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                         !rte_is_power_of_2(RTE_HASH_BUCKET_ENTRIES) ||
 111                         (params->key_len == 0)) {
 112                 rte_errno = EINVAL;
 113                 RTE_LOG(ERR, HASH, "rte_hash_create has invalid parameters\n");
 114                 return NULL;
 115         }
 116
 117         /* Check extra flags field to check extra options. */
 118         if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT)
 119                 hw_trans_mem_support = 1;
 120
 121         /* Store all keys and leave the first entry as a dummy entry for lookup_bulk */
 122         if (hw_trans_mem_support)
 123                 /*
 124                  * Increase number of slots by total number of indices
 125                  * that can be stored in the lcore caches
 126                  * except for the first cache
 127                  */
 128                 num_key_slots = params->entries + (RTE_MAX_LCORE - 1) *
 129                                         LCORE_CACHE_SIZE + 1;
 130         else
 131                 num_key_slots = params->entries + 1;
 132
 133         snprintf(ring_name, sizeof(ring_name), "HT_%s", params->name);
 134         /* Create ring (Dummy slot index is not enqueued) */
 135         r = rte_ring_create(ring_name, rte_align32pow2(num_key_slots - 1),
 136                         params->socket_id, 0);
 137         if (r == NULL) {
 138                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 139                 goto err;
 140         }
 141
 142         snprintf(hash_name, sizeof(hash_name), "HT_%s", params->name);
 143
 144         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 145
 146         /* guarantee there's no existing: this is normally already checked
 147          * by ring creation above */
 148         TAILQ_FOREACH(te, hash_list, next) {
 149                 h = (struct rte_hash *) te->data;
 150                 if (strncmp(params->name, h->name, RTE_HASH_NAMESIZE) == 0)
 151                         break;
 152         }
 153         h = NULL;
 154         if (te != NULL) {
 155                 rte_errno = EEXIST;
 156                 te = NULL;
 157                 goto err_unlock;
 158         }
 159
 160         te = rte_zmalloc("HASH_TAILQ_ENTRY", sizeof(*te), 0);
 161         if (te == NULL) {
 162                 RTE_LOG(ERR, HASH, "tailq entry allocation failed\n");
 163                 goto err_unlock;
 164         }
 165
 166         h = (struct rte_hash *)rte_zmalloc_socket(hash_name, sizeof(struct rte_hash),
 167                                         RTE_CACHE_LINE_SIZE, params->socket_id);
 168
 169         if (h == NULL) {
 170                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 171                 goto err_unlock;
 172         }
 173
 174         const uint32_t num_buckets = rte_align32pow2(params->entries)
 175                                         / RTE_HASH_BUCKET_ENTRIES;
 176
 177         buckets = rte_zmalloc_socket(NULL,
 178                                 num_buckets * sizeof(struct rte_hash_bucket),
 179                                 RTE_CACHE_LINE_SIZE, params->socket_id);
 180
 181         if (buckets == NULL) {
 182                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 183                 goto err_unlock;
 184         }
 185
 186         const uint32_t key_entry_size = sizeof(struct rte_hash_key) + params->key_len;
 187         const uint64_t key_tbl_size = (uint64_t) key_entry_size * num_key_slots;
 188
 189         k = rte_zmalloc_socket(NULL, key_tbl_size,
 190                         RTE_CACHE_LINE_SIZE, params->socket_id);
 191
 192         if (k == NULL) {
 193                 RTE_LOG(ERR, HASH, "memory allocation failed\n");
 194                 goto err_unlock;
 195         }
 196
 197 /*
 198  * If x86 architecture is used, select appropriate compare function,
 199  * which may use x86 intrinsics, otherwise use memcmp
 200  */
 201 #if defined(RTE_ARCH_X86) || defined(RTE_ARCH_ARM64)
 202         /* Select function to compare keys */
 203         switch (params->key_len) {
 204         case 16:
 205                 h->cmp_jump_table_idx = KEY_16_BYTES;
 206                 break;
 207         case 32:
 208                 h->cmp_jump_table_idx = KEY_32_BYTES;
 209                 break;
 210         case 48:
 211                 h->cmp_jump_table_idx = KEY_48_BYTES;
 212                 break;
 213         case 64:
 214                 h->cmp_jump_table_idx = KEY_64_BYTES;
 215                 break;
 216         case 80:
 217                 h->cmp_jump_table_idx = KEY_80_BYTES;
 218                 break;
 219         case 96:
 220                 h->cmp_jump_table_idx = KEY_96_BYTES;
 221                 break;
 222         case 112:
 223                 h->cmp_jump_table_idx = KEY_112_BYTES;
 224                 break;
 225         case 128:
 226                 h->cmp_jump_table_idx = KEY_128_BYTES;
 227                 break;
 228         default:
 229                 /* If key is not multiple of 16, use generic memcmp */
 230                 h->cmp_jump_table_idx = KEY_OTHER_BYTES;
 231         }
 232 #else
 233         h->cmp_jump_table_idx = KEY_OTHER_BYTES;
 234 #endif
 235
 236         if (hw_trans_mem_support) {
 237                 h->local_free_slots = rte_zmalloc_socket(NULL,
 238                                 sizeof(struct lcore_cache) * RTE_MAX_LCORE,
 239                                 RTE_CACHE_LINE_SIZE, params->socket_id);
 240         }
 241
 242         /* Default hash function */
 243 #if defined(RTE_ARCH_X86)
 244         default_hash_func = (rte_hash_function)rte_hash_crc;
 245 #elif defined(RTE_ARCH_ARM64)
 246         if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_CRC32))
 247                 default_hash_func = (rte_hash_function)rte_hash_crc;
 248 #endif
 249         /* Setup hash context */
 250         snprintf(h->name, sizeof(h->name), "%s", params->name);
 251         h->entries = params->entries;
 252         h->key_len = params->key_len;
 253         h->key_entry_size = key_entry_size;
 254         h->hash_func_init_val = params->hash_func_init_val;
 255
 256         h->num_buckets = num_buckets;
 257         h->bucket_bitmask = h->num_buckets - 1;
 258         h->buckets = buckets;
 259         h->hash_func = (params->hash_func == NULL) ?
