[linux-2.6-block.git] / mm / dmapool.c

/*
 * DMA Pool allocator
 *
 * Copyright 2001 David Brownell
 * Copyright 2007 Intel Corporation
 *   Author: Matthew Wilcox <willy@linux.intel.com>
 *
 * This software may be redistributed and/or modified under the terms of
 * the GNU General Public License ("GPL") version 2 as published by the
 * Free Software Foundation.
 *
 * This allocator returns small blocks of a given size which are DMA-able by
 * the given device.  It uses the dma_alloc_coherent page allocator to get
 * new pages, then splits them up into blocks of the required size.
 * Many older drivers still have their own code to do this.
 *
 * The current design of this allocator is fairly simple.  The pool is
 * represented by the 'struct dma_pool' which keeps a doubly-linked list of
 * allocated pages.  Each page in the page_list is split into blocks of at
 * least 'size' bytes.
 */

#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/poison.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/wait.h>

struct dma_pool {		/* the pool */
	struct list_head page_list;
	spinlock_t lock;
	size_t blocks_per_page;
	size_t size;
	struct device *dev;
	size_t allocation;
	char name[32];
	wait_queue_head_t waitq;
	struct list_head pools;
};

struct dma_page {		/* cacheable header for 'allocation' bytes */
	struct list_head page_list;
	void *vaddr;
	dma_addr_t dma;
	unsigned in_use;
	unsigned long bitmap[0];
};

#define	POOL_TIMEOUT_JIFFIES	((100 /* msec */ * HZ) / 1000)

static DEFINE_MUTEX(pools_lock);

static ssize_t
show_pools(struct device *dev, struct device_attribute *attr, char *buf)
{
	unsigned temp;
	unsigned size;
	char *next;
	struct dma_page *page;
	struct dma_pool *pool;

	next = buf;
	size = PAGE_SIZE;

	temp = scnprintf(next, size, "poolinfo - 0.1\n");
	size -= temp;
	next += temp;

	mutex_lock(&pools_lock);
	list_for_each_entry(pool, &dev->dma_pools, pools) {
		unsigned pages = 0;
		unsigned blocks = 0;

		list_for_each_entry(page, &pool->page_list, page_list) {
			pages++;
			blocks += page->in_use;
		}

		/* per-pool info, no real statistics yet */
		temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
				 pool->name,
				 blocks, pages * pool->blocks_per_page,
				 pool->size, pages);
		size -= temp;
		next += temp;
	}
	mutex_unlock(&pools_lock);

	return PAGE_SIZE - size;
}

static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);

/**
 * dma_pool_create - Creates a pool of consistent memory blocks, for dma.
 * @name: name of pool, for diagnostics
 * @dev: device that will be doing the DMA
 * @size: size of the blocks in this pool.
 * @align: alignment requirement for blocks; must be a power of two
 * @allocation: returned blocks won't cross this boundary (or zero)
 * Context: !in_interrupt()
 *
 * Returns a dma allocation pool with the requested characteristics, or
 * null if one can't be created.  Given one of these pools, dma_pool_alloc()
 * may be used to allocate memory.  Such memory will all have "consistent"
 * DMA mappings, accessible by the device and its driver without using
 * cache flushing primitives.  The actual size of blocks allocated may be
 * larger than requested because of alignment.
 *
 * If allocation is nonzero, objects returned from dma_pool_alloc() won't
 * cross that size boundary.  This is useful for devices which have
 * addressing restrictions on individual DMA transfers, such as not crossing
 * boundaries of 4KBytes.
 */
struct dma_pool *dma_pool_create(const char *name, struct device *dev,
				 size_t size, size_t align, size_t allocation)
{
	struct dma_pool *retval;

	if (align == 0) {
		align = 1;
	} else if (align & (align - 1)) {
		return NULL;
	}

	if (size == 0)
		return NULL;

	if ((size % align) != 0)
		size = ALIGN(size, align);

	if (allocation == 0) {
		if (PAGE_SIZE < size)
			allocation = size;
		else
			allocation = PAGE_SIZE;
		/* FIXME: round up for less fragmentation */
	} else if (allocation < size)
		return NULL;

	if (!
	    (retval =
	     kmalloc_node(sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
		return retval;

	strlcpy(retval->name, name, sizeof retval->name);

	retval->dev = dev;

