lib/librte_hash/rte_cuckoo_hash.c

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <string.h>
  35 #include <stdint.h>
  36 #include <errno.h>
  37 #include <stdio.h>
  38 #include <stdarg.h>
  39 #include <sys/queue.h>
  40
  41 #include <rte_common.h>
  42 #include <rte_memory.h>         /* for definition of RTE_CACHE_LINE_SIZE */
  43 #include <rte_log.h>
  44 #include <rte_memcpy.h>
  45 #include <rte_prefetch.h>
  46 #include <rte_branch_prediction.h>
  47 #include <rte_memzone.h>
  48 #include <rte_malloc.h>
  49 #include <rte_eal.h>
  50 #include <rte_eal_memconfig.h>
  51 #include <rte_per_lcore.h>
  52 #include <rte_errno.h>
  53 #include <rte_string_fns.h>
  54 #include <rte_cpuflags.h>
  55 #include <rte_log.h>
  56 #include <rte_rwlock.h>
  57 #include <rte_spinlock.h>
  58 #include <rte_ring.h>
  59 #include <rte_compat.h>
  60
  61 #include "rte_hash.h"
  62 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
  63 #include "rte_cmp_x86.h"
  64 #endif
  65
  66 TAILQ_HEAD(rte_hash_list, rte_tailq_entry);
  67
  68 static struct rte_tailq_elem rte_hash_tailq = {
  69         .name = "RTE_HASH",
  70 };
  71 EAL_REGISTER_TAILQ(rte_hash_tailq)
  72
  73 /* Macro to enable/disable run-time checking of function parameters */
  74 #if defined(RTE_LIBRTE_HASH_DEBUG)
  75 #define RETURN_IF_TRUE(cond, retval) do { \
  76         if (cond) \
  77                 return retval; \
  78 } while (0)
  79 #else
  80 #define RETURN_IF_TRUE(cond, retval)
  81 #endif
  82
  83 /* Hash function used if none is specified */
  84 #ifdef RTE_MACHINE_CPUFLAG_SSE4_2
  85 #include <rte_hash_crc.h>
  86 #define DEFAULT_HASH_FUNC       rte_hash_crc
  87 #else
  88 #include <rte_jhash.h>
  89 #define DEFAULT_HASH_FUNC       rte_jhash
  90 #endif
  91
  92 /** Number of items per bucket. */
  93 #define RTE_HASH_BUCKET_ENTRIES         4
  94
  95 #define NULL_SIGNATURE                  0
  96
  97 #define KEY_ALIGNMENT                   16
  98
  99 typedef int (*rte_hash_cmp_eq_t)(const void *key1, const void *key2, size_t key_len);
 100
 101 /** A hash table structure. */
 102 struct rte_hash {
 103         char name[RTE_HASH_NAMESIZE];   /**< Name of the hash. */
 104         uint32_t entries;               /**< Total table entries. */
 105         uint32_t num_buckets;           /**< Number of buckets in table. */
 106         uint32_t key_len;               /**< Length of hash key. */
 107         rte_hash_function hash_func;    /**< Function used to calculate hash. */
 108         uint32_t hash_func_init_val;    /**< Init value used by hash_func. */
 109         rte_hash_cmp_eq_t rte_hash_cmp_eq; /**< Function used to compare keys. */
 110         uint32_t bucket_bitmask;        /**< Bitmask for getting bucket index
 111                                                 from hash signature. */
 112         uint32_t key_entry_size;         /**< Size of each key entry. */
 113
 114         struct rte_ring *free_slots;    /**< Ring that stores all indexes
 115                                                 of the free slots in the key table */
 116         void *key_store;                /**< Table storing all keys and data */
 117         struct rte_hash_bucket *buckets;        /**< Table with buckets storing all the
 118                                                         hash values and key indexes
 119                                                         to the key table*/
 120 } __rte_cache_aligned;
 121
 122 /* Structure storing both primary and secondary hashes */
 123 struct rte_hash_signatures {
 124         union {
 125                 struct {
 126                         hash_sig_t current;
 127                         hash_sig_t alt;
 128                 };
 129                 uint64_t sig;
 130         };
 131 };
 132
 133 /* Structure that stores key-value pair */
 134 struct rte_hash_key {
 135         union {
 136                 uintptr_t idata;
 137                 void *pdata;
 138         };
 139         /* Variable key size */
 140         char key[0];
 141 } __attribute__((aligned(KEY_ALIGNMENT)));
 142
 143 /** Bucket structure */
 144 struct rte_hash_bucket {
 145         struct rte_hash_signatures signatures[RTE_HASH_BUCKET_ENTRIES];
 146         /* Includes dummy key index that always contains index 0 */
 147         uint32_t key_idx[RTE_HASH_BUCKET_ENTRIES + 1];
 148         uint8_t flag[RTE_HASH_BUCKET_ENTRIES];
 149 } __rte_cache_aligned;
 150
 151 struct rte_hash *
 152 rte_hash_find_existing(const char *name)
 153 {
 154         struct rte_hash *h = NULL;
 155         struct rte_tailq_entry *te;
 156         struct rte_hash_list *hash_list;
 157
 158         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 159
 160         rte_rwlock_read_lock(RTE_EAL_TAILQ_RWLOCK);
 161         TAILQ_FOREACH(te, hash_list, next) {
 162                 h = (struct rte_hash *) te->data;
 163                 if (strncmp(name, h->name, RTE_HASH_NAMESIZE) == 0)
 164                         break;
 165         }
 166         rte_rwlock_read_unlock(RTE_EAL_TAILQ_RWLOCK);
 167
 168         if (te == NULL) {
 169                 rte_errno = ENOENT;
 170                 return NULL;
 171         }
 172         return h;
 173 }
 174
 175 struct rte_hash *
 176 rte_hash_create(const struct rte_hash_parameters *params)