 260                 default_hash_func : params->hash_func;
 261         h->key_store = k;
 262         h->free_slots = r;
 263         h->hw_trans_mem_support = hw_trans_mem_support;
 264
 265 #if defined(RTE_ARCH_X86)
 266         if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2))
 267                 h->sig_cmp_fn = RTE_HASH_COMPARE_AVX2;
 268         else if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SSE2))
 269                 h->sig_cmp_fn = RTE_HASH_COMPARE_SSE;
 270         else
 271 #endif
 272                 h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;
 273
 274         /* Turn on multi-writer only with explicit flat from user and TM
 275          * support.
 276          */
 277         if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD) {
 278                 if (h->hw_trans_mem_support) {
 279                         h->add_key = ADD_KEY_MULTIWRITER_TM;
 280                 } else {
 281                         h->add_key = ADD_KEY_MULTIWRITER;
 282                         h->multiwriter_lock = rte_malloc(NULL,
 283                                                         sizeof(rte_spinlock_t),
 284                                                         LCORE_CACHE_SIZE);
 285                         rte_spinlock_init(h->multiwriter_lock);
 286                 }
 287         } else
 288                 h->add_key = ADD_KEY_SINGLEWRITER;
 289
 290         /* Populate free slots ring. Entry zero is reserved for key misses. */
 291         for (i = 1; i < params->entries + 1; i++)
 292                 rte_ring_sp_enqueue(r, (void *)((uintptr_t) i));
 293
 294         te->data = (void *) h;
 295         TAILQ_INSERT_TAIL(hash_list, te, next);
 296         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 297
 298         return h;
 299 err_unlock:
 300         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 301 err:
 302         rte_ring_free(r);
 303         rte_free(te);
 304         rte_free(h);
 305         rte_free(buckets);
 306         rte_free(k);
 307         return NULL;
 308 }
 309
 310 void
 311 rte_hash_free(struct rte_hash *h)
 312 {
 313         struct rte_tailq_entry *te;
 314         struct rte_hash_list *hash_list;
 315
 316         if (h == NULL)
 317                 return;
 318
 319         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 320
 321         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 322
 323         /* find out tailq entry */
 324         TAILQ_FOREACH(te, hash_list, next) {
 325                 if (te->data == (void *) h)
 326                         break;
 327         }
 328
 329         if (te == NULL) {
 330                 rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 331                 return;
 332         }
 333
 334         TAILQ_REMOVE(hash_list, te, next);
 335
 336         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 337
 338         if (h->hw_trans_mem_support)
 339                 rte_free(h->local_free_slots);
 340
 341         if (h->add_key == ADD_KEY_MULTIWRITER)
 342                 rte_free(h->multiwriter_lock);
 343         rte_ring_free(h->free_slots);
 344         rte_free(h->key_store);
 345         rte_free(h->buckets);
 346         rte_free(h);
 347         rte_free(te);
 348 }
 349
 350 hash_sig_t
 351 rte_hash_hash(const struct rte_hash *h, const void *key)
 352 {
 353         /* calc hash result by key */
 354         return h->hash_func(key, h->key_len, h->hash_func_init_val);
 355 }
 356
 357 /* Calc the secondary hash value from the primary hash value of a given key */
 358 static inline hash_sig_t
 359 rte_hash_secondary_hash(const hash_sig_t primary_hash)
 360 {
 361         static const unsigned all_bits_shift = 12;
 362         static const unsigned alt_bits_xor = 0x5bd1e995;
 363
 364         uint32_t tag = primary_hash >> all_bits_shift;
 365
 366         return primary_hash ^ ((tag + 1) * alt_bits_xor);
 367 }
 368
 369 void
 370 rte_hash_reset(struct rte_hash *h)
 371 {
 372         void *ptr;
 373         unsigned i;
 374
 375         if (h == NULL)
 376                 return;
 377
 378         memset(h->buckets, 0, h->num_buckets * sizeof(struct rte_hash_bucket));
 379         memset(h->key_store, 0, h->key_entry_size * (h->entries + 1));
 380
 381         /* clear the free ring */
 382         while (rte_ring_dequeue(h->free_slots, &ptr) == 0)
 383                 rte_pause();
 384
 385         /* Repopulate the free slots ring. Entry zero is reserved for key misses */
 386         for (i = 1; i < h->entries + 1; i++)
 387                 rte_ring_sp_enqueue(h->free_slots, (void *)((uintptr_t) i));
 388
 389         if (h->hw_trans_mem_support) {
 390                 /* Reset local caches per lcore */
 391                 for (i = 0; i < RTE_MAX_LCORE; i++)
 392                         h->local_free_slots[i].len = 0;
 393         }
 394 }
 395
 396 /* Search for an entry that can be pushed to its alternative location */
 397 static inline int
 398 make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt,
 399                 unsigned int *nr_pushes)
 400 {
 401         unsigned i, j;