	INIT_LIST_HEAD(&retval->page_list);
	spin_lock_init(&retval->lock);
	retval->size = size;
	retval->allocation = allocation;
	retval->blocks_per_page = allocation / size;
	init_waitqueue_head(&retval->waitq);

	if (dev) {
		int ret;

		mutex_lock(&pools_lock);
		if (list_empty(&dev->dma_pools))
			ret = device_create_file(dev, &dev_attr_pools);
		else
			ret = 0;
		/* note:  not currently insisting "name" be unique */
		if (!ret)
			list_add(&retval->pools, &dev->dma_pools);
		else {
			kfree(retval);
			retval = NULL;
		}
		mutex_unlock(&pools_lock);
	} else
		INIT_LIST_HEAD(&retval->pools);

	return retval;
}
EXPORT_SYMBOL(dma_pool_create);

static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags)
{
	struct dma_page *page;
	int mapsize;

	mapsize = pool->blocks_per_page;
	mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
	mapsize *= sizeof(long);

	page = kmalloc(mapsize + sizeof *page, mem_flags);
	if (!page)
		return NULL;
	page->vaddr = dma_alloc_coherent(pool->dev,
					 pool->allocation,
					 &page->dma, mem_flags);
	if (page->vaddr) {
		memset(page->bitmap, 0xff, mapsize);	/* bit set == free */
#ifdef	CONFIG_DEBUG_SLAB
		memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
#endif
		list_add(&page->page_list, &pool->page_list);
		page->in_use = 0;
	} else {
		kfree(page);
		page = NULL;
	}
	return page;
}

static inline int is_page_busy(int blocks, unsigned long *bitmap)
{
	while (blocks > 0) {
		if (*bitmap++ != ~0UL)
			return 1;
		blocks -= BITS_PER_LONG;
	}
	return 0;
}

static void pool_free_page(struct dma_pool *pool, struct dma_page *page)
{
	dma_addr_t dma = page->dma;

#ifdef	CONFIG_DEBUG_SLAB
	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
#endif
	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
	list_del(&page->page_list);
	kfree(page);
}

/**
 * dma_pool_destroy - destroys a pool of dma memory blocks.
 * @pool: dma pool that will be destroyed
 * Context: !in_interrupt()
 *
 * Caller guarantees that no more memory from the pool is in use,
 * and that nothing will try to use the pool after this call.
 */
void dma_pool_destroy(struct dma_pool *pool)
{
	mutex_lock(&pools_lock);
	list_del(&pool->pools);
	if (pool->dev && list_empty(&pool->dev->dma_pools))
		device_remove_file(pool->dev, &dev_attr_pools);
	mutex_unlock(&pools_lock);

	while (!list_empty(&pool->page_list)) {
		struct dma_page *page;
		page = list_entry(pool->page_list.next,
				  struct dma_page, page_list);
		if (is_page_busy(pool->blocks_per_page, page->bitmap)) {
			if (pool->dev)
				dev_err(pool->dev,
					"dma_pool_destroy %s, %p busy\n",
					pool->name, page->vaddr);
			else
				printk(KERN_ERR
				       "dma_pool_destroy %s, %p busy\n",
				       pool->name, page->vaddr);
			/* leak the still-in-use consistent memory */
			list_del(&page->page_list);
			kfree(page);
		} else
			pool_free_page(pool, page);
	}

	kfree(pool);
}
EXPORT_SYMBOL(dma_pool_destroy);

/**
 * dma_pool_alloc - get a block of consistent memory
 * @pool: dma pool that will produce the block
 * @mem_flags: GFP_* bitmask
 * @handle: pointer to dma address of block
 *
 * This returns the kernel virtual address of a currently unused block,
 * and reports its dma address through the handle.
 * If such a memory block can't be allocated, %NULL is returned.
 */
void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
		     dma_addr_t *handle)
{
	unsigned long flags;
	struct dma_page *page;
	int map, block;
	size_t offset;
	void *retval;

	spin_lock_irqsave(&pool->lock, flags);
 restart:
	list_for_each_entry(page, &pool->page_list, page_list) {
		int i;
		/* only cachable accesses here ... */
		for (map = 0, i = 0;
		     i < pool->blocks_per_page; i += BITS_PER_LONG, map++) {
			if (page->bitmap[map] == 0)
				continue;
			block = ffz(~page->bitmap[map]);
			if ((i + block) < pool->blocks_per_page) {
				clear_bit(block, &page->bitmap[map]);
				offset = (BITS_PER_LONG * map) + block;
				offset *= pool->size;
				goto ready;
			}
		}
	}
	page = pool_alloc_page(pool, GFP_ATOMIC);
	if (!page) {
		if (mem_flags & __GFP_WAIT) {
			DECLARE_WAITQUEUE(wait, current);