 177 {
 178         struct rte_hash *h = NULL;
 179         struct rte_tailq_entry *te = NULL;
 180         struct rte_hash_list *hash_list;
 181         struct rte_ring *r = NULL;
 182         char hash_name[RTE_HASH_NAMESIZE];
 183         void *k = NULL;
 184         void *buckets = NULL;
 185         char ring_name[RTE_RING_NAMESIZE];
 186         unsigned i;
 187
 188         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 189
 190         if (params == NULL) {
 191                 RTE_LOG(ERR, HASH, "rte_hash_create has no parameters\n");
 192                 return NULL;
 193         }
 194
 195         /* Check for valid parameters */
 196         if ((params->entries > RTE_HASH_ENTRIES_MAX) ||
 197                         (params->entries < RTE_HASH_BUCKET_ENTRIES) ||
 198                         !rte_is_power_of_2(RTE_HASH_BUCKET_ENTRIES) ||
 199                         (params->key_len == 0)) {
 200                 rte_errno = EINVAL;
 201                 RTE_LOG(ERR, HASH, "rte_hash_create has invalid parameters\n");
 202                 return NULL;
 203         }
 204
 205         snprintf(hash_name, sizeof(hash_name), "HT_%s", params->name);
 206
 207         /* Guarantee there's no existing */
 208         h = rte_hash_find_existing(params->name);
 209         if (h != NULL)
 210                 return h;
 211
 212         te = rte_zmalloc("HASH_TAILQ_ENTRY", sizeof(*te), 0);
 213         if (te == NULL) {
 214                 RTE_LOG(ERR, HASH, "tailq entry allocation failed\n");
 215                 goto err;
 216         }
 217
 218         h = (struct rte_hash *)rte_zmalloc_socket(hash_name, sizeof(struct rte_hash),
 219                                         RTE_CACHE_LINE_SIZE, params->socket_id);
 220
 221         if (h == NULL) {
 222                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 223                 goto err;
 224         }
 225
 226         const uint32_t num_buckets = rte_align32pow2(params->entries)
 227                                         / RTE_HASH_BUCKET_ENTRIES;
 228
 229         buckets = rte_zmalloc_socket(NULL,
 230                                 num_buckets * sizeof(struct rte_hash_bucket),
 231                                 RTE_CACHE_LINE_SIZE, params->socket_id);
 232
 233         if (buckets == NULL) {
 234                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 235                 goto err;
 236         }
 237
 238         const uint32_t key_entry_size = sizeof(struct rte_hash_key) + params->key_len;
 239
 240         /* Store all keys and leave the first entry as a dummy entry for lookup_bulk */
 241         const uint64_t key_tbl_size = (uint64_t) key_entry_size * (params->entries + 1);
 242
 243         k = rte_zmalloc_socket(NULL, key_tbl_size,
 244                         RTE_CACHE_LINE_SIZE, params->socket_id);
 245
 246         if (k == NULL) {
 247                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 248                 goto err;
 249         }
 250
 251 /*
 252  * If x86 architecture is used, select appropriate compare function,
 253  * which may use x86 instrinsics, otherwise use memcmp
 254  */
 255 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_X32)
 256         /* Select function to compare keys */
 257         switch (params->key_len) {
 258         case 16:
 259                 h->rte_hash_cmp_eq = rte_hash_k16_cmp_eq;
 260                 break;
 261         case 32:
 262                 h->rte_hash_cmp_eq = rte_hash_k32_cmp_eq;
 263                 break;
 264         case 48:
 265                 h->rte_hash_cmp_eq = rte_hash_k48_cmp_eq;
 266                 break;
 267         case 64:
 268                 h->rte_hash_cmp_eq = rte_hash_k64_cmp_eq;
 269                 break;
 270         case 80:
 271                 h->rte_hash_cmp_eq = rte_hash_k80_cmp_eq;
 272                 break;
 273         case 96:
 274                 h->rte_hash_cmp_eq = rte_hash_k96_cmp_eq;
 275                 break;
 276         case 112:
 277                 h->rte_hash_cmp_eq = rte_hash_k112_cmp_eq;
 278                 break;
 279         case 128:
 280                 h->rte_hash_cmp_eq = rte_hash_k128_cmp_eq;
 281                 break;
 282         default:
 283                 /* If key is not multiple of 16, use generic memcmp */
 284                 h->rte_hash_cmp_eq = memcmp;
 285         }
 286 #else
 287         h->rte_hash_cmp_eq = memcmp;
 288 #endif
 289
 290         snprintf(ring_name, sizeof(ring_name), "HT_%s", params->name);
 291         r = rte_ring_create(ring_name, rte_align32pow2(params->entries + 1),
 292                                 params->socket_id, 0);
 293         if (r == NULL) {
 294                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 295                 goto err;
 296         }
 297
 298         /* Setup hash context */
 299         snprintf(h->name, sizeof(h->name), "%s", params->name);
 300         h->entries = params->entries;
 301         h->key_len = params->key_len;
 302         h->key_entry_size = key_entry_size;
 303         h->hash_func_init_val = params->hash_func_init_val;
 304
 305         h->num_buckets = num_buckets;
 306         h->bucket_bitmask = h->num_buckets - 1;
 307         h->buckets = buckets;
 308         h->hash_func = (params->hash_func == NULL) ?
