drivers/gpu/drm/i915/i915_vma.h - third_party/linux - Git at Google

 /*
  * Copyright © 2016 Intel Corporation
  *
  * 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, sublicense,
  * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS 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.
  *
  */

 #ifndef __I915_VMA_H__
 #define __I915_VMA_H__

 #include <linux/io-mapping.h>

 #include <drm/drm_mm.h>

 #include "i915_gem_gtt.h"
 #include "i915_gem_fence_reg.h"
 #include "i915_gem_object.h"

 #include "i915_request.h"

 enum i915_cache_level;

 /**
  * A VMA represents a GEM BO that is bound into an address space. Therefore, a
  * VMA's presence cannot be guaranteed before binding, or after unbinding the
  * object into/from the address space.
  *
  * To make things as simple as possible (ie. no refcounting), a VMA's lifetime
  * will always be <= an objects lifetime. So object refcounting should cover us.
  */
 struct i915_vma {
 	struct drm_mm_node node;
 	struct drm_i915_gem_object *obj;
 	struct i915_address_space *vm;
 	struct drm_i915_fence_reg *fence;
 	struct reservation_object *resv; /** Alias of obj->resv */
 	struct sg_table *pages;
 	void __iomem *iomap;
 	u64 size;
 	u64 display_alignment;
 	struct i915_page_sizes page_sizes;

 	u32 fence_size;
 	u32 fence_alignment;

 	/**
 	 * Count of the number of times this vma has been opened by different
 	 * handles (but same file) for execbuf, i.e. the number of aliases
 	 * that exist in the ctx->handle_vmas LUT for this vma.
 	 */
 	unsigned int open_count;
 	unsigned long flags;
 	/**
 	 * How many users have pinned this object in GTT space. The following
 	 * users can each hold at most one reference: pwrite/pread, execbuffer
 	 * (objects are not allowed multiple times for the same batchbuffer),
 	 * and the framebuffer code. When switching/pageflipping, the
 	 * framebuffer code has at most two buffers pinned per crtc.
 	 *
 	 * In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3
 	 * bits with absolutely no headroom. So use 4 bits.
 	 */
 #define I915_VMA_PIN_MASK 0xf
 #define I915_VMA_PIN_OVERFLOW	BIT(5)

 	/** Flags and address space this VMA is bound to */
 #define I915_VMA_GLOBAL_BIND	BIT(6)
 #define I915_VMA_LOCAL_BIND	BIT(7)
 #define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND | I915_VMA_PIN_OVERFLOW)

 #define I915_VMA_GGTT		BIT(8)
 #define I915_VMA_CAN_FENCE	BIT(9)
 #define I915_VMA_CLOSED		BIT(10)
 #define I915_VMA_USERFAULT_BIT	11
 #define I915_VMA_USERFAULT	BIT(I915_VMA_USERFAULT_BIT)
 #define I915_VMA_GGTT_WRITE	BIT(12)

 	unsigned int active;
 	struct i915_gem_active last_read[I915_NUM_ENGINES];
 	struct i915_gem_active last_fence;

 	/**
 	 * Support different GGTT views into the same object.
 	 * This means there can be multiple VMA mappings per object and per VM.
 	 * i915_ggtt_view_type is used to distinguish between those entries.
 	 * The default one of zero (I915_GGTT_VIEW_NORMAL) is default and also
 	 * assumed in GEM functions which take no ggtt view parameter.
 	 */
 	struct i915_ggtt_view ggtt_view;

 	/** This object's place on the active/inactive lists */
 	struct list_head vm_link;

 	struct list_head obj_link; /* Link in the object's VMA list */
 	struct rb_node obj_node;
 	struct hlist_node obj_hash;

 	/** This vma's place in the execbuf reservation list */
 	struct list_head exec_link;
 	struct list_head reloc_link;

 	/** This vma's place in the eviction list */
 	struct list_head evict_link;

 	struct list_head closed_link;

