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      1 /*	$NetBSD: drm_hashtab.h,v 1.4 2021/12/18 23:45:46 riastradh Exp $	*/
      2 
      3 /**************************************************************************
      4  *
      5  * Copyright 2006 Tungsten Graphics, Inc., Bismack, ND. USA.
      6  * All Rights Reserved.
      7  *
      8  * Permission is hereby granted, free of charge, to any person obtaining a
      9  * copy of this software and associated documentation files (the
     10  * "Software"), to deal in the Software without restriction, including
     11  * without limitation the rights to use, copy, modify, merge, publish,
     12  * distribute, sub license, and/or sell copies of the Software, and to
     13  * permit persons to whom the Software is furnished to do so, subject to
     14  * the following conditions:
     15  *
     16  * The above copyright notice and this permission notice (including the
     17  * next paragraph) shall be included in all copies or substantial portions
     18  * of the Software.
     19  *
     20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     22  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
     23  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
     24  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
     25  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
     26  * USE OR OTHER DEALINGS IN THE SOFTWARE.
     27  *
     28  *
     29  **************************************************************************/
     30 /*
     31  * Simple open hash tab implementation.
     32  *
     33  * Authors:
     34  * Thomas Hellstrm <thomas-at-tungstengraphics-dot-com>
     35  */
     36 
     37 #ifndef DRM_HASHTAB_H
     38 #define DRM_HASHTAB_H
     39 
     40 #include <linux/kernel.h>
     41 #include <linux/list.h>
     42 #include <linux/types.h>
     43 
     44 #define drm_hash_entry(_ptr, _type, _member) container_of(_ptr, _type, _member)
     45 
     46 struct drm_hash_item {
     47 	struct hlist_node head;
     48 	unsigned long key;
     49 };
     50 
     51 struct drm_open_hash {
     52 	struct hlist_head *table;
     53 	u8 order;
     54 };
     55 
     56 int drm_ht_create(struct drm_open_hash *ht, unsigned int order);
     57 int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item);
     58 int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
     59 			      unsigned long seed, int bits, int shift,
     60 			      unsigned long add);
     61 int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, struct drm_hash_item **item);
     62 
     63 void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key);
     64 int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key);
     65 int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item);
     66 void drm_ht_remove(struct drm_open_hash *ht);
     67 
     68 /*
     69  * RCU-safe interface
     70  *
     71  * The user of this API needs to make sure that two or more instances of the
     72  * hash table manipulation functions are never run simultaneously.
     73  * The lookup function drm_ht_find_item_rcu may, however, run simultaneously
     74  * with any of the manipulation functions as long as it's called from within
     75  * an RCU read-locked section.
     76  */
     77 #define drm_ht_insert_item_rcu drm_ht_insert_item
     78 #define drm_ht_just_insert_please_rcu drm_ht_just_insert_please
     79 #define drm_ht_remove_key_rcu drm_ht_remove_key
     80 #define drm_ht_remove_item_rcu drm_ht_remove_item
     81 #define drm_ht_find_item_rcu drm_ht_find_item
     82 
     83 #endif
     84