lib/librte_hash/rte_cuckoo_hash.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2016 Intel Corporation
   3  */
   4
   5 #include <string.h>
   6 #include <stdint.h>
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <stdarg.h>
  10 #include <sys/queue.h>
  11
  12 #include <rte_common.h>
  13 #include <rte_memory.h>         /* for definition of RTE_CACHE_LINE_SIZE */
  14 #include <rte_log.h>
  15 #include <rte_memcpy.h>
  16 #include <rte_prefetch.h>
  17 #include <rte_branch_prediction.h>
  18 #include <rte_malloc.h>
  19 #include <rte_eal.h>
  20 #include <rte_eal_memconfig.h>
  21 #include <rte_per_lcore.h>
  22 #include <rte_errno.h>
  23 #include <rte_string_fns.h>
  24 #include <rte_cpuflags.h>
  25 #include <rte_rwlock.h>
  26 #include <rte_spinlock.h>
  27 #include <rte_ring.h>
  28 #include <rte_compat.h>
  29 #include <rte_pause.h>
  30
  31 #include "rte_hash.h"
  32 #include "rte_cuckoo_hash.h"
  33
  34 #if defined(RTE_ARCH_X86)
  35 #include "rte_cuckoo_hash_x86.h"
  36 #endif
  37
  38 TAILQ_HEAD(rte_hash_list, rte_tailq_entry);
  39
  40 static struct rte_tailq_elem rte_hash_tailq = {
  41         .name = "RTE_HASH",
  42 };
  43 EAL_REGISTER_TAILQ(rte_hash_tailq)
  44
  45 struct rte_hash *
  46 rte_hash_find_existing(const char *name)
  47 {
  48         struct rte_hash *h = NULL;
  49         struct rte_tailq_entry *te;
  50         struct rte_hash_list *hash_list;
  51
  52         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
  53
  54         rte_rwlock_read_lock(RTE_EAL_TAILQ_RWLOCK);
  55         TAILQ_FOREACH(te, hash_list, next) {
  56                 h = (struct rte_hash *) te->data;
  57                 if (strncmp(name, h->name, RTE_HASH_NAMESIZE) == 0)
  58                         break;
  59         }
  60         rte_rwlock_read_unlock(RTE_EAL_TAILQ_RWLOCK);
  61
  62         if (te == NULL) {
  63                 rte_errno = ENOENT;
  64                 return NULL;
  65         }
  66         return h;
  67 }
  68
  69 void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func)
  70 {
  71         h->cmp_jump_table_idx = KEY_CUSTOM;
  72         h->rte_hash_custom_cmp_eq = func;
  73 }
  74
  75 static inline int
  76 rte_hash_cmp_eq(const void *key1, const void *key2, const struct rte_hash *h)
  77 {
  78         if (h->cmp_jump_table_idx == KEY_CUSTOM)
  79                 return h->rte_hash_custom_cmp_eq(key1, key2, h->key_len);
  80         else
  81                 return cmp_jump_table[h->cmp_jump_table_idx](key1, key2, h->key_len);
  82 }
  83
  84 struct rte_hash *
  85 rte_hash_create(const struct rte_hash_parameters *params)
  86 {
  87         struct rte_hash *h = NULL;
  88         struct rte_tailq_entry *te = NULL;
  89         struct rte_hash_list *hash_list;
  90         struct rte_ring *r = NULL;
  91         char hash_name[RTE_HASH_NAMESIZE];
  92         void *k = NULL;
  93         void *buckets = NULL;
  94         char ring_name[RTE_RING_NAMESIZE];
  95         unsigned num_key_slots;
  96         unsigned hw_trans_mem_support = 0;
  97         unsigned i;
  98         rte_hash_function default_hash_func = (rte_hash_function)rte_jhash;
  99
 100         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 101
 102         if (params == NULL) {
 103                 RTE_LOG(ERR, HASH, "rte_hash_create has no parameters\n");
 104                 return NULL;
 105         }
 106
 107         /* Check for valid parameters */
 108         if ((params->entries > RTE_HASH_ENTRIES_MAX) ||
 109                         (params->entries < RTE_HASH_BUCKET_ENTRIES) ||
 110                         (params->key_len == 0)) {
 111                 rte_errno = EINVAL;
 112                 RTE_LOG(ERR, HASH, "rte_hash_create has invalid parameters\n");
 113                 return NULL;
 114         }
 115
 116         /* Check extra flags field to check extra options. */
 117         if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT)
 118                 hw_trans_mem_support = 1;
 119
 120         /* Store all keys and leave the first entry as a dummy entry for lookup_bulk */
 121         if (hw_trans_mem_support)
 122                 /*
 123                  * Increase number of slots by total number of indices
 124                  * that can be stored in the lcore caches
 125                  * except for the first cache
 126                  */
 127                 num_key_slots = params->entries + (RTE_MAX_LCORE - 1) *
 128                                         LCORE_CACHE_SIZE + 1;
 129         else
 130                 num_key_slots = params->entries + 1;
 131
 132         snprintf(ring_name, sizeof(ring_name), "HT_%s", params->name);
 133         /* Create ring (Dummy slot index is not enqueued) */
 134         r = rte_ring_create(ring_name, rte_align32pow2(num_key_slots - 1),
 135                         params->socket_id, 0);
 136         if (r == NULL) {
 137                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 138                 goto err;
 139         }
 140
 141         snprintf(hash_name, sizeof(hash_name), "HT_%s", params->name);
 142
 143         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 144
 145         /* guarantee there's no existing: this is normally already checked