 	/**
 	 * Used for performing relocations during execbuffer insertion.
 	 */
 	unsigned int *exec_flags;
 	struct hlist_node exec_node;
 	u32 exec_handle;
 };

 struct i915_vma *
 i915_vma_instance(struct drm_i915_gem_object *obj,
 		  struct i915_address_space *vm,
 		  const struct i915_ggtt_view *view);

 void i915_vma_unpin_and_release(struct i915_vma **p_vma);

 static inline bool i915_vma_is_ggtt(const struct i915_vma *vma)
 {
 	return vma->flags & I915_VMA_GGTT;
 }

 static inline bool i915_vma_has_ggtt_write(const struct i915_vma *vma)
 {
 	return vma->flags & I915_VMA_GGTT_WRITE;
 }

 static inline void i915_vma_set_ggtt_write(struct i915_vma *vma)
 {
 	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
 	vma->flags |= I915_VMA_GGTT_WRITE;
 }

 static inline void i915_vma_unset_ggtt_write(struct i915_vma *vma)
 {
 	vma->flags &= ~I915_VMA_GGTT_WRITE;
 }

 void i915_vma_flush_writes(struct i915_vma *vma);

 static inline bool i915_vma_is_map_and_fenceable(const struct i915_vma *vma)
 {
 	return vma->flags & I915_VMA_CAN_FENCE;
 }

 static inline bool i915_vma_is_closed(const struct i915_vma *vma)
 {
 	return vma->flags & I915_VMA_CLOSED;
 }

 static inline bool i915_vma_set_userfault(struct i915_vma *vma)
 {
 	GEM_BUG_ON(!i915_vma_is_map_and_fenceable(vma));
 	return __test_and_set_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
 }

 static inline void i915_vma_unset_userfault(struct i915_vma *vma)
 {
 	return __clear_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
 }

 static inline bool i915_vma_has_userfault(const struct i915_vma *vma)
 {
 	return test_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
 }

 static inline unsigned int i915_vma_get_active(const struct i915_vma *vma)
 {
 	return vma->active;
 }

 static inline bool i915_vma_is_active(const struct i915_vma *vma)
 {
 	return i915_vma_get_active(vma);
 }

 static inline void i915_vma_set_active(struct i915_vma *vma,
 				       unsigned int engine)
 {
 	vma->active |= BIT(engine);
 }

 static inline void i915_vma_clear_active(struct i915_vma *vma,
 					 unsigned int engine)
 {
 	vma->active &= ~BIT(engine);
 }

 static inline bool i915_vma_has_active_engine(const struct i915_vma *vma,
 					      unsigned int engine)
 {
 	return vma->active & BIT(engine);
 }

 static inline u32 i915_ggtt_offset(const struct i915_vma *vma)
 {
 	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
 	GEM_BUG_ON(!vma->node.allocated);
 	GEM_BUG_ON(upper_32_bits(vma->node.start));
 	GEM_BUG_ON(upper_32_bits(vma->node.start + vma->node.size - 1));
 	return lower_32_bits(vma->node.start);
 }

 static inline struct i915_vma *i915_vma_get(struct i915_vma *vma)
 {
 	i915_gem_object_get(vma->obj);
 	return vma;
 }

 static inline void i915_vma_put(struct i915_vma *vma)
 {
 	i915_gem_object_put(vma->obj);
 }

 static __always_inline ptrdiff_t ptrdiff(const void *a, const void *b)
 {
 	return a - b;
 }

 static inline long
 i915_vma_compare(struct i915_vma *vma,
 		 struct i915_address_space *vm,
 		 const struct i915_ggtt_view *view)
 {
 	ptrdiff_t cmp;

 	GEM_BUG_ON(view && !i915_is_ggtt(vm));

 	cmp = ptrdiff(vma->vm, vm);
 	if (cmp)
 		return cmp;

 	BUILD_BUG_ON(I915_GGTT_VIEW_NORMAL != 0);
 	cmp = vma->ggtt_view.type;
 	if (!view)
 		return cmp;

 	cmp -= view->type;
 	if (cmp)
 		return cmp;

