drivers/gpu/drm/ttm/ttm_tt.c - third_party/kernel - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
 /**************************************************************************
  *
  * 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>
  */

 #define pr_fmt(fmt) "[TTM] " fmt

 #include <linux/cc_platform.h>
 #include <linux/sched.h>
 #include <linux/shmem_fs.h>
 #include <linux/file.h>
 #include <linux/module.h>
 #include <drm/drm_cache.h>
 #include <drm/drm_device.h>
 #include <drm/drm_util.h>
 #include <drm/ttm/ttm_bo.h>
 #include <drm/ttm/ttm_tt.h>

 #include "ttm_module.h"

 static unsigned long ttm_pages_limit;

 MODULE_PARM_DESC(pages_limit, "Limit for the allocated pages");
 module_param_named(pages_limit, ttm_pages_limit, ulong, 0644);

 static unsigned long ttm_dma32_pages_limit;

 MODULE_PARM_DESC(dma32_pages_limit, "Limit for the allocated DMA32 pages");
 module_param_named(dma32_pages_limit, ttm_dma32_pages_limit, ulong, 0644);

 static atomic_long_t ttm_pages_allocated;
 static atomic_long_t ttm_dma32_pages_allocated;

 /*
  * Allocates a ttm structure for the given BO.
  */
 int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc)
 {
 	struct ttm_device *bdev = bo->bdev;
 	struct drm_device *ddev = bo->base.dev;
 	uint32_t page_flags = 0;

 	dma_resv_assert_held(bo->base.resv);

 	if (bo->ttm)
 		return 0;

 	switch (bo->type) {
 	case ttm_bo_type_device:
 		if (zero_alloc)
 			page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
 		break;
 	case ttm_bo_type_kernel:
 		break;
 	case ttm_bo_type_sg:
 		page_flags |= TTM_TT_FLAG_EXTERNAL;
 		break;
 	default:
 		pr_err("Illegal buffer object type\n");
 		return -EINVAL;
 	}
 	/*
 	 * When using dma_alloc_coherent with memory encryption the
 	 * mapped TT pages need to be decrypted or otherwise the drivers
 	 * will end up sending encrypted mem to the gpu.
 	 */
 	if (bdev->pool.use_dma_alloc && cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
 		page_flags |= TTM_TT_FLAG_DECRYPTED;
 		drm_info_once(ddev, "TT memory decryption enabled.");
 	}

 	bo->ttm = bdev->funcs->ttm_tt_create(bo, page_flags);
 	if (unlikely(bo->ttm == NULL))
 		return -ENOMEM;

 	WARN_ON(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE &&
 		!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL));

 	return 0;
 }

 /*
  * Allocates storage for pointers to the pages that back the ttm.
  */
 static int ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
 	ttm->pages = kvcalloc(ttm->num_pages, sizeof(void*), GFP_KERNEL);
 	if (!ttm->pages)
 		return -ENOMEM;

 	return 0;
 }

 static int ttm_dma_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
 	ttm->pages = kvcalloc(ttm->num_pages, sizeof(*ttm->pages) +
 			      sizeof(*ttm->dma_address), GFP_KERNEL);
 	if (!ttm->pages)
 		return -ENOMEM;

 	ttm->dma_address = (void *)(ttm->pages + ttm->num_pages);
 	return 0;
 }

 static int ttm_sg_tt_alloc_page_directory(struct ttm_tt *ttm)
 {
 	ttm->dma_address = kvcalloc(ttm->num_pages, sizeof(*ttm->dma_address),
 				    GFP_KERNEL);
 	if (!ttm->dma_address)
 		return -ENOMEM;

 	return 0;
 }

 void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
 {
 	bdev->funcs->ttm_tt_destroy(bdev, ttm);
 }

 static void ttm_tt_init_fields(struct ttm_tt *ttm,
 			       struct ttm_buffer_object *bo,
 			       uint32_t page_flags,
 			       enum ttm_caching caching,
 			       unsigned long extra_pages)
 {
 	ttm->num_pages = (PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT) + extra_pages;
 	ttm->page_flags = page_flags;
 	ttm->dma_address = NULL;
 	ttm->swap_storage = NULL;
 	ttm->sg = bo->sg;
 	ttm->caching = caching;
 }

