drivers/gpu/drm/radeon/radeon_sa.c - linux - Git at Google

 /*
  * Copyright 2011 Red Hat Inc.
  * 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 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.
  *
  * The above copyright notice and this permission notice (including the
  * next paragraph) shall be included in all copies or substantial portions
  * of the Software.
  *
  */
 /*
  * Authors:
  *    Jerome Glisse <glisse@freedesktop.org>
  */
 /* Algorithm:
  *
  * We store the last allocated bo in "hole", we always try to allocate
  * after the last allocated bo. Principle is that in a linear GPU ring
  * progression was is after last is the oldest bo we allocated and thus
  * the first one that should no longer be in use by the GPU.
  *
  * If it's not the case we skip over the bo after last to the closest
  * done bo if such one exist. If none exist and we are not asked to
  * block we report failure to allocate.
  *
  * If we are asked to block we wait on all the oldest fence of all
  * rings. We just wait for any of those fence to complete.
  */
 #include <drm/drmP.h>
 #include "radeon.h"

 static void radeon_sa_bo_remove_locked(struct radeon_sa_bo *sa_bo);
 static void radeon_sa_bo_try_free(struct radeon_sa_manager *sa_manager);

 int radeon_sa_bo_manager_init(struct radeon_device *rdev,
 			      struct radeon_sa_manager *sa_manager,
 			      unsigned size, u32 domain)
 {
 	int i, r;

 	init_waitqueue_head(&sa_manager->wq);
 	sa_manager->bo = NULL;
 	sa_manager->size = size;
 	sa_manager->domain = domain;
 	sa_manager->hole = &sa_manager->olist;
 	INIT_LIST_HEAD(&sa_manager->olist);
 	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
 		INIT_LIST_HEAD(&sa_manager->flist[i]);
 	}

 	r = radeon_bo_create(rdev, size, RADEON_GPU_PAGE_SIZE, true,
 			     RADEON_GEM_DOMAIN_CPU, NULL, &sa_manager->bo);
 	if (r) {
 		dev_err(rdev->dev, "(%d) failed to allocate bo for manager\n", r);
 		return r;
 	}

 	return r;
 }

 void radeon_sa_bo_manager_fini(struct radeon_device *rdev,
 			       struct radeon_sa_manager *sa_manager)
 {
 	struct radeon_sa_bo *sa_bo, *tmp;

 	if (!list_empty(&sa_manager->olist)) {
 		sa_manager->hole = &sa_manager->olist,
 		radeon_sa_bo_try_free(sa_manager);
 		if (!list_empty(&sa_manager->olist)) {
 			dev_err(rdev->dev, "sa_manager is not empty, clearing anyway\n");
 		}
 	}
 	list_for_each_entry_safe(sa_bo, tmp, &sa_manager->olist, olist) {
 		radeon_sa_bo_remove_locked(sa_bo);
 	}
 	radeon_bo_unref(&sa_manager->bo);
 	sa_manager->size = 0;
 }

 int radeon_sa_bo_manager_start(struct radeon_device *rdev,
 			       struct radeon_sa_manager *sa_manager)
 {
 	int r;

 	if (sa_manager->bo == NULL) {
 		dev_err(rdev->dev, "no bo for sa manager\n");
 		return -EINVAL;
 	}

 	/* map the buffer */
 	r = radeon_bo_reserve(sa_manager->bo, false);
 	if (r) {
 		dev_err(rdev->dev, "(%d) failed to reserve manager bo\n", r);
 		return r;
 	}
 	r = radeon_bo_pin(sa_manager->bo, sa_manager->domain, &sa_manager->gpu_addr);
 	if (r) {
 		radeon_bo_unreserve(sa_manager->bo);
 		dev_err(rdev->dev, "(%d) failed to pin manager bo\n", r);
 		return r;
 	}
 	r = radeon_bo_kmap(sa_manager->bo, &sa_manager->cpu_ptr);
 	radeon_bo_unreserve(sa_manager->bo);
 	return r;
 }