 	/* ggtt_view.type also encodes its size so that we both distinguish
 	 * different views using it as a "type" and also use a compact (no
 	 * accessing of uninitialised padding bytes) memcmp without storing
 	 * an extra parameter or adding more code.
 	 *
 	 * To ensure that the memcmp is valid for all branches of the union,
 	 * even though the code looks like it is just comparing one branch,
 	 * we assert above that all branches have the same address, and that
 	 * each branch has a unique type/size.
 	 */
 	BUILD_BUG_ON(I915_GGTT_VIEW_NORMAL >= I915_GGTT_VIEW_PARTIAL);
 	BUILD_BUG_ON(I915_GGTT_VIEW_PARTIAL >= I915_GGTT_VIEW_ROTATED);
 	BUILD_BUG_ON(offsetof(typeof(*view), rotated) !=
 		     offsetof(typeof(*view), partial));
 	return memcmp(&vma->ggtt_view.partial, &view->partial, view->type);
 }

 int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
 		  u32 flags);
 bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level);
 bool i915_vma_misplaced(const struct i915_vma *vma,
 			u64 size, u64 alignment, u64 flags);
 void __i915_vma_set_map_and_fenceable(struct i915_vma *vma);
 void i915_vma_revoke_mmap(struct i915_vma *vma);
 int __must_check i915_vma_unbind(struct i915_vma *vma);
 void i915_vma_unlink_ctx(struct i915_vma *vma);
 void i915_vma_close(struct i915_vma *vma);
 void i915_vma_reopen(struct i915_vma *vma);
 void i915_vma_destroy(struct i915_vma *vma);

 int __i915_vma_do_pin(struct i915_vma *vma,
 		      u64 size, u64 alignment, u64 flags);
 static inline int __must_check
 i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 {
 	BUILD_BUG_ON(PIN_MBZ != I915_VMA_PIN_OVERFLOW);
 	BUILD_BUG_ON(PIN_GLOBAL != I915_VMA_GLOBAL_BIND);
 	BUILD_BUG_ON(PIN_USER != I915_VMA_LOCAL_BIND);

 	/* Pin early to prevent the shrinker/eviction logic from destroying
 	 * our vma as we insert and bind.
 	 */
 	if (likely(((++vma->flags ^ flags) & I915_VMA_BIND_MASK) == 0)) {
 		GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
 		GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
 		return 0;
 	}

 	return __i915_vma_do_pin(vma, size, alignment, flags);
 }

 static inline int i915_vma_pin_count(const struct i915_vma *vma)
 {
 	return vma->flags & I915_VMA_PIN_MASK;
 }

 static inline bool i915_vma_is_pinned(const struct i915_vma *vma)
 {
 	return i915_vma_pin_count(vma);
 }

 static inline void __i915_vma_pin(struct i915_vma *vma)
 {
 	vma->flags++;
 	GEM_BUG_ON(vma->flags & I915_VMA_PIN_OVERFLOW);
 }

 static inline void __i915_vma_unpin(struct i915_vma *vma)
 {
 	vma->flags--;
 }

 static inline void i915_vma_unpin(struct i915_vma *vma)
 {
 	GEM_BUG_ON(!i915_vma_is_pinned(vma));
 	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
 	__i915_vma_unpin(vma);
 }

 /**
  * i915_vma_pin_iomap - calls ioremap_wc to map the GGTT VMA via the aperture
  * @vma: VMA to iomap
  *
  * The passed in VMA has to be pinned in the global GTT mappable region.
  * An extra pinning of the VMA is acquired for the return iomapping,
  * the caller must call i915_vma_unpin_iomap to relinquish the pinning
  * after the iomapping is no longer required.
  *
  * Callers must hold the struct_mutex.
  *
  * Returns a valid iomapped pointer or ERR_PTR.
  */
 void __iomem *i915_vma_pin_iomap(struct i915_vma *vma);
 #define IO_ERR_PTR(x) ((void __iomem *)ERR_PTR(x))

 /**
  * i915_vma_unpin_iomap - unpins the mapping returned from i915_vma_iomap
  * @vma: VMA to unpin
  *
  * Unpins the previously iomapped VMA from i915_vma_pin_iomap().
  *
  * Callers must hold the struct_mutex. This function is only valid to be
  * called on a VMA previously iomapped by the caller with i915_vma_pin_iomap().
  */
 void i915_vma_unpin_iomap(struct i915_vma *vma);

 static inline struct page *i915_vma_first_page(struct i915_vma *vma)
 {
 	GEM_BUG_ON(!vma->pages);
 	return sg_page(vma->pages->sgl);
 }

