11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * Implementation of the hash table type. 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Author : Stephen Smalley, <sds@epoch.ncsc.mil> 51da177e4SLinus Torvalds */ 61da177e4SLinus Torvalds #include <linux/kernel.h> 71da177e4SLinus Torvalds #include <linux/slab.h> 81da177e4SLinus Torvalds #include <linux/errno.h> 91da177e4SLinus Torvalds #include "hashtab.h" 101da177e4SLinus Torvalds 11bb242497SChad Sellers struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key), 12bb242497SChad Sellers int (*keycmp)(struct hashtab *h, const void *key1, const void *key2), 131da177e4SLinus Torvalds u32 size) 141da177e4SLinus Torvalds { 151da177e4SLinus Torvalds struct hashtab *p; 161da177e4SLinus Torvalds u32 i; 171da177e4SLinus Torvalds 1889d155efSJames Morris p = kzalloc(sizeof(*p), GFP_KERNEL); 191da177e4SLinus Torvalds if (p == NULL) 201da177e4SLinus Torvalds return p; 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds p->size = size; 231da177e4SLinus Torvalds p->nel = 0; 241da177e4SLinus Torvalds p->hash_value = hash_value; 251da177e4SLinus Torvalds p->keycmp = keycmp; 261da177e4SLinus Torvalds p->htable = kmalloc(sizeof(*(p->htable)) * size, GFP_KERNEL); 271da177e4SLinus Torvalds if (p->htable == NULL) { 281da177e4SLinus Torvalds kfree(p); 291da177e4SLinus Torvalds return NULL; 301da177e4SLinus Torvalds } 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds for (i = 0; i < size; i++) 331da177e4SLinus Torvalds p->htable[i] = NULL; 341da177e4SLinus Torvalds 351da177e4SLinus Torvalds return p; 361da177e4SLinus Torvalds } 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds int hashtab_insert(struct hashtab *h, void *key, void *datum) 391da177e4SLinus Torvalds { 401da177e4SLinus Torvalds u32 hvalue; 411da177e4SLinus Torvalds struct hashtab_node *prev, *cur, *newnode; 421da177e4SLinus Torvalds 431da177e4SLinus Torvalds if (!h || h->nel == HASHTAB_MAX_NODES) 441da177e4SLinus Torvalds return -EINVAL; 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds hvalue = h->hash_value(h, key); 471da177e4SLinus Torvalds prev = NULL; 481da177e4SLinus Torvalds cur = h->htable[hvalue]; 491da177e4SLinus Torvalds while (cur && h->keycmp(h, key, cur->key) > 0) { 501da177e4SLinus Torvalds prev = cur; 511da177e4SLinus Torvalds cur = cur->next; 521da177e4SLinus Torvalds } 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds if (cur && (h->keycmp(h, key, cur->key) == 0)) 551da177e4SLinus Torvalds return -EEXIST; 561da177e4SLinus Torvalds 5789d155efSJames Morris newnode = kzalloc(sizeof(*newnode), GFP_KERNEL); 581da177e4SLinus Torvalds if (newnode == NULL) 591da177e4SLinus Torvalds return -ENOMEM; 601da177e4SLinus Torvalds newnode->key = key; 611da177e4SLinus Torvalds newnode->datum = datum; 621da177e4SLinus Torvalds if (prev) { 631da177e4SLinus Torvalds newnode->next = prev->next; 641da177e4SLinus Torvalds prev->next = newnode; 651da177e4SLinus Torvalds } else { 661da177e4SLinus Torvalds newnode->next = h->htable[hvalue]; 671da177e4SLinus Torvalds h->htable[hvalue] = newnode; 681da177e4SLinus Torvalds } 691da177e4SLinus Torvalds 701da177e4SLinus Torvalds h->nel++; 711da177e4SLinus Torvalds return 0; 721da177e4SLinus Torvalds } 731da177e4SLinus Torvalds 74bb242497SChad Sellers void *hashtab_search(struct hashtab *h, const void *key) 751da177e4SLinus Torvalds { 761da177e4SLinus Torvalds u32 hvalue; 771da177e4SLinus Torvalds struct hashtab_node *cur; 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds if (!h) 801da177e4SLinus Torvalds return NULL; 