 int ttm_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
 		uint32_t page_flags, enum ttm_caching caching,
 		unsigned long extra_pages)
 {
 	ttm_tt_init_fields(ttm, bo, page_flags, caching, extra_pages);

 	if (ttm_tt_alloc_page_directory(ttm)) {
 		pr_err("Failed allocating page table\n");
 		return -ENOMEM;
 	}
 	return 0;
 }
 EXPORT_SYMBOL(ttm_tt_init);

 void ttm_tt_fini(struct ttm_tt *ttm)
 {
 	WARN_ON(ttm->page_flags & TTM_TT_FLAG_PRIV_POPULATED);

 	if (ttm->swap_storage)
 		fput(ttm->swap_storage);
 	ttm->swap_storage = NULL;

 	if (ttm->pages)
 		kvfree(ttm->pages);
 	else
 		kvfree(ttm->dma_address);
 	ttm->pages = NULL;
 	ttm->dma_address = NULL;
 }
 EXPORT_SYMBOL(ttm_tt_fini);

 int ttm_sg_tt_init(struct ttm_tt *ttm, struct ttm_buffer_object *bo,
 		   uint32_t page_flags, enum ttm_caching caching)
 {
 	int ret;

 	ttm_tt_init_fields(ttm, bo, page_flags, caching, 0);

 	if (page_flags & TTM_TT_FLAG_EXTERNAL)
 		ret = ttm_sg_tt_alloc_page_directory(ttm);
 	else
 		ret = ttm_dma_tt_alloc_page_directory(ttm);
 	if (ret) {
 		pr_err("Failed allocating page table\n");
 		return -ENOMEM;
 	}
 	return 0;
 }
 EXPORT_SYMBOL(ttm_sg_tt_init);

 int ttm_tt_swapin(struct ttm_tt *ttm)
 {
 	struct address_space *swap_space;
 	struct file *swap_storage;
 	struct page *from_page;
 	struct page *to_page;
 	gfp_t gfp_mask;
 	int i, ret;

 	swap_storage = ttm->swap_storage;
 	BUG_ON(swap_storage == NULL);

 	swap_space = swap_storage->f_mapping;
 	gfp_mask = mapping_gfp_mask(swap_space);

 	for (i = 0; i < ttm->num_pages; ++i) {
 		from_page = shmem_read_mapping_page_gfp(swap_space, i,
 							gfp_mask);
 		if (IS_ERR(from_page)) {
 			ret = PTR_ERR(from_page);
 			goto out_err;
 		}
 		to_page = ttm->pages[i];
 		if (unlikely(to_page == NULL)) {
 			ret = -ENOMEM;
 			goto out_err;
 		}

 		copy_highpage(to_page, from_page);
 		put_page(from_page);
 	}

 	fput(swap_storage);
 	ttm->swap_storage = NULL;
 	ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;

 	return 0;

 out_err:
 	return ret;
 }

 /**
  * ttm_tt_swapout - swap out tt object
  *
  * @bdev: TTM device structure.
  * @ttm: The struct ttm_tt.
  * @gfp_flags: Flags to use for memory allocation.
  *
  * Swapout a TT object to a shmem_file, return number of pages swapped out or
  * negative error code.
  */
 int ttm_tt_swapout(struct ttm_device *bdev, struct ttm_tt *ttm,
 		   gfp_t gfp_flags)
 {
 	loff_t size = (loff_t)ttm->num_pages << PAGE_SHIFT;
 	struct address_space *swap_space;
 	struct file *swap_storage;
 	struct page *from_page;
 	struct page *to_page;
 	int i, ret;

 	swap_storage = shmem_file_setup("ttm swap", size, 0);
 	if (IS_ERR(swap_storage)) {
 		pr_err("Failed allocating swap storage\n");
 		return PTR_ERR(swap_storage);
 	}

 	swap_space = swap_storage->f_mapping;
 	gfp_flags &= mapping_gfp_mask(swap_space);

 	for (i = 0; i < ttm->num_pages; ++i) {
 		from_page = ttm->pages[i];
 		if (unlikely(from_page == NULL))
 			continue;