			__set_current_state(TASK_INTERRUPTIBLE);
			__add_wait_queue(&pool->waitq, &wait);
			spin_unlock_irqrestore(&pool->lock, flags);

			schedule_timeout(POOL_TIMEOUT_JIFFIES);

			spin_lock_irqsave(&pool->lock, flags);
			__remove_wait_queue(&pool->waitq, &wait);
			goto restart;
		}
		retval = NULL;
		goto done;
	}

	clear_bit(0, &page->bitmap[0]);
	offset = 0;
 ready:
	page->in_use++;
	retval = offset + page->vaddr;
	*handle = offset + page->dma;
#ifdef	CONFIG_DEBUG_SLAB
	memset(retval, POOL_POISON_ALLOCATED, pool->size);
#endif
 done:
	spin_unlock_irqrestore(&pool->lock, flags);
	return retval;
}
EXPORT_SYMBOL(dma_pool_alloc);

static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma)
{
	unsigned long flags;
	struct dma_page *page;

	spin_lock_irqsave(&pool->lock, flags);
	list_for_each_entry(page, &pool->page_list, page_list) {
		if (dma < page->dma)
			continue;
		if (dma < (page->dma + pool->allocation))
			goto done;
	}
	page = NULL;
 done:
	spin_unlock_irqrestore(&pool->lock, flags);
	return page;
}

/**
 * dma_pool_free - put block back into dma pool
 * @pool: the dma pool holding the block
 * @vaddr: virtual address of block
 * @dma: dma address of block
 *
 * Caller promises neither device nor driver will again touch this block
 * unless it is first re-allocated.
 */
void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
{
	struct dma_page *page;
	unsigned long flags;
	int map, block;

	page = pool_find_page(pool, dma);
	if (!page) {
		if (pool->dev)
			dev_err(pool->dev,
				"dma_pool_free %s, %p/%lx (bad dma)\n",
				pool->name, vaddr, (unsigned long)dma);
		else
			printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
			       pool->name, vaddr, (unsigned long)dma);
		return;
	}

	block = dma - page->dma;
	block /= pool->size;
	map = block / BITS_PER_LONG;
	block %= BITS_PER_LONG;

#ifdef	CONFIG_DEBUG_SLAB
	if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
		if (pool->dev)
			dev_err(pool->dev,
				"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
				pool->name, vaddr, (unsigned long long)dma);
		else
			printk(KERN_ERR
			       "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
			       pool->name, vaddr, (unsigned long long)dma);
		return;
	}
	if (page->bitmap[map] & (1UL << block)) {
		if (pool->dev)
			dev_err(pool->dev,
				"dma_pool_free %s, dma %Lx already free\n",
				pool->name, (unsigned long long)dma);
		else
			printk(KERN_ERR
			       "dma_pool_free %s, dma %Lx already free\n",
			       pool->name, (unsigned long long)dma);
		return;
	}
	memset(vaddr, POOL_POISON_FREED, pool->size);
#endif

	spin_lock_irqsave(&pool->lock, flags);
	page->in_use--;
	set_bit(block, &page->bitmap[map]);
	if (waitqueue_active(&pool->waitq))
		wake_up_locked(&pool->waitq);
	/*
	 * Resist a temptation to do
	 *    if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
	 * Better have a few empty pages hang around.
	 */
	spin_unlock_irqrestore(&pool->lock, flags);
}
EXPORT_SYMBOL(dma_pool_free);

/*
 * Managed DMA pool
 */
static void dmam_pool_release(struct device *dev, void *res)
{
	struct dma_pool *pool = *(struct dma_pool **)res;

	dma_pool_destroy(pool);
}

static int dmam_pool_match(struct device *dev, void *res, void *match_data)
{
	return *(struct dma_pool **)res == match_data;
}

/**
 * dmam_pool_create - Managed dma_pool_create()
 * @name: name of pool, for diagnostics
 * @dev: device that will be doing the DMA
 * @size: size of the blocks in this pool.
 * @align: alignment requirement for blocks; must be a power of two
 * @allocation: returned blocks won't cross this boundary (or zero)
 *
 * Managed dma_pool_create().  DMA pool created with this function is
 * automatically destroyed on driver detach.
 */
struct dma_pool *dmam_pool_create(const char *name, struct device *dev,
				  size_t size, size_t align, size_t allocation)
{
	struct dma_pool **ptr, *pool;

	ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return NULL;

	pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
	if (pool)
		devres_add(dev, ptr);
	else
		devres_free(ptr);

	return pool;
}
EXPORT_SYMBOL(dmam_pool_create);

/**
 * dmam_pool_destroy - Managed dma_pool_destroy()
 * @pool: dma pool that will be destroyed
 *
 * Managed dma_pool_destroy().
 */
void dmam_pool_destroy(struct dma_pool *pool)
{
	struct device *dev = pool->dev;

	dma_pool_destroy(pool);
	WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
}
EXPORT_SYMBOL(dmam_pool_destroy);
Commit	Line	Data
6182a094 MW	1	/*
	2	* DMA Pool allocator
	3	*
	4	* Copyright 2001 David Brownell
	5	* Copyright 2007 Intel Corporation
	6	* Author: Matthew Wilcox <willy@linux.intel.com>
	7	*
	8	* This software may be redistributed and/or modified under the terms of
	9	* the GNU General Public License ("GPL") version 2 as published by the
	10	* Free Software Foundation.
	11	*
	12	* This allocator returns small blocks of a given size which are DMA-able by
	13	* the given device. It uses the dma_alloc_coherent page allocator to get
	14	* new pages, then splits them up into blocks of the required size.
	15	* Many older drivers still have their own code to do this.
	16	*
	17	* The current design of this allocator is fairly simple. The pool is
	18	* represented by the 'struct dma_pool' which keeps a doubly-linked list of
	19	* allocated pages. Each page in the page_list is split into blocks of at
	20	* least 'size' bytes.
	21	*/
1da177e4 LT	22
1da177e4 LT	23	#include <linux/device.h>
1da177e4 LT	24	#include <linux/dma-mapping.h>
1da177e4 LT	25	#include <linux/dmapool.h>
6182a094 MW	26	#include <linux/kernel.h>
6182a094 MW	27	#include <linux/list.h>
1da177e4	28	#include <linux/module.h>
6182a094	29	#include <linux/mutex.h>
c9cf5528	30	#include <linux/poison.h>
e8edc6e0	31	#include <linux/sched.h>
6182a094 MW	32	#include <linux/slab.h>
	33	#include <linux/spinlock.h>
	34	#include <linux/string.h>
	35	#include <linux/types.h>
	36	#include <linux/wait.h>
1da177e4	37
e87aa773 MW	38	struct dma_pool { /* the pool */
	39	struct list_head page_list;
	40	spinlock_t lock;
	41	size_t blocks_per_page;
	42	size_t size;
	43	struct device *dev;
	44	size_t allocation;
	45	char name[32];
	46	wait_queue_head_t waitq;
	47	struct list_head pools;
1da177e4 LT	48	};
1da177e4 LT	49
e87aa773 MW	50	struct dma_page { /* cacheable header for 'allocation' bytes */
	51	struct list_head page_list;
	52	void *vaddr;
	53	dma_addr_t dma;
	54	unsigned in_use;
	55	unsigned long bitmap[0];
1da177e4 LT	56	};
	57
	58	#define POOL_TIMEOUT_JIFFIES ((100 /* msec / HZ) / 1000)
1da177e4	59
e87aa773	60	static DEFINE_MUTEX(pools_lock);
1da177e4 LT	61
1da177e4 LT	62	static ssize_t
e87aa773	63	show_pools(struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	64	{
	65	unsigned temp;
	66	unsigned size;
	67	char *next;
	68	struct dma_page *page;
	69	struct dma_pool *pool;
	70
	71	next = buf;
	72	size = PAGE_SIZE;
	73
	74	temp = scnprintf(next, size, "poolinfo - 0.1\n");
	75	size -= temp;
	76	next += temp;
	77
b2366d68	78	mutex_lock(&pools_lock);
1da177e4 LT	79	list_for_each_entry(pool, &dev->dma_pools, pools) {
	80	unsigned pages = 0;
	81	unsigned blocks = 0;
	82
	83	list_for_each_entry(page, &pool->page_list, page_list) {
	84	pages++;
	85	blocks += page->in_use;
	86	}
	87
	88	/* per-pool info, no real statistics yet */
	89	temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
e87aa773 MW	90	pool->name,
