![Thomas Hellstrom](/assets/img/avatar_default.png)
The mostly used lookup+get put+potential_destroy path of TTM objects is converted to use RCU locks. This will substantially decrease the amount of locked bus cycles during normal operation. Since we use kfree_rcu to free the objects, no rcu synchronization is needed at module unload time. v2: Don't touch include/linux/kref.h v3: Adapt to kref_get_unless_zero return value change Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
276 lines
8.8 KiB
C
276 lines
8.8 KiB
C
/**************************************************************************
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*
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* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., 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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* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
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*/
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/** @file ttm_object.h
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*
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* Base- and reference object implementation for the various
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* ttm objects. Implements reference counting, minimal security checks
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* and release on file close.
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*/
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#ifndef _TTM_OBJECT_H_
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#define _TTM_OBJECT_H_
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#include <linux/list.h>
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#include <drm/drm_hashtab.h>
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#include <linux/kref.h>
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#include <linux/rcupdate.h>
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#include <ttm/ttm_memory.h>
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/**
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* enum ttm_ref_type
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*
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* Describes what type of reference a ref object holds.
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*
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* TTM_REF_USAGE is a simple refcount on a base object.
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*
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* TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
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* buffer object.
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*
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* TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
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* buffer object.
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*
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*/
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enum ttm_ref_type {
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TTM_REF_USAGE,
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TTM_REF_SYNCCPU_READ,
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TTM_REF_SYNCCPU_WRITE,
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TTM_REF_NUM
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};
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/**
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* enum ttm_object_type
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*
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* One entry per ttm object type.
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* Device-specific types should use the
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* ttm_driver_typex types.
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*/
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enum ttm_object_type {
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ttm_fence_type,
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ttm_buffer_type,
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ttm_lock_type,
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ttm_driver_type0 = 256,
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ttm_driver_type1,
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ttm_driver_type2,
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ttm_driver_type3,
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ttm_driver_type4,
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ttm_driver_type5
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};
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struct ttm_object_file;
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struct ttm_object_device;
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/**
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* struct ttm_base_object
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*
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* @hash: hash entry for the per-device object hash.
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* @type: derived type this object is base class for.
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* @shareable: Other ttm_object_files can access this object.
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*
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* @tfile: Pointer to ttm_object_file of the creator.
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* NULL if the object was not created by a user request.
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* (kernel object).
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*
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* @refcount: Number of references to this object, not
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* including the hash entry. A reference to a base object can
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* only be held by a ref object.
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*
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* @refcount_release: A function to be called when there are
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* no more references to this object. This function should
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* destroy the object (or make sure destruction eventually happens),
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* and when it is called, the object has
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* already been taken out of the per-device hash. The parameter
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* "base" should be set to NULL by the function.
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*
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* @ref_obj_release: A function to be called when a reference object
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* with another ttm_ref_type than TTM_REF_USAGE is deleted.
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* This function may, for example, release a lock held by a user-space
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* process.
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*
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* This struct is intended to be used as a base struct for objects that
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* are visible to user-space. It provides a global name, race-safe
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* access and refcounting, minimal access contol and hooks for unref actions.
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*/
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struct ttm_base_object {
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struct rcu_head rhead;
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struct drm_hash_item hash;
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enum ttm_object_type object_type;
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bool shareable;
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struct ttm_object_file *tfile;
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struct kref refcount;
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void (*refcount_release) (struct ttm_base_object **base);
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void (*ref_obj_release) (struct ttm_base_object *base,
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enum ttm_ref_type ref_type);
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};
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/**
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* ttm_base_object_init
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*
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* @tfile: Pointer to a struct ttm_object_file.
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* @base: The struct ttm_base_object to initialize.
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* @shareable: This object is shareable with other applcations.
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* (different @tfile pointers.)
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* @type: The object type.
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* @refcount_release: See the struct ttm_base_object description.
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* @ref_obj_release: See the struct ttm_base_object description.
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*
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* Initializes a struct ttm_base_object.