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds hvalue = h->hash_value(h, key); 831da177e4SLinus Torvalds cur = h->htable[hvalue]; 841da177e4SLinus Torvalds while (cur != NULL && h->keycmp(h, key, cur->key) > 0) 851da177e4SLinus Torvalds cur = cur->next; 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds if (cur == NULL || (h->keycmp(h, key, cur->key) != 0)) 881da177e4SLinus Torvalds return NULL; 891da177e4SLinus Torvalds 901da177e4SLinus Torvalds return cur->datum; 911da177e4SLinus Torvalds } 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds void hashtab_destroy(struct hashtab *h) 941da177e4SLinus Torvalds { 951da177e4SLinus Torvalds u32 i; 961da177e4SLinus Torvalds struct hashtab_node *cur, *temp; 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds if (!h) 991da177e4SLinus Torvalds return; 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds for (i = 0; i < h->size; i++) { 1021da177e4SLinus Torvalds cur = h->htable[i]; 1031da177e4SLinus Torvalds while (cur != NULL) { 1041da177e4SLinus Torvalds temp = cur; 1051da177e4SLinus Torvalds cur = cur->next; 1061da177e4SLinus Torvalds kfree(temp); 1071da177e4SLinus Torvalds } 1081da177e4SLinus Torvalds h->htable[i] = NULL; 1091da177e4SLinus Torvalds } 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds kfree(h->htable); 1121da177e4SLinus Torvalds h->htable = NULL; 1131da177e4SLinus Torvalds 1141da177e4SLinus Torvalds kfree(h); 1151da177e4SLinus Torvalds } 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds int hashtab_map(struct hashtab *h, 1181da177e4SLinus Torvalds int (*apply)(void *k, void *d, void *args), 1191da177e4SLinus Torvalds void *args) 1201da177e4SLinus Torvalds { 1211da177e4SLinus Torvalds u32 i; 1221da177e4SLinus Torvalds int ret; 1231da177e4SLinus Torvalds struct hashtab_node *cur; 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds if (!h) 1261da177e4SLinus Torvalds return 0; 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds for (i = 0; i < h->size; i++) { 1291da177e4SLinus Torvalds cur = h->htable[i]; 1301da177e4SLinus Torvalds while (cur != NULL) { 1311da177e4SLinus Torvalds ret = apply(cur->key, cur->datum, args); 1321da177e4SLinus Torvalds if (ret) 1331da177e4SLinus Torvalds return ret; 1341da177e4SLinus Torvalds cur = cur->next; 1351da177e4SLinus Torvalds } 1361da177e4SLinus Torvalds } 1371da177e4SLinus Torvalds return 0; 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds 1411da177e4SLinus Torvalds void hashtab_stat(struct hashtab *h, struct hashtab_info *info) 1421da177e4SLinus Torvalds { 1431da177e4SLinus Torvalds u32 i, chain_len, slots_used, max_chain_len; 1441da177e4SLinus Torvalds struct hashtab_node *cur; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds slots_used = 0; 1471da177e4SLinus Torvalds max_chain_len = 0; 1481da177e4SLinus Torvalds for (slots_used = max_chain_len = i = 0; i < h->size; i++) { 1491da177e4SLinus Torvalds cur = h->htable[i]; 1501da177e4SLinus Torvalds if (cur) { 1511da177e4SLinus Torvalds slots_used++; 1521da177e4SLinus Torvalds chain_len = 0; 1531da177e4SLinus Torvalds while (cur) { 1541da177e4SLinus Torvalds chain_len++; 1551da177e4SLinus Torvalds cur = cur->next; 1561da177e4SLinus Torvalds } 1571da177e4SLinus Torvalds 1581da177e4SLinus Torvalds if (chain_len > max_chain_len) 1591da177e4SLinus Torvalds max_chain_len = chain_len; 1601da177e4SLinus Torvalds } 1611da177e4SLinus Torvalds } 1621da177e4SLinus Torvalds 1631da177e4SLinus Torvalds info->slots_used = slots_used; 1641da177e4SLinus Torvalds info->max_chain_len = max_chain_len; 1651da177e4SLinus Torvalds } 166