 309                 DEFAULT_HASH_FUNC : params->hash_func;
 310
 311         h->key_store = k;
 312         h->free_slots = r;
 313
 314         /* populate the free slots ring. Entry zero is reserved for key misses */
 315         for (i = 1; i < params->entries + 1; i++)
 316                 rte_ring_sp_enqueue(r, (void *)((uintptr_t) i));
 317
 318         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 319         te->data = (void *) h;
 320         TAILQ_INSERT_TAIL(hash_list, te, next);
 321         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 322
 323         return h;
 324 err:
 325         rte_free(te);
 326         rte_free(h);
 327         rte_free(buckets);
 328         rte_free(k);
 329         return NULL;
 330 }
 331
 332 void
 333 rte_hash_free(struct rte_hash *h)
 334 {
 335         struct rte_tailq_entry *te;
 336         struct rte_hash_list *hash_list;
 337
 338         if (h == NULL)
 339                 return;
 340
 341         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 342
 343         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 344
 345         /* find out tailq entry */
 346         TAILQ_FOREACH(te, hash_list, next) {
 347                 if (te->data == (void *) h)
 348                         break;
 349         }
 350
 351         if (te == NULL) {
 352                 rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 353                 return;
 354         }
 355
 356         TAILQ_REMOVE(hash_list, te, next);
 357
 358         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 359
 360         rte_ring_free(h->free_slots);
 361         rte_free(h->key_store);
 362         rte_free(h->buckets);
 363         rte_free(h);
 364         rte_free(te);
 365 }
 366
 367 hash_sig_t
 368 rte_hash_hash(const struct rte_hash *h, const void *key)
 369 {
 370         /* calc hash result by key */
 371         return h->hash_func(key, h->key_len, h->hash_func_init_val);
 372 }
 373
 374 /* Calc the secondary hash value from the primary hash value of a given key */
 375 static inline hash_sig_t
 376 rte_hash_secondary_hash(const hash_sig_t primary_hash)
 377 {
 378         static const unsigned all_bits_shift = 12;
 379         static const unsigned alt_bits_xor = 0x5bd1e995;
 380
 381         uint32_t tag = primary_hash >> all_bits_shift;
 382
 383         return (primary_hash ^ ((tag + 1) * alt_bits_xor));
 384 }
 385
 386 void
 387 rte_hash_reset(struct rte_hash *h)
 388 {
 389         void *ptr;
 390         unsigned i;
 391
 392         if (h == NULL)
 393                 return;
 394
 395         memset(h->buckets, 0, h->num_buckets * sizeof(struct rte_hash_bucket));
 396         memset(h->key_store, 0, h->key_entry_size * (h->entries + 1));
 397
 398         /* clear the free ring */
 399         while (rte_ring_dequeue(h->free_slots, &ptr) == 0)
 400                 rte_pause();
 401
 402         /* Repopulate the free slots ring. Entry zero is reserved for key misses */
 403         for (i = 1; i < h->entries + 1; i++)
 404                 rte_ring_sp_enqueue(h->free_slots, (void *)((uintptr_t) i));
 405 }
 406
 407 /* Search for an entry that can be pushed to its alternative location */
 408 static inline int
 409 make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt)
 410 {
 411         unsigned i, j;
 412         int ret;
 413         uint32_t next_bucket_idx;
 414         struct rte_hash_bucket *next_bkt[RTE_HASH_BUCKET_ENTRIES];
 415
 416         /*
 417          * Push existing item (search for bucket with space in
 418          * alternative locations) to its alternative location
 419          */
 420         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 421                 /* Search for space in alternative locations */
 422                 next_bucket_idx = bkt->signatures[i].alt & h->bucket_bitmask;
 423                 next_bkt[i] = &h->buckets[next_bucket_idx];
 424                 for (j = 0; j < RTE_HASH_BUCKET_ENTRIES; j++) {
 425                         if (next_bkt[i]->signatures[j].sig == NULL_SIGNATURE)
 426                                 break;
 427                 }
 428
 429                 if (j != RTE_HASH_BUCKET_ENTRIES)
 430                         break;
 431         }
 432
 433         /* Alternative location has spare room (end of recursive function) */
 434         if (i != RTE_HASH_BUCKET_ENTRIES) {
 435                 next_bkt[i]->signatures[j].alt = bkt->signatures[i].current;
 436                 next_bkt[i]->signatures[j].current = bkt->signatures[i].alt;
 437                 next_bkt[i]->key_idx[j] = bkt->key_idx[i];
 438                 return i;
 439         }
 440
 441         /* Pick entry that has not been pushed yet */
 442         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++)
 443                 if (bkt->flag[i] == 0)
 444                         break;
 445
 446         /* All entries have been pushed, so entry cannot be added */
 447         if (i == RTE_HASH_BUCKET_ENTRIES)
 448                 return -ENOSPC;
 449
 450         /* Set flag to indicate that this entry is going to be pushed */
 451         bkt->flag[i] = 1;
 452         /* Need room in alternative bucket to insert the pushed entry */
 453         ret = make_space_bucket(h, next_bkt[i]);
 454         /*
 455          * After recursive function.