 int radeon_sa_bo_manager_suspend(struct radeon_device *rdev,
 				 struct radeon_sa_manager *sa_manager)
 {
 	int r;

 	if (sa_manager->bo == NULL) {
 		dev_err(rdev->dev, "no bo for sa manager\n");
 		return -EINVAL;
 	}

 	r = radeon_bo_reserve(sa_manager->bo, false);
 	if (!r) {
 		radeon_bo_kunmap(sa_manager->bo);
 		radeon_bo_unpin(sa_manager->bo);
 		radeon_bo_unreserve(sa_manager->bo);
 	}
 	return r;
 }

 static void radeon_sa_bo_remove_locked(struct radeon_sa_bo *sa_bo)
 {
 	struct radeon_sa_manager *sa_manager = sa_bo->manager;
 	if (sa_manager->hole == &sa_bo->olist) {
 		sa_manager->hole = sa_bo->olist.prev;
 	}
 	list_del_init(&sa_bo->olist);
 	list_del_init(&sa_bo->flist);
 	radeon_fence_unref(&sa_bo->fence);
 	kfree(sa_bo);
 }

 static void radeon_sa_bo_try_free(struct radeon_sa_manager *sa_manager)
 {
 	struct radeon_sa_bo *sa_bo, *tmp;

 	if (sa_manager->hole->next == &sa_manager->olist)
 		return;

 	sa_bo = list_entry(sa_manager->hole->next, struct radeon_sa_bo, olist);
 	list_for_each_entry_safe_from(sa_bo, tmp, &sa_manager->olist, olist) {
 		if (sa_bo->fence == NULL || !radeon_fence_signaled(sa_bo->fence)) {
 			return;
 		}
 		radeon_sa_bo_remove_locked(sa_bo);
 	}
 }

 static inline unsigned radeon_sa_bo_hole_soffset(struct radeon_sa_manager *sa_manager)
 {
 	struct list_head *hole = sa_manager->hole;

 	if (hole != &sa_manager->olist) {
 		return list_entry(hole, struct radeon_sa_bo, olist)->eoffset;
 	}
 	return 0;
 }

 static inline unsigned radeon_sa_bo_hole_eoffset(struct radeon_sa_manager *sa_manager)
 {
 	struct list_head *hole = sa_manager->hole;

 	if (hole->next != &sa_manager->olist) {
 		return list_entry(hole->next, struct radeon_sa_bo, olist)->soffset;
 	}
 	return sa_manager->size;
 }

 static bool radeon_sa_bo_try_alloc(struct radeon_sa_manager *sa_manager,
 				   struct radeon_sa_bo *sa_bo,
 				   unsigned size, unsigned align)
 {
 	unsigned soffset, eoffset, wasted;

 	soffset = radeon_sa_bo_hole_soffset(sa_manager);
 	eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
 	wasted = (align - (soffset % align)) % align;

 	if ((eoffset - soffset) >= (size + wasted)) {
 		soffset += wasted;

 		sa_bo->manager = sa_manager;
 		sa_bo->soffset = soffset;
 		sa_bo->eoffset = soffset + size;
 		list_add(&sa_bo->olist, sa_manager->hole);
 		INIT_LIST_HEAD(&sa_bo->flist);
 		sa_manager->hole = &sa_bo->olist;
 		return true;
 	}
 	return false;
 }

 /**
  * radeon_sa_event - Check if we can stop waiting
  *
  * @sa_manager: pointer to the sa_manager
  * @size: number of bytes we want to allocate
  * @align: alignment we need to match
  *
  * Check if either there is a fence we can wait for or
  * enough free memory to satisfy the allocation directly
  */
 static bool radeon_sa_event(struct radeon_sa_manager *sa_manager,
 			    unsigned size, unsigned align)
 {
 	unsigned soffset, eoffset, wasted;
 	int i;