 		to_page = shmem_read_mapping_page_gfp(swap_space, i, gfp_flags);
 		if (IS_ERR(to_page)) {
 			ret = PTR_ERR(to_page);
 			goto out_err;
 		}
 		copy_highpage(to_page, from_page);
 		set_page_dirty(to_page);
 		mark_page_accessed(to_page);
 		put_page(to_page);
 	}

 	ttm_tt_unpopulate(bdev, ttm);
 	ttm->swap_storage = swap_storage;
 	ttm->page_flags |= TTM_TT_FLAG_SWAPPED;

 	return ttm->num_pages;

 out_err:
 	fput(swap_storage);

 	return ret;
 }

 int ttm_tt_populate(struct ttm_device *bdev,
 		    struct ttm_tt *ttm, struct ttm_operation_ctx *ctx)
 {
 	int ret;

 	if (!ttm)
 		return -EINVAL;

 	if (ttm_tt_is_populated(ttm))
 		return 0;

 	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
 		atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
 		if (bdev->pool.use_dma32)
 			atomic_long_add(ttm->num_pages,
 					&ttm_dma32_pages_allocated);
 	}

 	while (atomic_long_read(&ttm_pages_allocated) > ttm_pages_limit ||
 	       atomic_long_read(&ttm_dma32_pages_allocated) >
 	       ttm_dma32_pages_limit) {

 		ret = ttm_global_swapout(ctx, GFP_KERNEL);
 		if (ret == 0)
 			break;
 		if (ret < 0)
 			goto error;
 	}

 	if (bdev->funcs->ttm_tt_populate)
 		ret = bdev->funcs->ttm_tt_populate(bdev, ttm, ctx);
 	else
 		ret = ttm_pool_alloc(&bdev->pool, ttm, ctx);
 	if (ret)
 		goto error;

 	ttm->page_flags |= TTM_TT_FLAG_PRIV_POPULATED;
 	if (unlikely(ttm->page_flags & TTM_TT_FLAG_SWAPPED)) {
 		ret = ttm_tt_swapin(ttm);
 		if (unlikely(ret != 0)) {
 			ttm_tt_unpopulate(bdev, ttm);
 			return ret;
 		}
 	}

 	return 0;

 error:
 	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
 		atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
 		if (bdev->pool.use_dma32)
 			atomic_long_sub(ttm->num_pages,
 					&ttm_dma32_pages_allocated);
 	}
 	return ret;
 }
 EXPORT_SYMBOL(ttm_tt_populate);

 void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
 {
 	if (!ttm_tt_is_populated(ttm))
 		return;

 	if (bdev->funcs->ttm_tt_unpopulate)
 		bdev->funcs->ttm_tt_unpopulate(bdev, ttm);
 	else
 		ttm_pool_free(&bdev->pool, ttm);

 	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
 		atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
 		if (bdev->pool.use_dma32)
 			atomic_long_sub(ttm->num_pages,
 					&ttm_dma32_pages_allocated);
 	}

 	ttm->page_flags &= ~TTM_TT_FLAG_PRIV_POPULATED;
 }

 #ifdef CONFIG_DEBUG_FS

 /* Test the shrinker functions and dump the result */
 static int ttm_tt_debugfs_shrink_show(struct seq_file *m, void *data)
 {
 	struct ttm_operation_ctx ctx = { false, false };

 	seq_printf(m, "%d\n", ttm_global_swapout(&ctx, GFP_KERNEL));
 	return 0;
 }
 DEFINE_SHOW_ATTRIBUTE(ttm_tt_debugfs_shrink);