 146          * by ring creation above */
 147         TAILQ_FOREACH(te, hash_list, next) {
 148                 h = (struct rte_hash *) te->data;
 149                 if (strncmp(params->name, h->name, RTE_HASH_NAMESIZE) == 0)
 150                         break;
 151         }
 152         h = NULL;
 153         if (te != NULL) {
 154                 rte_errno = EEXIST;
 155                 te = NULL;
 156                 goto err_unlock;
 157         }
 158
 159         te = rte_zmalloc("HASH_TAILQ_ENTRY", sizeof(*te), 0);
 160         if (te == NULL) {
 161                 RTE_LOG(ERR, HASH, "tailq entry allocation failed\n");
 162                 goto err_unlock;
 163         }
 164
 165         h = (struct rte_hash *)rte_zmalloc_socket(hash_name, sizeof(struct rte_hash),
 166                                         RTE_CACHE_LINE_SIZE, params->socket_id);
 167
 168         if (h == NULL) {
 169                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 170                 goto err_unlock;
 171         }
 172
 173         const uint32_t num_buckets = rte_align32pow2(params->entries)
 174                                         / RTE_HASH_BUCKET_ENTRIES;
 175
 176         buckets = rte_zmalloc_socket(NULL,
 177                                 num_buckets * sizeof(struct rte_hash_bucket),
 178                                 RTE_CACHE_LINE_SIZE, params->socket_id);
 179
 180         if (buckets == NULL) {
 181                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 182                 goto err_unlock;
 183         }
 184
 185         const uint32_t key_entry_size = sizeof(struct rte_hash_key) + params->key_len;
 186         const uint64_t key_tbl_size = (uint64_t) key_entry_size * num_key_slots;
 187
 188         k = rte_zmalloc_socket(NULL, key_tbl_size,
 189                         RTE_CACHE_LINE_SIZE, params->socket_id);
 190
 191         if (k == NULL) {
 192                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 193                 goto err_unlock;
 194         }
 195
 196 /*
 197  * If x86 architecture is used, select appropriate compare function,
 198  * which may use x86 intrinsics, otherwise use memcmp
 199  */
 200 #if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
 201         /* Select function to compare keys */
 202         switch (params->key_len) {
 203         case 16:
 204                 h->cmp_jump_table_idx = KEY_16_BYTES;
 205                 break;
 206         case 32:
 207                 h->cmp_jump_table_idx = KEY_32_BYTES;
 208                 break;
 209         case 48:
 210                 h->cmp_jump_table_idx = KEY_48_BYTES;
 211                 break;
 212         case 64:
 213                 h->cmp_jump_table_idx = KEY_64_BYTES;
 214                 break;
 215         case 80:
 216                 h->cmp_jump_table_idx = KEY_80_BYTES;
 217                 break;
 218         case 96:
 219                 h->cmp_jump_table_idx = KEY_96_BYTES;
 220                 break;
 221         case 112:
 222                 h->cmp_jump_table_idx = KEY_112_BYTES;
 223                 break;
 224         case 128:
 225                 h->cmp_jump_table_idx = KEY_128_BYTES;
 226                 break;
 227         default:
 228                 /* If key is not multiple of 16, use generic memcmp */
 229                 h->cmp_jump_table_idx = KEY_OTHER_BYTES;
 230         }
 231 #else
 232         h->cmp_jump_table_idx = KEY_OTHER_BYTES;
 233 #endif
 234
 235         if (hw_trans_mem_support) {
 236                 h->local_free_slots = rte_zmalloc_socket(NULL,
 237                                 sizeof(struct lcore_cache) * RTE_MAX_LCORE,
 238                                 RTE_CACHE_LINE_SIZE, params->socket_id);
 239         }
 240
 241         /* Default hash function */
 242 #if defined(RTE_ARCH_X86)
 243         default_hash_func = (rte_hash_function)rte_hash_crc;
 244 #elif defined(RTE_ARCH_ARM64)
 245         if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_CRC32))
 246                 default_hash_func = (rte_hash_function)rte_hash_crc;
 247 #endif
 248         /* Setup hash context */
 249         snprintf(h->name, sizeof(h->name), "%s", params->name);
 250         h->entries = params->entries;
 251         h->key_len = params->key_len;
 252         h->key_entry_size = key_entry_size;
 253         h->hash_func_init_val = params->hash_func_init_val;
 254
 255         h->num_buckets = num_buckets;
 256         h->bucket_bitmask = h->num_buckets - 1;
 257         h->buckets = buckets;
 258         h->hash_func = (params->hash_func == NULL) ?
 259                 default_hash_func : params->hash_func;
 260         h->key_store = k;
 261         h->free_slots = r;
 262         h->hw_trans_mem_support = hw_trans_mem_support;
 263
 264 #if defined(RTE_ARCH_X86)
 265         if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2))
 266                 h->sig_cmp_fn = RTE_HASH_COMPARE_AVX2;
 267         else if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE2))
 268                 h->sig_cmp_fn = RTE_HASH_COMPARE_SSE;
 269         else
 270 #endif
 271                 h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;
 272
 273         /* Turn on multi-writer only with explicit flat from user and TM
 274          * support.
