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https://github.com/torvalds/linux
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384cc2f968
While hashtab should now be RCU-safe, Add a drm_ht_xxx_api for consumers to use to make it obvious what locking mechanism is used. Document the way the rcu-safe interface should be used. Don't use rcu-safe list traversal in modify operations where we should use a spinlock / mutex anyway. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
79 lines
3.1 KiB
C
79 lines
3.1 KiB
C
/**************************************************************************
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*
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* Copyright 2006 Tungsten Graphics, Inc., Bismack, ND. USA.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*
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**************************************************************************/
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/*
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* Simple open hash tab implementation.
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*
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* Authors:
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* Thomas Hellström <thomas-at-tungstengraphics-dot-com>
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*/
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#ifndef DRM_HASHTAB_H
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#define DRM_HASHTAB_H
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#include <linux/list.h>
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#define drm_hash_entry(_ptr, _type, _member) container_of(_ptr, _type, _member)
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struct drm_hash_item {
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struct hlist_node head;
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unsigned long key;
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};
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struct drm_open_hash {
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struct hlist_head *table;
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u8 order;
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};
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extern int drm_ht_create(struct drm_open_hash *ht, unsigned int order);
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extern int drm_ht_insert_item(struct drm_open_hash *ht, struct drm_hash_item *item);
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extern int drm_ht_just_insert_please(struct drm_open_hash *ht, struct drm_hash_item *item,
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unsigned long seed, int bits, int shift,
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unsigned long add);
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extern int drm_ht_find_item(struct drm_open_hash *ht, unsigned long key, struct drm_hash_item **item);
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extern void drm_ht_verbose_list(struct drm_open_hash *ht, unsigned long key);
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extern int drm_ht_remove_key(struct drm_open_hash *ht, unsigned long key);
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extern int drm_ht_remove_item(struct drm_open_hash *ht, struct drm_hash_item *item);
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extern void drm_ht_remove(struct drm_open_hash *ht);
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/*
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* RCU-safe interface
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*
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* The user of this API needs to make sure that two or more instances of the
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* hash table manipulation functions are never run simultaneously.
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* The lookup function drm_ht_find_item_rcu may, however, run simultaneously
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* with any of the manipulation functions as long as it's called from within
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* an RCU read-locked section.
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*/
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#define drm_ht_insert_item_rcu drm_ht_insert_item
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#define drm_ht_just_insert_please_rcu drm_ht_just_insert_please
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#define drm_ht_remove_key_rcu drm_ht_remove_key
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#define drm_ht_remove_item_rcu drm_ht_remove_item
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#define drm_ht_find_item_rcu drm_ht_find_item
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#endif
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