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                                                         LCORE_CACHE_SIZE);
 284                         rte_spinlock_init(h->multiwriter_lock);
 285                 }
 286         } else
 287                 h->add_key = ADD_KEY_SINGLEWRITER;
 288
 289         /* Populate free slots ring. Entry zero is reserved for key misses. */
 290         for (i = 1; i < params->entries + 1; i++)
 291                 rte_ring_sp_enqueue(r, (void *)((uintptr_t) i));
 292
 293         te->data = (void *) h;
 294         TAILQ_INSERT_TAIL(hash_list, te, next);
 295         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 296
 297         return h;
 298 err_unlock:
 299         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 300 err:
 301         rte_ring_free(r);
 302         rte_free(te);
 303         rte_free(h);
 304         rte_free(buckets);
 305         rte_free(k);
 306         return NULL;
 307 }
 308
 309 void
 310 rte_hash_free(struct rte_hash *h)
 311 {
 312         struct rte_tailq_entry *te;
 313         struct rte_hash_list *hash_list;
 314
 315         if (h == NULL)
 316                 return;
 317
 318         hash_list = RTE_TAILQ_CAST(rte_hash_tailq.head, rte_hash_list);
 319
 320         rte_rwlock_write_lock(RTE_EAL_TAILQ_RWLOCK);
 321
 322         /* find out tailq entry */
 323         TAILQ_FOREACH(te, hash_list, next) {
 324                 if (te->data == (void *) h)
 325                         break;
 326         }
 327
 328         if (te == NULL) {
 329                 rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 330                 return;
 331         }
 332
 333         TAILQ_REMOVE(hash_list, te, next);
 334
 335         rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
 336
 337         if (h->hw_trans_mem_support)
 338                 rte_free(h->local_free_slots);
 339
 340         if (h->add_key == ADD_KEY_MULTIWRITER)
 341                 rte_free(h->multiwriter_lock);
 342         rte_ring_free(h->free_slots);
 343         rte_free(h->key_store);
 344         rte_free(h->buckets);
 345         rte_free(h);
 346         rte_free(te);
 347 }
 348
 349 hash_sig_t
 350 rte_hash_hash(const struct rte_hash *h, const void *key)
 351 {
 352         /* calc hash result by key */
 353         return h->hash_func(key, h->key_len, h->hash_func_init_val);
 354 }
 355
 356 /* Calc the secondary hash value from the primary hash value of a given key */
 357 static inline hash_sig_t
 358 rte_hash_secondary_hash(const hash_sig_t primary_hash)
 359 {
 360         static const unsigned all_bits_shift = 12;
 361         static const unsigned alt_bits_xor = 0x5bd1e995;
 362
 363         uint32_t tag = primary_hash >> all_bits_shift;
 364
 365         return primary_hash ^ ((tag + 1) * alt_bits_xor);
 366 }
 367
 368 void
 369 rte_hash_reset(struct rte_hash *h)
 370 {
 371         void *ptr;
 372         unsigned i;
 373
 374         if (h == NULL)
 375                 return;
 376
 377         memset(h->buckets, 0, h->num_buckets * sizeof(struct rte_hash_bucket));
 378         memset(h->key_store, 0, h->key_entry_size * (h->entries + 1));
 379
 380         /* clear the free ring */
 381         while (rte_ring_dequeue(h->free_slots, &ptr) == 0)
 382                 rte_pause();
 383
 384         /* Repopulate the free slots ring. Entry zero is reserved for key misses */
 385         for (i = 1; i < h->entries + 1; i++)
 386                 rte_ring_sp_enqueue(h->free_slots, (void *)((uintptr_t) i));
 387
 388         if (h->hw_trans_mem_support) {
 389                 /* Reset local caches per lcore */
 390                 for (i = 0; i < RTE_MAX_LCORE; i++)
 391                         h->local_free_slots[i].len = 0;
 392         }
 393 }
 394
 395 /* Search for an entry that can be pushed to its alternative location */
 396 static inline int
 397 make_space_bucket(const struct rte_hash *h, struct rte_hash_bucket *bkt,
 398                 unsigned int *nr_pushes)
 399 {
 400         unsigned i, j;
 401         int ret;
 402         uint32_t next_bucket_idx;
 403         struct rte_hash_bucket *next_bkt[RTE_HASH_BUCKET_ENTRIES];
 404
 405         /*
 406          * Push existing item (search for bucket with space in
 407          * alternative locations) to its alternative location
 408          */
 409         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 410                 /* Search for space in alternative locations */