 /**
  * i915_vma_pin_fence - pin fencing state
  * @vma: vma to pin fencing for
  *
  * This pins the fencing state (whether tiled or untiled) to make sure the
  * vma (and its object) is ready to be used as a scanout target. Fencing
  * status must be synchronize first by calling i915_vma_get_fence():
  *
  * The resulting fence pin reference must be released again with
  * i915_vma_unpin_fence().
  *
  * Returns:
  *
  * True if the vma has a fence, false otherwise.
  */
 int i915_vma_pin_fence(struct i915_vma *vma);
 int __must_check i915_vma_put_fence(struct i915_vma *vma);

 static inline void __i915_vma_unpin_fence(struct i915_vma *vma)
 {
 	GEM_BUG_ON(vma->fence->pin_count <= 0);
 	vma->fence->pin_count--;
 }

 /**
  * i915_vma_unpin_fence - unpin fencing state
  * @vma: vma to unpin fencing for
  *
  * This releases the fence pin reference acquired through
  * i915_vma_pin_fence. It will handle both objects with and without an
  * attached fence correctly, callers do not need to distinguish this.
  */
 static inline void
 i915_vma_unpin_fence(struct i915_vma *vma)
 {
 	lockdep_assert_held(&vma->obj->base.dev->struct_mutex);
 	if (vma->fence)
 		__i915_vma_unpin_fence(vma);
 }

 void i915_vma_parked(struct drm_i915_private *i915);

 #define for_each_until(cond) if (cond) break; else

 /**
  * for_each_ggtt_vma - Iterate over the GGTT VMA belonging to an object.
  * @V: the #i915_vma iterator
  * @OBJ: the #drm_i915_gem_object
  *
  * GGTT VMA are placed at the being of the object's vma_list, see
  * vma_create(), so we can stop our walk as soon as we see a ppgtt VMA,
  * or the list is empty ofc.
  */
 #define for_each_ggtt_vma(V, OBJ) \
 	list_for_each_entry(V, &(OBJ)->vma_list, obj_link)		\
 		for_each_until(!i915_vma_is_ggtt(V))

 #endif
	/*
	* Copyright © 2016 Intel Corporation
	*
	* 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, sublicense,
	* 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 NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS 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.
	*
	*/

	#ifndef __I915_VMA_H__
	#define __I915_VMA_H__

	#include <linux/io-mapping.h>

	#include <drm/drm_mm.h>

	#include "i915_gem_gtt.h"
	#include "i915_gem_fence_reg.h"
	#include "i915_gem_object.h"

	#include "i915_request.h"

	enum i915_cache_level;

	/**
	* A VMA represents a GEM BO that is bound into an address space. Therefore, a
	* VMA's presence cannot be guaranteed before binding, or after unbinding the
	* object into/from the address space.
	*
	* To make things as simple as possible (ie. no refcounting), a VMA's lifetime
	* will always be <= an objects lifetime. So object refcounting should cover us.
	*/
	struct i915_vma {
	struct drm_mm_node node;
	struct drm_i915_gem_object *obj;
	struct i915_address_space *vm;
	struct drm_i915_fence_reg *fence;
	struct reservation_object resv; /* Alias of obj->resv */
	struct sg_table *pages;
	void __iomem *iomap;
	u64 size;
	u64 display_alignment;
	struct i915_page_sizes page_sizes;

	u32 fence_size;
	u32 fence_alignment;

	/**
	* Count of the number of times this vma has been opened by different
	* handles (but same file) for execbuf, i.e. the number of aliases
	* that exist in the ctx->handle_vmas LUT for this vma.
	*/
	unsigned int open_count;
	unsigned long flags;
	/**
	* How many users have pinned this object in GTT space. The following
	* users can each hold at most one reference: pwrite/pread, execbuffer
	* (objects are not allowed multiple times for the same batchbuffer),
	* and the framebuffer code. When switching/pageflipping, the
	* framebuffer code has at most two buffers pinned per crtc.
	*
	* In the worst case this is 1 + 1 + 1 + 2*2 = 7. That would fit into 3
	* bits with absolutely no headroom. So use 4 bits.
	*/
	#define I915_VMA_PIN_MASK 0xf
	#define I915_VMA_PIN_OVERFLOW BIT(5)