 275          */
 276         if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD) {
 277                 if (h->hw_trans_mem_support) {
 278                         h->add_key = ADD_KEY_MULTIWRITER_TM;
 279                 } else {
 280                         h->add_key = ADD_KEY_MULTIWRITER;
 281                         h->multiwriter_lock = rte_malloc(NULL,
 282                                                         sizeof(rte_spinlock_t),
 283                                                         RTE_CACHE_LINE_SIZE);
 284                         if (h->multiwriter_lock == NULL)
 285                                 goto err_unlock;
 286
 287                         rte_spinlock_init(h->multiwriter_lock);
 288                 }
 289         } else
 290                 h->add_key = ADD_KEY_SINGLEWRITER;
 291
 292         /* Populate free slots ring. Entry zero is reserved for key misses. */
 293         for (i = 1; i < params->entries + 1; i++)
 294                 rte_ring_sp_enqueue(r, (void *)((uintptr_t) i));
 295
 296         te->data = (void *) h;
 297         TAILQ_INSERT_TAIL(hash_list, te, next);
 298         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 299
 300         return h;
 301 err_unlock:
 302         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 303 err:
 304         rte_ring_free(r);
 305         rte_free(te);
 306         rte_free(h);
 307         rte_free(buckets);
 308         rte_free(k);
 309         return NULL;
 310 }
 311
 312 void
 313 rte_hash_free(struct rte_hash *h)
 314 {
 315         struct rte_tailq_entry *te;
 316         struct rte_hash_list *hash_list;
 317
 318         if (h == NULL)
 319                 return;
 320
 321         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 322
 323         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 324
 325         /* find out tailq entry */
 326         TAILQ_FOREACH(te, hash_list, next) {
 327                 if (te->data == (void *) h)
 328                         break;
 329         }
 330
 331         if (te == NULL) {
 332                 rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 333                 return;
 334         }
 335
 336         TAILQ_REMOVE(hash_list, te, next);
 337
 338         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 339
 340         if (h->hw_trans_mem_support)
 341                 rte_free(h->local_free_slots);
 342
 343         if (h->add_key == ADD_KEY_MULTIWRITER)
 344                 rte_free(h->multiwriter_lock);
 345         rte_ring_free(h->free_slots);
 346         rte_free(h->key_store);
 347         rte_free(h->buckets);
 348         rte_free(h);
 349         rte_free(te);
 350 }
 351
 352 hash_sig_t
 353 rte_hash_hash(const struct rte_hash *h, const void *key)
 354 {
 355         /* calc hash result by key */
 356         return h->hash_func(key, h->key_len, h->hash_func_init_val);
 357 }
 358
 359 /* Calc the secondary hash value from the primary hash value of a given key */
 360 static inline hash_sig_t
 361 rte_hash_secondary_hash(const hash_sig_t primary_hash)
 362 {
 363         static const unsigned all_bits_shift = 12;
 364         static const unsigned alt_bits_xor = 0x5bd1e995;
 365
 366         uint32_t tag = primary_hash >> all_bits_shift;
 367
 368         return primary_hash ^ ((tag + 1) * alt_bits_xor);
 369 }
 370
 371 void
 372 rte_hash_reset(struct rte_hash *h)
 373 {
 374         void *ptr;
 375         unsigned i;
 376
 377         if (h == NULL)
 378                 return;
 379
 380         memset(h->buckets, 0, h->num_buckets * sizeof(struct rte_hash_bucket));
 381         memset(h->key_store, 0, h->key_entry_size * (h->entries + 1));
 382
 383         /* clear the free ring */
 384         while (rte_ring_dequeue(h->free_slots, &ptr) == 0)
 385                 rte_pause();
 386
 387         /* Repopulate the free slots ring. Entry zero is reserved for key misses */
 388         for (i = 1; i < h->entries + 1; i++)
 389                 rte_ring_sp_enqueue(h->free_slots, (void *)((uintptr_t) i));
 390
 391         if (h->hw_trans_mem_support) {
 392                 /* Reset local caches per lcore */
 393                 for (i = 0; i < RTE_MAX_LCORE; i++)
 394                         h->local_free_slots[i].len = 0;
 395         }
 396 }
 397
 398 /* Search for an entry that can be pushed to its alternative location */
 399 static inline int
 400 make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt,
 401                 unsigned int *nr_pushes)
 402 {
 403         unsigned i, j;
 404         int ret;
 405         uint32_t next_bucket_idx;
 406         struct rte_hash_bucket *next_bkt[RTE_HASH_BUCKET_ENTRIES];
 407
 408         /*
 409          * Push existing item (search for bucket with space in
 410          * alternative locations) to its alternative location
 411          */
 412         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 413                 /* Search for space in alternative locations */
 414                 next_bucket_idx = bkt->sig_alt[i] & h->bucket_bitmask;
 415                 next_bkt[i] = &h->buckets[next_bucket_idx];
 416                 for (j = 0; j < RTE_HASH_BUCKET_ENTRIES; j++) {
 417                         if (next_bkt[i]->key_idx[j] == EMPTY_SLOT)
 418                                 break;
 419                 }
 420
 421                 if (j != RTE_HASH_BUCKET_ENTRIES)
 422                         break;
 423         }
 424
 425         /* Alternative location has spare room (end of recursive function) */
 426         if (i != RTE_HASH_BUCKET_ENTRIES) {
 427                 next_bkt[i]->sig_alt[j] = bkt->sig_current[i];
 428                 next_bkt[i]->sig_current[j] = bkt->sig_alt[i];
 429                 next_bkt[i]->key_idx[j] = bkt->key_idx[i];
 430                 return i;
 431         }
 432
 433         /* Pick entry that has not been pushed yet */
 434         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++)
 435                 if (bkt->flag[i] == 0)
 436                         break;
 437
 438         /* All entries have been pushed, so entry cannot be added */
 439         if (i == RTE_HASH_BUCKET_ENTRIES || ++(*nr_pushes) > RTE_HASH_MAX_PUSHES)
 440                 return -ENOSPC;
 441
 442         /* Set flag to indicate that this entry is going to be pushed */
 443         bkt->flag[i] = 1;
 444
 445         /* Need room in alternative bucket to insert the pushed entry */
 446         ret = make_space_bucket(h, next_bkt[i], nr_pushes);
 447         /*
 448          * After recursive function.