 402         int ret;
 403         uint32_t next_bucket_idx;
 404         struct rte_hash_bucket *next_bkt[RTE_HASH_BUCKET_ENTRIES];
 405
 406         /*
 407          * Push existing item (search for bucket with space in
 408          * alternative locations) to its alternative location
 409          */
 410         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 411                 /* Search for space in alternative locations */
 412                 next_bucket_idx = bkt->sig_alt[i] & h->bucket_bitmask;
 413                 next_bkt[i] = &h->buckets[next_bucket_idx];
 414                 for (j = 0; j < RTE_HASH_BUCKET_ENTRIES; j++) {
 415                         if (next_bkt[i]->key_idx[j] == EMPTY_SLOT)
 416                                 break;
 417                 }
 418
 419                 if (j != RTE_HASH_BUCKET_ENTRIES)
 420                         break;
 421         }
 422
 423         /* Alternative location has spare room (end of recursive function) */
 424         if (i != RTE_HASH_BUCKET_ENTRIES) {
 425                 next_bkt[i]->sig_alt[j] = bkt->sig_current[i];
 426                 next_bkt[i]->sig_current[j] = bkt->sig_alt[i];
 427                 next_bkt[i]->key_idx[j] = bkt->key_idx[i];
 428                 return i;
 429         }
 430
 431         /* Pick entry that has not been pushed yet */
 432         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++)
 433                 if (bkt->flag[i] == 0)
 434                         break;
 435
 436         /* All entries have been pushed, so entry cannot be added */
 437         if (i == RTE_HASH_BUCKET_ENTRIES || ++(*nr_pushes) > RTE_HASH_MAX_PUSHES)
 438                 return -ENOSPC;
 439
 440         /* Set flag to indicate that this entry is going to be pushed */
 441         bkt->flag[i] = 1;
 442
 443         /* Need room in alternative bucket to insert the pushed entry */
 444         ret = make_space_bucket(h, next_bkt[i], nr_pushes);
 445         /*
 446          * After recursive function.
 447          * Clear flags and insert the pushed entry
 448          * in its alternative location if successful,
 449          * or return error
 450          */
 451         bkt->flag[i] = 0;
 452         if (ret >= 0) {
 453                 next_bkt[i]->sig_alt[ret] = bkt->sig_current[i];
 454                 next_bkt[i]->sig_current[ret] = bkt->sig_alt[i];
 455                 next_bkt[i]->key_idx[ret] = bkt->key_idx[i];
 456                 return i;
 457         } else
 458                 return ret;
 459
 460 }
 461
 462 /*
 463  * Function called to enqueue back an index in the cache/ring,
 464  * as slot has not being used and it can be used in the
 465  * next addition attempt.
 466  */
 467 static inline void
 468 enqueue_slot_back(const struct rte_hash *h,
 469                 struct lcore_cache *cached_free_slots,
 470                 void *slot_id)
 471 {
 472         if (h->hw_trans_mem_support) {
 473                 cached_free_slots->objs[cached_free_slots->len] = slot_id;
 474                 cached_free_slots->len++;
 475         } else
 476                 rte_ring_sp_enqueue(h->free_slots, slot_id);
 477 }
 478
 479 static inline int32_t
 480 __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
 481                                                 hash_sig_t sig, void *data)
 482 {
 483         hash_sig_t alt_hash;
 484         uint32_t prim_bucket_idx, sec_bucket_idx;
 485         unsigned i;
 486         struct rte_hash_bucket *prim_bkt, *sec_bkt;
 487         struct rte_hash_key *new_k, *k, *keys = h->key_store;
 488         void *slot_id = NULL;
 489         uint32_t new_idx;
 490         int ret;
 491         unsigned n_slots;
 492         unsigned lcore_id;
 493         struct lcore_cache *cached_free_slots = NULL;
 494         unsigned int nr_pushes = 0;
 495
 496         if (h->add_key == ADD_KEY_MULTIWRITER)
 497                 rte_spinlock_lock(h->multiwriter_lock);
 498
 499         prim_bucket_idx = sig & h->bucket_bitmask;
 500         prim_bkt = &h->buckets[prim_bucket_idx];
 501         rte_prefetch0(prim_bkt);
 502
 503         alt_hash = rte_hash_secondary_hash(sig);
 504         sec_bucket_idx = alt_hash & h->bucket_bitmask;
 505         sec_bkt = &h->buckets[sec_bucket_idx];
 506         rte_prefetch0(sec_bkt);
 507
 508         /* Get a new slot for storing the new key */
 509         if (h->hw_trans_mem_support) {
 510                 lcore_id = rte_lcore_id();
 511                 cached_free_slots = &h->local_free_slots[lcore_id];
 512                 /* Try to get a free slot from the local cache */
 513                 if (cached_free_slots->len == 0) {
 514                         /* Need to get another burst of free slots from global ring */
 515                         n_slots = rte_ring_mc_dequeue_burst(h->free_slots,
 516                                         cached_free_slots->objs,
 517                                         LCORE_CACHE_SIZE, NULL);
 518                         if (n_slots == 0) {
 519                                 ret = -ENOSPC;
 520                                 goto failure;