 456          * Clear flags and insert the pushed entry
 457          * in its alternative location if successful,
 458          * or return error
 459          */
 460         bkt->flag[i] = 0;
 461         if (ret >= 0) {
 462                 next_bkt[i]->signatures[ret].alt = bkt->signatures[i].current;
 463                 next_bkt[i]->signatures[ret].current = bkt->signatures[i].alt;
 464                 next_bkt[i]->key_idx[ret] = bkt->key_idx[i];
 465                 return i;
 466         } else
 467                 return ret;
 468
 469 }
 470
 471 static inline int32_t
 472 __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
 473                                                 hash_sig_t sig, void *data)
 474 {
 475         hash_sig_t alt_hash;
 476         uint32_t prim_bucket_idx, sec_bucket_idx;
 477         unsigned i;
 478         struct rte_hash_bucket *prim_bkt, *sec_bkt;
 479         struct rte_hash_key *new_k, *k, *keys = h->key_store;
 480         void *slot_id;
 481         uint32_t new_idx;
 482         int ret;
 483
 484         prim_bucket_idx = sig & h->bucket_bitmask;
 485         prim_bkt = &h->buckets[prim_bucket_idx];
 486         rte_prefetch0(prim_bkt);
 487
 488         alt_hash = rte_hash_secondary_hash(sig);
 489         sec_bucket_idx = alt_hash & h->bucket_bitmask;
 490         sec_bkt = &h->buckets[sec_bucket_idx];
 491         rte_prefetch0(sec_bkt);
 492
 493         /* Get a new slot for storing the new key */
 494         if (rte_ring_sc_dequeue(h->free_slots, &slot_id) != 0)
 495                 return -ENOSPC;
 496         new_k = RTE_PTR_ADD(keys, (uintptr_t)slot_id * h->key_entry_size);
 497         rte_prefetch0(new_k);
 498         new_idx = (uint32_t)((uintptr_t) slot_id);
 499
 500         /* Check if key is already inserted in primary location */
 501         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 502                 if (prim_bkt->signatures[i].current == sig &&
 503                                 prim_bkt->signatures[i].alt == alt_hash)  {
 504                         k = (struct rte_hash_key *) ((char *)keys +
 505                                         prim_bkt->key_idx[i] * h->key_entry_size);
 506                         if (h->rte_hash_cmp_eq(key, k->key, h->key_len) == 0) {
 507                                 rte_ring_sp_enqueue(h->free_slots, slot_id);
 508                                 /* Update data */
 509                                 k->pdata = data;
 510                                 /*
 511                                  * Return index where key is stored,
 512                                  * substracting the first dummy index
 513                                  */
 514                                 return (prim_bkt->key_idx[i] - 1);
 515                         }
 516                 }
 517         }
 518
 519         /* Check if key is already inserted in secondary location */
 520         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 521                 if (sec_bkt->signatures[i].alt == sig &&
 522                                 sec_bkt->signatures[i].current == alt_hash)  {
 523                         k = (struct rte_hash_key *) ((char *)keys +
 524                                         sec_bkt->key_idx[i] * h->key_entry_size);
 525                         if (h->rte_hash_cmp_eq(key, k->key, h->key_len) == 0) {
 526                                 rte_ring_sp_enqueue(h->free_slots, slot_id);
 527                                 /* Update data */
 528                                 k->pdata = data;
 529                                 /*
 530                                  * Return index where key is stored,
 531                                  * substracting the first dummy index
 532                                  */
 533                                 return (sec_bkt->key_idx[i] - 1);
 534                         }
 535                 }
 536         }
 537
 538         /* Copy key */
 539         rte_memcpy(new_k->key, key, h->key_len);
 540         new_k->pdata = data;
 541
 542         /* Insert new entry is there is room in the primary bucket */
 543         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 544                 /* Check if slot is available */
 545                 if (likely(prim_bkt->signatures[i].sig == NULL_SIGNATURE)) {
 546                         prim_bkt->signatures[i].current = sig;
 547                         prim_bkt->signatures[i].alt = alt_hash;
 548                         prim_bkt->key_idx[i] = new_idx;
 549                         return new_idx - 1;
 550                 }
 551         }
 552
 553         /* Primary bucket is full, so we need to make space for new entry */
 554         ret = make_space_bucket(h, prim_bkt);
 555         /*
 556          * After recursive function.
 557          * Insert the new entry in the position of the pushed entry
 558          * if successful or return error and
 559          * store the new slot back in the ring
 560          */
 561         if (ret >= 0) {
 562                 prim_bkt->signatures[ret].current = sig;
 563                 prim_bkt->signatures[ret].alt = alt_hash;
 564                 prim_bkt->key_idx[ret] = new_idx;
 565                 return (new_idx - 1);
 566         }
 567
 568         /* Error in addition, store new slot back in the ring and return error */
 569         rte_ring_sp_enqueue(h->free_slots,
 570                 (void *)((uintptr_t) new_idx));
 571         return ret;
 572
 573 }
 574
 575 int32_t
 576 rte_hash_add_key_with_hash(const struct rte_hash *h,
 577                         const void *key, hash_sig_t sig)
 578 {
 579         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 580         return __rte_hash_add_key_with_hash(h, key, sig, 0);
 581 }
 582
 583 int32_t
 584 rte_hash_add_key(const struct rte_hash *h, const void *key)
 585 {