	/** Flags and address space this VMA is bound to */
	#define I915_VMA_GLOBAL_BIND BIT(6)
	#define I915_VMA_LOCAL_BIND BIT(7)
	#define I915_VMA_BIND_MASK (I915_VMA_GLOBAL_BIND \| I915_VMA_LOCAL_BIND \| I915_VMA_PIN_OVERFLOW)

	#define I915_VMA_GGTT BIT(8)
	#define I915_VMA_CAN_FENCE BIT(9)
	#define I915_VMA_CLOSED BIT(10)
	#define I915_VMA_USERFAULT_BIT 11
	#define I915_VMA_USERFAULT BIT(I915_VMA_USERFAULT_BIT)
	#define I915_VMA_GGTT_WRITE BIT(12)

	unsigned int active;
	struct i915_gem_active last_read[I915_NUM_ENGINES];
	struct i915_gem_active last_fence;

	/**
	* Support different GGTT views into the same object.
	* This means there can be multiple VMA mappings per object and per VM.
	* i915_ggtt_view_type is used to distinguish between those entries.
	* The default one of zero (I915_GGTT_VIEW_NORMAL) is default and also
	* assumed in GEM functions which take no ggtt view parameter.
	*/
	struct i915_ggtt_view ggtt_view;

	/** This object's place on the active/inactive lists */
	struct list_head vm_link;

	struct list_head obj_link; /* Link in the object's VMA list */
	struct rb_node obj_node;
	struct hlist_node obj_hash;

	/** This vma's place in the execbuf reservation list */
	struct list_head exec_link;
	struct list_head reloc_link;

	/** This vma's place in the eviction list */
	struct list_head evict_link;

	struct list_head closed_link;

	/**
	* Used for performing relocations during execbuffer insertion.
	*/
	unsigned int *exec_flags;
	struct hlist_node exec_node;
	u32 exec_handle;
	};

	struct i915_vma *
	i915_vma_instance(struct drm_i915_gem_object *obj,
	struct i915_address_space *vm,
	const struct i915_ggtt_view *view);

	void i915_vma_unpin_and_release(struct i915_vma **p_vma);

	static inline bool i915_vma_is_ggtt(const struct i915_vma *vma)
	{
	return vma->flags & I915_VMA_GGTT;
	}

	static inline bool i915_vma_has_ggtt_write(const struct i915_vma *vma)
	{
	return vma->flags & I915_VMA_GGTT_WRITE;
	}

	static inline void i915_vma_set_ggtt_write(struct i915_vma *vma)
	{
	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
	vma->flags \|= I915_VMA_GGTT_WRITE;
	}

	static inline void i915_vma_unset_ggtt_write(struct i915_vma *vma)
	{
	vma->flags &= ~I915_VMA_GGTT_WRITE;
	}

	void i915_vma_flush_writes(struct i915_vma *vma);

	static inline bool i915_vma_is_map_and_fenceable(const struct i915_vma *vma)
	{
	return vma->flags & I915_VMA_CAN_FENCE;
	}

	static inline bool i915_vma_is_closed(const struct i915_vma *vma)
	{
	return vma->flags & I915_VMA_CLOSED;
	}

	static inline bool i915_vma_set_userfault(struct i915_vma *vma)
	{
	GEM_BUG_ON(!i915_vma_is_map_and_fenceable(vma));
	return __test_and_set_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
	}

	static inline void i915_vma_unset_userfault(struct i915_vma *vma)
	{
	return __clear_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
	}

	static inline bool i915_vma_has_userfault(const struct i915_vma *vma)
	{
	return test_bit(I915_VMA_USERFAULT_BIT, &vma->flags);
	}

	static inline unsigned int i915_vma_get_active(const struct i915_vma *vma)
	{
	return vma->active;
	}

	static inline bool i915_vma_is_active(const struct i915_vma *vma)
	{
	return i915_vma_get_active(vma);
	}

	static inline void i915_vma_set_active(struct i915_vma *vma,
	unsigned int engine)
	{
	vma->active \|= BIT(engine);
	}

	static inline void i915_vma_clear_active(struct i915_vma *vma,
	unsigned int engine)
	{
	vma->active &= ~BIT(engine);
	}