 521                         }
 522
 523                         cached_free_slots->len += n_slots;
 524                 }
 525
 526                 /* Get a free slot from the local cache */
 527                 cached_free_slots->len--;
 528                 slot_id = cached_free_slots->objs[cached_free_slots->len];
 529         } else {
 530                 if (rte_ring_sc_dequeue(h->free_slots, &slot_id) != 0) {
 531                         ret = -ENOSPC;
 532                         goto failure;
 533                 }
 534         }
 535
 536         new_k = RTE_PTR_ADD(keys, (uintptr_t)slot_id * h->key_entry_size);
 537         rte_prefetch0(new_k);
 538         new_idx = (uint32_t)((uintptr_t) slot_id);
 539
 540         /* Check if key is already inserted in primary location */
 541         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 542                 if (prim_bkt->sig_current[i] == sig &&
 543                                 prim_bkt->sig_alt[i] == alt_hash) {
 544                         k = (struct rte_hash_key *) ((char *)keys +
 545                                         prim_bkt->key_idx[i] * h->key_entry_size);
 546                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 547                                 /* Enqueue index of free slot back in the ring. */
 548                                 enqueue_slot_back(h, cached_free_slots, slot_id);
 549                                 /* Update data */
 550                                 k->pdata = data;
 551                                 /*
 552                                  * Return index where key is stored,
 553                                  * subtracting the first dummy index
 554                                  */
 555                                 return prim_bkt->key_idx[i] - 1;
 556                         }
 557                 }
 558         }
 559
 560         /* Check if key is already inserted in secondary location */
 561         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 562                 if (sec_bkt->sig_alt[i] == sig &&
 563                                 sec_bkt->sig_current[i] == alt_hash) {
 564                         k = (struct rte_hash_key *) ((char *)keys +
 565                                         sec_bkt->key_idx[i] * h->key_entry_size);
 566                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 567                                 /* Enqueue index of free slot back in the ring. */
 568                                 enqueue_slot_back(h, cached_free_slots, slot_id);
 569                                 /* Update data */
 570                                 k->pdata = data;
 571                                 /*
 572                                  * Return index where key is stored,
 573                                  * subtracting the first dummy index
 574                                  */
 575                                 return sec_bkt->key_idx[i] - 1;
 576                         }
 577                 }
 578         }
 579
 580         /* Copy key */
 581         rte_memcpy(new_k->key, key, h->key_len);
 582         new_k->pdata = data;
 583
 584 #if defined(RTE_ARCH_X86) /* currently only x86 support HTM */
 585         if (h->add_key == ADD_KEY_MULTIWRITER_TM) {
 586                 ret = rte_hash_cuckoo_insert_mw_tm(prim_bkt,
 587                                 sig, alt_hash, new_idx);
 588                 if (ret >= 0)
 589                         return new_idx - 1;
 590
 591                 /* Primary bucket full, need to make space for new entry */
 592                 ret = rte_hash_cuckoo_make_space_mw_tm(h, prim_bkt, sig,
 593                                                         alt_hash, new_idx);
 594
 595                 if (ret >= 0)
 596                         return new_idx - 1;
 597
 598                 /* Also search secondary bucket to get better occupancy */
 599                 ret = rte_hash_cuckoo_make_space_mw_tm(h, sec_bkt, sig,
 600                                                         alt_hash, new_idx);
 601
 602                 if (ret >= 0)
 603                         return new_idx - 1;
 604         } else {
 605 #endif
 606                 for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 607                         /* Check if slot is available */
 608                         if (likely(prim_bkt->key_idx[i] == EMPTY_SLOT)) {
 609                                 prim_bkt->sig_current[i] = sig;
 610                                 prim_bkt->sig_alt[i] = alt_hash;
 611                                 prim_bkt->key_idx[i] = new_idx;
 612                                 break;
 613                         }
 614                 }
 615
 616                 if (i != RTE_HASH_BUCKET_ENTRIES) {
 617                         if (h->add_key == ADD_KEY_MULTIWRITER)
 618                                 rte_spinlock_unlock(h->multiwriter_lock);
 619                         return new_idx - 1;
 620                 }
 621
 622                 /* Primary bucket full, need to make space for new entry
 623                  * After recursive function.
