/************************************************************************** * * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA. * All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sub license, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice (including the * next paragraph) shall be included in all copies or substantial portions * of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE * USE OR OTHER DEALINGS IN THE SOFTWARE. * * **************************************************************************/ /* * Simple open hash tab implementation. * * Authors: * Thomas Hellström <thomas-at-tungstengraphics-dot-com> */ #include <linux/hash.h> #include <linux/mm.h> #include <linux/rculist.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <drm/drm_print.h> #include "drm_legacy.h" int drm_ht_create(struct drm_open_hash *ht, unsigned int order) { unsigned int size = 1 << order; ht->order = order; ht->table = NULL; if (size <= PAGE_SIZE / sizeof(*ht->table)) ht->table = kcalloc(size, sizeof(*ht->table), GFP_KERNEL); else ht->table = vzalloc(array_size(size, sizeof(*ht->table))); if (!ht->table) { DRM_ERROR("Out of memory for hash table\n"); return -ENOMEM; } return 0; } void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key) { struct drm_hash_item *entry; struct hlist_head *h_list; unsigned int hashed_key; int count = 0; hashed_key = hash_long(key, ht->order); DRM_DEBUG("Key is 0x%08lx, Hashed key is 0x%08x\n", key, hashed_key); h_list = &ht->table[hashed_key]; hlist_for_each_entry(entry, h_list, head) DRM_DEBUG("count %d, key: 0x%08lx\n", count++, entry->key); } static struct hlist_node *drm_ht_find_key(struct drm_open_hash *ht, unsigned long key) { struct drm_hash_item *entry; struct hlist_head *h_list; unsigned int hashed_key; hashed_key = hash_long(key, ht->order); h_list = &ht->table[hashed_key]; hlist_for_each_entry(entry, h_list, head) { if (entry->key == key) return &entry->head; if (entry->key > key) break; } return NULL; } static struct hlist_node *drm_ht_find_key_rcu(struct drm_open_hash *ht, unsigned long key) { struct drm_hash_item *entry; struct hlist_head *h_list; unsigned int hashed_key; hashed_key = hash_long(key, ht->order); h_list = &ht->table[hashed_key]; hlist_for_each_entry_rcu(entry, h_list, head) { if (entry->key == key) return &entry->head; if (entry->key > key) break; } return NULL; } int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item) { struct drm_hash_item *entry; struct hlist_head *h_list; struct hlist_node *parent; unsigned int hashed_key; unsigned long key = item->key; hashed_key = hash_long(key, ht->order); h_list = &ht->table[hashed_key]; parent = NULL; hlist_for_each_entry(entry, h_list, head) { if (entry->key == key) return -EINVAL; if (entry->key > key) break; parent = &entry->head; } if (parent) { hlist_add_behind_rcu(&item->head, parent); } else { hlist_add_head_rcu(&item->head, h_list); } return 0; } /* * Just insert an item and return any "bits" bit key that hasn't been * used before. */ int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item, unsigned long seed, int bits, int shift, unsigned long add) { int ret; unsigned long mask = (1UL << bits) - 1; unsigned long first, unshifted_key; unshifted_key = hash_long(seed, bits); first = unshifted_key; do { item->key = (unshifted_key << shift) + add; ret = drm_ht_insert_item(ht, item); if (ret) unshifted_key = (unshifted_key + 1) & mask; } while(ret && (unshifted_key != first)); if (ret) { DRM_ERROR("Available key bit space exhausted\n"); return -EINVAL; } return 0; } int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, struct drm_hash_item **item) { struct hlist_node *list; list = drm_ht_find_key_rcu(ht, key); if (!list) return -EINVAL; *item = hlist_entry(list, struct drm_hash_item, head); return 0; } int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key) { struct hlist_node *list; list = drm_ht_find_key(ht, key); if (list) { hlist_del_init_rcu(list); return 0; } return -EINVAL; } int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item) { hlist_del_init_rcu(&item->head); return 0; } void drm_ht_remove(struct drm_open_hash *ht) { if (ht->table) { kvfree(ht->table); ht->table = NULL; } }