_hash; 463 mutex_exit(&mh_head_lock); 464 465 return (mod_hash); 466 } 467 468 /* 469 * mod_hash_destroy_hash() 470 * destroy a hash table, destroying all of its stored keys and values 471 * as well. 472 */ 473 void 474 mod_hash_destroy_hash(mod_hash_t *hash) 475 { 476 mod_hash_t *mhp, *mhpp; 477 478 mutex_enter(&mh_head_lock); 479 /* 480 * Remove the hash from the hash list 481 */ 482 if (hash == mh_head) { /* removing 1st list elem */ 483 mh_head = mh_head->mh_next; 484 } else { 485 /* 486 * mhpp can start out NULL since we know the 1st elem isn't the 487 * droid we're looking for. 488 */ 489 mhpp = NULL; 490 for (mhp = mh_head; mhp != NULL; mhp = mhp->mh_next) { 491 if (mhp == hash) { 492 mhpp->mh_next = mhp->mh_next; 493 break; 494 } 495 mhpp = mhp; 496 } 497 } 498 mutex_exit(&mh_head_lock); 499 500 /* 501 * Clean out keys and values. 502 */ 503 mod_hash_clear(hash); 504 505 kmem_free(hash->mh_name, strlen(hash->mh_name) + 1); 506 kmem_free(hash, MH_SIZE(hash->mh_nchains)); 507 } 508 509 /* 510 * i_mod_hash() 511 * Call the hashing algorithm for this hash table, with the given key. 512 */ 513 uint_t 514 i_mod_hash(mod_hash_t *hash, mod_hash_key_t key) 515 { 516 uint_t h; 517 /* 518 * Prevent div by 0 problems; 519 * Also a nice shortcut when using a hash as a list 520 */ 521 if (hash->mh_nchains == 1) 522 return (0); 523 524 h = (hash->mh_hashalg)(hash->mh_hashalg_data, key); 525 return (h % (hash->mh_nchains - 1)); 526 } 527 528 /* 529 * i_mod_hash_insert_nosync() 530 * mod_hash_insert() 531 * mod_hash_insert_reserve() 532 * insert 'val' into the hash table, using 'key' as its key. If 'key' is 533 * already a key in the hash, an error will be returned, and the key-val 534 * pair will not be inserted. i_mod_hash_insert_nosync() supports a simple 535 * handle abstraction, allowing hash entry allocation to be separated from 536 * the hash insertion. this abstraction allows simple use of the mod_hash 537 * structure in situations where mod_hash_insert() with a KM_SLEEP 538 * allocation policy would otherwise be unsafe. 539 */ 540 int 541 i_mod_hash_insert_nosync(mod_hash_t *hash, mod_hash_key_t key, 542 mod_hash_val_t val, mod_hash_hndl_t handle) 543 { 544 uint_t hashidx; 545 struct mod_hash_entry *entry; 546 547 ASSERT(hash); 548 549 /* 550 * If we've not been given reserved storage, allocate storage directly, 551 * using the hash's allocation policy. 552 */ 553 if (handle == (mod_hash_hndl_t)0) { 554 entry = kmem_cache_alloc(mh_e_cache, hash->mh_sleep); 555 if (entry == NULL) { 556 hash->mh_stat.mhs_nomem++; 557 return (MH_ERR_NOMEM); 558 } 559 } else { 560 entry = (struct mod_hash_entry *)handle; 561 } 562 563 hashidx = i_mod_hash(hash, key); 564 entry->mhe_key = key; 565 entry->mhe_val = val; 566 entry->mhe_next = hash->mh_entries[hashidx]; 567 568 hash->mh_entries[hashidx] = entry; 569 hash->mh_stat.mhs_nelems++; 570 571 return (0); 572 } 573 574 int 575 mod_hash_insert(mod_hash_t *hash, mod_hash_key_t key, mod_hash_val_t val) 576 { 577 int res; 578 mod_hash_val_t v; 579 580 rw_enter(&hash->mh_contents, RW_WRITER); 581 582 /* 583 * Disallow duplicate keys in the hash 584 */ 585 if (i_mod_hash_find_nosync(hash, key, &v) == 0) { 586 rw_exit(&hash->mh_contents); 587 hash->mh_stat.mhs_coll++; 588 return (MH_ERR_DUPLICATE); 589 } 590 591 res = i_mod_hash_insert_nosync(hash, key, val, (mod_hash_hndl_t)0); 592 rw_exit(&hash->mh_contents); 593 594 return (res); 595 } 596 597 int 598 mod_hash_insert_reserve(mod_hash_t *hash, mod_hash_key_t key, 599 mod_hash_val_t val, mod_hash_hndl_t handle) 600 { 601 int res; 602 mod_hash_val_t v; 603 604 rw_enter(&hash->mh_contents, RW_WRITER); 605 606 /* 607 * Disallow duplicate keys in the hash 608 */ 609 if (i_mod_hash_find_nosync(hash, key, &v) == 0) { 610 rw_exit(&hash->mh_contents); 611 hash->mh_stat.mhs_coll++; 612 return (MH_ERR_DUPLICATE); 613 } 614 res = i_mod_hash_insert_nosync(hash, key, val, handle); 615 rw_exit(&hash->mh_contents); 616 617 return (res); 618 } 619 620 /* 621 * mod_hash_reserve() 622 * mod_hash_reserve_nosleep() 623 * mod_hash_cancel() 624 * Make or cancel a mod_hash_entry_t reservation. Reservations are used in 625 * mod_hash_insert_reserve() above. 