 624                  * Insert the new entry in the position of the pushed entry
 625                  * if successful or return error and
 626                  * store the new slot back in the ring
 627                  */
 628                 ret = make_space_bucket(h, prim_bkt, &nr_pushes);
 629                 if (ret >= 0) {
 630                         prim_bkt->sig_current[ret] = sig;
 631                         prim_bkt->sig_alt[ret] = alt_hash;
 632                         prim_bkt->key_idx[ret] = new_idx;
 633                         if (h->add_key == ADD_KEY_MULTIWRITER)
 634                                 rte_spinlock_unlock(h->multiwriter_lock);
 635                         return new_idx - 1;
 636                 }
 637 #if defined(RTE_ARCH_X86)
 638         }
 639 #endif
 640         /* Error in addition, store new slot back in the ring and return error */
 641         enqueue_slot_back(h, cached_free_slots, (void *)((uintptr_t) new_idx));
 642
 643 failure:
 644         if (h->add_key == ADD_KEY_MULTIWRITER)
 645                 rte_spinlock_unlock(h->multiwriter_lock);
 646         return ret;
 647 }
 648
 649 int32_t
 650 rte_hash_add_key_with_hash(const struct rte_hash *h,
 651                         const void *key, hash_sig_t sig)
 652 {
 653         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 654         return __rte_hash_add_key_with_hash(h, key, sig, 0);
 655 }
 656
 657 int32_t
 658 rte_hash_add_key(const struct rte_hash *h, const void *key)
 659 {
 660         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 661         return __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), 0);
 662 }
 663
 664 int
 665 rte_hash_add_key_with_hash_data(const struct rte_hash *h,
 666                         const void *key, hash_sig_t sig, void *data)
 667 {
 668         int ret;
 669
 670         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 671         ret = __rte_hash_add_key_with_hash(h, key, sig, data);
 672         if (ret >= 0)
 673                 return 0;
 674         else
 675                 return ret;
 676 }
 677
 678 int
 679 rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data)
 680 {
 681         int ret;
 682
 683         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 684
 685         ret = __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), data);
 686         if (ret >= 0)
 687                 return 0;
 688         else
 689                 return ret;
 690 }
 691 static inline int32_t
 692 __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
 693                                         hash_sig_t sig, void **data)
 694 {
 695         uint32_t bucket_idx;
 696         hash_sig_t alt_hash;
 697         unsigned i;
 698         struct rte_hash_bucket *bkt;
 699         struct rte_hash_key *k, *keys = h->key_store;
 700
 701         bucket_idx = sig & h->bucket_bitmask;
 702         bkt = &h->buckets[bucket_idx];
 703
 704         /* Check if key is in primary location */
 705         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 706                 if (bkt->sig_current[i] == sig &&
 707                                 bkt->key_idx[i] != EMPTY_SLOT) {
 708                         k = (struct rte_hash_key *) ((char *)keys +
 709                                         bkt->key_idx[i] * h->key_entry_size);
 710                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 711                                 if (data != NULL)
 712                                         *data = k->pdata;
 713                                 /*
 714                                  * Return index where key is stored,
 715                                  * subtracting the first dummy index
 716                                  */
 717                                 return bkt->key_idx[i] - 1;
 718                         }
 719                 }
 720         }
 721
 722         /* Calculate secondary hash */
 723         alt_hash = rte_hash_secondary_hash(sig);
 724         bucket_idx = alt_hash & h->bucket_bitmask;
 725         bkt = &h->buckets[bucket_idx];
 726
 727         /* Check if key is in secondary location */
 728         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 729                 if (bkt->sig_current[i] == alt_hash &&
 730                                 bkt->sig_alt[i] == sig) {
 731                         k = (struct rte_hash_key *) ((char *)keys +
 732                                         bkt->key_idx[i] * h->key_entry_size);
 733                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 734                                 if (data != NULL)
 735                                         *data = k->pdata;
 736                                 /*
 737                                  * Return index where key is stored,
 738                                  * subtracting the first dummy index
 739                                  */
 740                                 return bkt->key_idx[i] - 1;
 741                         }
 742                 }
 743         }
 744
 745         return -ENOENT;
 746 }
 747
 748 int32_t
 749 rte_hash_lookup_with_hash(const struct rte_hash *h,
 750                         const void *key, hash_sig_t sig)
 751 {
 752         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 753         return __rte_hash_lookup_with_hash(h, key, sig, NULL);
 754 }
 755
 756 int32_t
 757 rte_hash_lookup(const struct rte_hash *h, const void *key)
 758 {
 759         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 760         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), NULL);
 761 }
 762
 763 int
 764 rte_hash_lookup_with_hash_data(const struct rte_hash *h,
 765                         const void *key, hash_sig_t sig, void **data)
 766 {
 767         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 768         return __rte_hash_lookup_with_hash(h, key, sig, data);
 769 }
 770
 771 int