 #endif


 /*
  * ttm_tt_mgr_init - register with the MM shrinker
  *
  * Register with the MM shrinker for swapping out BOs.
  */
 void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages)
 {
 #ifdef CONFIG_DEBUG_FS
 	debugfs_create_file("tt_shrink", 0400, ttm_debugfs_root, NULL,
 			    &ttm_tt_debugfs_shrink_fops);
 #endif

 	if (!ttm_pages_limit)
 		ttm_pages_limit = num_pages;

 	if (!ttm_dma32_pages_limit)
 		ttm_dma32_pages_limit = num_dma32_pages;
 }

 static void ttm_kmap_iter_tt_map_local(struct ttm_kmap_iter *iter,
 				       struct iosys_map *dmap,
 				       pgoff_t i)
 {
 	struct ttm_kmap_iter_tt *iter_tt =
 		container_of(iter, typeof(*iter_tt), base);

 	iosys_map_set_vaddr(dmap, kmap_local_page_prot(iter_tt->tt->pages[i],
 						       iter_tt->prot));
 }

 static void ttm_kmap_iter_tt_unmap_local(struct ttm_kmap_iter *iter,
 					 struct iosys_map *map)
 {
 	kunmap_local(map->vaddr);
 }

 static const struct ttm_kmap_iter_ops ttm_kmap_iter_tt_ops = {
 	.map_local = ttm_kmap_iter_tt_map_local,
 	.unmap_local = ttm_kmap_iter_tt_unmap_local,
 	.maps_tt = true,
 };

 /**
  * ttm_kmap_iter_tt_init - Initialize a struct ttm_kmap_iter_tt
  * @iter_tt: The struct ttm_kmap_iter_tt to initialize.
  * @tt: Struct ttm_tt holding page pointers of the struct ttm_resource.
  *
  * Return: Pointer to the embedded struct ttm_kmap_iter.
  */
 struct ttm_kmap_iter *
 ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
 		      struct ttm_tt *tt)
 {
 	iter_tt->base.ops = &ttm_kmap_iter_tt_ops;
 	iter_tt->tt = tt;
 	if (tt)
 		iter_tt->prot = ttm_prot_from_caching(tt->caching, PAGE_KERNEL);
 	else
 		iter_tt->prot = PAGE_KERNEL;

 	return &iter_tt->base;
 }
 EXPORT_SYMBOL(ttm_kmap_iter_tt_init);

 unsigned long ttm_tt_pages_limit(void)
 {
 	return ttm_pages_limit;
 }
 EXPORT_SYMBOL(ttm_tt_pages_limit);
	/* SPDX-License-Identifier: GPL-2.0 OR MIT */
	/**************************************************************************
	*
	* 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>
	*/

	#define pr_fmt(fmt) "[TTM] " fmt

	#include <linux/cc_platform.h>
	#include <linux/sched.h>
	#include <linux/shmem_fs.h>
	#include <linux/file.h>
	#include <linux/module.h>
	#include <drm/drm_cache.h>
	#include <drm/drm_device.h>
	#include <drm/drm_util.h>
	#include <drm/ttm/ttm_bo.h>
	#include <drm/ttm/ttm_tt.h>

	#include "ttm_module.h"

	static unsigned long ttm_pages_limit;

	MODULE_PARM_DESC(pages_limit, "Limit for the allocated pages");
	module_param_named(pages_limit, ttm_pages_limit, ulong, 0644);

	static unsigned long ttm_dma32_pages_limit;

	MODULE_PARM_DESC(dma32_pages_limit, "Limit for the allocated DMA32 pages");
	module_param_named(dma32_pages_limit, ttm_dma32_pages_limit, ulong, 0644);

	static atomic_long_t ttm_pages_allocated;
	static atomic_long_t ttm_dma32_pages_allocated;

	/*
	* Allocates a ttm structure for the given BO.
	*/
	int ttm_tt_create(struct ttm_buffer_object *bo, bool zero_alloc)
	{
	struct ttm_device *bdev = bo->bdev;
	struct drm_device *ddev = bo->base.dev;
	uint32_t page_flags = 0;

	dma_resv_assert_held(bo->base.resv);

	if (bo->ttm)
	return 0;

	switch (bo->type) {
	case ttm_bo_type_device:
	if (zero_alloc)
	page_flags \|= TTM_TT_FLAG_ZERO_ALLOC;
	break;
	case ttm_bo_type_kernel:
	break;
	case ttm_bo_type_sg:
	page_flags \|= TTM_TT_FLAG_EXTERNAL;
	break;
	default:
	pr_err("Illegal buffer object type\n");
	return -EINVAL;
	}
	/*
	* When using dma_alloc_coherent with memory encryption the
	* mapped TT pages need to be decrypted or otherwise the drivers
	* will end up sending encrypted mem to the gpu.
	*/
	if (bdev->pool.use_dma_alloc && cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
	page_flags \|= TTM_TT_FLAG_DECRYPTED;
	drm_info_once(ddev, "TT memory decryption enabled.");
	}

	bo->ttm = bdev->funcs->ttm_tt_create(bo, page_flags);
	if (unlikely(bo->ttm == NULL))
	return -ENOMEM;