626 */ 627 int 628 mod_hash_reserve(mod_hash_t *hash, mod_hash_hndl_t *handlep) 629 { 630 *handlep = kmem_cache_alloc(mh_e_cache, hash->mh_sleep); 631 if (*handlep == NULL) { 632 hash->mh_stat.mhs_nomem++; 633 return (MH_ERR_NOMEM); 634 } 635 636 return (0); 637 } 638 639 int 640 mod_hash_reserve_nosleep(mod_hash_t *hash, mod_hash_hndl_t *handlep) 641 { 642 *handlep = kmem_cache_alloc(mh_e_cache, KM_NOSLEEP); 643 if (*handlep == NULL) { 644 hash->mh_stat.mhs_nomem++; 645 return (MH_ERR_NOMEM); 646 } 647 648 return (0); 649 650 } 651 652 /*ARGSUSED*/ 653 void 654 mod_hash_cancel(mod_hash_t *hash, mod_hash_hndl_t *handlep) 655 { 656 kmem_cache_free(mh_e_cache, *handlep); 657 *handlep = (mod_hash_hndl_t)0; 658 } 659 660 /* 661 * i_mod_hash_remove_nosync() 662 * mod_hash_remove() 663 * Remove an element from the hash table. 664 */ 665 int 666 i_mod_hash_remove_nosync(mod_hash_t *hash, mod_hash_key_t key, 667 mod_hash_val_t *val) 668 { 669 int hashidx; 670 struct mod_hash_entry *e, *ep; 671 672 hashidx = i_mod_hash(hash, key); 673 ep = NULL; /* e's parent */ 674 675 for (e = hash->mh_entries[hashidx]; e != NULL; e = e->mhe_next) { 676 if (MH_KEYCMP(hash, e->mhe_key, key) == 0) 677 break; 678 ep = e; 679 } 680 681 if (e == NULL) { /* not found */ 682 return (MH_ERR_NOTFOUND); 683 } 684 685 if (ep == NULL) /* special case 1st element in bucket */ 686 hash->mh_entries[hashidx] = e->mhe_next; 687 else 688 ep->mhe_next = e->mhe_next; 689 690 /* 691 * Clean up resources used by the node's key. 692 */ 693 MH_KEY_DESTROY(hash, e->mhe_key); 694 695 *val = e->mhe_val; 696 kmem_cache_free(mh_e_cache, e); 697 hash->mh_stat.mhs_nelems--; 698 699 return (0); 700 } 701 702 int 703 mod_hash_remove(mod_hash_t *hash, mod_hash_key_t key, mod_hash_val_t *val) 704 { 705 int res; 706 707 rw_enter(&hash->mh_contents, RW_WRITER); 708 res = i_mod_hash_remove_nosync(hash, key, val); 709 rw_exit(&hash->mh_contents); 710 711 return (res); 712 } 713 714 /* 715 * mod_hash_replace() 716 * atomically remove an existing key-value pair from a hash, and replace 717 * the key and value with the ones supplied. The removed key and value 718 * (if any) are destroyed. 719 */ 720 int 721 mod_hash_replace(mod_hash_t *hash, mod_hash_key_t key, mod_hash_val_t val) 722 { 723 int res; 724 mod_hash_val_t v; 725 726 rw_enter(&hash->mh_contents, RW_WRITER); 727 728 if (i_mod_hash_remove_nosync(hash, key, &v) == 0) { 729 /* 730 * mod_hash_remove() takes care of freeing up the key resources. 731 */ 732 MH_VAL_DESTROY(hash, v); 733 } 734 res = i_mod_hash_insert_nosync(hash, key, val, (mod_hash_hndl_t)0); 735 736 rw_exit(&hash->mh_contents); 737 738 return (res); 739 } 740 741 /* 742 * mod_hash_destroy() 743 * Remove an element from the hash table matching 'key', and destroy it. 744 */ 745 int 746 mod_hash_destroy(mod_hash_t *hash, mod_hash_key_t key) 747 { 748 mod_hash_val_t val; 749 int rv; 750 751 rw_enter(&hash->mh_contents, RW_WRITER); 752 753 if ((rv = i_mod_hash_remove_nosync(hash, key, &val)) == 0) { 754 /* 755 * mod_hash_remove() takes care of freeing up the key resources. 