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/*

 * Copyright (c) Red Hat Inc.

 * 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 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.

 *

 * Authors: Dave Airlie 

 *          Jerome Glisse 

 *          Pauli Nieminen 

 */

/* simple list based uncached page pool

 * - Pool collects resently freed pages for reuse

 * - Use page->lru to keep a free list

 * - doesn't track currently in use pages

 */

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

#include 

#include 

//#include 

//#include 

#include 

#include 

#include  /* for seq_printf */

#include 

//#include 

#include 

#include 

#include 

#ifdef TTM_HAS_AGP

#include 

#endif

#define NUM_PAGES_TO_ALLOC		(PAGE_SIZE/sizeof(struct page *))

#define SMALL_ALLOCATION		16

#define FREE_ALL_PAGES			(~0U)

/* times are in msecs */

#define PAGE_FREE_INTERVAL		1000

/**

 * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.

 *

 * @lock: Protects the shared pool from concurrnet access. Must be used with

 * irqsave/irqrestore variants because pool allocator maybe called from

 * delayed work.

 * @fill_lock: Prevent concurrent calls to fill.

 * @list: Pool of free uc/wc pages for fast reuse.

 * @gfp_flags: Flags to pass for alloc_page.

 * @npages: Number of pages in pool.

 */

struct ttm_page_pool {

	spinlock_t		lock;

	bool			fill_lock;

	struct list_head	list;

	gfp_t			gfp_flags;

	unsigned		npages;

	char			*name;

	unsigned long		nfrees;

	unsigned long		nrefills;

};

/**

 * Limits for the pool. They are handled without locks because only place where

 * they may change is in sysfs store. They won't have immediate effect anyway

 * so forcing serialization to access them is pointless.

 */

struct ttm_pool_opts {

	unsigned	alloc_size;

	unsigned	max_size;

	unsigned	small;

};

#define NUM_POOLS 4

/**

 * struct ttm_pool_manager - Holds memory pools for fst allocation

 *

 * Manager is read only object for pool code so it doesn't need locking.

 *

 * @free_interval: minimum number of jiffies between freeing pages from pool.

 * @page_alloc_inited: reference counting for pool allocation.

 * @work: Work that is used to shrink the pool. Work is only run when there is

 * some pages to free.

 * @small_allocation: Limit in number of pages what is small allocation.

 *

 * @pools: All pool objects in use.

 **/

struct ttm_pool_manager {

	struct kobject		kobj;

	struct ttm_pool_opts	options;

	union {

		struct ttm_page_pool	pools[NUM_POOLS];

		struct {

			struct ttm_page_pool	wc_pool;

			struct ttm_page_pool	uc_pool;

			struct ttm_page_pool	wc_pool_dma32;

			struct ttm_page_pool	uc_pool_dma32;

		} ;

	};

};

static struct ttm_pool_manager *_manager;

/**

 * Select the right pool or requested caching state and ttm flags. */

static struct ttm_page_pool *ttm_get_pool(int flags,

		enum ttm_caching_state cstate)

{

	int pool_index;

	if (cstate == tt_cached)

		return NULL;

	if (cstate == tt_wc)

		pool_index = 0x0;

	else

		pool_index = 0x1;

	if (flags & TTM_PAGE_FLAG_DMA32)

		pool_index |= 0x2;

	return &_manager->pools[pool_index];

}

/* set memory back to wb and free the pages. */

static void ttm_pages_put(struct page *pages[], unsigned npages)

{

	unsigned i;

	for (i = 0; i < npages; ++i)

		__free_page(pages[i]);

}

static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,

		unsigned freed_pages)

{

	pool->npages -= freed_pages;

	pool->nfrees += freed_pages;

}

/* Put all pages in pages list to correct pool to wait for reuse */

static void ttm_put_pages(struct page **pages, unsigned npages, int flags,

			  enum ttm_caching_state cstate)

{

	unsigned long irq_flags;

	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);

	unsigned i;

	if (1) {

		/* No pool for this memory type so free the pages */

		for (i = 0; i < npages; i++) {

			if (pages[i]) {

				__free_page(pages[i]);

				pages[i] = NULL;

			}

		}

		return;

	}

}

/*

 * On success pages list will hold count number of correctly

 * cached pages.

 */

static int ttm_get_pages(struct page **pages, unsigned npages, int flags,

			 enum ttm_caching_state cstate)

{

	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);

	struct list_head plist;

	struct page *p = NULL;

	gfp_t gfp_flags = 0;

	unsigned count;

	int r;

	/* No pool for cached pages */

	if (1) {

		for (r = 0; r < npages; ++r) {

			p = alloc_page(gfp_flags);

			if (!p) {

				return -ENOMEM;

			}

			pages[r] = p;

		}

		return 0;

	}

	return 0;

}

static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, gfp_t flags,

		char *name)

{

	spin_lock_init(&pool->lock);

	pool->fill_lock = false;

	INIT_LIST_HEAD(&pool->list);

	pool->npages = pool->nfrees = 0;

	pool->gfp_flags = flags;

	pool->name = name;

}

int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)

{

	int ret;

	WARN_ON(_manager);

	_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);

	_manager->options.max_size = max_pages;

	_manager->options.small = SMALL_ALLOCATION;

	_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;

	return 0;

}

void ttm_page_alloc_fini(void)

{

	int i;

	_manager = NULL;

}

int ttm_pool_populate(struct ttm_tt *ttm)

{

	struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;

	unsigned i;

	int ret;

	if (ttm->state != tt_unpopulated)

		return 0;

	for (i = 0; i < ttm->num_pages; ++i) {

		ret = ttm_get_pages(&ttm->pages[i], 1,

				    ttm->page_flags,

				    ttm->caching_state);

		if (ret != 0) {

			ttm_pool_unpopulate(ttm);

			return -ENOMEM;

		}

	}

	ttm->state = tt_unbound;

	return 0;

}

EXPORT_SYMBOL(ttm_pool_populate);

void ttm_pool_unpopulate(struct ttm_tt *ttm)

{

	unsigned i;

	for (i = 0; i < ttm->num_pages; ++i) {

		if (ttm->pages[i]) {

			ttm_put_pages(&ttm->pages[i], 1,

				      ttm->page_flags,

				      ttm->caching_state);

		}

	}

	ttm->state = tt_unpopulated;

}

EXPORT_SYMBOL(ttm_pool_unpopulate);