 449          * Clear flags and insert the pushed entry
 450          * in its alternative location if successful,
 451          * or return error
 452          */
 453         bkt->flag[i] = 0;
 454         if (ret >= 0) {
 455                 next_bkt[i]->sig_alt[ret] = bkt->sig_current[i];
 456                 next_bkt[i]->sig_current[ret] = bkt->sig_alt[i];
 457                 next_bkt[i]->key_idx[ret] = bkt->key_idx[i];
 458                 return i;
 459         } else
 460                 return ret;
 461
 462 }
 463
 464 /*
 465  * Function called to enqueue back an index in the cache/ring,
 466  * as slot has not being used and it can be used in the
 467  * next addition attempt.
 468  */
 469 static inline void
 470 enqueue_slot_back(const struct rte_hash *h,
 471                 struct lcore_cache *cached_free_slots,
 472                 void *slot_id)
 473 {
 474         if (h->hw_trans_mem_support) {
 475                 cached_free_slots->objs[cached_free_slots->len] = slot_id;
 476                 cached_free_slots->len++;
 477         } else
 478                 rte_ring_sp_enqueue(h->free_slots, slot_id);
 479 }
 480
 481 static inline int32_t
 482 __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
 483                                                 hash_sig_t sig, void *data)
 484 {
 485         hash_sig_t alt_hash;
 486         uint32_t prim_bucket_idx, sec_bucket_idx;
 487         unsigned i;
 488         struct rte_hash_bucket *prim_bkt, *sec_bkt;
 489         struct rte_hash_key *new_k, *k, *keys = h->key_store;
 490         void *slot_id = NULL;
 491         uint32_t new_idx;
 492         int ret;
 493         unsigned n_slots;
 494         unsigned lcore_id;
 495         struct lcore_cache *cached_free_slots = NULL;
 496         unsigned int nr_pushes = 0;
 497
 498         if (h->add_key == ADD_KEY_MULTIWRITER)
 499                 rte_spinlock_lock(h->multiwriter_lock);
 500
 501         prim_bucket_idx = sig & h->bucket_bitmask;
 502         prim_bkt = &h->buckets[prim_bucket_idx];
 503         rte_prefetch0(prim_bkt);
 504
 505         alt_hash = rte_hash_secondary_hash(sig);
 506         sec_bucket_idx = alt_hash & h->bucket_bitmask;
 507         sec_bkt = &h->buckets[sec_bucket_idx];
 508         rte_prefetch0(sec_bkt);
 509
 510         /* Get a new slot for storing the new key */
 511         if (h->hw_trans_mem_support) {
 512                 lcore_id = rte_lcore_id();
 513                 cached_free_slots = &h->local_free_slots[lcore_id];
 514                 /* Try to get a free slot from the local cache */
 515                 if (cached_free_slots->len == 0) {
 516                         /* Need to get another burst of free slots from global ring */
 517                         n_slots = rte_ring_mc_dequeue_burst(h->free_slots,
 518                                         cached_free_slots->objs,
 519                                         LCORE_CACHE_SIZE, NULL);
 520                         if (n_slots == 0) {
 521                                 ret = -ENOSPC;
 522                                 goto failure;
 523                         }
 524
 525                         cached_free_slots->len += n_slots;
 526                 }
 527
 528                 /* Get a free slot from the local cache */
 529                 cached_free_slots->len--;
 530                 slot_id = cached_free_slots->objs[cached_free_slots->len];
 531         } else {
 532                 if (rte_ring_sc_dequeue(h->free_slots, &slot_id) != 0) {
 533                         ret = -ENOSPC;
 534                         goto failure;
 535                 }
 536         }
 537
 538         new_k = RTE_PTR_ADD(keys, (uintptr_t)slot_id * h->key_entry_size);
 539         rte_prefetch0(new_k);
 540         new_idx = (uint32_t)((uintptr_t) slot_id);
 541
 542         /* Check if key is already inserted in primary location */
 543         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 544                 if (prim_bkt->sig_current[i] == sig &&
 545                                 prim_bkt->sig_alt[i] == alt_hash) {
 546                         k = (struct rte_hash_key *) ((char *)keys +
 547                                         prim_bkt->key_idx[i] * h->key_entry_size);
 548                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 549                                 /* Enqueue index of free slot back in the ring. */
 550                                 enqueue_slot_back(h, cached_free_slots, slot_id);
 551                                 /* Update data */
 552                                 k->pdata = data;
 553                                 /*
 554                                  * Return index where key is stored,
 555                                  * subtracting the first dummy index
 556                                  */
 557                                 ret = prim_bkt->key_idx[i] - 1;
 558                                 goto failure;
 559                         }
 560                 }
 561         }
 562
 563         /* Check if key is already inserted in secondary location */
 564         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 565                 if (sec_bkt->sig_alt[i] == sig &&
 566                                 sec_bkt->sig_current[i] == alt_hash) {
 567                         k = (struct rte_hash_key *) ((char *)keys +
 568                                         sec_bkt->key_idx[i] * h->key_entry_size);
 569                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 570                                 /* Enqueue index of free slot back in the ring. */
 571                                 enqueue_slot_back(h, cached_free_slots, slot_id);
 572                                 /* Update data */
 573                                 k->pdata = data;
 574                                 /*
 575                                  * Return index where key is stored,
 576                                  * subtracting the first dummy index
 577                                  */
 578                                 ret = sec_bkt->key_idx[i] - 1;
 579                                 goto failure;
 580                         }
 581                 }
 582         }
 583
 584         /* Copy key */
 585         rte_memcpy(new_k->key, key, h->key_len);
 586         new_k->pdata = data;
 587
 588 #if defined(RTE_ARCH_X86) /* currently only x86 support HTM */