	WARN_ON(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL_MAPPABLE &&
	!(bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL));

	return 0;
	}

	/*
	* Allocates storage for pointers to the pages that back the ttm.
	*/
	static int ttm_tt_alloc_page_directory(struct ttm_tt *ttm)
	{
	ttm->pages = kvcalloc(ttm->num_pages, sizeof(void*), GFP_KERNEL);
	if (!ttm->pages)
	return -ENOMEM;

	return 0;
	}

	static int ttm_dma_tt_alloc_page_directory(struct ttm_tt *ttm)
	{
	ttm->pages = kvcalloc(ttm->num_pages, sizeof(*ttm->pages) +
	sizeof(*ttm->dma_address), GFP_KERNEL);
	if (!ttm->pages)
	return -ENOMEM;

	ttm->dma_address = (void *)(ttm->pages + ttm->num_pages);
	return 0;
	}

	static int ttm_sg_tt_alloc_page_directory(struct ttm_tt *ttm)
	{
	ttm->dma_address = kvcalloc(ttm->num_pages, sizeof(*ttm->dma_address),
	GFP_KERNEL);
	if (!ttm->dma_address)
	return -ENOMEM;

	return 0;
	}

	void ttm_tt_destroy(struct ttm_device bdev, struct ttm_tt ttm)
	{
	bdev->funcs->ttm_tt_destroy(bdev, ttm);
	}

	static void ttm_tt_init_fields(struct ttm_tt *ttm,
	struct ttm_buffer_object *bo,
	uint32_t page_flags,
	enum ttm_caching caching,
	unsigned long extra_pages)
	{
	ttm->num_pages = (PAGE_ALIGN(bo->base.size) >> PAGE_SHIFT) + extra_pages;
	ttm->page_flags = page_flags;
	ttm->dma_address = NULL;
	ttm->swap_storage = NULL;
	ttm->sg = bo->sg;
	ttm->caching = caching;
	}

	int ttm_tt_init(struct ttm_tt ttm, struct ttm_buffer_object bo,
	uint32_t page_flags, enum ttm_caching caching,
	unsigned long extra_pages)
	{
	ttm_tt_init_fields(ttm, bo, page_flags, caching, extra_pages);

	if (ttm_tt_alloc_page_directory(ttm)) {
	pr_err("Failed allocating page table\n");
	return -ENOMEM;
	}
	return 0;
	}
	EXPORT_SYMBOL(ttm_tt_init);

	void ttm_tt_fini(struct ttm_tt *ttm)
	{
	WARN_ON(ttm->page_flags & TTM_TT_FLAG_PRIV_POPULATED);

	if (ttm->swap_storage)
	fput(ttm->swap_storage);
	ttm->swap_storage = NULL;

	if (ttm->pages)
	kvfree(ttm->pages);
	else
	kvfree(ttm->dma_address);
	ttm->pages = NULL;
	ttm->dma_address = NULL;
	}
	EXPORT_SYMBOL(ttm_tt_fini);

	int ttm_sg_tt_init(struct ttm_tt ttm, struct ttm_buffer_object bo,
	uint32_t page_flags, enum ttm_caching caching)
	{
	int ret;

	ttm_tt_init_fields(ttm, bo, page_flags, caching, 0);

	if (page_flags & TTM_TT_FLAG_EXTERNAL)
	ret = ttm_sg_tt_alloc_page_directory(ttm);
	else
	ret = ttm_dma_tt_alloc_page_directory(ttm);
	if (ret) {
	pr_err("Failed allocating page table\n");
	return -ENOMEM;
	}
	return 0;
	}
	EXPORT_SYMBOL(ttm_sg_tt_init);