 586         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 587         return __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), 0);
 588 }
 589
 590 int
 591 rte_hash_add_key_with_hash_data(const struct rte_hash *h,
 592                         const void *key, hash_sig_t sig, void *data)
 593 {
 594         int ret;
 595
 596         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 597         ret = __rte_hash_add_key_with_hash(h, key, sig, data);
 598         if (ret >= 0)
 599                 return 0;
 600         else
 601                 return ret;
 602 }
 603
 604 int
 605 rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data)
 606 {
 607         int ret;
 608
 609         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 610
 611         ret = __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), data);
 612         if (ret >= 0)
 613                 return 0;
 614         else
 615                 return ret;
 616 }
 617 static inline int32_t
 618 __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
 619                                         hash_sig_t sig, void **data)
 620 {
 621         uint32_t bucket_idx;
 622         hash_sig_t alt_hash;
 623         unsigned i;
 624         struct rte_hash_bucket *bkt;
 625         struct rte_hash_key *k, *keys = h->key_store;
 626
 627         bucket_idx = sig & h->bucket_bitmask;
 628         bkt = &h->buckets[bucket_idx];
 629
 630         /* Check if key is in primary location */
 631         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 632                 if (bkt->signatures[i].current == sig &&
 633                                 bkt->signatures[i].sig != NULL_SIGNATURE) {
 634                         k = (struct rte_hash_key *) ((char *)keys +
 635                                         bkt->key_idx[i] * h->key_entry_size);
 636                         if (h->rte_hash_cmp_eq(key, k->key, h->key_len) == 0) {
 637                                 if (data != NULL)
 638                                         *data = k->pdata;
 639                                 /*
 640                                  * Return index where key is stored,
 641                                  * substracting the first dummy index
 642                                  */
 643                                 return (bkt->key_idx[i] - 1);
 644                         }
 645                 }
 646         }
 647
 648         /* Calculate secondary hash */
 649         alt_hash = rte_hash_secondary_hash(sig);
 650         bucket_idx = alt_hash & h->bucket_bitmask;
 651         bkt = &h->buckets[bucket_idx];
 652
 653         /* Check if key is in secondary location */
 654         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 655                 if (bkt->signatures[i].current == alt_hash &&
 656                                 bkt->signatures[i].alt == sig) {
 657                         k = (struct rte_hash_key *) ((char *)keys +
 658                                         bkt->key_idx[i] * h->key_entry_size);
 659                         if (h->rte_hash_cmp_eq(key, k->key, h->key_len) == 0) {
 660                                 if (data != NULL)
 661                                         *data = k->pdata;
 662                                 /*
 663                                  * Return index where key is stored,
 664                                  * substracting the first dummy index
 665                                  */
 666                                 return (bkt->key_idx[i] - 1);
 667                         }
 668                 }
 669         }
 670
 671         return -ENOENT;
 672 }
 673
 674 int32_t
 675 rte_hash_lookup_with_hash(const struct rte_hash *h,
 676                         const void *key, hash_sig_t sig)
 677 {
 678         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 679         return __rte_hash_lookup_with_hash(h, key, sig, NULL);
 680 }
 681
 682 int32_t
 683 rte_hash_lookup(const struct rte_hash *h, const void *key)
 684 {
 685         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 686         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), NULL);
 687 }
 688
 689 int
 690 rte_hash_lookup_with_hash_data(const struct rte_hash *h,
 691                         const void *key, hash_sig_t sig, void **data)
 692 {
 693         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 694         return __rte_hash_lookup_with_hash(h, key, sig, data);
 695 }
 696
 697 int
 698 rte_hash_lookup_data(const struct rte_hash *h, const void *key, void **data)
 699 {
 700         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 701         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), data);
 702 }
 703
 704 static inline int32_t
 705 __rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
 706                                                 hash_sig_t sig)
 707 {
 708         uint32_t bucket_idx;
 709         hash_sig_t alt_hash;
 710         unsigned i;
 711         struct rte_hash_bucket *bkt;
 712         struct rte_hash_key *k, *keys = h->key_store;
 713
 714         bucket_idx = sig & h->bucket_bitmask;
 715         bkt = &h->buckets[bucket_idx];
 716
 717         /* Check if key is in primary location */
 718         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 719                 if (bkt->signatures[i].current == sig &&
 720                                 bkt->signatures[i].sig != NULL_SIGNATURE) {
 721                         k = (struct rte_hash_key *) ((char *)keys +
 722                                         bkt->key_idx[i] * h->key_entry_size);
 723                         if (h->rte_hash_cmp_eq(key, k->key, h->key_len) == 0) {
 724                                 bkt->signatures[i].sig = NULL_SIGNATURE;
 725                                 rte_ring_sp_enqueue(h->free_slots,
 726                                                 (void *)((uintptr_t)bkt->key_idx[i]));
 727                                 /*