 411                 next_bucket_idx = bkt->sig_alt[i] & h->bucket_bitmask;
 412                 next_bkt[i] = &h->buckets[next_bucket_idx];
 413                 for (j = 0; j < RTE_HASH_BUCKET_ENTRIES; j++) {
 414                         if (next_bkt[i]->key_idx[j] == EMPTY_SLOT)
 415                                 break;
 416                 }
 417
 418                 if (j != RTE_HASH_BUCKET_ENTRIES)
 419                         break;
 420         }
 421
 422         /* Alternative location has spare room (end of recursive function) */
 423         if (i != RTE_HASH_BUCKET_ENTRIES) {
 424                 next_bkt[i]->sig_alt[j] = bkt->sig_current[i];
 425                 next_bkt[i]->sig_current[j] = bkt->sig_alt[i];
 426                 next_bkt[i]->key_idx[j] = bkt->key_idx[i];
 427                 return i;
 428         }
 429
 430         /* Pick entry that has not been pushed yet */
 431         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++)
 432                 if (bkt->flag[i] == 0)
 433                         break;
 434
 435         /* All entries have been pushed, so entry cannot be added */
 436         if (i == RTE_HASH_BUCKET_ENTRIES || ++(*nr_pushes) > RTE_HASH_MAX_PUSHES)
 437                 return -ENOSPC;
 438
 439         /* Set flag to indicate that this entry is going to be pushed */
 440         bkt->flag[i] = 1;
 441
 442         /* Need room in alternative bucket to insert the pushed entry */
 443         ret = make_space_bucket(h, next_bkt[i], nr_pushes);
 444         /*
 445          * After recursive function.
 446          * Clear flags and insert the pushed entry
 447          * in its alternative location if successful,
 448          * or return error
 449          */
 450         bkt->flag[i] = 0;
 451         if (ret >= 0) {
 452                 next_bkt[i]->sig_alt[ret] = bkt->sig_current[i];
 453                 next_bkt[i]->sig_current[ret] = bkt->sig_alt[i];
 454                 next_bkt[i]->key_idx[ret] = bkt->key_idx[i];
 455                 return i;
 456         } else
 457                 return ret;
 458
 459 }
 460
 461 /*
 462  * Function called to enqueue back an index in the cache/ring,
 463  * as slot has not being used and it can be used in the
 464  * next addition attempt.
 465  */
 466 static inline void
 467 enqueue_slot_back(const struct rte_hash *h,
 468                 struct lcore_cache *cached_free_slots,
 469                 void *slot_id)
 470 {
 471         if (h->hw_trans_mem_support) {
 472                 cached_free_slots->objs[cached_free_slots->len] = slot_id;
 473                 cached_free_slots->len++;
 474         } else
 475                 rte_ring_sp_enqueue(h->free_slots, slot_id);
 476 }
 477
 478 static inline int32_t
 479 __rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key,
 480                                                 hash_sig_t sig, void *data)
 481 {
 482         hash_sig_t alt_hash;
 483         uint32_t prim_bucket_idx, sec_bucket_idx;
 484         unsigned i;
 485         struct rte_hash_bucket *prim_bkt, *sec_bkt;
 486         struct rte_hash_key *new_k, *k, *keys = h->key_store;
 487         void *slot_id = NULL;
 488         uint32_t new_idx;
 489         int ret;
 490         unsigned n_slots;
 491         unsigned lcore_id;
 492         struct lcore_cache *cached_free_slots = NULL;
 493         unsigned int nr_pushes = 0;
 494
 495         if (h->add_key == ADD_KEY_MULTIWRITER)
 496                 rte_spinlock_lock(h->multiwriter_lock);
 497
 498         prim_bucket_idx = sig & h->bucket_bitmask;
 499         prim_bkt = &h->buckets[prim_bucket_idx];
 500         rte_prefetch0(prim_bkt);
 501
 502         alt_hash = rte_hash_secondary_hash(sig);
 503         sec_bucket_idx = alt_hash & h->bucket_bitmask;
 504         sec_bkt = &h->buckets[sec_bucket_idx];
 505         rte_prefetch0(sec_bkt);
 506
 507         /* Get a new slot for storing the new key */
 508         if (h->hw_trans_mem_support) {
 509                 lcore_id = rte_lcore_id();
 510                 cached_free_slots = &h->local_free_slots[lcore_id];
 511                 /* Try to get a free slot from the local cache */
 512                 if (cached_free_slots->len == 0) {
 513                         /* Need to get another burst of free slots from global ring */
 514                         n_slots = rte_ring_mc_dequeue_burst(h->free_slots,
