drm/ttm: Add user-space objects.

Add objects needed for user-space to maintain reference counts on ttm objects.
This is used by the vmwgfx driver which allows user-space to maintain
map-counts on dma buffers, lock-counts on the ttm lock and ref-counts on
gpu surfaces, gpu contexts and dma buffer.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ttm/Makefile

@@ -3,6 +3,7 @@
 
 ccflags-y := -Iinclude/drm
 ttm-y := ttm_agp_backend.o ttm_memory.o ttm_tt.o ttm_bo.o \
-	ttm_bo_util.o ttm_bo_vm.o ttm_module.o ttm_global.o
+	ttm_bo_util.o ttm_bo_vm.o ttm_module.o ttm_global.o \
+	ttm_object.o
 
 obj-$(CONFIG_DRM_TTM) += ttm.o

include/drm/ttm/ttm_object.h

+/**************************************************************************
+ *
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+/*
+ * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
+ */
+/** @file ttm_object.h
+ *
+ * Base- and reference object implementation for the various
+ * ttm objects. Implements reference counting, minimal security checks
+ * and release on file close.
+ */
+
+#ifndef _TTM_OBJECT_H_
+#define _TTM_OBJECT_H_
+
+#include <linux/list.h>
+#include "drm_hashtab.h"
+#include <linux/kref.h>
+#include <ttm/ttm_memory.h>
+
+/**
+ * enum ttm_ref_type
+ *
+ * Describes what type of reference a ref object holds.
+ *
+ * TTM_REF_USAGE is a simple refcount on a base object.
+ *
+ * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
+ * buffer object.
+ *
+ * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
+ * buffer object.
+ *
+ */
+
+enum ttm_ref_type {
+	TTM_REF_USAGE,
+	TTM_REF_SYNCCPU_READ,
+	TTM_REF_SYNCCPU_WRITE,
+	TTM_REF_NUM
+};
+
+/**
+ * enum ttm_object_type
+ *
+ * One entry per ttm object type.
+ * Device-specific types should use the
+ * ttm_driver_typex types.
+ */
+
+enum ttm_object_type {
+	ttm_fence_type,
+	ttm_buffer_type,
+	ttm_lock_type,
+	ttm_driver_type0 = 256,
+	ttm_driver_type1
+};
+
+struct ttm_object_file;
+struct ttm_object_device;
+
+/**
+ * struct ttm_base_object
+ *
+ * @hash: hash entry for the per-device object hash.
+ * @type: derived type this object is base class for.
+ * @shareable: Other ttm_object_files can access this object.
+ *
+ * @tfile: Pointer to ttm_object_file of the creator.
+ * NULL if the object was not created by a user request.
+ * (kernel object).
+ *
+ * @refcount: Number of references to this object, not
+ * including the hash entry. A reference to a base object can
+ * only be held by a ref object.
+ *
+ * @refcount_release: A function to be called when there are
+ * no more references to this object. This function should
+ * destroy the object (or make sure destruction eventually happens),
+ * and when it is called, the object has
+ * already been taken out of the per-device hash. The parameter
+ * "base" should be set to NULL by the function.
+ *
+ * @ref_obj_release: A function to be called when a reference object
+ * with another ttm_ref_type than TTM_REF_USAGE is deleted.
+ * this function may, for example, release a lock held by a user-space
+ * process.
+ *
+ * This struct is intended to be used as a base struct for objects that
+ * are visible to user-space. It provides a global name, race-safe
+ * access and refcounting, minimal access contol and hooks for unref actions.
+ */
+
+struct ttm_base_object {
+	struct drm_hash_item hash;
+	enum ttm_object_type object_type;
+	bool shareable;
+	struct ttm_object_file *tfile;
+	struct kref refcount;
+	void (*refcount_release) (struct ttm_base_object **base);
+	void (*ref_obj_release) (struct ttm_base_object *base,
+				 enum ttm_ref_type ref_type);
+};
+
+/**
+ * ttm_base_object_init
+ *
+ * @tfile: Pointer to a struct ttm_object_file.
+ * @base: The struct ttm_base_object to initialize.
+ * @shareable: This object is shareable with other applcations.
+ * (different @tfile pointers.)
+ * @type: The object type.
+ * @refcount_release: See the struct ttm_base_object description.
+ * @ref_obj_release: See the struct ttm_base_object description.
+ *
+ * Initializes a struct ttm_base_object.
+ */
+
+extern int ttm_base_object_init(struct ttm_object_file *tfile,
+				struct ttm_base_object *base,
+				bool shareable,
+				enum ttm_object_type type,