 728                                  * Return index where key is stored,
 729                                  * substracting the first dummy index
 730                                  */
 731                                 return (bkt->key_idx[i] - 1);
 732                         }
 733                 }
 734         }
 735
 736         /* Calculate secondary hash */
 737         alt_hash = rte_hash_secondary_hash(sig);
 738         bucket_idx = alt_hash & h->bucket_bitmask;
 739         bkt = &h->buckets[bucket_idx];
 740
 741         /* Check if key is in secondary location */
 742         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 743                 if (bkt->signatures[i].current == alt_hash &&
 744                                 bkt->signatures[i].sig != NULL_SIGNATURE) {
 745                         k = (struct rte_hash_key *) ((char *)keys +
 746                                         bkt->key_idx[i] * h->key_entry_size);
 747                         if (h->rte_hash_cmp_eq(key, k->key, h->key_len) == 0) {
 748                                 bkt->signatures[i].sig = NULL_SIGNATURE;
 749                                 rte_ring_sp_enqueue(h->free_slots,
 750                                                 (void *)((uintptr_t)bkt->key_idx[i]));
 751                                 /*
 752                                  * Return index where key is stored,
 753                                  * substracting the first dummy index
 754                                  */
 755                                 return (bkt->key_idx[i] - 1);
 756                         }
 757                 }
 758         }
 759
 760         return -ENOENT;
 761 }
 762
 763 int32_t
 764 rte_hash_del_key_with_hash(const struct rte_hash *h,
 765                         const void *key, hash_sig_t sig)
 766 {
 767         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 768         return __rte_hash_del_key_with_hash(h, key, sig);
 769 }
 770
 771 int32_t
 772 rte_hash_del_key(const struct rte_hash *h, const void *key)
 773 {
 774         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 775         return __rte_hash_del_key_with_hash(h, key, rte_hash_hash(h, key));
 776 }
 777
 778 /* Lookup bulk stage 0: Prefetch input key */
 779 static inline void
 780 lookup_stage0(unsigned *idx, uint64_t *lookup_mask,
 781                 const void * const *keys)
 782 {
 783         *idx = __builtin_ctzl(*lookup_mask);
 784         if (*lookup_mask == 0)
 785                 *idx = 0;
 786
 787         rte_prefetch0(keys[*idx]);
 788         *lookup_mask &= ~(1llu << *idx);
 789 }
 790
 791 /*
 792  * Lookup bulk stage 1: Calculate primary/secondary hashes
 793  * and prefetch primary/secondary buckets
 794  */
 795 static inline void
 796 lookup_stage1(unsigned idx, hash_sig_t *prim_hash, hash_sig_t *sec_hash,
 797                 const struct rte_hash_bucket **primary_bkt,
 798                 const struct rte_hash_bucket **secondary_bkt,
 799                 hash_sig_t *hash_vals, const void * const *keys,
 800                 const struct rte_hash *h)
 801 {
 802         *prim_hash = rte_hash_hash(h, keys[idx]);
 803         hash_vals[idx] = *prim_hash;
 804         *sec_hash = rte_hash_secondary_hash(*prim_hash);
 805
 806         *primary_bkt = &h->buckets[*prim_hash & h->bucket_bitmask];
 807         *secondary_bkt = &h->buckets[*sec_hash & h->bucket_bitmask];
 808
 809         rte_prefetch0(*primary_bkt);
 810         rte_prefetch0(*secondary_bkt);
 811 }
 812
 813 /*
 814  * Lookup bulk stage 2:  Search for match hashes in primary/secondary locations
 815  * and prefetch first key slot
 816  */
 817 static inline void
 818 lookup_stage2(unsigned idx, hash_sig_t prim_hash, hash_sig_t sec_hash,
 819                 const struct rte_hash_bucket *prim_bkt,
 820                 const struct rte_hash_bucket *sec_bkt,
 821                 const struct rte_hash_key **key_slot, int32_t *positions,
 822                 uint64_t *extra_hits_mask, const void *keys,
 823                 const struct rte_hash *h)
 824 {
 825         unsigned prim_hash_matches, sec_hash_matches, key_idx, i;
 826         unsigned total_hash_matches;
 827
 828         prim_hash_matches = 1 << RTE_HASH_BUCKET_ENTRIES;
 829         sec_hash_matches = 1 << RTE_HASH_BUCKET_ENTRIES;
 830         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 831                 prim_hash_matches |= ((prim_hash == prim_bkt->signatures[i].current) << i);
 832                 sec_hash_matches |= ((sec_hash == sec_bkt->signatures[i].current) << i);
 833         }
 834
 835         key_idx = prim_bkt->key_idx[__builtin_ctzl(prim_hash_matches)];
 836         if (key_idx == 0)
 837                 key_idx = sec_bkt->key_idx[__builtin_ctzl(sec_hash_matches)];
 838
 839         total_hash_matches = (prim_hash_matches |
 840                                 (sec_hash_matches << (RTE_HASH_BUCKET_ENTRIES + 1)));
 841         *key_slot = (const struct rte_hash_key *) ((const char *)keys +
 842                                         key_idx * h->key_entry_size);
 843
 844         rte_prefetch0(*key_slot);
 845         /*
 846          * Return index where key is stored,
 847          * substracting the first dummy index
 848          */
 849         positions[idx] = (key_idx - 1);
 850
 851         *extra_hits_mask |= (uint64_t)(__builtin_popcount(total_hash_matches) > 3) << idx;
 852
 853 }
 854
 855
 856 /* Lookup bulk stage 3: Check if key matches, update hit mask and return data */
 857 static inline void
 858 lookup_stage3(unsigned idx, const struct rte_hash_key *key_slot, const void * const *keys,
 859                 void *data[], uint64_t *hits, const struct rte_hash *h)
 860 {
 861         unsigned hit;
 862
 863         hit = !h->rte_hash_cmp_eq(key_slot->key, keys[idx], h->key_len);
 864         if (data != NULL)
 865                 data[idx] = key_slot->pdata;
 866
 867         *hits |= (uint64_t)(hit) << idx;
 868 }
 869