 515                                         cached_free_slots->objs,
 516                                         LCORE_CACHE_SIZE, NULL);
 517                         if (n_slots == 0) {
 518                                 ret = -ENOSPC;
 519                                 goto failure;
 520                         }
 521
 522                         cached_free_slots->len += n_slots;
 523                 }
 524
 525                 /* Get a free slot from the local cache */
 526                 cached_free_slots->len--;
 527                 slot_id = cached_free_slots->objs[cached_free_slots->len];
 528         } else {
 529                 if (rte_ring_sc_dequeue(h->free_slots, &slot_id) != 0) {
 530                         ret = -ENOSPC;
 531                         goto failure;
 532                 }
 533         }
 534
 535         new_k = RTE_PTR_ADD(keys, (uintptr_t)slot_id * h->key_entry_size);
 536         rte_prefetch0(new_k);
 537         new_idx = (uint32_t)((uintptr_t) slot_id);
 538
 539         /* Check if key is already inserted in primary location */
 540         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 541                 if (prim_bkt->sig_current[i] == sig &&
 542                                 prim_bkt->sig_alt[i] == alt_hash) {
 543                         k = (struct rte_hash_key *) ((char *)keys +
 544                                         prim_bkt->key_idx[i] * h->key_entry_size);
 545                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 546                                 /* Enqueue index of free slot back in the ring. */
 547                                 enqueue_slot_back(h, cached_free_slots, slot_id);
 548                                 /* Update data */
 549                                 k->pdata = data;
 550                                 /*
 551                                  * Return index where key is stored,
 552                                  * subtracting the first dummy index
 553                                  */
 554                                 ret = prim_bkt->key_idx[i] - 1;
 555                                 goto failure;
 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                                 ret = sec_bkt->key_idx[i] - 1;
 576                                 goto failure;
 577                         }
 578                 }
 579         }
 580
 581         /* Copy key */
 582         rte_memcpy(new_k->key, key, h->key_len);
 583         new_k->pdata = data;
 584
 585 #if defined(RTE_ARCH_X86) /* currently only x86 support HTM */
 586         if (h->add_key == ADD_KEY_MULTIWRITER_TM) {
 587                 ret = rte_hash_cuckoo_insert_mw_tm(prim_bkt,
 588                                 sig, alt_hash, new_idx);
 589                 if (ret >= 0)
 590                         return new_idx - 1;
 591
 592                 /* Primary bucket full, need to make space for new entry */
 593                 ret = rte_hash_cuckoo_make_space_mw_tm(h, prim_bkt, sig,
 594                                                         alt_hash, new_idx);
 595
 596                 if (ret >= 0)
 597                         return new_idx - 1;
 598
 599                 /* Also search secondary bucket to get better occupancy */
 600                 ret = rte_hash_cuckoo_make_space_mw_tm(h, sec_bkt, sig,
 601                                                         alt_hash, new_idx);
 602
 603                 if (ret >= 0)
 604                         return new_idx - 1;
 605         } else {
 606 #endif
 607                 for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 608                         /* Check if slot is available */
 609                         if (likely(prim_bkt->key_idx[i] == EMPTY_SLOT)) {
 610                                 prim_bkt->sig_current[i] = sig;
 611                                 prim_bkt->sig_alt[i] = alt_hash;
 612                                 prim_bkt->key_idx[i] = new_idx;
 613                                 break;
 614                         }
 615                 }
 616
 617                 if (i != RTE_HASH_BUCKET_ENTRIES) {
 618                         if (h->add_key == ADD_KEY_MULTIWRITER)
 619                                 rte_spinlock_unlock(h->multiwriter_lock);
 620                         return new_idx - 1;
 621                 }
 622
 623                 /* Primary bucket full, need to make space for new entry
 624                  * After recursive function.