 	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
 		if (!list_empty(&sa_manager->flist[i])) {
 			return true;
 		}
 	}

 	soffset = radeon_sa_bo_hole_soffset(sa_manager);
 	eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
 	wasted = (align - (soffset % align)) % align;

 	if ((eoffset - soffset) >= (size + wasted)) {
 		return true;
 	}

 	return false;
 }

 static bool radeon_sa_bo_next_hole(struct radeon_sa_manager *sa_manager,
 				   struct radeon_fence **fences,
 				   unsigned *tries)
 {
 	struct radeon_sa_bo *best_bo = NULL;
 	unsigned i, soffset, best, tmp;

 	/* if hole points to the end of the buffer */
 	if (sa_manager->hole->next == &sa_manager->olist) {
 		/* try again with its beginning */
 		sa_manager->hole = &sa_manager->olist;
 		return true;
 	}

 	soffset = radeon_sa_bo_hole_soffset(sa_manager);
 	/* to handle wrap around we add sa_manager->size */
 	best = sa_manager->size * 2;
 	/* go over all fence list and try to find the closest sa_bo
 	 * of the current last
 	 */
 	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
 		struct radeon_sa_bo *sa_bo;

 		if (list_empty(&sa_manager->flist[i])) {
 			continue;
 		}

 		sa_bo = list_first_entry(&sa_manager->flist[i],
 					 struct radeon_sa_bo, flist);

 		if (!radeon_fence_signaled(sa_bo->fence)) {
 			fences[i] = sa_bo->fence;
 			continue;
 		}

 		/* limit the number of tries each ring gets */
 		if (tries[i] > 2) {
 			continue;
 		}

 		tmp = sa_bo->soffset;
 		if (tmp < soffset) {
 			/* wrap around, pretend it's after */
 			tmp += sa_manager->size;
 		}
 		tmp -= soffset;
 		if (tmp < best) {
 			/* this sa bo is the closest one */
 			best = tmp;
 			best_bo = sa_bo;
 		}
 	}

 	if (best_bo) {
 		++tries[best_bo->fence->ring];
 		sa_manager->hole = best_bo->olist.prev;

 		/* we knew that this one is signaled,
 		   so it's save to remote it */
 		radeon_sa_bo_remove_locked(best_bo);
 		return true;
 	}
 	return false;
 }

 int radeon_sa_bo_new(struct radeon_device *rdev,
 		     struct radeon_sa_manager *sa_manager,
 		     struct radeon_sa_bo **sa_bo,
 		     unsigned size, unsigned align, bool block)
 {
 	struct radeon_fence *fences[RADEON_NUM_RINGS];
 	unsigned tries[RADEON_NUM_RINGS];
 	int i, r;

 	BUG_ON(align > RADEON_GPU_PAGE_SIZE);
 	BUG_ON(size > sa_manager->size);

 	*sa_bo = kmalloc(sizeof(struct radeon_sa_bo), GFP_KERNEL);
 	if ((*sa_bo) == NULL) {
 		return -ENOMEM;
 	}
 	(*sa_bo)->manager = sa_manager;
 	(*sa_bo)->fence = NULL;
 	INIT_LIST_HEAD(&(*sa_bo)->olist);
 	INIT_LIST_HEAD(&(*sa_bo)->flist);

 	spin_lock(&sa_manager->wq.lock);
 	do {
 		for (i = 0; i < RADEON_NUM_RINGS; ++i) {
 			fences[i] = NULL;
 			tries[i] = 0;
 		}

 		do {
 			radeon_sa_bo_try_free(sa_manager);

 			if (radeon_sa_bo_try_alloc(sa_manager, *sa_bo,
 						   size, align)) {
 				spin_unlock(&sa_manager->wq.lock);
 				return 0;
 			}