+				void (*refcount_release) (struct ttm_base_object
+							  **),
+				void (*ref_obj_release) (struct ttm_base_object
+							 *,
+							 enum ttm_ref_type
+							 ref_type));
+
+/**
+ * ttm_base_object_lookup
+ *
+ * @tfile: Pointer to a struct ttm_object_file.
+ * @key: Hash key
+ *
+ * Looks up a struct ttm_base_object with the key @key.
+ * Also verifies that the object is visible to the application, by
+ * comparing the @tfile argument and checking the object shareable flag.
+ */
+
+extern struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file
+						      *tfile, uint32_t key);
+
+/**
+ * ttm_base_object_unref
+ *
+ * @p_base: Pointer to a pointer referncing a struct ttm_base_object.
+ *
+ * Decrements the base object refcount and clears the pointer pointed to by
+ * p_base.
+ */
+
+extern void ttm_base_object_unref(struct ttm_base_object **p_base);
+
+/**
+ * ttm_ref_object_add.
+ *
+ * @tfile: A struct ttm_object_file representing the application owning the
+ * ref_object.
+ * @base: The base object to reference.
+ * @ref_type: The type of reference.
+ * @existed: Upon completion, indicates that an identical reference object
+ * already existed, and the refcount was upped on that object instead.
+ *
+ * Adding a ref object to a base object is basically like referencing the
+ * base object, but a user-space application holds the reference. When the
+ * file corresponding to @tfile is closed, all its reference objects are
+ * deleted. A reference object can have different types depending on what
+ * it's intended for. It can be refcounting to prevent object destruction,
+ * When user-space takes a lock, it can add a ref object to that lock to
+ * make sure the lock is released if the application dies. A ref object
+ * will hold a single reference on a base object.
+ */
+extern int ttm_ref_object_add(struct ttm_object_file *tfile,
+			      struct ttm_base_object *base,
+			      enum ttm_ref_type ref_type, bool *existed);
+/**
+ * ttm_ref_object_base_unref
+ *
+ * @key: Key representing the base object.
+ * @ref_type: Ref type of the ref object to be dereferenced.
+ *
+ * Unreference a ref object with type @ref_type
+ * on the base object identified by @key. If there are no duplicate
+ * references, the ref object will be destroyed and the base object
+ * will be unreferenced.
+ */
+extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
+				     unsigned long key,
+				     enum ttm_ref_type ref_type);
+
+/**
+ * ttm_object_file_init - initialize a struct ttm_object file
+ *
+ * @tdev: A struct ttm_object device this file is initialized on.
+ * @hash_order: Order of the hash table used to hold the reference objects.
+ *
+ * This is typically called by the file_ops::open function.
+ */
+
+extern struct ttm_object_file *ttm_object_file_init(struct ttm_object_device
+						    *tdev,
+						    unsigned int hash_order);
+
+/**
+ * ttm_object_file_release - release data held by a ttm_object_file
+ *
+ * @p_tfile: Pointer to pointer to the ttm_object_file object to release.
+ * *p_tfile will be set to NULL by this function.
+ *
+ * Releases all data associated by a ttm_object_file.
+ * Typically called from file_ops::release. The caller must
+ * ensure that there are no concurrent users of tfile.
+ */
+
+extern void ttm_object_file_release(struct ttm_object_file **p_tfile);
+
+/**
+ * ttm_object device init - initialize a struct ttm_object_device
+ *
+ * @hash_order: Order of hash table used to hash the base objects.
+ *
+ * This function is typically called on device initialization to prepare
+ * data structures needed for ttm base and ref objects.
+ */
+
+extern struct ttm_object_device *ttm_object_device_init
+    (struct ttm_mem_global *mem_glob, unsigned int hash_order);
+
+/**
+ * ttm_object_device_release - release data held by a ttm_object_device
+ *
+ * @p_tdev: Pointer to pointer to the ttm_object_device object to release.
+ * *p_tdev will be set to NULL by this function.
+ *
+ * Releases all data associated by a ttm_object_device.
+ * Typically called from driver::unload before the destruction of the
+ * device private data structure.
+ */
+
+extern void ttm_object_device_release(struct ttm_object_device **p_tdev);
+
+#endif