 625                  * Insert the new entry in the position of the pushed entry
 626                  * if successful or return error and
 627                  * store the new slot back in the ring
 628                  */
 629                 ret = make_space_bucket(h, prim_bkt, &nr_pushes);
 630                 if (ret >= 0) {
 631                         prim_bkt->sig_current[ret] = sig;
 632                         prim_bkt->sig_alt[ret] = alt_hash;
 633                         prim_bkt->key_idx[ret] = new_idx;
 634                         if (h->add_key == ADD_KEY_MULTIWRITER)
 635                                 rte_spinlock_unlock(h->multiwriter_lock);
 636                         return new_idx - 1;
 637                 }
 638 #if defined(RTE_ARCH_X86)
 639         }
 640 #endif
 641         /* Error in addition, store new slot back in the ring and return error */
 642         enqueue_slot_back(h, cached_free_slots, (void *)((uintptr_t) new_idx));
 643
 644 failure:
 645         if (h->add_key == ADD_KEY_MULTIWRITER)
 646                 rte_spinlock_unlock(h->multiwriter_lock);
 647         return ret;
 648 }
 649
 650 int32_t
 651 rte_hash_add_key_with_hash(const struct rte_hash *h,
 652                         const void *key, hash_sig_t sig)
 653 {
 654         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 655         return __rte_hash_add_key_with_hash(h, key, sig, 0);
 656 }
 657
 658 int32_t
 659 rte_hash_add_key(const struct rte_hash *h, const void *key)
 660 {
 661         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 662         return __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), 0);
 663 }
 664
 665 int
 666 rte_hash_add_key_with_hash_data(const struct rte_hash *h,
 667                         const void *key, hash_sig_t sig, void *data)
 668 {
 669         int ret;
 670
 671         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 672         ret = __rte_hash_add_key_with_hash(h, key, sig, data);
 673         if (ret >= 0)
 674                 return 0;
 675         else
 676                 return ret;
 677 }
 678
 679 int
 680 rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data)
 681 {
 682         int ret;
 683
 684         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 685
 686         ret = __rte_hash_add_key_with_hash(h, key, rte_hash_hash(h, key), data);
 687         if (ret >= 0)
 688                 return 0;
 689         else
 690                 return ret;
 691 }
 692 static inline int32_t
 693 __rte_hash_lookup_with_hash(const struct rte_hash *h, const void *key,
 694                                         hash_sig_t sig, void **data)
 695 {
 696         uint32_t bucket_idx;
 697         hash_sig_t alt_hash;
 698         unsigned i;
 699         struct rte_hash_bucket *bkt;
 700         struct rte_hash_key *k, *keys = h->key_store;
 701
 702         bucket_idx = sig & h->bucket_bitmask;
 703         bkt = &h->buckets[bucket_idx];
 704
 705         /* Check if key is in primary location */
 706         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 707                 if (bkt->sig_current[i] == sig &&
 708                                 bkt->key_idx[i] != EMPTY_SLOT) {
 709                         k = (struct rte_hash_key *) ((char *)keys +
 710                                         bkt->key_idx[i] * h->key_entry_size);
 711                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 712                                 if (data != NULL)
 713                                         *data = k->pdata;
 714                                 /*
 715                                  * Return index where key is stored,
 716                                  * subtracting the first dummy index
 717                                  */
 718                                 return bkt->key_idx[i] - 1;
 719                         }
 720                 }
 721         }
 722
 723         /* Calculate secondary hash */
 724         alt_hash = rte_hash_secondary_hash(sig);
 725         bucket_idx = alt_hash & h->bucket_bitmask;
 726         bkt = &h->buckets[bucket_idx];
 727
 728         /* Check if key is in secondary location */
 729         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 730                 if (bkt->sig_current[i] == alt_hash &&
 731                                 bkt->sig_alt[i] == sig) {
 732                         k = (struct rte_hash_key *) ((char *)keys +
 733                                         bkt->key_idx[i] * h->key_entry_size);
 734                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 735                                 if (data != NULL)
 736                                         *data = k->pdata;
 737                                 /*