 			/* see if we can skip over some allocations */
 		} while (radeon_sa_bo_next_hole(sa_manager, fences, tries));

 		spin_unlock(&sa_manager->wq.lock);
 		r = radeon_fence_wait_any(rdev, fences, false);
 		spin_lock(&sa_manager->wq.lock);
 		/* if we have nothing to wait for block */
 		if (r == -ENOENT && block) {
 			r = wait_event_interruptible_locked(
 				sa_manager->wq,
 				radeon_sa_event(sa_manager, size, align)
 			);

 		} else if (r == -ENOENT) {
 			r = -ENOMEM;
 		}

 	} while (!r);

 	spin_unlock(&sa_manager->wq.lock);
 	kfree(*sa_bo);
 	*sa_bo = NULL;
 	return r;
 }

 void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo **sa_bo,
 		       struct radeon_fence *fence)
 {
 	struct radeon_sa_manager *sa_manager;

 	if (sa_bo == NULL || *sa_bo == NULL) {
 		return;
 	}

 	sa_manager = (*sa_bo)->manager;
 	spin_lock(&sa_manager->wq.lock);
 	if (fence && !radeon_fence_signaled(fence)) {
 		(*sa_bo)->fence = radeon_fence_ref(fence);
 		list_add_tail(&(*sa_bo)->flist,
 			      &sa_manager->flist[fence->ring]);
 	} else {
 		radeon_sa_bo_remove_locked(*sa_bo);
 	}
 	wake_up_all_locked(&sa_manager->wq);
 	spin_unlock(&sa_manager->wq.lock);
 	*sa_bo = NULL;
 }

 #if defined(CONFIG_DEBUG_FS)
 void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
 				  struct seq_file *m)
 {
 	struct radeon_sa_bo *i;

 	spin_lock(&sa_manager->wq.lock);
 	list_for_each_entry(i, &sa_manager->olist, olist) {
 		if (&i->olist == sa_manager->hole) {
 			seq_printf(m, ">");
 		} else {
 			seq_printf(m, " ");
 		}
 		seq_printf(m, "[0x%08x 0x%08x] size %8d",
 			   i->soffset, i->eoffset, i->eoffset - i->soffset);
 		if (i->fence) {
 			seq_printf(m, " protected by 0x%016llx on ring %d",
 				   i->fence->seq, i->fence->ring);
 		}
 		seq_printf(m, "\n");
 	}
 	spin_unlock(&sa_manager->wq.lock);
 }
 #endif
	/*
	* Copyright 2011 Red Hat Inc.
	* 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 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.
	*
	* The above copyright notice and this permission notice (including the
	* next paragraph) shall be included in all copies or substantial portions
	* of the Software.
	*
	*/
	/*
	* Authors:
	* Jerome Glisse <glisse@freedesktop.org>
	*/
	/* Algorithm:
	*
	* We store the last allocated bo in "hole", we always try to allocate
	* after the last allocated bo. Principle is that in a linear GPU ring
	* progression was is after last is the oldest bo we allocated and thus
	* the first one that should no longer be in use by the GPU.
	*
	* If it's not the case we skip over the bo after last to the closest
	* done bo if such one exist. If none exist and we are not asked to
	* block we report failure to allocate.
	*
	* If we are asked to block we wait on all the oldest fence of all
	* rings. We just wait for any of those fence to complete.
	*/
	#include <drm/drmP.h>
	#include "radeon.h"

	static void radeon_sa_bo_remove_locked(struct radeon_sa_bo *sa_bo);
	static void radeon_sa_bo_try_free(struct radeon_sa_manager *sa_manager);

	int radeon_sa_bo_manager_init(struct radeon_device *rdev,
	struct radeon_sa_manager *sa_manager,
	unsigned size, u32 domain)
	{
	int i, r;

	init_waitqueue_head(&sa_manager->wq);
	sa_manager->bo = NULL;
	sa_manager->size = size;
	sa_manager->domain = domain;
	sa_manager->hole = &sa_manager->olist;
	INIT_LIST_HEAD(&sa_manager->olist);
	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
	INIT_LIST_HEAD(&sa_manager->flist[i]);
	}