 772 rte_hash_lookup_data(const struct rte_hash *h, const void *key, void **data)
 773 {
 774         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 775         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), data);
 776 }
 777
 778 static inline void
 779 remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt, unsigned i)
 780 {
 781         unsigned lcore_id, n_slots;
 782         struct lcore_cache *cached_free_slots;
 783
 784         bkt->sig_current[i] = NULL_SIGNATURE;
 785         bkt->sig_alt[i] = NULL_SIGNATURE;
 786         if (h->hw_trans_mem_support) {
 787                 lcore_id = rte_lcore_id();
 788                 cached_free_slots = &h->local_free_slots[lcore_id];
 789                 /* Cache full, need to free it. */
 790                 if (cached_free_slots->len == LCORE_CACHE_SIZE) {
 791                         /* Need to enqueue the free slots in global ring. */
 792                         n_slots = rte_ring_mp_enqueue_burst(h->free_slots,
 793                                                 cached_free_slots->objs,
 794                                                 LCORE_CACHE_SIZE, NULL);
 795                         cached_free_slots->len -= n_slots;
 796                 }
 797                 /* Put index of new free slot in cache. */
 798                 cached_free_slots->objs[cached_free_slots->len] =
 799                                 (void *)((uintptr_t)bkt->key_idx[i]);
 800                 cached_free_slots->len++;
 801         } else {
 802                 rte_ring_sp_enqueue(h->free_slots,
 803                                 (void *)((uintptr_t)bkt->key_idx[i]));
 804         }
 805 }
 806
 807 static inline int32_t
 808 __rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
 809                                                 hash_sig_t sig)
 810 {
 811         uint32_t bucket_idx;
 812         hash_sig_t alt_hash;
 813         unsigned i;
 814         struct rte_hash_bucket *bkt;
 815         struct rte_hash_key *k, *keys = h->key_store;
 816         int32_t ret;
 817
 818         bucket_idx = sig & h->bucket_bitmask;
 819         bkt = &h->buckets[bucket_idx];
 820
 821         /* Check if key is in primary location */
 822         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 823                 if (bkt->sig_current[i] == sig &&
 824                                 bkt->key_idx[i] != EMPTY_SLOT) {
 825                         k = (struct rte_hash_key *) ((char *)keys +
 826                                         bkt->key_idx[i] * h->key_entry_size);
 827                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 828                                 remove_entry(h, bkt, i);
 829
 830                                 /*
 831                                  * Return index where key is stored,
 832                                  * subtracting the first dummy index
 833                                  */
 834                                 ret = bkt->key_idx[i] - 1;
 835                                 bkt->key_idx[i] = EMPTY_SLOT;
 836                                 return ret;
 837                         }
 838                 }
 839         }
 840
 841         /* Calculate secondary hash */
 842         alt_hash = rte_hash_secondary_hash(sig);
 843         bucket_idx = alt_hash & h->bucket_bitmask;
 844         bkt = &h->buckets[bucket_idx];
 845
 846         /* Check if key is in secondary location */
 847         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 848                 if (bkt->sig_current[i] == alt_hash &&
 849                                 bkt->key_idx[i] != EMPTY_SLOT) {
 850                         k = (struct rte_hash_key *) ((char *)keys +
 851                                         bkt->key_idx[i] * h->key_entry_size);
 852                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 853                                 remove_entry(h, bkt, i);
 854
 855                                 /*
 856                                  * Return index where key is stored,
 857                                  * subtracting the first dummy index
 858                                  */
 859                                 ret = bkt->key_idx[i] - 1;
 860                                 bkt->key_idx[i] = EMPTY_SLOT;
 861                                 return ret;
 862                         }
 863                 }
 864         }
 865
 866         return -ENOENT;
 867 }
 868
 869 int32_t
 870 rte_hash_del_key_with_hash(const struct rte_hash *h,
 871                         const void *key, hash_sig_t sig)
 872 {
 873         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 874         return __rte_hash_del_key_with_hash(h, key, sig);
 875 }
 876
 877 int32_t
 878 rte_hash_del_key(const struct rte_hash *h, const void *key)
 879 {
 880         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 881         return __rte_hash_del_key_with_hash(h, key, rte_hash_hash(h, key));
 882 }
 883
 884 int
 885 rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
 886                                void **key)
 887 {
 888         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 889
 890         struct rte_hash_key *k, *keys = h->key_store;
 891         k = (struct rte_hash_key *) ((char *) keys + (position + 1) *
 892                                      h->key_entry_size);
 893         *key = k->key;
 894
 895         if (position !=
 896             __rte_hash_lookup_with_hash(h, *key, rte_hash_hash(h, *key),
 897                                         NULL)) {
 898                 return -ENOENT;
 899         }
 900
 901         return 0;
 902 }
 903
 904 static inline void
 905 compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
 906                         const struct rte_hash_bucket *prim_bkt,
 907                         const struct rte_hash_bucket *sec_bkt,
 908                         hash_sig_t prim_hash, hash_sig_t sec_hash,