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*/
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extern int ttm_base_object_init(struct ttm_object_file *tfile,
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struct ttm_base_object *base,
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bool shareable,
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enum ttm_object_type type,
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void (*refcount_release) (struct ttm_base_object
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**),
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void (*ref_obj_release) (struct ttm_base_object
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*,
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enum ttm_ref_type
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ref_type));
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/**
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* ttm_base_object_lookup
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*
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* @tfile: Pointer to a struct ttm_object_file.
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* @key: Hash key
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*
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* Looks up a struct ttm_base_object with the key @key.
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* Also verifies that the object is visible to the application, by
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* comparing the @tfile argument and checking the object shareable flag.
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*/
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extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
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*tfile, uint32_t key);
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/**
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* ttm_base_object_unref
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*
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* @p_base: Pointer to a pointer referencing a struct ttm_base_object.
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*
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* Decrements the base object refcount and clears the pointer pointed to by
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* p_base.
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*/
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extern void ttm_base_object_unref(struct ttm_base_object **p_base);
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/**
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* ttm_ref_object_add.
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*
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* @tfile: A struct ttm_object_file representing the application owning the
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* ref_object.
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* @base: The base object to reference.
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* @ref_type: The type of reference.
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* @existed: Upon completion, indicates that an identical reference object
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* already existed, and the refcount was upped on that object instead.
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*
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* Adding a ref object to a base object is basically like referencing the
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* base object, but a user-space application holds the reference. When the
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* file corresponding to @tfile is closed, all its reference objects are
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* deleted. A reference object can have different types depending on what
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* it's intended for. It can be refcounting to prevent object destruction,
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* When user-space takes a lock, it can add a ref object to that lock to
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* make sure the lock is released if the application dies. A ref object
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* will hold a single reference on a base object.
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*/
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extern int ttm_ref_object_add(struct ttm_object_file *tfile,
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struct ttm_base_object *base,
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enum ttm_ref_type ref_type, bool *existed);
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/**
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* ttm_ref_object_base_unref
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*
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* @key: Key representing the base object.
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* @ref_type: Ref type of the ref object to be dereferenced.
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*
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* Unreference a ref object with type @ref_type
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* on the base object identified by @key. If there are no duplicate
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* references, the ref object will be destroyed and the base object
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* will be unreferenced.
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*/
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extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
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unsigned long key,
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enum ttm_ref_type ref_type);
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/**
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* ttm_object_file_init - initialize a struct ttm_object file
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*
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* @tdev: A struct ttm_object device this file is initialized on.
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* @hash_order: Order of the hash table used to hold the reference objects.
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*
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* This is typically called by the file_ops::open function.
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*/
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extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
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*tdev,
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unsigned int hash_order);
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/**
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* ttm_object_file_release - release data held by a ttm_object_file
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*
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* @p_tfile: Pointer to pointer to the ttm_object_file object to release.
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* *p_tfile will be set to NULL by this function.
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*
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* Releases all data associated by a ttm_object_file.
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* Typically called from file_ops::release. The caller must
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* ensure that there are no concurrent users of tfile.
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*/
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extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
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/**
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* ttm_object device init - initialize a struct ttm_object_device
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*
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* @hash_order: Order of hash table used to hash the base objects.
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*
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* This function is typically called on device initialization to prepare
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* data structures needed for ttm base and ref objects.
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*/
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extern struct ttm_object_device *ttm_object_device_init
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(struct ttm_mem_global *mem_glob, unsigned int hash_order);
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/**
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* ttm_object_device_release - release data held by a ttm_object_device
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*
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* @p_tdev: Pointer to pointer to the ttm_object_device object to release.
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* *p_tdev will be set to NULL by this function.
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*
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* Releases all data associated by a ttm_object_device.
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* Typically called from driver::unload before the destruction of the
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* device private data structure.
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*/
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extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
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#define ttm_base_object_kfree(__object, __base)\
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kfree_rcu(__object, __base.rhead)
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#endif
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