	r = radeon_bo_create(rdev, size, RADEON_GPU_PAGE_SIZE, true,
	RADEON_GEM_DOMAIN_CPU, NULL, &sa_manager->bo);
	if (r) {
	dev_err(rdev->dev, "(%d) failed to allocate bo for manager\n", r);
	return r;
	}

	return r;
	}

	void radeon_sa_bo_manager_fini(struct radeon_device *rdev,
	struct radeon_sa_manager *sa_manager)
	{
	struct radeon_sa_bo sa_bo, tmp;

	if (!list_empty(&sa_manager->olist)) {
	sa_manager->hole = &sa_manager->olist,
	radeon_sa_bo_try_free(sa_manager);
	if (!list_empty(&sa_manager->olist)) {
	dev_err(rdev->dev, "sa_manager is not empty, clearing anyway\n");
	}
	}
	list_for_each_entry_safe(sa_bo, tmp, &sa_manager->olist, olist) {
	radeon_sa_bo_remove_locked(sa_bo);
	}
	radeon_bo_unref(&sa_manager->bo);
	sa_manager->size = 0;
	}

	int radeon_sa_bo_manager_start(struct radeon_device *rdev,
	struct radeon_sa_manager *sa_manager)
	{
	int r;

	if (sa_manager->bo == NULL) {
	dev_err(rdev->dev, "no bo for sa manager\n");
	return -EINVAL;
	}

	/* map the buffer */
	r = radeon_bo_reserve(sa_manager->bo, false);
	if (r) {
	dev_err(rdev->dev, "(%d) failed to reserve manager bo\n", r);
	return r;
	}
	r = radeon_bo_pin(sa_manager->bo, sa_manager->domain, &sa_manager->gpu_addr);
	if (r) {
	radeon_bo_unreserve(sa_manager->bo);
	dev_err(rdev->dev, "(%d) failed to pin manager bo\n", r);
	return r;
	}
	r = radeon_bo_kmap(sa_manager->bo, &sa_manager->cpu_ptr);
	radeon_bo_unreserve(sa_manager->bo);
	return r;
	}

	int radeon_sa_bo_manager_suspend(struct radeon_device *rdev,
	struct radeon_sa_manager *sa_manager)
	{
	int r;

	if (sa_manager->bo == NULL) {
	dev_err(rdev->dev, "no bo for sa manager\n");
	return -EINVAL;
	}

	r = radeon_bo_reserve(sa_manager->bo, false);
	if (!r) {
	radeon_bo_kunmap(sa_manager->bo);
	radeon_bo_unpin(sa_manager->bo);
	radeon_bo_unreserve(sa_manager->bo);
	}
	return r;
	}

	static void radeon_sa_bo_remove_locked(struct radeon_sa_bo *sa_bo)
	{
	struct radeon_sa_manager *sa_manager = sa_bo->manager;
	if (sa_manager->hole == &sa_bo->olist) {
	sa_manager->hole = sa_bo->olist.prev;
	}
	list_del_init(&sa_bo->olist);
	list_del_init(&sa_bo->flist);
	radeon_fence_unref(&sa_bo->fence);
	kfree(sa_bo);
	}

	static void radeon_sa_bo_try_free(struct radeon_sa_manager *sa_manager)
	{
	struct radeon_sa_bo sa_bo, tmp;

	if (sa_manager->hole->next == &sa_manager->olist)
	return;

	sa_bo = list_entry(sa_manager->hole->next, struct radeon_sa_bo, olist);
	list_for_each_entry_safe_from(sa_bo, tmp, &sa_manager->olist, olist) {
	if (sa_bo->fence == NULL \|\| !radeon_fence_signaled(sa_bo->fence)) {
	return;
	}
	radeon_sa_bo_remove_locked(sa_bo);
	}
	}