 589         if (h->add_key == ADD_KEY_MULTIWRITER_TM) {
 590                 ret = rte_hash_cuckoo_insert_mw_tm(prim_bkt,
 591                                 sig, alt_hash, new_idx);
 592                 if (ret >= 0)
 593                         return new_idx - 1;
 594
 595                 /* Primary bucket full, need to make space for new entry */
 596                 ret = rte_hash_cuckoo_make_space_mw_tm(h, prim_bkt, sig,
 597                                                         alt_hash, new_idx);
 598
 599                 if (ret >= 0)
 600                         return new_idx - 1;
 601
 602                 /* Also search secondary bucket to get better occupancy */
 603                 ret = rte_hash_cuckoo_make_space_mw_tm(h, sec_bkt, sig,
 604                                                         alt_hash, new_idx);
 605
 606                 if (ret >= 0)
 607                         return new_idx - 1;
 608         } else {
 609 #endif
 610                 for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 611                         /* Check if slot is available */
 612                         if (likely(prim_bkt->key_idx[i] == EMPTY_SLOT)) {
 613                                 prim_bkt->sig_current[i] = sig;
 614                                 prim_bkt->sig_alt[i] = alt_hash;
 615                                 prim_bkt->key_idx[i] = new_idx;
 616                                 break;
 617                         }
 618                 }
 619
 620                 if (i != RTE_HASH_BUCKET_ENTRIES) {
 621                         if (h->add_key == ADD_KEY_MULTIWRITER)
 622                                 rte_spinlock_unlock(h->multiwriter_lock);
 623                         return new_idx - 1;
 624                 }
 625
 626                 /* Primary bucket full, need to make space for new entry
 627                  * After recursive function.
 628                  * Insert the new entry in the position of the pushed entry
 629                  * if successful or return error and
 630                  * store the new slot back in the ring
 631                  */
 632                 ret = make_space_bucket(h, prim_bkt, &nr_pushes);
 633                 if (ret >= 0) {
 634                         prim_bkt->sig_current[ret] = sig;
 635                         prim_bkt->sig_alt[ret] = alt_hash;
 636                         prim_bkt->key_idx[ret] = new_idx;
 637                         if (h->add_key == ADD_KEY_MULTIWRITER)
 638                                 rte_spinlock_unlock(h->multiwriter_lock);
 639                         return new_idx - 1;
 640                 }
 641 #if defined(RTE_ARCH_X86)
 642         }
 643 #endif
 644         /* Error in addition, store new slot back in the ring and return error */
 645         enqueue_slot_back(h, cached_free_slots, (void *)((uintptr_t) new_idx));
 646
 647 failure:
 648         if (h->add_key == ADD_KEY_MULTIWRITER)
 649                 rte_spinlock_unlock(h->multiwriter_lock);
 650         return ret;
 651 }
 652
 653 int32_t
 654 rte_hash_add_key_with_hash(const struct rte_hash *h,
 655                         const void *key, hash_sig_t sig)
 656 {
 657         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 658         return __rte_hash_add_key_with_hash(h, key, sig, 0);
 659 }
 660
 661 int32_t
 662 rte_hash_add_key(const struct rte_hash *h, const void *key)
 663 {
 664         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 665         return __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), 0);
 666 }
 667
 668 int
 669 rte_hash_add_key_with_hash_data(const struct rte_hash *h,
 670                         const void *key, hash_sig_t sig, void *data)
 671 {
 672         int ret;
 673
 674         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 675         ret = __rte_hash_add_key_with_hash(h, key, sig, data);
 676         if (ret >= 0)
 677                 return 0;
 678         else
 679                 return ret;
 680 }
 681
 682 int
 683 rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data)
 684 {
 685         int ret;
 686
 687         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 688
 689         ret = __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), data);
 690         if (ret >= 0)
 691                 return 0;
 692         else
 693                 return ret;
 694 }
 695 static inline int32_t
 696 __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
 697                                         hash_sig_t sig, void **data)
 698 {
 699         uint32_t bucket_idx;
 700         hash_sig_t alt_hash;
 701         unsigned i;
 702         struct rte_hash_bucket *bkt;
 703         struct rte_hash_key *k, *keys = h->key_store;
 704
 705         bucket_idx = sig & h->bucket_bitmask;
 706         bkt = &h->buckets[bucket_idx];
 707
 708         /* Check if key is in primary location */
 709         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 710                 if (bkt->sig_current[i] == sig &&
 711                                 bkt->key_idx[i] != EMPTY_SLOT) {
 712                         k = (struct rte_hash_key *) ((char *)keys +
 713                                         bkt->key_idx[i] * h->key_entry_size);
 714                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 715                                 if (data != NULL)
 716                                         *data = k->pdata;
 717                                 /*
 718                                  * Return index where key is stored,
 719                                  * subtracting the first dummy index
 720                                  */
 721                                 return bkt->key_idx[i] - 1;
 722                         }
 723                 }
 724         }
 725
 726         /* Calculate secondary hash */
 727         alt_hash = rte_hash_secondary_hash(sig);
 728         bucket_idx = alt_hash & h->bucket_bitmask;
 729         bkt = &h->buckets[bucket_idx];
 730
 731         /* Check if key is in secondary location */
 732         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 733                 if (bkt->sig_current[i] == alt_hash &&
 734                                 bkt->sig_alt[i] == sig) {
 735                         k = (struct rte_hash_key *) ((char *)keys +
 736                                         bkt->key_idx[i] * h->key_entry_size);