 909                         enum rte_hash_sig_compare_function sig_cmp_fn)
 910 {
 911         unsigned int i;
 912
 913         switch (sig_cmp_fn) {
 914 #ifdef RTE_MACHINE_CPUFLAG_AVX2
 915         case RTE_HASH_COMPARE_AVX2:
 916                 *prim_hash_matches = _mm256_movemask_ps((__m256)_mm256_cmpeq_epi32(
 917                                 _mm256_load_si256(
 918                                         (__m256i const *)prim_bkt->sig_current),
 919                                 _mm256_set1_epi32(prim_hash)));
 920                 *sec_hash_matches = _mm256_movemask_ps((__m256)_mm256_cmpeq_epi32(
 921                                 _mm256_load_si256(
 922                                         (__m256i const *)sec_bkt->sig_current),
 923                                 _mm256_set1_epi32(sec_hash)));
 924                 break;
 925 #endif
 926 #ifdef RTE_MACHINE_CPUFLAG_SSE2
 927         case RTE_HASH_COMPARE_SSE:
 928                 /* Compare the first 4 signatures in the bucket */
 929                 *prim_hash_matches = _mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 930                                 _mm_load_si128(
 931                                         (__m128i const *)prim_bkt->sig_current),
 932                                 _mm_set1_epi32(prim_hash)));
 933                 *prim_hash_matches |= (_mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 934                                 _mm_load_si128(
 935                                         (__m128i const *)&prim_bkt->sig_current[4]),
 936                                 _mm_set1_epi32(prim_hash)))) << 4;
 937                 /* Compare the first 4 signatures in the bucket */
 938                 *sec_hash_matches = _mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 939                                 _mm_load_si128(
 940                                         (__m128i const *)sec_bkt->sig_current),
 941                                 _mm_set1_epi32(sec_hash)));
 942                 *sec_hash_matches |= (_mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 943                                 _mm_load_si128(
 944                                         (__m128i const *)&sec_bkt->sig_current[4]),
 945                                 _mm_set1_epi32(sec_hash)))) << 4;
 946                 break;
 947 #endif
 948         default:
 949                 for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 950                         *prim_hash_matches |=
 951                                 ((prim_hash == prim_bkt->sig_current[i]) << i);
 952                         *sec_hash_matches |=
 953                                 ((sec_hash == sec_bkt->sig_current[i]) << i);
 954                 }
 955         }
 956
 957 }
 958
 959 #define PREFETCH_OFFSET 4
 960 static inline void
 961 __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
 962                         int32_t num_keys, int32_t *positions,
 963                         uint64_t *hit_mask, void *data[])
 964 {
 965         uint64_t hits = 0;
 966         int32_t i;
 967         uint32_t prim_hash[RTE_HASH_LOOKUP_BULK_MAX];
 968         uint32_t sec_hash[RTE_HASH_LOOKUP_BULK_MAX];
 969         const struct rte_hash_bucket *primary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
 970         const struct rte_hash_bucket *secondary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
 971         uint32_t prim_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
 972         uint32_t sec_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
 973
 974         /* Prefetch first keys */
 975         for (i = 0; i < PREFETCH_OFFSET && i < num_keys; i++)
 976                 rte_prefetch0(keys[i]);
 977
 978         /*
 979          * Prefetch rest of the keys, calculate primary and
 980          * secondary bucket and prefetch them
 981          */
 982         for (i = 0; i < (num_keys - PREFETCH_OFFSET); i++) {
 983                 rte_prefetch0(keys[i + PREFETCH_OFFSET]);
 984
 985                 prim_hash[i] = rte_hash_hash(h, keys[i]);
 986                 sec_hash[i] = rte_hash_secondary_hash(prim_hash[i]);
 987
 988                 primary_bkt[i] = &h->buckets[prim_hash[i] & h->bucket_bitmask];
 989                 secondary_bkt[i] = &h->buckets[sec_hash[i] & h->bucket_bitmask];
 990
 991                 rte_prefetch0(primary_bkt[i]);
 992                 rte_prefetch0(secondary_bkt[i]);
 993         }
 994
 995         /* Calculate and prefetch rest of the buckets */
 996         for (; i < num_keys; i++) {
 997                 prim_hash[i] = rte_hash_hash(h, keys[i]);
 998                 sec_hash[i] = rte_hash_secondary_hash(prim_hash[i]);
 999
1000                 primary_bkt[i] = &h->buckets[prim_hash[i] & h->bucket_bitmask];
1001                 secondary_bkt[i] = &h->buckets[sec_hash[i] & h->bucket_bitmask];
1002
1003                 rte_prefetch0(primary_bkt[i]);
1004                 rte_prefetch0(secondary_bkt[i]);
1005         }
1006
1007         /* Compare signatures and prefetch key slot of first hit */
1008         for (i = 0; i < num_keys; i++) {
1009                 compare_signatures(&prim_hitmask[i], &sec_hitmask[i],
1010                                 primary_bkt[i], secondary_bkt[i],
1011                                 prim_hash[i], sec_hash[i], h->sig_cmp_fn);
1012
1013                 if (prim_hitmask[i]) {
1014                         uint32_t first_hit = __builtin_ctzl(prim_hitmask[i]);
1015                         uint32_t key_idx = primary_bkt[i]->key_idx[first_hit];
1016                         const struct rte_hash_key *key_slot =
1017                                 (const struct rte_hash_key *)(
1018                                 (const char *)h->key_store +
1019                                 key_idx * h->key_entry_size);
1020                         rte_prefetch0(key_slot);
1021                         continue;
1022                 }
1023
