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drm_hashtab.h revision 1.1.1.1.4.3 
      1 /**************************************************************************
      2  *
      3  * Copyright 2006 Tungsten Graphics, Inc., Bismack, ND. USA.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
     21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
     22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
     23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
     24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  *
     27  **************************************************************************/
     28 /*
     29  * Simple open hash tab implementation.
     30  *
     31  * Authors:
     32  * Thomas Hellstrm <thomas-at-tungstengraphics-dot-com>
     33  */
     34 
     35 #ifndef DRM_HASHTAB_H
     36 #define DRM_HASHTAB_H
     37 
     38 #include <linux/kernel.h>
     39 #include <linux/list.h>
     40 #include <linux/types.h>
     41 
     42 #define drm_hash_entry(_ptr, _type, _member) container_of(_ptr, _type, _member)
     43 
     44 struct drm_hash_item {
     45 	struct hlist_node head;
     46 	unsigned long key;
     47 };
     48 
     49 struct drm_open_hash {
     50 	struct hlist_head *table;
     51 	u8 order;
     52 };
     53 
     54 extern int drm_ht_create(struct drm_open_hash *ht, unsigned int order);
     55 extern int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item);
     56 extern int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
     57 				     unsigned long seed, int bits, int shift,
     58 				     unsigned long add);
     59 extern int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, struct drm_hash_item **item);
     60 
     61 extern void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key);
     62 extern int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key);
     63 extern int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item);
     64 extern void drm_ht_remove(struct drm_open_hash *ht);
     65 
     66 /*
     67  * RCU-safe interface
     68  *
     69  * The user of this API needs to make sure that two or more instances of the
     70  * hash table manipulation functions are never run simultaneously.
     71  * The lookup function drm_ht_find_item_rcu may, however, run simultaneously
     72  * with any of the manipulation functions as long as it's called from within
     73  * an RCU read-locked section.
     74  */
     75 #define drm_ht_insert_item_rcu drm_ht_insert_item
     76 #define drm_ht_just_insert_please_rcu drm_ht_just_insert_please
     77 #define drm_ht_remove_key_rcu drm_ht_remove_key
     78 #define drm_ht_remove_item_rcu drm_ht_remove_item
     79 #define drm_ht_find_item_rcu drm_ht_find_item
     80 
     81 #endif
     82