	int ttm_tt_swapin(struct ttm_tt *ttm)
	{
	struct address_space *swap_space;
	struct file *swap_storage;
	struct page *from_page;
	struct page *to_page;
	gfp_t gfp_mask;
	int i, ret;

	swap_storage = ttm->swap_storage;
	BUG_ON(swap_storage == NULL);

	swap_space = swap_storage->f_mapping;
	gfp_mask = mapping_gfp_mask(swap_space);

	for (i = 0; i < ttm->num_pages; ++i) {
	from_page = shmem_read_mapping_page_gfp(swap_space, i,
	gfp_mask);
	if (IS_ERR(from_page)) {
	ret = PTR_ERR(from_page);
	goto out_err;
	}
	to_page = ttm->pages[i];
	if (unlikely(to_page == NULL)) {
	ret = -ENOMEM;
	goto out_err;
	}

	copy_highpage(to_page, from_page);
	put_page(from_page);
	}

	fput(swap_storage);
	ttm->swap_storage = NULL;
	ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;

	return 0;

	out_err:
	return ret;
	}

	/**
	* ttm_tt_swapout - swap out tt object
	*
	* @bdev: TTM device structure.
	* @ttm: The struct ttm_tt.
	* @gfp_flags: Flags to use for memory allocation.
	*
	* Swapout a TT object to a shmem_file, return number of pages swapped out or
	* negative error code.
	*/
	int ttm_tt_swapout(struct ttm_device bdev, struct ttm_tt ttm,
	gfp_t gfp_flags)
	{
	loff_t size = (loff_t)ttm->num_pages << PAGE_SHIFT;
	struct address_space *swap_space;
	struct file *swap_storage;
	struct page *from_page;
	struct page *to_page;
	int i, ret;

	swap_storage = shmem_file_setup("ttm swap", size, 0);
	if (IS_ERR(swap_storage)) {
	pr_err("Failed allocating swap storage\n");
	return PTR_ERR(swap_storage);
	}

	swap_space = swap_storage->f_mapping;
	gfp_flags &= mapping_gfp_mask(swap_space);

	for (i = 0; i < ttm->num_pages; ++i) {
	from_page = ttm->pages[i];
	if (unlikely(from_page == NULL))
	continue;

	to_page = shmem_read_mapping_page_gfp(swap_space, i, gfp_flags);
	if (IS_ERR(to_page)) {
	ret = PTR_ERR(to_page);
	goto out_err;
	}
	copy_highpage(to_page, from_page);
	set_page_dirty(to_page);
	mark_page_accessed(to_page);
	put_page(to_page);
	}

	ttm_tt_unpopulate(bdev, ttm);
	ttm->swap_storage = swap_storage;
	ttm->page_flags \|= TTM_TT_FLAG_SWAPPED;

	return ttm->num_pages;

	out_err:
	fput(swap_storage);

	return ret;
	}

	int ttm_tt_populate(struct ttm_device *bdev,
	struct ttm_tt ttm, struct ttm_operation_ctx ctx)
	{
	int ret;

	if (!ttm)
	return -EINVAL;

	if (ttm_tt_is_populated(ttm))
	return 0;

	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
	atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
	if (bdev->pool.use_dma32)
	atomic_long_add(ttm->num_pages,
	&ttm_dma32_pages_allocated);
	}

	while (atomic_long_read(&ttm_pages_allocated) > ttm_pages_limit \|\|
	atomic_long_read(&ttm_dma32_pages_allocated) >
	ttm_dma32_pages_limit) {

	ret = ttm_global_swapout(ctx, GFP_KERNEL);
	if (ret == 0)
	break;
	if (ret < 0)
	goto error;
	}

	if (bdev->funcs->ttm_tt_populate)
	ret = bdev->funcs->ttm_tt_populate(bdev, ttm, ctx);
	else
	ret = ttm_pool_alloc(&bdev->pool, ttm, ctx);
	if (ret)
	goto error;

	ttm->page_flags \|= TTM_TT_FLAG_PRIV_POPULATED;
	if (unlikely(ttm->page_flags & TTM_TT_FLAG_SWAPPED)) {
	ret = ttm_tt_swapin(ttm);
	if (unlikely(ret != 0)) {
	ttm_tt_unpopulate(bdev, ttm);
	return ret;
	}
	}