	static inline unsigned radeon_sa_bo_hole_soffset(struct radeon_sa_manager *sa_manager)
	{
	struct list_head *hole = sa_manager->hole;

	if (hole != &sa_manager->olist) {
	return list_entry(hole, struct radeon_sa_bo, olist)->eoffset;
	}
	return 0;
	}

	static inline unsigned radeon_sa_bo_hole_eoffset(struct radeon_sa_manager *sa_manager)
	{
	struct list_head *hole = sa_manager->hole;

	if (hole->next != &sa_manager->olist) {
	return list_entry(hole->next, struct radeon_sa_bo, olist)->soffset;
	}
	return sa_manager->size;
	}

	static bool radeon_sa_bo_try_alloc(struct radeon_sa_manager *sa_manager,
	struct radeon_sa_bo *sa_bo,
	unsigned size, unsigned align)
	{
	unsigned soffset, eoffset, wasted;

	soffset = radeon_sa_bo_hole_soffset(sa_manager);
	eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
	wasted = (align - (soffset % align)) % align;

	if ((eoffset - soffset) >= (size + wasted)) {
	soffset += wasted;

	sa_bo->manager = sa_manager;
	sa_bo->soffset = soffset;
	sa_bo->eoffset = soffset + size;
	list_add(&sa_bo->olist, sa_manager->hole);
	INIT_LIST_HEAD(&sa_bo->flist);
	sa_manager->hole = &sa_bo->olist;
	return true;
	}
	return false;
	}

	/**
	* radeon_sa_event - Check if we can stop waiting
	*
	* @sa_manager: pointer to the sa_manager
	* @size: number of bytes we want to allocate
	* @align: alignment we need to match
	*
	* Check if either there is a fence we can wait for or
	* enough free memory to satisfy the allocation directly
	*/
	static bool radeon_sa_event(struct radeon_sa_manager *sa_manager,
	unsigned size, unsigned align)
	{
	unsigned soffset, eoffset, wasted;
	int i;

	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
	if (!list_empty(&sa_manager->flist[i])) {
	return true;
	}
	}

	soffset = radeon_sa_bo_hole_soffset(sa_manager);
	eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
	wasted = (align - (soffset % align)) % align;

	if ((eoffset - soffset) >= (size + wasted)) {
	return true;
	}

	return false;
	}

	static bool radeon_sa_bo_next_hole(struct radeon_sa_manager *sa_manager,
	struct radeon_fence **fences,
	unsigned *tries)
	{
	struct radeon_sa_bo *best_bo = NULL;
	unsigned i, soffset, best, tmp;

	/* if hole points to the end of the buffer */
	if (sa_manager->hole->next == &sa_manager->olist) {
	/* try again with its beginning */
	sa_manager->hole = &sa_manager->olist;
	return true;
	}

	soffset = radeon_sa_bo_hole_soffset(sa_manager);
	/* to handle wrap around we add sa_manager->size */
	best = sa_manager->size * 2;
	/* go over all fence list and try to find the closest sa_bo
	* of the current last
	*/
	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
	struct radeon_sa_bo *sa_bo;

	if (list_empty(&sa_manager->flist[i])) {
	continue;
	}

	sa_bo = list_first_entry(&sa_manager->flist[i],
	struct radeon_sa_bo, flist);

	if (!radeon_fence_signaled(sa_bo->fence)) {
	fences[i] = sa_bo->fence;
	continue;
	}

	/* limit the number of tries each ring gets */
	if (tries[i] > 2) {
	continue;
	}

	tmp = sa_bo->soffset;
	if (tmp < soffset) {
	/* wrap around, pretend it's after */
	tmp += sa_manager->size;
	}
	tmp -= soffset;
	if (tmp < best) {
	/* this sa bo is the closest one */
	best = tmp;
	best_bo = sa_bo;
	}
	}

	if (best_bo) {
	++tries[best_bo->fence->ring];
	sa_manager->hole = best_bo->olist.prev;