	91	blocks, pages * pool->blocks_per_page,
	92	pool->size, pages);
1da177e4 LT	93	size -= temp;
	94	next += temp;
	95	}
b2366d68	96	mutex_unlock(&pools_lock);
1da177e4 LT	97
	98	return PAGE_SIZE - size;
	99	}
e87aa773 MW	100
e87aa773 MW	101	static DEVICE_ATTR(pools, S_IRUGO, show_pools, NULL);
1da177e4 LT	102
	103	/**
	104	* dma_pool_create - Creates a pool of consistent memory blocks, for dma.
	105	* @name: name of pool, for diagnostics
	106	* @dev: device that will be doing the DMA
	107	* @size: size of the blocks in this pool.
	108	* @align: alignment requirement for blocks; must be a power of two
	109	* @allocation: returned blocks won't cross this boundary (or zero)
	110	* Context: !in_interrupt()
	111	*
	112	* Returns a dma allocation pool with the requested characteristics, or
	113	* null if one can't be created. Given one of these pools, dma_pool_alloc()
	114	* may be used to allocate memory. Such memory will all have "consistent"
	115	* DMA mappings, accessible by the device and its driver without using
	116	* cache flushing primitives. The actual size of blocks allocated may be
	117	* larger than requested because of alignment.
	118	*
	119	* If allocation is nonzero, objects returned from dma_pool_alloc() won't
	120	* cross that size boundary. This is useful for devices which have
	121	* addressing restrictions on individual DMA transfers, such as not crossing
	122	* boundaries of 4KBytes.
	123	*/
e87aa773 MW	124	struct dma_pool dma_pool_create(const char name, struct device *dev,
e87aa773 MW	125	size_t size, size_t align, size_t allocation)
1da177e4	126	{
e87aa773	127	struct dma_pool *retval;
1da177e4	128
399154be	129	if (align == 0) {
1da177e4	130	align = 1;
399154be	131	} else if (align & (align - 1)) {
1da177e4	132	return NULL;
1da177e4 LT	133	}
1da177e4 LT	134
399154be MW	135	if (size == 0)
	136	return NULL;
	137
	138	if ((size % align) != 0)
	139	size = ALIGN(size, align);
	140
1da177e4 LT	141	if (allocation == 0) {
	142	if (PAGE_SIZE < size)
	143	allocation = size;
	144	else
	145	allocation = PAGE_SIZE;
e87aa773	146	/* FIXME: round up for less fragmentation */
1da177e4 LT	147	} else if (allocation < size)
	148	return NULL;
	149
e87aa773 MW	150	if (!
	151	(retval =
	152	kmalloc_node(sizeof *retval, GFP_KERNEL, dev_to_node(dev))))
1da177e4 LT	153	return retval;
1da177e4 LT	154
e87aa773	155	strlcpy(retval->name, name, sizeof retval->name);
1da177e4 LT	156
	157	retval->dev = dev;
	158
e87aa773 MW	159	INIT_LIST_HEAD(&retval->page_list);
e87aa773 MW	160	spin_lock_init(&retval->lock);
1da177e4 LT	161	retval->size = size;
	162	retval->allocation = allocation;
	163	retval->blocks_per_page = allocation / size;
e87aa773	164	init_waitqueue_head(&retval->waitq);
1da177e4 LT	165
1da177e4 LT	166	if (dev) {
141ecc53 CH	167	int ret;
141ecc53 CH	168
b2366d68	169	mutex_lock(&pools_lock);
e87aa773 MW	170	if (list_empty(&dev->dma_pools))
e87aa773 MW	171	ret = device_create_file(dev, &dev_attr_pools);
141ecc53 CH	172	else
141ecc53 CH	173	ret = 0;
1da177e4	174	/* note: not currently insisting "name" be unique */
141ecc53	175	if (!ret)
e87aa773	176	list_add(&retval->pools, &dev->dma_pools);
141ecc53 CH	177	else {
	178	kfree(retval);
	179	retval = NULL;
	180	}
b2366d68	181	mutex_unlock(&pools_lock);
1da177e4	182	} else
e87aa773	183	INIT_LIST_HEAD(&retval->pools);
1da177e4 LT	184
	185	return retval;
	186	}
e87aa773	187	EXPORT_SYMBOL(dma_pool_create);
1da177e4	188
e87aa773	189	static struct dma_page pool_alloc_page(struct dma_pool pool, gfp_t mem_flags)