 870 static inline void
 871 __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
 872                         uint32_t num_keys, int32_t *positions,
 873                         uint64_t *hit_mask, void *data[])
 874 {
 875         uint64_t hits = 0;
 876         uint64_t extra_hits_mask = 0;
 877         uint64_t lookup_mask, miss_mask;
 878         unsigned idx;
 879         const void *key_store = h->key_store;
 880         int ret;
 881         hash_sig_t hash_vals[RTE_HASH_LOOKUP_BULK_MAX];
 882
 883         unsigned idx00, idx01, idx10, idx11, idx20, idx21, idx30, idx31;
 884         const struct rte_hash_bucket *primary_bkt10, *primary_bkt11;
 885         const struct rte_hash_bucket *secondary_bkt10, *secondary_bkt11;
 886         const struct rte_hash_bucket *primary_bkt20, *primary_bkt21;
 887         const struct rte_hash_bucket *secondary_bkt20, *secondary_bkt21;
 888         const struct rte_hash_key *k_slot20, *k_slot21, *k_slot30, *k_slot31;
 889         hash_sig_t primary_hash10, primary_hash11;
 890         hash_sig_t secondary_hash10, secondary_hash11;
 891         hash_sig_t primary_hash20, primary_hash21;
 892         hash_sig_t secondary_hash20, secondary_hash21;
 893
 894         lookup_mask = (uint64_t) -1 >> (64 - num_keys);
 895         miss_mask = lookup_mask;
 896
 897         lookup_stage0(&idx00, &lookup_mask, keys);
 898         lookup_stage0(&idx01, &lookup_mask, keys);
 899
 900         idx10 = idx00, idx11 = idx01;
 901
 902         lookup_stage0(&idx00, &lookup_mask, keys);
 903         lookup_stage0(&idx01, &lookup_mask, keys);
 904         lookup_stage1(idx10, &primary_hash10, &secondary_hash10,
 905                         &primary_bkt10, &secondary_bkt10, hash_vals, keys, h);
 906         lookup_stage1(idx11, &primary_hash11, &secondary_hash11,
 907                         &primary_bkt11, &secondary_bkt11, hash_vals, keys, h);
 908
 909         primary_bkt20 = primary_bkt10;
 910         primary_bkt21 = primary_bkt11;
 911         secondary_bkt20 = secondary_bkt10;
 912         secondary_bkt21 = secondary_bkt11;
 913         primary_hash20 = primary_hash10;
 914         primary_hash21 = primary_hash11;
 915         secondary_hash20 = secondary_hash10;
 916         secondary_hash21 = secondary_hash11;
 917         idx20 = idx10, idx21 = idx11;
 918         idx10 = idx00, idx11 = idx01;
 919
 920         lookup_stage0(&idx00, &lookup_mask, keys);
 921         lookup_stage0(&idx01, &lookup_mask, keys);
 922         lookup_stage1(idx10, &primary_hash10, &secondary_hash10,
 923                         &primary_bkt10, &secondary_bkt10, hash_vals, keys, h);
 924         lookup_stage1(idx11, &primary_hash11, &secondary_hash11,
 925                         &primary_bkt11, &secondary_bkt11, hash_vals, keys, h);
 926         lookup_stage2(idx20, primary_hash20, secondary_hash20, primary_bkt20,
 927                         secondary_bkt20, &k_slot20, positions, &extra_hits_mask,
 928                         key_store, h);
 929         lookup_stage2(idx21, primary_hash21, secondary_hash21, primary_bkt21,
 930                         secondary_bkt21, &k_slot21, positions, &extra_hits_mask,
 931                         key_store, h);
 932
 933         while (lookup_mask) {
 934                 k_slot30 = k_slot20, k_slot31 = k_slot21;
 935                 idx30 = idx20, idx31 = idx21;
 936                 primary_bkt20 = primary_bkt10;
 937                 primary_bkt21 = primary_bkt11;
 938                 secondary_bkt20 = secondary_bkt10;
 939                 secondary_bkt21 = secondary_bkt11;
 940                 primary_hash20 = primary_hash10;
 941                 primary_hash21 = primary_hash11;
 942                 secondary_hash20 = secondary_hash10;
 943                 secondary_hash21 = secondary_hash11;
 944                 idx20 = idx10, idx21 = idx11;
 945                 idx10 = idx00, idx11 = idx01;
 946
 947                 lookup_stage0(&idx00, &lookup_mask, keys);
 948                 lookup_stage0(&idx01, &lookup_mask, keys);
 949                 lookup_stage1(idx10, &primary_hash10, &secondary_hash10,
 950                         &primary_bkt10, &secondary_bkt10, hash_vals, keys, h);
 951                 lookup_stage1(idx11, &primary_hash11, &secondary_hash11,
 952                         &primary_bkt11, &secondary_bkt11, hash_vals, keys, h);
 953                 lookup_stage2(idx20, primary_hash20, secondary_hash20,
 954                         primary_bkt20, secondary_bkt20, &k_slot20, positions,
 955                         &extra_hits_mask, key_store, h);
 956                 lookup_stage2(idx21, primary_hash21, secondary_hash21,
 957                         primary_bkt21, secondary_bkt21, &k_slot21, positions,
 958                         &extra_hits_mask, key_store, h);
 959                 lookup_stage3(idx30, k_slot30, keys, data, &hits, h);
 960                 lookup_stage3(idx31, k_slot31, keys, data, &hits, h);
 961         }
 962
 963         k_slot30 = k_slot20, k_slot31 = k_slot21;
 964         idx30 = idx20, idx31 = idx21;
 965         primary_bkt20 = primary_bkt10;
 966         primary_bkt21 = primary_bkt11;
 967         secondary_bkt20 = secondary_bkt10;
 968         secondary_bkt21 = secondary_bkt11;
 969         primary_hash20 = primary_hash10;
 970         primary_hash21 = primary_hash11;
 971         secondary_hash20 = secondary_hash10;
 972         secondary_hash21 = secondary_hash11;
 973         idx20 = idx10, idx21 = idx11;
 974         idx10 = idx00, idx11 = idx01;
 975
 976         lookup_stage1(idx10, &primary_hash10, &secondary_hash10,
 977                 &primary_bkt10, &secondary_bkt10, hash_vals, keys, h);
 978         lookup_stage1(idx11, &primary_hash11, &secondary_hash11,
 979                 &primary_bkt11, &secondary_bkt11, hash_vals, keys, h);
 980         lookup_stage2(idx20, primary_hash20, secondary_hash20, primary_bkt20,
 981                 secondary_bkt20, &k_slot20, positions, &extra_hits_mask,
