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> 9ed1c9642SDave Jones #include <linux/sched.h> 101da177e4SLinus Torvalds #include "hashtab.h" 111da177e4SLinus Torvalds 12bb242497SChad Sellers struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key), 13bb242497SChad Sellers int (*keycmp)(struct hashtab *h, const void *key1, const void *key2), 141da177e4SLinus Torvalds u32 size) 151da177e4SLinus Torvalds { 161da177e4SLinus Torvalds struct hashtab *p; 171da177e4SLinus Torvalds u32 i; 181da177e4SLinus Torvalds 1989d155efSJames Morris p = kzalloc(sizeof(*p), GFP_KERNEL); 20cb8d21e3SMarkus Elfring if (!p) 211da177e4SLinus Torvalds return p; 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds p->size = size; 241da177e4SLinus Torvalds p->nel = 0; 251da177e4SLinus Torvalds p->hash_value = hash_value; 261da177e4SLinus Torvalds p->keycmp = keycmp; 272f00e680SMarkus Elfring p->htable = kmalloc_array(size, sizeof(*p->htable), GFP_KERNEL); 28cb8d21e3SMarkus Elfring if (!p->htable) { 291da177e4SLinus Torvalds kfree(p); 301da177e4SLinus Torvalds return NULL; 311da177e4SLinus Torvalds } 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds for (i = 0; i < size; i++) 341da177e4SLinus Torvalds p->htable[i] = NULL; 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds return p; 371da177e4SLinus Torvalds } 381da177e4SLinus Torvalds 391da177e4SLinus Torvalds int hashtab_insert(struct hashtab *h, void *key, void *datum) 401da177e4SLinus Torvalds { 411da177e4SLinus Torvalds u32 hvalue; 421da177e4SLinus Torvalds struct hashtab_node *prev, *cur, *newnode; 431da177e4SLinus Torvalds 44ed1c9642SDave Jones cond_resched(); 45ed1c9642SDave Jones 461da177e4SLinus Torvalds if (!h || h->nel == HASHTAB_MAX_NODES) 471da177e4SLinus Torvalds return -EINVAL; 481da177e4SLinus Torvalds 491da177e4SLinus Torvalds hvalue = h->hash_value(h, key); 501da177e4SLinus Torvalds prev = NULL; 511da177e4SLinus Torvalds cur = h->htable[hvalue]; 521da177e4SLinus Torvalds while (cur && h->keycmp(h, key, cur->key) > 0) { 531da177e4SLinus Torvalds prev = cur; 541da177e4SLinus Torvalds cur = cur->next; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds if (cur && (h->keycmp(h, key, cur->key) == 0)) 581da177e4SLinus Torvalds return -EEXIST; 591da177e4SLinus Torvalds 6089d155efSJames Morris newnode = kzalloc(sizeof(*newnode), GFP_KERNEL); 61cb8d21e3SMarkus Elfring if (!newnode) 621da177e4SLinus Torvalds return -ENOMEM; 631da177e4SLinus Torvalds newnode->key = key; 641da177e4SLinus Torvalds newnode->datum = datum; 651da177e4SLinus Torvalds if (prev) { 661da177e4SLinus Torvalds newnode->next = prev->next; 671da177e4SLinus Torvalds prev->next = newnode; 681da177e4SLinus Torvalds } else { 691da177e4SLinus Torvalds newnode->next = h->htable[hvalue]; 701da177e4SLinus Torvalds h->htable[hvalue] = newnode; 711da177e4SLinus Torvalds } 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds h->nel++; 741da177e4SLinus Torvalds return 0; 751da177e4SLinus Torvalds } 761da177e4SLinus Torvalds 77bb242497SChad Sellers void *hashtab_search(struct hashtab *h, const void *key) 781da177e4SLinus Torvalds { 791da177e4SLinus Torvalds u32 hvalue; 801da177e4SLinus Torvalds struct hashtab_node *cur; 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds if (!h) 831da177e4SLinus Torvalds return NULL; 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds hvalue = h->hash_value(h, key); 861da177e4SLinus Torvalds cur = h->htable[hvalue]; 