1da177e4	190	{
e87aa773 MW	191	struct dma_page *page;
e87aa773 MW	192	int mapsize;
1da177e4 LT	193
	194	mapsize = pool->blocks_per_page;
	195	mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
e87aa773	196	mapsize *= sizeof(long);
1da177e4	197
5cbded58	198	page = kmalloc(mapsize + sizeof *page, mem_flags);
1da177e4 LT	199	if (!page)
1da177e4 LT	200	return NULL;
e87aa773 MW	201	page->vaddr = dma_alloc_coherent(pool->dev,
	202	pool->allocation,
	203	&page->dma, mem_flags);
1da177e4	204	if (page->vaddr) {
e87aa773	205	memset(page->bitmap, 0xff, mapsize); /* bit set == free */
1da177e4	206	#ifdef CONFIG_DEBUG_SLAB
e87aa773	207	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
1da177e4	208	#endif
e87aa773	209	list_add(&page->page_list, &pool->page_list);
1da177e4 LT	210	page->in_use = 0;
1da177e4 LT	211	} else {
e87aa773	212	kfree(page);
1da177e4 LT	213	page = NULL;
	214	}
	215	return page;
	216	}
	217
e87aa773	218	static inline int is_page_busy(int blocks, unsigned long *bitmap)
1da177e4 LT	219	{
	220	while (blocks > 0) {
	221	if (*bitmap++ != ~0UL)
	222	return 1;
	223	blocks -= BITS_PER_LONG;
	224	}
	225	return 0;
	226	}
	227
e87aa773	228	static void pool_free_page(struct dma_pool pool, struct dma_page page)
1da177e4	229	{
e87aa773	230	dma_addr_t dma = page->dma;
1da177e4 LT	231
1da177e4 LT	232	#ifdef CONFIG_DEBUG_SLAB
e87aa773	233	memset(page->vaddr, POOL_POISON_FREED, pool->allocation);
1da177e4	234	#endif
e87aa773 MW	235	dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma);
	236	list_del(&page->page_list);
	237	kfree(page);
1da177e4 LT	238	}
1da177e4 LT	239
1da177e4 LT	240	/**
	241	* dma_pool_destroy - destroys a pool of dma memory blocks.
	242	* @pool: dma pool that will be destroyed
	243	* Context: !in_interrupt()
	244	*
	245	* Caller guarantees that no more memory from the pool is in use,
	246	* and that nothing will try to use the pool after this call.
	247	*/
e87aa773	248	void dma_pool_destroy(struct dma_pool *pool)
1da177e4	249	{
b2366d68	250	mutex_lock(&pools_lock);
e87aa773 MW	251	list_del(&pool->pools);
	252	if (pool->dev && list_empty(&pool->dev->dma_pools))
	253	device_remove_file(pool->dev, &dev_attr_pools);
b2366d68	254	mutex_unlock(&pools_lock);
1da177e4	255
e87aa773 MW	256	while (!list_empty(&pool->page_list)) {
	257	struct dma_page *page;
	258	page = list_entry(pool->page_list.next,
	259	struct dma_page, page_list);
	260	if (is_page_busy(pool->blocks_per_page, page->bitmap)) {
1da177e4	261	if (pool->dev)
e87aa773 MW	262	dev_err(pool->dev,
e87aa773 MW	263	"dma_pool_destroy %s, %p busy\n",
1da177e4 LT	264	pool->name, page->vaddr);
1da177e4 LT	265	else
e87aa773 MW	266	printk(KERN_ERR
	267	"dma_pool_destroy %s, %p busy\n",
	268	pool->name, page->vaddr);
1da177e4	269	/* leak the still-in-use consistent memory */
e87aa773 MW	270	list_del(&page->page_list);
e87aa773 MW	271	kfree(page);
1da177e4	272	} else
e87aa773	273	pool_free_page(pool, page);
1da177e4 LT	274	}
1da177e4 LT	275
e87aa773	276	kfree(pool);
1da177e4	277	}
e87aa773	278	EXPORT_SYMBOL(dma_pool_destroy);
1da177e4 LT	279
	280	/**
	281	* dma_pool_alloc - get a block of consistent memory
	282	* @pool: dma pool that will produce the block
	283	* @mem_flags: GFP_* bitmask
	284	* @handle: pointer to dma address of block
	285	*
	286	* This returns the kernel virtual address of a currently unused block,
	287	* and reports its dma address through the handle.
6182a094	288	* If such a memory block can't be allocated, %NULL is returned.