 982                 key_store, h);
 983         lookup_stage2(idx21, primary_hash21, secondary_hash21, primary_bkt21,
 984                 secondary_bkt21, &k_slot21, positions, &extra_hits_mask,
 985                 key_store, h);
 986         lookup_stage3(idx30, k_slot30, keys, data, &hits, h);
 987         lookup_stage3(idx31, k_slot31, keys, data, &hits, h);
 988
 989         k_slot30 = k_slot20, k_slot31 = k_slot21;
 990         idx30 = idx20, idx31 = idx21;
 991         primary_bkt20 = primary_bkt10;
 992         primary_bkt21 = primary_bkt11;
 993         secondary_bkt20 = secondary_bkt10;
 994         secondary_bkt21 = secondary_bkt11;
 995         primary_hash20 = primary_hash10;
 996         primary_hash21 = primary_hash11;
 997         secondary_hash20 = secondary_hash10;
 998         secondary_hash21 = secondary_hash11;
 999         idx20 = idx10, idx21 = idx11;
1000
1001         lookup_stage2(idx20, primary_hash20, secondary_hash20, primary_bkt20,
1002                 secondary_bkt20, &k_slot20, positions, &extra_hits_mask,
1003                 key_store, h);
1004         lookup_stage2(idx21, primary_hash21, secondary_hash21, primary_bkt21,
1005                 secondary_bkt21, &k_slot21, positions, &extra_hits_mask,
1006                 key_store, h);
1007         lookup_stage3(idx30, k_slot30, keys, data, &hits, h);
1008         lookup_stage3(idx31, k_slot31, keys, data, &hits, h);
1009
1010         k_slot30 = k_slot20, k_slot31 = k_slot21;
1011         idx30 = idx20, idx31 = idx21;
1012
1013         lookup_stage3(idx30, k_slot30, keys, data, &hits, h);
1014         lookup_stage3(idx31, k_slot31, keys, data, &hits, h);
1015
1016         /* ignore any items we have already found */
1017         extra_hits_mask &= ~hits;
1018
1019         if (unlikely(extra_hits_mask)) {
1020                 /* run a single search for each remaining item */
1021                 do {
1022                         idx = __builtin_ctzl(extra_hits_mask);
1023                         if (data != NULL) {
1024                                 ret = rte_hash_lookup_with_hash_data(h,
1025                                                 keys[idx], hash_vals[idx], &data[idx]);
1026                                 if (ret >= 0)
1027                                         hits |= 1ULL << idx;
1028                         } else {
1029                                 positions[idx] = rte_hash_lookup_with_hash(h,
1030                                                         keys[idx], hash_vals[idx]);
1031                                 if (positions[idx] >= 0)
1032                                         hits |= 1llu << idx;
1033                         }
1034                         extra_hits_mask &= ~(1llu << idx);
1035                 } while (extra_hits_mask);
1036         }
1037
1038         miss_mask &= ~hits;
1039         if (unlikely(miss_mask)) {
1040                 do {
1041                         idx = __builtin_ctzl(miss_mask);
1042                         positions[idx] = -ENOENT;
1043                         miss_mask &= ~(1llu << idx);
1044                 } while (miss_mask);
1045         }
1046
1047         if (hit_mask != NULL)
1048                 *hit_mask = hits;
1049 }
1050
1051 int
1052 rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
1053                       uint32_t num_keys, int32_t *positions)
1054 {
1055         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1056                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1057                         (positions == NULL)), -EINVAL);
1058
1059         __rte_hash_lookup_bulk(h, keys, num_keys, positions, NULL, NULL);
1060         return 0;
1061 }
1062
1063 int
1064 rte_hash_lookup_bulk_data(const struct rte_hash *h, const void **keys,
1065                       uint32_t num_keys, uint64_t *hit_mask, void *data[])
1066 {
1067         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1068                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1069                         (hit_mask == NULL)), -EINVAL);
1070
1071         int32_t positions[num_keys];
1072
1073         __rte_hash_lookup_bulk(h, keys, num_keys, positions, hit_mask, data);
1074
1075         /* Return number of hits */
1076         return __builtin_popcountl(*hit_mask);
1077 }
1078
1079 int32_t
1080 rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32_t *next)
1081 {
1082         uint32_t bucket_idx, idx, position;
1083         struct rte_hash_key *next_key;
1084
1085         RETURN_IF_TRUE(((h == NULL) || (next == NULL)), -EINVAL);
1086
1087         const uint32_t total_entries = h->num_buckets * RTE_HASH_BUCKET_ENTRIES;
1088         /* Out of bounds */
1089         if (*next >= total_entries)
1090                 return -ENOENT;
1091
1092         /* Calculate bucket and index of current iterator */
1093         bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1094         idx = *next % RTE_HASH_BUCKET_ENTRIES;
1095
1096         /* If current position is empty, go to the next one */
1097         while (h->buckets[bucket_idx].signatures[idx].sig == NULL_SIGNATURE) {
1098                 (*next)++;
1099                 /* End of table */
1100                 if (*next == total_entries)
1101                         return -ENOENT;
1102                 bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1103                 idx = *next % RTE_HASH_BUCKET_ENTRIES;
1104         }
1105
1106         /* Get position of entry in key table */
1107         position = h->buckets[bucket_idx].key_idx[idx];
1108         next_key = (struct rte_hash_key *) ((char *)h->key_store +
1109                                 position * h->key_entry_size);
1110         /* Return key and data */
1111         *key = next_key->key;
1112         *data = next_key->pdata;
1113
1114         /* Increment iterator */
1115         (*next)++;
1116
1117         return (position - 1);
1118 }