 737                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 738                                 if (data != NULL)
 739                                         *data = k->pdata;
 740                                 /*
 741                                  * Return index where key is stored,
 742                                  * subtracting the first dummy index
 743                                  */
 744                                 return bkt->key_idx[i] - 1;
 745                         }
 746                 }
 747         }
 748
 749         return -ENOENT;
 750 }
 751
 752 int32_t
 753 rte_hash_lookup_with_hash(const struct rte_hash *h,
 754                         const void *key, hash_sig_t sig)
 755 {
 756         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 757         return __rte_hash_lookup_with_hash(h, key, sig, NULL);
 758 }
 759
 760 int32_t
 761 rte_hash_lookup(const struct rte_hash *h, const void *key)
 762 {
 763         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 764         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), NULL);
 765 }
 766
 767 int
 768 rte_hash_lookup_with_hash_data(const struct rte_hash *h,
 769                         const void *key, hash_sig_t sig, void **data)
 770 {
 771         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 772         return __rte_hash_lookup_with_hash(h, key, sig, data);
 773 }
 774
 775 int
 776 rte_hash_lookup_data(const struct rte_hash *h, const void *key, void **data)
 777 {
 778         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 779         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), data);
 780 }
 781
 782 static inline void
 783 remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt, unsigned i)
 784 {
 785         unsigned lcore_id, n_slots;
 786         struct lcore_cache *cached_free_slots;
 787
 788         bkt->sig_current[i] = NULL_SIGNATURE;
 789         bkt->sig_alt[i] = NULL_SIGNATURE;
 790         if (h->hw_trans_mem_support) {
 791                 lcore_id = rte_lcore_id();
 792                 cached_free_slots = &h->local_free_slots[lcore_id];
 793                 /* Cache full, need to free it. */
 794                 if (cached_free_slots->len == LCORE_CACHE_SIZE) {
 795                         /* Need to enqueue the free slots in global ring. */
 796                         n_slots = rte_ring_mp_enqueue_burst(h->free_slots,
 797                                                 cached_free_slots->objs,
 798                                                 LCORE_CACHE_SIZE, NULL);
 799                         cached_free_slots->len -= n_slots;
 800                 }
 801                 /* Put index of new free slot in cache. */
 802                 cached_free_slots->objs[cached_free_slots->len] =
 803                                 (void *)((uintptr_t)bkt->key_idx[i]);
 804                 cached_free_slots->len++;
 805         } else {
 806                 rte_ring_sp_enqueue(h->free_slots,
 807                                 (void *)((uintptr_t)bkt->key_idx[i]));
 808         }
 809 }
 810
 811 static inline int32_t
 812 __rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
 813                                                 hash_sig_t sig)
 814 {
 815         uint32_t bucket_idx;
 816         hash_sig_t alt_hash;
 817         unsigned i;
 818         struct rte_hash_bucket *bkt;
 819         struct rte_hash_key *k, *keys = h->key_store;
 820         int32_t ret;
 821
 822         bucket_idx = sig & h->bucket_bitmask;
 823         bkt = &h->buckets[bucket_idx];
 824
 825         /* Check if key is in primary location */
 826         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 827                 if (bkt->sig_current[i] == sig &&
 828                                 bkt->key_idx[i] != EMPTY_SLOT) {
 829                         k = (struct rte_hash_key *) ((char *)keys +
 830                                         bkt->key_idx[i] * h->key_entry_size);
 831                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 832                                 remove_entry(h, bkt, i);
 833
 834                                 /*
 835                                  * Return index where key is stored,
 836                                  * subtracting the first dummy index
 837                                  */
 838                                 ret = bkt->key_idx[i] - 1;
 839                                 bkt->key_idx[i] = EMPTY_SLOT;
 840                                 return ret;
 841                         }
 842                 }
 843         }
 844
 845         /* Calculate secondary hash */
 846         alt_hash = rte_hash_secondary_hash(sig);
 847         bucket_idx = alt_hash & h->bucket_bitmask;
 848         bkt = &h->buckets[bucket_idx];
 849
 850         /* Check if key is in secondary location */
 851         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 852                 if (bkt->sig_current[i] == alt_hash &&
 853                                 bkt->key_idx[i] != EMPTY_SLOT) {
 854                         k = (struct rte_hash_key *) ((char *)keys +
 855                                         bkt->key_idx[i] * h->key_entry_size);
 856                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 857                                 remove_entry(h, bkt, i);
 858
 859                                 /*
 860                                  * Return index where key is stored,
 861                                  * subtracting the first dummy index
 862                                  */
 863                                 ret = bkt->key_idx[i] - 1;
 864                                 bkt->key_idx[i] = EMPTY_SLOT;
 865                                 return ret;
 866                         }
 867                 }
 868         }
 869
 870         return -ENOENT;
 871 }
 872
 873 int32_t
 874 rte_hash_del_key_with_hash(const struct rte_hash *h,
 875                         const void *key, hash_sig_t sig)
 876 {
 877         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 878         return __rte_hash_del_key_with_hash(h, key, sig);
 879 }
 880
 881 int32_t
 882 rte_hash_del_key(const struct rte_hash *h, const void *key)
 883 {
 884         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 885         return __rte_hash_del_key_with_hash(h, key, rte_hash_hash(h, key));
 886 }
 887
 888 int