 738                                  * Return index where key is stored,
 739                                  * subtracting the first dummy index
 740                                  */
 741                                 return bkt->key_idx[i] - 1;
 742                         }
 743                 }
 744         }
 745
 746         return -ENOENT;
 747 }
 748
 749 int32_t
 750 rte_hash_lookup_with_hash(const struct rte_hash *h,
 751                         const void *key, hash_sig_t sig)
 752 {
 753         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 754         return __rte_hash_lookup_with_hash(h, key, sig, NULL);
 755 }
 756
 757 int32_t
 758 rte_hash_lookup(const struct rte_hash *h, const void *key)
 759 {
 760         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 761         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), NULL);
 762 }
 763
 764 int
 765 rte_hash_lookup_with_hash_data(const struct rte_hash *h,
 766                         const void *key, hash_sig_t sig, void **data)
 767 {
 768         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 769         return __rte_hash_lookup_with_hash(h, key, sig, data);
 770 }
 771
 772 int
 773 rte_hash_lookup_data(const struct rte_hash *h, const void *key, void **data)
 774 {
 775         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 776         return __rte_hash_lookup_with_hash(h, key, rte_hash_hash(h, key), data);
 777 }
 778
 779 static inline void
 780 remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt, unsigned i)
 781 {
 782         unsigned lcore_id, n_slots;
 783         struct lcore_cache *cached_free_slots;
 784
 785         bkt->sig_current[i] = NULL_SIGNATURE;
 786         bkt->sig_alt[i] = NULL_SIGNATURE;
 787         if (h->hw_trans_mem_support) {
 788                 lcore_id = rte_lcore_id();
 789                 cached_free_slots = &h->local_free_slots[lcore_id];
 790                 /* Cache full, need to free it. */
 791                 if (cached_free_slots->len == LCORE_CACHE_SIZE) {
 792                         /* Need to enqueue the free slots in global ring. */
 793                         n_slots = rte_ring_mp_enqueue_burst(h->free_slots,
 794                                                 cached_free_slots->objs,
 795                                                 LCORE_CACHE_SIZE, NULL);
 796                         cached_free_slots->len -= n_slots;
 797                 }
 798                 /* Put index of new free slot in cache. */
 799                 cached_free_slots->objs[cached_free_slots->len] =
 800                                 (void *)((uintptr_t)bkt->key_idx[i]);
 801                 cached_free_slots->len++;
 802         } else {
 803                 rte_ring_sp_enqueue(h->free_slots,
 804                                 (void *)((uintptr_t)bkt->key_idx[i]));
 805         }
 806 }
 807
 808 static inline int32_t
 809 __rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key,
 810                                                 hash_sig_t sig)
 811 {
 812         uint32_t bucket_idx;
 813         hash_sig_t alt_hash;
 814         unsigned i;
 815         struct rte_hash_bucket *bkt;
 816         struct rte_hash_key *k, *keys = h->key_store;
 817         int32_t ret;
 818
 819         bucket_idx = sig & h->bucket_bitmask;
 820         bkt = &h->buckets[bucket_idx];
 821
 822         /* Check if key is in primary location */
 823         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 824                 if (bkt->sig_current[i] == sig &&
 825                                 bkt->key_idx[i] != EMPTY_SLOT) {
 826                         k = (struct rte_hash_key *) ((char *)keys +
 827                                         bkt->key_idx[i] * h->key_entry_size);
 828                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 829                                 remove_entry(h, bkt, i);
 830
 831                                 /*
 832                                  * Return index where key is stored,
 833                                  * subtracting the first dummy index
 834                                  */
 835                                 ret = bkt->key_idx[i] - 1;
 836                                 bkt->key_idx[i] = EMPTY_SLOT;
 837                                 return ret;
 838                         }
 839                 }
 840         }
 841
 842         /* Calculate secondary hash */
 843         alt_hash = rte_hash_secondary_hash(sig);
 844         bucket_idx = alt_hash & h->bucket_bitmask;
 845         bkt = &h->buckets[bucket_idx];
 846
 847         /* Check if key is in secondary location */
 848         for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 849                 if (bkt->sig_current[i] == alt_hash &&