	/* we knew that this one is signaled,
	so it's save to remote it */
	radeon_sa_bo_remove_locked(best_bo);
	return true;
	}
	return false;
	}

	int radeon_sa_bo_new(struct radeon_device *rdev,
	struct radeon_sa_manager *sa_manager,
	struct radeon_sa_bo **sa_bo,
	unsigned size, unsigned align, bool block)
	{
	struct radeon_fence *fences[RADEON_NUM_RINGS];
	unsigned tries[RADEON_NUM_RINGS];
	int i, r;

	BUG_ON(align > RADEON_GPU_PAGE_SIZE);
	BUG_ON(size > sa_manager->size);

	*sa_bo = kmalloc(sizeof(struct radeon_sa_bo), GFP_KERNEL);
	if ((*sa_bo) == NULL) {
	return -ENOMEM;
	}
	(*sa_bo)->manager = sa_manager;
	(*sa_bo)->fence = NULL;
	INIT_LIST_HEAD(&(*sa_bo)->olist);
	INIT_LIST_HEAD(&(*sa_bo)->flist);

	spin_lock(&sa_manager->wq.lock);
	do {
	for (i = 0; i < RADEON_NUM_RINGS; ++i) {
	fences[i] = NULL;
	tries[i] = 0;
	}

	do {
	radeon_sa_bo_try_free(sa_manager);

	if (radeon_sa_bo_try_alloc(sa_manager, *sa_bo,
	size, align)) {
	spin_unlock(&sa_manager->wq.lock);
	return 0;
	}

	/* see if we can skip over some allocations */
	} while (radeon_sa_bo_next_hole(sa_manager, fences, tries));

	spin_unlock(&sa_manager->wq.lock);
	r = radeon_fence_wait_any(rdev, fences, false);
	spin_lock(&sa_manager->wq.lock);
	/* if we have nothing to wait for block */
	if (r == -ENOENT && block) {
	r = wait_event_interruptible_locked(
	sa_manager->wq,
	radeon_sa_event(sa_manager, size, align)
	);

	} else if (r == -ENOENT) {
	r = -ENOMEM;
	}

	} while (!r);

	spin_unlock(&sa_manager->wq.lock);
	kfree(*sa_bo);
	*sa_bo = NULL;
	return r;
	}

	void radeon_sa_bo_free(struct radeon_device rdev, struct radeon_sa_bo *sa_bo,
	struct radeon_fence *fence)
	{
	struct radeon_sa_manager *sa_manager;

	if (sa_bo == NULL \|\| *sa_bo == NULL) {
	return;
	}

	sa_manager = (*sa_bo)->manager;
	spin_lock(&sa_manager->wq.lock);
	if (fence && !radeon_fence_signaled(fence)) {
	(*sa_bo)->fence = radeon_fence_ref(fence);
	list_add_tail(&(*sa_bo)->flist,
	&sa_manager->flist[fence->ring]);
	} else {
	radeon_sa_bo_remove_locked(*sa_bo);
	}
	wake_up_all_locked(&sa_manager->wq);
	spin_unlock(&sa_manager->wq.lock);
	*sa_bo = NULL;
	}

	#if defined(CONFIG_DEBUG_FS)
	void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
	struct seq_file *m)
	{
	struct radeon_sa_bo *i;

	spin_lock(&sa_manager->wq.lock);
	list_for_each_entry(i, &sa_manager->olist, olist) {
	if (&i->olist == sa_manager->hole) {
	seq_printf(m, ">");
	} else {
	seq_printf(m, " ");
	}
	seq_printf(m, "[0x%08x 0x%08x] size %8d",
	i->soffset, i->eoffset, i->eoffset - i->soffset);
	if (i->fence) {
	seq_printf(m, " protected by 0x%016llx on ring %d",
	i->fence->seq, i->fence->ring);
	}
	seq_printf(m, "\n");
	}
	spin_unlock(&sa_manager->wq.lock);
	}
	#endif