1da177e4	289	*/
e87aa773 MW	290	void dma_pool_alloc(struct dma_pool pool, gfp_t mem_flags,
e87aa773 MW	291	dma_addr_t *handle)
1da177e4	292	{
e87aa773 MW	293	unsigned long flags;
	294	struct dma_page *page;
	295	int map, block;
	296	size_t offset;
	297	void *retval;
	298
e87aa773	299	spin_lock_irqsave(&pool->lock, flags);
2cae367e	300	restart:
1da177e4	301	list_for_each_entry(page, &pool->page_list, page_list) {
e87aa773	302	int i;
1da177e4 LT	303	/* only cachable accesses here ... */
1da177e4 LT	304	for (map = 0, i = 0;
e87aa773 MW	305	i < pool->blocks_per_page; i += BITS_PER_LONG, map++) {
e87aa773 MW	306	if (page->bitmap[map] == 0)
1da177e4	307	continue;
e87aa773	308	block = ffz(~page->bitmap[map]);
1da177e4	309	if ((i + block) < pool->blocks_per_page) {
e87aa773	310	clear_bit(block, &page->bitmap[map]);
1da177e4 LT	311	offset = (BITS_PER_LONG * map) + block;
	312	offset *= pool->size;
	313	goto ready;
	314	}
	315	}
	316	}
e87aa773 MW	317	page = pool_alloc_page(pool, GFP_ATOMIC);
e87aa773 MW	318	if (!page) {
1da177e4	319	if (mem_flags & __GFP_WAIT) {
e87aa773	320	DECLARE_WAITQUEUE(wait, current);
1da177e4	321
d9aacccf	322	__set_current_state(TASK_INTERRUPTIBLE);
2cae367e	323	__add_wait_queue(&pool->waitq, &wait);
e87aa773	324	spin_unlock_irqrestore(&pool->lock, flags);
1da177e4	325
e87aa773	326	schedule_timeout(POOL_TIMEOUT_JIFFIES);
1da177e4	327
2cae367e MW	328	spin_lock_irqsave(&pool->lock, flags);
2cae367e MW	329	__remove_wait_queue(&pool->waitq, &wait);
1da177e4 LT	330	goto restart;
	331	}
	332	retval = NULL;
	333	goto done;
	334	}
	335
e87aa773	336	clear_bit(0, &page->bitmap[0]);
1da177e4	337	offset = 0;
e87aa773	338	ready:
1da177e4 LT	339	page->in_use++;
	340	retval = offset + page->vaddr;
	341	*handle = offset + page->dma;
	342	#ifdef CONFIG_DEBUG_SLAB
e87aa773	343	memset(retval, POOL_POISON_ALLOCATED, pool->size);
1da177e4	344	#endif
e87aa773 MW	345	done:
e87aa773 MW	346	spin_unlock_irqrestore(&pool->lock, flags);
1da177e4 LT	347	return retval;
1da177e4 LT	348	}
e87aa773	349	EXPORT_SYMBOL(dma_pool_alloc);
1da177e4	350
e87aa773	351	static struct dma_page pool_find_page(struct dma_pool pool, dma_addr_t dma)
1da177e4	352	{
e87aa773 MW	353	unsigned long flags;
e87aa773 MW	354	struct dma_page *page;
1da177e4	355
e87aa773	356	spin_lock_irqsave(&pool->lock, flags);
1da177e4 LT	357	list_for_each_entry(page, &pool->page_list, page_list) {
	358	if (dma < page->dma)
	359	continue;
	360	if (dma < (page->dma + pool->allocation))
	361	goto done;
	362	}
	363	page = NULL;
e87aa773 MW	364	done:
e87aa773 MW	365	spin_unlock_irqrestore(&pool->lock, flags);
1da177e4 LT	366	return page;
	367	}
	368
1da177e4 LT	369	/**
	370	* dma_pool_free - put block back into dma pool
	371	* @pool: the dma pool holding the block
	372	* @vaddr: virtual address of block
	373	* @dma: dma address of block
	374	*
	375	* Caller promises neither device nor driver will again touch this block
	376	* unless it is first re-allocated.
	377	*/
e87aa773	378	void dma_pool_free(struct dma_pool pool, void vaddr, dma_addr_t dma)
1da177e4	379	{
e87aa773 MW	380	struct dma_page *page;
	381	unsigned long flags;
	382	int map, block;
1da177e4	383
e87aa773 MW	384	page = pool_find_page(pool, dma);
e87aa773 MW	385	if (!page) {
1da177e4	386	if (pool->dev)
e87aa773 MW	387	dev_err(pool->dev,
	388	"dma_pool_free %s, %p/%lx (bad dma)\n",
	389	pool->name, vaddr, (unsigned long)dma);
1da177e4	390	else
e87aa773 MW	391	printk(KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