1024                 if (sec_hitmask[i]) {
1025                         uint32_t first_hit = __builtin_ctzl(sec_hitmask[i]);
1026                         uint32_t key_idx = secondary_bkt[i]->key_idx[first_hit];
1027                         const struct rte_hash_key *key_slot =
1028                                 (const struct rte_hash_key *)(
1029                                 (const char *)h->key_store +
1030                                 key_idx * h->key_entry_size);
1031                         rte_prefetch0(key_slot);
1032                 }
1033         }
1034
1035         /* Compare keys, first hits in primary first */
1036         for (i = 0; i < num_keys; i++) {
1037                 positions[i] = -ENOENT;
1038                 while (prim_hitmask[i]) {
1039                         uint32_t hit_index = __builtin_ctzl(prim_hitmask[i]);
1040
1041                         uint32_t key_idx = primary_bkt[i]->key_idx[hit_index];
1042                         const struct rte_hash_key *key_slot =
1043                                 (const struct rte_hash_key *)(
1044                                 (const char *)h->key_store +
1045                                 key_idx * h->key_entry_size);
1046                         /*
1047                          * If key index is 0, do not compare key,
1048                          * as it is checking the dummy slot
1049                          */
1050                         if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
1051                                 if (data != NULL)
1052                                         data[i] = key_slot->pdata;
1053
1054                                 hits |= 1ULL << i;
1055                                 positions[i] = key_idx - 1;
1056                                 goto next_key;
1057                         }
1058                         prim_hitmask[i] &= ~(1 << (hit_index));
1059                 }
1060
1061                 while (sec_hitmask[i]) {
1062                         uint32_t hit_index = __builtin_ctzl(sec_hitmask[i]);
1063
1064                         uint32_t key_idx = secondary_bkt[i]->key_idx[hit_index];
1065                         const struct rte_hash_key *key_slot =
1066                                 (const struct rte_hash_key *)(
1067                                 (const char *)h->key_store +
1068                                 key_idx * h->key_entry_size);
1069                         /*
1070                          * If key index is 0, do not compare key,
1071                          * as it is checking the dummy slot
1072                          */
1073
1074                         if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
1075                                 if (data != NULL)
1076                                         data[i] = key_slot->pdata;
1077
1078                                 hits |= 1ULL << i;
1079                                 positions[i] = key_idx - 1;
1080                                 goto next_key;
1081                         }
1082                         sec_hitmask[i] &= ~(1 << (hit_index));
1083                 }
1084
1085 next_key:
1086                 continue;
1087         }
1088
1089         if (hit_mask != NULL)
1090                 *hit_mask = hits;
1091 }
1092
1093 int
1094 rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
1095                       uint32_t num_keys, int32_t *positions)
1096 {
1097         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1098                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1099                         (positions == NULL)), -EINVAL);
1100
1101         __rte_hash_lookup_bulk(h, keys, num_keys, positions, NULL, NULL);
1102         return 0;
1103 }
1104
1105 int
1106 rte_hash_lookup_bulk_data(const struct rte_hash *h, const void **keys,
1107                       uint32_t num_keys, uint64_t *hit_mask, void *data[])
1108 {
1109         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1110                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1111                         (hit_mask == NULL)), -EINVAL);
1112
1113         int32_t positions[num_keys];
1114
1115         __rte_hash_lookup_bulk(h, keys, num_keys, positions, hit_mask, data);
1116
1117         /* Return number of hits */
1118         return __builtin_popcountl(*hit_mask);
1119 }
1120
1121 int32_t
1122 rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32_t *next)
1123 {
1124         uint32_t bucket_idx, idx, position;
1125         struct rte_hash_key *next_key;
1126
1127         RETURN_IF_TRUE(((h == NULL) || (next == NULL)), -EINVAL);
1128
1129         const uint32_t total_entries = h->num_buckets * RTE_HASH_BUCKET_ENTRIES;
1130         /* Out of bounds */
1131         if (*next >= total_entries)
1132                 return -ENOENT;
1133
1134         /* Calculate bucket and index of current iterator */
1135         bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1136         idx = *next % RTE_HASH_BUCKET_ENTRIES;
1137
1138         /* If current position is empty, go to the next one */
1139         while (h->buckets[bucket_idx].key_idx[idx] == EMPTY_SLOT) {
1140                 (*next)++;
1141                 /* End of table */
1142                 if (*next == total_entries)
1143                         return -ENOENT;
1144                 bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1145                 idx = *next % RTE_HASH_BUCKET_ENTRIES;
1146         }
1147
1148         /* Get position of entry in key table */
1149         position = h->buckets[bucket_idx].key_idx[idx];
1150         next_key = (struct rte_hash_key *) ((char *)h->key_store +
1151                                 position * h->key_entry_size);
1152         /* Return key and data */
1153         *key = next_key->key;
1154         *data = next_key->pdata;
1155
1156         /* Increment iterator */
1157         (*next)++;
1158
1159         return position - 1;
1160 }