 850                                 bkt->key_idx[i] != EMPTY_SLOT) {
 851                         k = (struct rte_hash_key *) ((char *)keys +
 852                                         bkt->key_idx[i] * h->key_entry_size);
 853                         if (rte_hash_cmp_eq(key, k->key, h) == 0) {
 854                                 remove_entry(h, bkt, i);
 855
 856                                 /*
 857                                  * Return index where key is stored,
 858                                  * subtracting the first dummy index
 859                                  */
 860                                 ret = bkt->key_idx[i] - 1;
 861                                 bkt->key_idx[i] = EMPTY_SLOT;
 862                                 return ret;
 863                         }
 864                 }
 865         }
 866
 867         return -ENOENT;
 868 }
 869
 870 int32_t
 871 rte_hash_del_key_with_hash(const struct rte_hash *h,
 872                         const void *key, hash_sig_t sig)
 873 {
 874         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 875         return __rte_hash_del_key_with_hash(h, key, sig);
 876 }
 877
 878 int32_t
 879 rte_hash_del_key(const struct rte_hash *h, const void *key)
 880 {
 881         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 882         return __rte_hash_del_key_with_hash(h, key, rte_hash_hash(h, key));
 883 }
 884
 885 int
 886 rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
 887                                void **key)
 888 {
 889         RETURN_IF_TRUE(((h == NULL) || (key == NULL)), -EINVAL);
 890
 891         struct rte_hash_key *k, *keys = h->key_store;
 892         k = (struct rte_hash_key *) ((char *) keys + (position + 1) *
 893                                      h->key_entry_size);
 894         *key = k->key;
 895
 896         if (position !=
 897             __rte_hash_lookup_with_hash(h, *key, rte_hash_hash(h, *key),
 898                                         NULL)) {
 899                 return -ENOENT;
 900         }
 901
 902         return 0;
 903 }
 904
 905 static inline void
 906 compare_signatures(uint32_t *prim_hash_matches, uint32_t *sec_hash_matches,
 907                         const struct rte_hash_bucket *prim_bkt,
 908                         const struct rte_hash_bucket *sec_bkt,
 909                         hash_sig_t prim_hash, hash_sig_t sec_hash,
 910                         enum rte_hash_sig_compare_function sig_cmp_fn)
 911 {
 912         unsigned int i;
 913
 914         switch (sig_cmp_fn) {
 915 #ifdef RTE_MACHINE_CPUFLAG_AVX2
 916         case RTE_HASH_COMPARE_AVX2:
 917                 *prim_hash_matches = _mm256_movemask_ps((__m256)_mm256_cmpeq_epi32(
 918                                 _mm256_load_si256(
 919                                         (__m256i const *)prim_bkt->sig_current),
 920                                 _mm256_set1_epi32(prim_hash)));
 921                 *sec_hash_matches = _mm256_movemask_ps((__m256)_mm256_cmpeq_epi32(
 922                                 _mm256_load_si256(
 923                                         (__m256i const *)sec_bkt->sig_current),
 924                                 _mm256_set1_epi32(sec_hash)));
 925                 break;
 926 #endif
 927 #ifdef RTE_MACHINE_CPUFLAG_SSE2
 928         case RTE_HASH_COMPARE_SSE:
 929                 /* Compare the first 4 signatures in the bucket */
 930                 *prim_hash_matches = _mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 931                                 _mm_load_si128(
 932                                         (__m128i const *)prim_bkt->sig_current),
 933                                 _mm_set1_epi32(prim_hash)));
 934                 *prim_hash_matches |= (_mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 935                                 _mm_load_si128(
 936                                         (__m128i const *)&prim_bkt->sig_current[4]),
 937                                 _mm_set1_epi32(prim_hash)))) << 4;
 938                 /* Compare the first 4 signatures in the bucket */
 939                 *sec_hash_matches = _mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 940                                 _mm_load_si128(
 941                                         (__m128i const *)sec_bkt->sig_current),
 942                                 _mm_set1_epi32(sec_hash)));
 943                 *sec_hash_matches |= (_mm_movemask_ps((__m128)_mm_cmpeq_epi16(
 944                                 _mm_load_si128(
 945                                         (__m128i const *)&sec_bkt->sig_current[4]),
 946                                 _mm_set1_epi32(sec_hash)))) << 4;
 947                 break;
 948 #endif