e87aa773 MW	392	pool->name, vaddr, (unsigned long)dma);
1da177e4 LT	393	return;
	394	}
	395
	396	block = dma - page->dma;
	397	block /= pool->size;
	398	map = block / BITS_PER_LONG;
	399	block %= BITS_PER_LONG;
	400
	401	#ifdef CONFIG_DEBUG_SLAB
	402	if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
	403	if (pool->dev)
e87aa773 MW	404	dev_err(pool->dev,
	405	"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
	406	pool->name, vaddr, (unsigned long long)dma);
1da177e4	407	else
e87aa773 MW	408	printk(KERN_ERR
	409	"dma_pool_free %s, %p (bad vaddr)/%Lx\n",
	410	pool->name, vaddr, (unsigned long long)dma);
1da177e4 LT	411	return;
1da177e4 LT	412	}
e87aa773	413	if (page->bitmap[map] & (1UL << block)) {
1da177e4	414	if (pool->dev)
e87aa773 MW	415	dev_err(pool->dev,
e87aa773 MW	416	"dma_pool_free %s, dma %Lx already free\n",
1da177e4 LT	417	pool->name, (unsigned long long)dma);
1da177e4 LT	418	else
e87aa773 MW	419	printk(KERN_ERR
	420	"dma_pool_free %s, dma %Lx already free\n",
	421	pool->name, (unsigned long long)dma);
1da177e4 LT	422	return;
1da177e4 LT	423	}
e87aa773	424	memset(vaddr, POOL_POISON_FREED, pool->size);
1da177e4 LT	425	#endif
1da177e4 LT	426
e87aa773	427	spin_lock_irqsave(&pool->lock, flags);
1da177e4	428	page->in_use--;
e87aa773 MW	429	set_bit(block, &page->bitmap[map]);
e87aa773 MW	430	if (waitqueue_active(&pool->waitq))
2cae367e	431	wake_up_locked(&pool->waitq);
1da177e4 LT	432	/*
	433	* Resist a temptation to do
	434	* if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
	435	* Better have a few empty pages hang around.
	436	*/
e87aa773	437	spin_unlock_irqrestore(&pool->lock, flags);
1da177e4	438	}
e87aa773	439	EXPORT_SYMBOL(dma_pool_free);
1da177e4	440
9ac7849e TH	441	/*
	442	* Managed DMA pool
	443	*/
	444	static void dmam_pool_release(struct device dev, void res)
	445	{
	446	struct dma_pool pool = (struct dma_pool **)res;
	447
	448	dma_pool_destroy(pool);
	449	}
	450
	451	static int dmam_pool_match(struct device dev, void res, void *match_data)
	452	{
	453	return (struct dma_pool *)res == match_data;
	454	}
	455
	456	/**
	457	* dmam_pool_create - Managed dma_pool_create()
	458	* @name: name of pool, for diagnostics
	459	* @dev: device that will be doing the DMA
	460	* @size: size of the blocks in this pool.
	461	* @align: alignment requirement for blocks; must be a power of two
	462	* @allocation: returned blocks won't cross this boundary (or zero)
	463	*
	464	* Managed dma_pool_create(). DMA pool created with this function is
	465	* automatically destroyed on driver detach.
	466	*/
	467	struct dma_pool dmam_pool_create(const char name, struct device *dev,
	468	size_t size, size_t align, size_t allocation)
	469	{
	470	struct dma_pool *ptr, pool;
	471
	472	ptr = devres_alloc(dmam_pool_release, sizeof(*ptr), GFP_KERNEL);
	473	if (!ptr)
	474	return NULL;
	475
	476	pool = *ptr = dma_pool_create(name, dev, size, align, allocation);
	477	if (pool)
	478	devres_add(dev, ptr);
	479	else
	480	devres_free(ptr);
	481
	482	return pool;
	483	}
e87aa773	484	EXPORT_SYMBOL(dmam_pool_create);
9ac7849e TH	485
	486	/**
	487	* dmam_pool_destroy - Managed dma_pool_destroy()
	488	* @pool: dma pool that will be destroyed
	489	*
	490	* Managed dma_pool_destroy().
	491	*/
	492	void dmam_pool_destroy(struct dma_pool *pool)
	493	{
	494	struct device *dev = pool->dev;
	495
	496	dma_pool_destroy(pool);
	497	WARN_ON(devres_destroy(dev, dmam_pool_release, dmam_pool_match, pool));
	498	}
e87aa773	499	EXPORT_SYMBOL(dmam_pool_destroy);