include/drm/drm_hashtab.h

   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,
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  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  *
  27  **************************************************************************/
  28 /*
  29  * Simple open hash tab implementation.
  30  *
  31  * Authors:
  32  * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
  33  */
  34
  35 #ifndef DRM_HASHTAB_H
  36 #define DRM_HASHTAB_H
  37
  38 #include <linux/list.h>
  39
  40 #define drm_hash_entry(_ptr, _type, _member) container_of(_ptr, _type, _member)
  41
  42 struct drm_hash_item {
  43         struct hlist_node head;
  44         unsigned long key;
  45 };
  46
  47 struct drm_open_hash {
  48         struct hlist_head *table;
  49         u8 order;
  50 };
  51
  52 extern int drm_ht_create(struct drm_open_hash *ht, unsigned int order);
  53 extern int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item);
  54 extern int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
  55                                      unsigned long seed, int bits, int shift,
  56                                      unsigned long add);
  57 extern int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, struct drm_hash_item **item);
  58
  59 extern void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key);
  60 extern int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key);
  61 extern int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item);
  62 extern void drm_ht_remove(struct drm_open_hash *ht);
  63
  64 /*
  65  * RCU-safe interface
  66  *
  67  * The user of this API needs to make sure that two or more instances of the
  68  * hash table manipulation functions are never run simultaneously.
  69  * The lookup function drm_ht_find_item_rcu may, however, run simultaneously
  70  * with any of the manipulation functions as long as it's called from within
  71  * an RCU read-locked section.
  72  */
  73 #define drm_ht_insert_item_rcu drm_ht_insert_item
  74 #define drm_ht_just_insert_please_rcu drm_ht_just_insert_please
  75 #define drm_ht_remove_key_rcu drm_ht_remove_key
  76 #define drm_ht_remove_item_rcu drm_ht_remove_item
  77 #define drm_ht_find_item_rcu drm_ht_find_item
  78
  79 #endif