 889 rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
 890                                void **key)
 891 {
 892         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 893
 894         struct rte_hash_key *k, *keys = h->key_store;
 895         k = (struct rte_hash_key *) ((char *) keys + (position + 1) *
 896                                      h->key_entry_size);
 897         *key = k->key;
 898
 899         if (position !=
 900             __rte_hash_lookup_with_hash(h, *key, rte_hash_hash(h, *key),
 901                                         NULL)) {
 902                 return -ENOENT;
 903         }
 904
 905         return 0;
 906 }
 907
 908 static inline void
 909 compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
 910                         const struct rte_hash_bucket *prim_bkt,
 911                         const struct rte_hash_bucket *sec_bkt,
 912                         hash_sig_t prim_hash, hash_sig_t sec_hash,
 913                         enum rte_hash_sig_compare_function sig_cmp_fn)
 914 {
 915         unsigned int i;
 916
 917         switch (sig_cmp_fn) {
 918 #ifdef RTE_MACHINE_CPUFLAG_AVX2
 919         case RTE_HASH_COMPARE_AVX2:
 920                 *prim_hash_matches = _mm256_movemask_ps((__m256)_mm256_cmpeq_epi32(
 921                                 _mm256_load_si256(
 922                                         (__m256i const *)prim_bkt->sig_current),
 923                                 _mm256_set1_epi32(prim_hash)));
 924                 *sec_hash_matches = _mm256_movemask_ps((__m256)_mm256_cmpeq_epi32(
 925                                 _mm256_load_si256(
 926                                         (__m256i const *)sec_bkt->sig_current),
 927                                 _mm256_set1_epi32(sec_hash)));
 928                 break;
 929 #endif
 930 #ifdef RTE_MACHINE_CPUFLAG_SSE2
 931         case RTE_HASH_COMPARE_SSE:
 932                 /* Compare the first 4 signatures in the bucket */
 933                 *prim_hash_matches = _mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 934                                 _mm_load_si128(
 935                                         (__m128i const *)prim_bkt->sig_current),
 936                                 _mm_set1_epi32(prim_hash)));
 937                 *prim_hash_matches |= (_mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 938                                 _mm_load_si128(
 939                                         (__m128i const *)&prim_bkt->sig_current[4]),
 940                                 _mm_set1_epi32(prim_hash)))) << 4;
 941                 /* Compare the first 4 signatures in the bucket */
 942                 *sec_hash_matches = _mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 943                                 _mm_load_si128(
 944                                         (__m128i const *)sec_bkt->sig_current),
 945                                 _mm_set1_epi32(sec_hash)));
 946                 *sec_hash_matches |= (_mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 947                                 _mm_load_si128(
 948                                         (__m128i const *)&sec_bkt->sig_current[4]),
 949                                 _mm_set1_epi32(sec_hash)))) << 4;
 950                 break;
 951 #endif
 952         default:
 953                 for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 954                         *prim_hash_matches |=
 955                                 ((prim_hash == prim_bkt->sig_current[i]) << i);
 956                         *sec_hash_matches |=
 957                                 ((sec_hash == sec_bkt->sig_current[i]) << i);
 958                 }
 959         }
 960
 961 }
 962
 963 #define PREFETCH_OFFSET 4
 964 static inline void
 965 __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
 966                         int32_t num_keys, int32_t *positions,
 967                         uint64_t *hit_mask, void *data[])
 968 {
 969         uint64_t hits = 0;
 970         int32_t i;
 971         uint32_t prim_hash[RTE_HASH_LOOKUP_BULK_MAX];
 972         uint32_t sec_hash[RTE_HASH_LOOKUP_BULK_MAX];
 973         const struct rte_hash_bucket *primary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
 974         const struct rte_hash_bucket *secondary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
 975         uint32_t prim_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
 976         uint32_t sec_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
 977
 978         /* Prefetch first keys */
 979         for (i = 0; i < PREFETCH_OFFSET && i < num_keys; i++)
 980                 rte_prefetch0(keys[i]);
 981
 982         /*
 983          * Prefetch rest of the keys, calculate primary and
 984          * secondary bucket and prefetch them
 985          */
 986         for (i = 0; i < (num_keys - PREFETCH_OFFSET); i++) {
 987                 rte_prefetch0(keys[i + PREFETCH_OFFSET]);
 988
 989                 prim_hash[i] = rte_hash_hash(h, keys[i]);
 990                 sec_hash[i] = rte_hash_secondary_hash(prim_hash[i]);
 991
 992                 primary_bkt[i] = &h->buckets[prim_hash[i] & h->bucket_bitmask];
 993                 secondary_bkt[i] = &h->buckets[sec_hash[i] & h->bucket_bitmask];
 994
 995                 rte_prefetch0(primary_bkt[i]);
 996                 rte_prefetch0(secondary_bkt[i]);
 997         }
 998
 999         /* Calculate and prefetch rest of the buckets */
1000         for (; i < num_keys; i++) {
1001                 prim_hash[i] = rte_hash_hash(h, keys[i]);
1002                 sec_hash[i] = rte_hash_secondary_hash(prim_hash[i]);
1003
1004                 primary_bkt[i] = &h->buckets[prim_hash[i] & h->bucket_bitmask];
1005                 secondary_bkt[i] = &h->buckets[sec_hash[i] & h->bucket_bitmask];
1006
1007                 rte_prefetch0(primary_bkt[i]);
1008                 rte_prefetch0(secondary_bkt[i]);
1009         }
1010
1011         /* Compare signatures and prefetch key slot of first hit */
1012         for (i = 0; i < num_keys; i++) {
1013                 compare_signatures(&prim_hitmask[i], &sec_hitmask[i],
1014                                 primary_bkt[i], secondary_bkt[i],
1015                                 prim_hash[i], sec_hash[i], h->sig_cmp_fn);
1016
1017                 if (prim_hitmask[i]) {
1018                         uint32_t first_hit = __builtin_ctzl(prim_hitmask[i]);