 949         default:
 950                 for (i = 0; i < RTE_HASH_BUCKET_ENTRIES; i++) {
 951                         *prim_hash_matches |=
 952                                 ((prim_hash == prim_bkt->sig_current[i]) << i);
 953                         *sec_hash_matches |=
 954                                 ((sec_hash == sec_bkt->sig_current[i]) << i);
 955                 }
 956         }
 957
 958 }
 959
 960 #define PREFETCH_OFFSET 4
 961 static inline void
 962 __rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
 963                         int32_t num_keys, int32_t *positions,
 964                         uint64_t *hit_mask, void *data[])
 965 {
 966         uint64_t hits = 0;
 967         int32_t i;
 968         uint32_t prim_hash[RTE_HASH_LOOKUP_BULK_MAX];
 969         uint32_t sec_hash[RTE_HASH_LOOKUP_BULK_MAX];
 970         const struct rte_hash_bucket *primary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
 971         const struct rte_hash_bucket *secondary_bkt[RTE_HASH_LOOKUP_BULK_MAX];
 972         uint32_t prim_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
 973         uint32_t sec_hitmask[RTE_HASH_LOOKUP_BULK_MAX] = {0};
 974
 975         /* Prefetch first keys */
 976         for (i = 0; i < PREFETCH_OFFSET && i < num_keys; i++)
 977                 rte_prefetch0(keys[i]);
 978
 979         /*
 980          * Prefetch rest of the keys, calculate primary and
 981          * secondary bucket and prefetch them
 982          */
 983         for (i = 0; i < (num_keys - PREFETCH_OFFSET); i++) {
 984                 rte_prefetch0(keys[i + PREFETCH_OFFSET]);
 985
 986                 prim_hash[i] = rte_hash_hash(h, keys[i]);
 987                 sec_hash[i] = rte_hash_secondary_hash(prim_hash[i]);
 988
 989                 primary_bkt[i] = &h->buckets[prim_hash[i] & h->bucket_bitmask];
 990                 secondary_bkt[i] = &h->buckets[sec_hash[i] & h->bucket_bitmask];
 991
 992                 rte_prefetch0(primary_bkt[i]);
 993                 rte_prefetch0(secondary_bkt[i]);
 994         }
 995
 996         /* Calculate and prefetch rest of the buckets */
 997         for (; i < num_keys; i++) {
 998                 prim_hash[i] = rte_hash_hash(h, keys[i]);
 999                 sec_hash[i] = rte_hash_secondary_hash(prim_hash[i]);
1000
1001                 primary_bkt[i] = &h->buckets[prim_hash[i] & h->bucket_bitmask];
1002                 secondary_bkt[i] = &h->buckets[sec_hash[i] & h->bucket_bitmask];
1003
1004                 rte_prefetch0(primary_bkt[i]);
1005                 rte_prefetch0(secondary_bkt[i]);
1006         }
1007
1008         /* Compare signatures and prefetch key slot of first hit */
1009         for (i = 0; i < num_keys; i++) {
1010                 compare_signatures(&prim_hitmask[i], &sec_hitmask[i],
1011                                 primary_bkt[i], secondary_bkt[i],
1012                                 prim_hash[i], sec_hash[i], h->sig_cmp_fn);
1013
1014                 if (prim_hitmask[i]) {
1015                         uint32_t first_hit = __builtin_ctzl(prim_hitmask[i]);
1016                         uint32_t key_idx = primary_bkt[i]->key_idx[first_hit];
1017                         const struct rte_hash_key *key_slot =
1018                                 (const struct rte_hash_key *)(
1019                                 (const char *)h->key_store +
1020                                 key_idx * h->key_entry_size);
1021                         rte_prefetch0(key_slot);
1022                         continue;
1023                 }
1024
1025                 if (sec_hitmask[i]) {
1026                         uint32_t first_hit = __builtin_ctzl(sec_hitmask[i]);
1027                         uint32_t key_idx = secondary_bkt[i]->key_idx[first_hit];
1028                         const struct rte_hash_key *key_slot =
1029                                 (const struct rte_hash_key *)(
1030                                 (const char *)h->key_store +
1031                                 key_idx * h->key_entry_size);
1032                         rte_prefetch0(key_slot);
1033                 }
1034         }
1035
1036         /* Compare keys, first hits in primary first */
1037         for (i = 0; i < num_keys; i++) {
1038                 positions[i] = -ENOENT;
1039                 while (prim_hitmask[i]) {
1040                         uint32_t hit_index = __builtin_ctzl(prim_hitmask[i]);
1041
1042                         uint32_t key_idx = primary_bkt[i]->key_idx[hit_index];
1043                         const struct rte_hash_key *key_slot =
1044                                 (const struct rte_hash_key *)(
1045                                 (const char *)h->key_store +
1046                                 key_idx * h->key_entry_size);