87dbc74c65SVesa-Matti Kari while (cur && h->keycmp(h, key, cur->key) > 0) 881da177e4SLinus Torvalds cur = cur->next; 891da177e4SLinus Torvalds 90cb8d21e3SMarkus Elfring if (!cur || (h->keycmp(h, key, cur->key) != 0)) 911da177e4SLinus Torvalds return NULL; 921da177e4SLinus Torvalds 931da177e4SLinus Torvalds return cur->datum; 941da177e4SLinus Torvalds } 951da177e4SLinus Torvalds 961da177e4SLinus Torvalds void hashtab_destroy(struct hashtab *h) 971da177e4SLinus Torvalds { 981da177e4SLinus Torvalds u32 i; 991da177e4SLinus Torvalds struct hashtab_node *cur, *temp; 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds if (!h) 1021da177e4SLinus Torvalds return; 1031da177e4SLinus Torvalds 1041da177e4SLinus Torvalds for (i = 0; i < h->size; i++) { 1051da177e4SLinus Torvalds cur = h->htable[i]; 106dbc74c65SVesa-Matti Kari while (cur) { 1071da177e4SLinus Torvalds temp = cur; 1081da177e4SLinus Torvalds cur = cur->next; 1091da177e4SLinus Torvalds kfree(temp); 1101da177e4SLinus Torvalds } 1111da177e4SLinus Torvalds h->htable[i] = NULL; 1121da177e4SLinus Torvalds } 1131da177e4SLinus Torvalds 1141da177e4SLinus Torvalds kfree(h->htable); 1151da177e4SLinus Torvalds h->htable = NULL; 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds kfree(h); 1181da177e4SLinus Torvalds } 1191da177e4SLinus Torvalds 1201da177e4SLinus Torvalds int hashtab_map(struct hashtab *h, 1211da177e4SLinus Torvalds int (*apply)(void *k, void *d, void *args), 1221da177e4SLinus Torvalds void *args) 1231da177e4SLinus Torvalds { 1241da177e4SLinus Torvalds u32 i; 1251da177e4SLinus Torvalds int ret; 1261da177e4SLinus Torvalds struct hashtab_node *cur; 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds if (!h) 1291da177e4SLinus Torvalds return 0; 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds for (i = 0; i < h->size; i++) { 1321da177e4SLinus Torvalds cur = h->htable[i]; 133dbc74c65SVesa-Matti Kari while (cur) { 1341da177e4SLinus Torvalds ret = apply(cur->key, cur->datum, args); 1351da177e4SLinus Torvalds if (ret) 1361da177e4SLinus Torvalds return ret; 1371da177e4SLinus Torvalds cur = cur->next; 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds } 1401da177e4SLinus Torvalds return 0; 1411da177e4SLinus Torvalds } 1421da177e4SLinus Torvalds 1431da177e4SLinus Torvalds 1441da177e4SLinus Torvalds void hashtab_stat(struct hashtab *h, struct hashtab_info *info) 1451da177e4SLinus Torvalds { 1461da177e4SLinus Torvalds u32 i, chain_len, slots_used, max_chain_len; 1471da177e4SLinus Torvalds struct hashtab_node *cur; 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds slots_used = 0; 1501da177e4SLinus Torvalds max_chain_len = 0; 1511da177e4SLinus Torvalds for (slots_used = max_chain_len = i = 0; i < h->size; i++) { 1521da177e4SLinus Torvalds cur = h->htable[i]; 1531da177e4SLinus Torvalds if (cur) { 1541da177e4SLinus Torvalds slots_used++; 1551da177e4SLinus Torvalds chain_len = 0; 1561da177e4SLinus Torvalds while (cur) { 1571da177e4SLinus Torvalds chain_len++; 1581da177e4SLinus Torvalds cur = cur->next; 1591da177e4SLinus Torvalds } 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds if (chain_len > max_chain_len) 1621da177e4SLinus Torvalds max_chain_len = chain_len; 1631da177e4SLinus Torvalds } 1641da177e4SLinus Torvalds } 1651da177e4SLinus Torvalds 1661da177e4SLinus Torvalds info->slots_used = slots_used; 1671da177e4SLinus Torvalds info->max_chain_len = max_chain_len; 1681da177e4SLinus Torvalds } 169