1019                         uint32_t key_idx = primary_bkt[i]->key_idx[first_hit];
1020                         const struct rte_hash_key *key_slot =
1021                                 (const struct rte_hash_key *)(
1022                                 (const char *)h->key_store +
1023                                 key_idx * h->key_entry_size);
1024                         rte_prefetch0(key_slot);
1025                         continue;
1026                 }
1027
1028                 if (sec_hitmask[i]) {
1029                         uint32_t first_hit = __builtin_ctzl(sec_hitmask[i]);
1030                         uint32_t key_idx = secondary_bkt[i]->key_idx[first_hit];
1031                         const struct rte_hash_key *key_slot =
1032                                 (const struct rte_hash_key *)(
1033                                 (const char *)h->key_store +
1034                                 key_idx * h->key_entry_size);
1035                         rte_prefetch0(key_slot);
1036                 }
1037         }
1038
1039         /* Compare keys, first hits in primary first */
1040         for (i = 0; i < num_keys; i++) {
1041                 positions[i] = -ENOENT;
1042                 while (prim_hitmask[i]) {
1043                         uint32_t hit_index = __builtin_ctzl(prim_hitmask[i]);
1044
1045                         uint32_t key_idx = primary_bkt[i]->key_idx[hit_index];
1046                         const struct rte_hash_key *key_slot =
1047                                 (const struct rte_hash_key *)(
1048                                 (const char *)h->key_store +
1049                                 key_idx * h->key_entry_size);
1050                         /*
1051                          * If key index is 0, do not compare key,
1052                          * as it is checking the dummy slot
1053                          */
1054                         if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
1055                                 if (data != NULL)
1056                                         data[i] = key_slot->pdata;
1057
1058                                 hits |= 1ULL << i;
1059                                 positions[i] = key_idx - 1;
1060                                 goto next_key;
1061                         }
1062                         prim_hitmask[i] &= ~(1 << (hit_index));
1063                 }
1064
1065                 while (sec_hitmask[i]) {
1066                         uint32_t hit_index = __builtin_ctzl(sec_hitmask[i]);
1067
1068                         uint32_t key_idx = secondary_bkt[i]->key_idx[hit_index];
1069                         const struct rte_hash_key *key_slot =
1070                                 (const struct rte_hash_key *)(
1071                                 (const char *)h->key_store +
1072                                 key_idx * h->key_entry_size);
1073                         /*
1074                          * If key index is 0, do not compare key,
1075                          * as it is checking the dummy slot
1076                          */
1077
1078                         if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
1079                                 if (data != NULL)
1080                                         data[i] = key_slot->pdata;
1081
1082                                 hits |= 1ULL << i;
1083                                 positions[i] = key_idx - 1;
1084                                 goto next_key;
1085                         }
1086                         sec_hitmask[i] &= ~(1 << (hit_index));
1087                 }
1088
1089 next_key:
1090                 continue;
1091         }
1092
1093         if (hit_mask != NULL)
1094                 *hit_mask = hits;
1095 }
1096
1097 int
1098 rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
1099                       uint32_t num_keys, int32_t *positions)
1100 {
1101         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1102                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1103                         (positions == NULL)), -EINVAL);
1104
1105         __rte_hash_lookup_bulk(h, keys, num_keys, positions, NULL, NULL);
1106         return 0;
1107 }
1108
1109 int
1110 rte_hash_lookup_bulk_data(const struct rte_hash *h, const void **keys,
1111                       uint32_t num_keys, uint64_t *hit_mask, void *data[])
1112 {
1113         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1114                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1115                         (hit_mask == NULL)), -EINVAL);
1116
1117         int32_t positions[num_keys];
1118
1119         __rte_hash_lookup_bulk(h, keys, num_keys, positions, hit_mask, data);
1120
1121         /* Return number of hits */
1122         return __builtin_popcountl(*hit_mask);
1123 }
1124
1125 int32_t
1126 rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32_t *next)
1127 {
1128         uint32_t bucket_idx, idx, position;
1129         struct rte_hash_key *next_key;
1130
1131         RETURN_IF_TRUE(((h == NULL) || (next == NULL)), -EINVAL);
1132
1133         const uint32_t total_entries = h->num_buckets * RTE_HASH_BUCKET_ENTRIES;
1134         /* Out of bounds */
1135         if (*next >= total_entries)
1136                 return -ENOENT;
1137
1138         /* Calculate bucket and index of current iterator */
1139         bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1140         idx = *next % RTE_HASH_BUCKET_ENTRIES;
1141
1142         /* If current position is empty, go to the next one */
1143         while (h->buckets[bucket_idx].key_idx[idx] == EMPTY_SLOT) {
1144                 (*next)++;
1145                 /* End of table */
1146                 if (*next == total_entries)
1147                         return -ENOENT;
1148                 bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1149                 idx = *next % RTE_HASH_BUCKET_ENTRIES;
1150         }
1151
1152         /* Get position of entry in key table */
1153         position = h->buckets[bucket_idx].key_idx[idx];
1154         next_key = (struct rte_hash_key *) ((char *)h->key_store +
1155                                 position * h->key_entry_size);
1156         /* Return key and data */
1157         *key = next_key->key;
1158         *data = next_key->pdata;
1159
1160         /* Increment iterator */
1161         (*next)++;
1162
1163         return position - 1;
1164 }