	static inline bool i915_vma_has_active_engine(const struct i915_vma *vma,
	unsigned int engine)
	{
	return vma->active & BIT(engine);
	}

	static inline u32 i915_ggtt_offset(const struct i915_vma *vma)
	{
	GEM_BUG_ON(!i915_vma_is_ggtt(vma));
	GEM_BUG_ON(!vma->node.allocated);
	GEM_BUG_ON(upper_32_bits(vma->node.start));
	GEM_BUG_ON(upper_32_bits(vma->node.start + vma->node.size - 1));
	return lower_32_bits(vma->node.start);
	}

	static inline struct i915_vma i915_vma_get(struct i915_vma vma)
	{
	i915_gem_object_get(vma->obj);
	return vma;
	}

	static inline void i915_vma_put(struct i915_vma *vma)
	{
	i915_gem_object_put(vma->obj);
	}

	static __always_inline ptrdiff_t ptrdiff(const void a, const void b)
	{
	return a - b;
	}

	static inline long
	i915_vma_compare(struct i915_vma *vma,
	struct i915_address_space *vm,
	const struct i915_ggtt_view *view)
	{
	ptrdiff_t cmp;

	GEM_BUG_ON(view && !i915_is_ggtt(vm));

	cmp = ptrdiff(vma->vm, vm);
	if (cmp)
	return cmp;

	BUILD_BUG_ON(I915_GGTT_VIEW_NORMAL != 0);
	cmp = vma->ggtt_view.type;
	if (!view)
	return cmp;

	cmp -= view->type;
	if (cmp)
	return cmp;

	/* ggtt_view.type also encodes its size so that we both distinguish
	* different views using it as a "type" and also use a compact (no
	* accessing of uninitialised padding bytes) memcmp without storing
	* an extra parameter or adding more code.
	*
	* To ensure that the memcmp is valid for all branches of the union,
	* even though the code looks like it is just comparing one branch,
	* we assert above that all branches have the same address, and that
	* each branch has a unique type/size.
	*/
	BUILD_BUG_ON(I915_GGTT_VIEW_NORMAL >= I915_GGTT_VIEW_PARTIAL);
	BUILD_BUG_ON(I915_GGTT_VIEW_PARTIAL >= I915_GGTT_VIEW_ROTATED);
	BUILD_BUG_ON(offsetof(typeof(*view), rotated) !=
	offsetof(typeof(*view), partial));
	return memcmp(&vma->ggtt_view.partial, &view->partial, view->type);
	}

	int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
	u32 flags);
	bool i915_gem_valid_gtt_space(struct i915_vma *vma, unsigned long cache_level);
	bool i915_vma_misplaced(const struct i915_vma *vma,
	u64 size, u64 alignment, u64 flags);
	void __i915_vma_set_map_and_fenceable(struct i915_vma *vma);
	void i915_vma_revoke_mmap(struct i915_vma *vma);
	int __must_check i915_vma_unbind(struct i915_vma *vma);
	void i915_vma_unlink_ctx(struct i915_vma *vma);
	void i915_vma_close(struct i915_vma *vma);
	void i915_vma_reopen(struct i915_vma *vma);
	void i915_vma_destroy(struct i915_vma *vma);

	int __i915_vma_do_pin(struct i915_vma *vma,
	u64 size, u64 alignment, u64 flags);
	static inline int __must_check
	i915_vma_pin(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
	{
	BUILD_BUG_ON(PIN_MBZ != I915_VMA_PIN_OVERFLOW);
	BUILD_BUG_ON(PIN_GLOBAL != I915_VMA_GLOBAL_BIND);
	BUILD_BUG_ON(PIN_USER != I915_VMA_LOCAL_BIND);