756 */ 757 MH_VAL_DESTROY(hash, val); 758 } 759 760 rw_exit(&hash->mh_contents); 761 return (rv); 762 } 763 764 /* 765 * i_mod_hash_find_nosync() 766 * mod_hash_find() 767 * Find a value in the hash table corresponding to the given key. 768 */ 769 int 770 i_mod_hash_find_nosync(mod_hash_t *hash, mod_hash_key_t key, 771 mod_hash_val_t *val) 772 { 773 uint_t hashidx; 774 struct mod_hash_entry *e; 775 776 hashidx = i_mod_hash(hash, key); 777 778 for (e = hash->mh_entries[hashidx]; e != NULL; e = e->mhe_next) { 779 if (MH_KEYCMP(hash, e->mhe_key, key) == 0) { 780 *val = e->mhe_val; 781 hash->mh_stat.mhs_hit++; 782 return (0); 783 } 784 } 785 hash->mh_stat.mhs_miss++; 786 return (MH_ERR_NOTFOUND); 787 } 788 789 int 790 mod_hash_find(mod_hash_t *hash, mod_hash_key_t key, mod_hash_val_t *val) 791 { 792 int res; 793 794 rw_enter(&hash->mh_contents, RW_READER); 795 res = i_mod_hash_find_nosync(hash, key, val); 796 rw_exit(&hash->mh_contents); 797 798 return (res); 799 } 800 801 int 802 mod_hash_find_cb(mod_hash_t *hash, mod_hash_key_t key, mod_hash_val_t *val, 803 void (*find_cb)(mod_hash_key_t, mod_hash_val_t)) 804 { 805 int res; 806 807 rw_enter(&hash->mh_contents, RW_READER); 808 res = i_mod_hash_find_nosync(hash, key, val); 809 if (res == 0) { 810 find_cb(key, *val); 811 } 812 rw_exit(&hash->mh_contents); 813 814 return (res); 815 } 816 817 int 818 mod_hash_find_cb_rval(mod_hash_t *hash, mod_hash_key_t key, mod_hash_val_t *val, 819 int (*find_cb)(mod_hash_key_t, mod_hash_val_t), int *cb_rval) 820 { 821 int res; 822 823 rw_enter(&hash->mh_contents, RW_READER); 824 res = i_mod_hash_find_nosync(hash, key, val); 825 if (res == 0) { 826 *cb_rval = find_cb(key, *val); 827 } 828 rw_exit(&hash->mh_contents); 829 830 return (res); 831 } 832 833 void 834 i_mod_hash_walk_nosync(mod_hash_t *hash, 835 uint_t (*callback)(mod_hash_key_t, mod_hash_val_t *, void *), void *arg) 836 { 837 struct mod_hash_entry *e; 838 uint_t hashidx; 839 int res = MH_WALK_CONTINUE; 840 841 for (hashidx = 0; 842 (hashidx < (hash->mh_nchains - 1)) && (res == MH_WALK_CONTINUE); 843 hashidx++) { 844 e = hash->mh_entries[hashidx]; 845 while ((e != NULL) && (res == MH_WALK_CONTINUE)) { 846 res = callback(e->mhe_key, e->mhe_val, arg); 847 e = e->mhe_next; 848 } 849 } 850 } 851 852 /* 853 * mod_hash_walk() 854 * Walks all the elements in the hashtable and invokes the callback 855 * function with the key/value pair for each element. The hashtable 856 * is locked for readers so the callback function should not attempt 857 * to do any updates to the hashable. The callback function should 858 * return MH_WALK_CONTINUE to continue walking the hashtable or 859 * MH_WALK_TERMINATE to abort the walk of the hashtable. 860 */ 861 void 862 mod_hash_walk(mod_hash_t *hash, 863 uint_t (*callback)(mod_hash_key_t, mod_hash_val_t *, void *), void *arg) 864 { 865 rw_enter(&hash->mh_contents, RW_READER); 866 i_mod_hash_walk_nosync(hash, callback, arg); 867 rw_exit(&hash->mh_contents); 868 } 869 870 871 /* 872 * i_mod_hash_clear_nosync() 873 * mod_hash_clear() 874 * Clears the given hash table by calling the destructor of every hash 875 * element and freeing up all mod_hash_entry's. 876 */ 877 void 878 i_mod_hash_clear_nosync(mod_hash_t *hash) 879 { 880 int i; 881 struct mod_hash_entry *e, *old_e; 882 883 for (i = 0; i < hash->mh_nchains; i++) { 884 e = hash->mh_entries[i]; 885 while (e != NULL) { 886 MH_KEY_DESTROY(hash, e->mhe_key); 887 MH_VAL_DESTROY(hash, e->mhe_val); 888 old_e = e; 889 e = e->mhe_next; 890 kmem_cache_free(mh_e_cache, old_e); 891 } 892 hash->mh_entries[i] = NULL; 893 } 894 hash->mh_stat.mhs_nelems = 0; 895 } 896 897 void 898 mod_hash_clear(mod_hash_t *hash) 899 { 900 ASSERT(hash); 901 rw_enter(&hash->mh_contents, RW_WRITER); 902 i_mod_hash_clear_nosync(hash); 903 rw_exit(&hash->mh_contents); 904 } 905