1047                         /*
1048                          * If key index is 0, do not compare key,
1049                          * as it is checking the dummy slot
1050                          */
1051                         if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
1052                                 if (data != NULL)
1053                                         data[i] = key_slot->pdata;
1054
1055                                 hits |= 1ULL << i;
1056                                 positions[i] = key_idx - 1;
1057                                 goto next_key;
1058                         }
1059                         prim_hitmask[i] &= ~(1 << (hit_index));
1060                 }
1061
1062                 while (sec_hitmask[i]) {
1063                         uint32_t hit_index = __builtin_ctzl(sec_hitmask[i]);
1064
1065                         uint32_t key_idx = secondary_bkt[i]->key_idx[hit_index];
1066                         const struct rte_hash_key *key_slot =
1067                                 (const struct rte_hash_key *)(
1068                                 (const char *)h->key_store +
1069                                 key_idx * h->key_entry_size);
1070                         /*
1071                          * If key index is 0, do not compare key,
1072                          * as it is checking the dummy slot
1073                          */
1074
1075                         if (!!key_idx & !rte_hash_cmp_eq(key_slot->key, keys[i], h)) {
1076                                 if (data != NULL)
1077                                         data[i] = key_slot->pdata;
1078
1079                                 hits |= 1ULL << i;
1080                                 positions[i] = key_idx - 1;
1081                                 goto next_key;
1082                         }
1083                         sec_hitmask[i] &= ~(1 << (hit_index));
1084                 }
1085
1086 next_key:
1087                 continue;
1088         }
1089
1090         if (hit_mask != NULL)
1091                 *hit_mask = hits;
1092 }
1093
1094 int
1095 rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
1096                       uint32_t num_keys, int32_t *positions)
1097 {
1098         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1099                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1100                         (positions == NULL)), -EINVAL);
1101
1102         __rte_hash_lookup_bulk(h, keys, num_keys, positions, NULL, NULL);
1103         return 0;
1104 }
1105
1106 int
1107 rte_hash_lookup_bulk_data(const struct rte_hash *h, const void **keys,
1108                       uint32_t num_keys, uint64_t *hit_mask, void *data[])
1109 {
1110         RETURN_IF_TRUE(((h == NULL) || (keys == NULL) || (num_keys == 0) ||
1111                         (num_keys > RTE_HASH_LOOKUP_BULK_MAX) ||
1112                         (hit_mask == NULL)), -EINVAL);
1113
1114         int32_t positions[num_keys];
1115
1116         __rte_hash_lookup_bulk(h, keys, num_keys, positions, hit_mask, data);
1117
1118         /* Return number of hits */
1119         return __builtin_popcountl(*hit_mask);
1120 }
1121
1122 int32_t
1123 rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32_t *next)
1124 {
1125         uint32_t bucket_idx, idx, position;
1126         struct rte_hash_key *next_key;
1127
1128         RETURN_IF_TRUE(((h == NULL) || (next == NULL)), -EINVAL);
1129
1130         const uint32_t total_entries = h->num_buckets * RTE_HASH_BUCKET_ENTRIES;
1131         /* Out of bounds */
1132         if (*next >= total_entries)
1133                 return -ENOENT;
1134
1135         /* Calculate bucket and index of current iterator */
1136         bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1137         idx = *next % RTE_HASH_BUCKET_ENTRIES;
1138
1139         /* If current position is empty, go to the next one */
1140         while (h->buckets[bucket_idx].key_idx[idx] == EMPTY_SLOT) {
1141                 (*next)++;
1142                 /* End of table */
1143                 if (*next == total_entries)
1144                         return -ENOENT;
1145                 bucket_idx = *next / RTE_HASH_BUCKET_ENTRIES;
1146                 idx = *next % RTE_HASH_BUCKET_ENTRIES;
1147         }
1148
1149         /* Get position of entry in key table */
1150         position = h->buckets[bucket_idx].key_idx[idx];
1151         next_key = (struct rte_hash_key *) ((char *)h->key_store +
1152                                 position * h->key_entry_size);
1153         /* Return key and data */
1154         *key = next_key->key;
1155         *data = next_key->pdata;
1156
1157         /* Increment iterator */
1158         (*next)++;
1159
1160         return position - 1;
1161 }