	/* Pin early to prevent the shrinker/eviction logic from destroying
	* our vma as we insert and bind.
	*/
	if (likely(((++vma->flags ^ flags) & I915_VMA_BIND_MASK) == 0)) {
	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
	GEM_BUG_ON(i915_vma_misplaced(vma, size, alignment, flags));
	return 0;
	}

	return __i915_vma_do_pin(vma, size, alignment, flags);
	}

	static inline int i915_vma_pin_count(const struct i915_vma *vma)
	{
	return vma->flags & I915_VMA_PIN_MASK;
	}

	static inline bool i915_vma_is_pinned(const struct i915_vma *vma)
	{
	return i915_vma_pin_count(vma);
	}

	static inline void __i915_vma_pin(struct i915_vma *vma)
	{
	vma->flags++;
	GEM_BUG_ON(vma->flags & I915_VMA_PIN_OVERFLOW);
	}

	static inline void __i915_vma_unpin(struct i915_vma *vma)
	{
	vma->flags--;
	}

	static inline void i915_vma_unpin(struct i915_vma *vma)
	{
	GEM_BUG_ON(!i915_vma_is_pinned(vma));
	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
	__i915_vma_unpin(vma);
	}

	/**
	* i915_vma_pin_iomap - calls ioremap_wc to map the GGTT VMA via the aperture
	* @vma: VMA to iomap
	*
	* The passed in VMA has to be pinned in the global GTT mappable region.
	* An extra pinning of the VMA is acquired for the return iomapping,
	* the caller must call i915_vma_unpin_iomap to relinquish the pinning
	* after the iomapping is no longer required.
	*
	* Callers must hold the struct_mutex.
	*
	* Returns a valid iomapped pointer or ERR_PTR.
	*/
	void __iomem i915_vma_pin_iomap(struct i915_vma vma);
	#define IO_ERR_PTR(x) ((void __iomem *)ERR_PTR(x))

	/**
	* i915_vma_unpin_iomap - unpins the mapping returned from i915_vma_iomap
	* @vma: VMA to unpin
	*
	* Unpins the previously iomapped VMA from i915_vma_pin_iomap().
	*
	* Callers must hold the struct_mutex. This function is only valid to be
	* called on a VMA previously iomapped by the caller with i915_vma_pin_iomap().
	*/
	void i915_vma_unpin_iomap(struct i915_vma *vma);

	static inline struct page i915_vma_first_page(struct i915_vma vma)
	{
	GEM_BUG_ON(!vma->pages);
	return sg_page(vma->pages->sgl);
	}

	/**
	* i915_vma_pin_fence - pin fencing state
	* @vma: vma to pin fencing for
	*
	* This pins the fencing state (whether tiled or untiled) to make sure the
	* vma (and its object) is ready to be used as a scanout target. Fencing
	* status must be synchronize first by calling i915_vma_get_fence():
	*
	* The resulting fence pin reference must be released again with
	* i915_vma_unpin_fence().
	*
	* Returns:
	*
	* True if the vma has a fence, false otherwise.
	*/
	int i915_vma_pin_fence(struct i915_vma *vma);
	int __must_check i915_vma_put_fence(struct i915_vma *vma);

	static inline void __i915_vma_unpin_fence(struct i915_vma *vma)
	{
	GEM_BUG_ON(vma->fence->pin_count <= 0);
	vma->fence->pin_count--;
	}

	/**
	* i915_vma_unpin_fence - unpin fencing state
	* @vma: vma to unpin fencing for
	*
	* This releases the fence pin reference acquired through
	* i915_vma_pin_fence. It will handle both objects with and without an
	* attached fence correctly, callers do not need to distinguish this.
	*/
	static inline void
	i915_vma_unpin_fence(struct i915_vma *vma)
	{
	lockdep_assert_held(&vma->obj->base.dev->struct_mutex);
	if (vma->fence)
	__i915_vma_unpin_fence(vma);
	}

	void i915_vma_parked(struct drm_i915_private *i915);

	#define for_each_until(cond) if (cond) break; else

	/**
	* for_each_ggtt_vma - Iterate over the GGTT VMA belonging to an object.
	* @V: the #i915_vma iterator
	* @OBJ: the #drm_i915_gem_object
	*
	* GGTT VMA are placed at the being of the object's vma_list, see
	* vma_create(), so we can stop our walk as soon as we see a ppgtt VMA,
	* or the list is empty ofc.
	*/
	#define for_each_ggtt_vma(V, OBJ) \
	list_for_each_entry(V, &(OBJ)->vma_list, obj_link) \
	for_each_until(!i915_vma_is_ggtt(V))

	#endif