	return 0;

	error:
	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
	atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
	if (bdev->pool.use_dma32)
	atomic_long_sub(ttm->num_pages,
	&ttm_dma32_pages_allocated);
	}
	return ret;
	}
	EXPORT_SYMBOL(ttm_tt_populate);

	void ttm_tt_unpopulate(struct ttm_device bdev, struct ttm_tt ttm)
	{
	if (!ttm_tt_is_populated(ttm))
	return;

	if (bdev->funcs->ttm_tt_unpopulate)
	bdev->funcs->ttm_tt_unpopulate(bdev, ttm);
	else
	ttm_pool_free(&bdev->pool, ttm);

	if (!(ttm->page_flags & TTM_TT_FLAG_EXTERNAL)) {
	atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
	if (bdev->pool.use_dma32)
	atomic_long_sub(ttm->num_pages,
	&ttm_dma32_pages_allocated);
	}

	ttm->page_flags &= ~TTM_TT_FLAG_PRIV_POPULATED;
	}

	#ifdef CONFIG_DEBUG_FS

	/* Test the shrinker functions and dump the result */
	static int ttm_tt_debugfs_shrink_show(struct seq_file m, void data)
	{
	struct ttm_operation_ctx ctx = { false, false };

	seq_printf(m, "%d\n", ttm_global_swapout(&ctx, GFP_KERNEL));
	return 0;
	}
	DEFINE_SHOW_ATTRIBUTE(ttm_tt_debugfs_shrink);

	#endif


	/*
	* ttm_tt_mgr_init - register with the MM shrinker
	*
	* Register with the MM shrinker for swapping out BOs.
	*/
	void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages)
	{
	#ifdef CONFIG_DEBUG_FS
	debugfs_create_file("tt_shrink", 0400, ttm_debugfs_root, NULL,
	&ttm_tt_debugfs_shrink_fops);
	#endif

	if (!ttm_pages_limit)
	ttm_pages_limit = num_pages;

	if (!ttm_dma32_pages_limit)
	ttm_dma32_pages_limit = num_dma32_pages;
	}

	static void ttm_kmap_iter_tt_map_local(struct ttm_kmap_iter *iter,
	struct iosys_map *dmap,
	pgoff_t i)
	{
	struct ttm_kmap_iter_tt *iter_tt =
	container_of(iter, typeof(*iter_tt), base);

	iosys_map_set_vaddr(dmap, kmap_local_page_prot(iter_tt->tt->pages[i],
	iter_tt->prot));
	}

	static void ttm_kmap_iter_tt_unmap_local(struct ttm_kmap_iter *iter,
	struct iosys_map *map)
	{
	kunmap_local(map->vaddr);
	}

	static const struct ttm_kmap_iter_ops ttm_kmap_iter_tt_ops = {
	.map_local = ttm_kmap_iter_tt_map_local,
	.unmap_local = ttm_kmap_iter_tt_unmap_local,
	.maps_tt = true,
	};

	/**
	* ttm_kmap_iter_tt_init - Initialize a struct ttm_kmap_iter_tt
	* @iter_tt: The struct ttm_kmap_iter_tt to initialize.
	* @tt: Struct ttm_tt holding page pointers of the struct ttm_resource.
	*
	* Return: Pointer to the embedded struct ttm_kmap_iter.
	*/
	struct ttm_kmap_iter *
	ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,
	struct ttm_tt *tt)
	{
	iter_tt->base.ops = &ttm_kmap_iter_tt_ops;
	iter_tt->tt = tt;
	if (tt)
	iter_tt->prot = ttm_prot_from_caching(tt->caching, PAGE_KERNEL);
	else
	iter_tt->prot = PAGE_KERNEL;

	return &iter_tt->base;
	}
	EXPORT_SYMBOL(ttm_kmap_iter_tt_init);

	unsigned long ttm_tt_pages_limit(void)
	{
	return ttm_pages_limit;
	}
	EXPORT_SYMBOL(ttm_tt_pages_limit);