[thirdparty/linux.git] / drivers / base / dma-contiguous.c

/*
 * Contiguous Memory Allocator for DMA mapping framework
 * Copyright (c) 2010-2011 by Samsung Electronics.
 * Written by:
 *	Marek Szyprowski <m.szyprowski@samsung.com>
 *	Michal Nazarewicz <mina86@mina86.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License or (at your optional) any later version of the license.
 */

#define pr_fmt(fmt) "cma: " fmt

#ifdef CONFIG_CMA_DEBUG
#ifndef DEBUG
#  define DEBUG
#endif
#endif

#include <asm/page.h>
#include <asm/dma-contiguous.h>

#include <linux/memblock.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/page-isolation.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/mm_types.h>
#include <linux/dma-contiguous.h>

struct cma {
	unsigned long	base_pfn;
	unsigned long	count;
	unsigned long	*bitmap;
	struct mutex	lock;
};

struct cma *dma_contiguous_default_area;

#ifdef CONFIG_CMA_SIZE_MBYTES
#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
#else
#define CMA_SIZE_MBYTES 0
#endif

/*
 * Default global CMA area size can be defined in kernel's .config.
 * This is useful mainly for distro maintainers to create a kernel
 * that works correctly for most supported systems.
 * The size can be set in bytes or as a percentage of the total memory
 * in the system.
 *
 * Users, who want to set the size of global CMA area for their system
 * should use cma= kernel parameter.
 */
static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
static phys_addr_t size_cmdline = -1;

static int __init early_cma(char *p)
{
	pr_debug("%s(%s)\n", __func__, p);
	size_cmdline = memparse(p, &p);
	return 0;
}
early_param("cma", early_cma);

#ifdef CONFIG_CMA_SIZE_PERCENTAGE

static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
{
	struct memblock_region *reg;
	unsigned long total_pages = 0;

	/*
	 * We cannot use memblock_phys_mem_size() here, because
	 * memblock_analyze() has not been called yet.
	 */
	for_each_memblock(memory, reg)
		total_pages += memblock_region_memory_end_pfn(reg) -
			       memblock_region_memory_base_pfn(reg);

	return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
}

#else

static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
{
	return 0;
}

#endif

/**
 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
 * @limit: End address of the reserved memory (optional, 0 for any).
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the early allocator (memblock or bootmem)
 * has been activated and all other subsystems have already allocated/reserved
 * memory.
 */
void __init dma_contiguous_reserve(phys_addr_t limit)
{
	phys_addr_t selected_size = 0;

	pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);

	if (size_cmdline != -1) {
		selected_size = size_cmdline;
	} else {
#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
		selected_size = size_bytes;
#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
		selected_size = cma_early_percent_memory();
#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
		selected_size = min(size_bytes, cma_early_percent_memory());
#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
		selected_size = max(size_bytes, cma_early_percent_memory());
#endif
	}

	if (selected_size && !dma_contiguous_default_area) {
		pr_debug("%s: reserving %ld MiB for global area\n", __func__,
			 (unsigned long)selected_size / SZ_1M);

		dma_contiguous_reserve_area(selected_size, 0, limit,
					    &dma_contiguous_default_area);
	}
};

static DEFINE_MUTEX(cma_mutex);

static int __init cma_activate_area(struct cma *cma)
{
	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
	unsigned i = cma->count >> pageblock_order;
	struct zone *zone;

	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);

	if (!cma->bitmap)
		return -ENOMEM;

	WARN_ON_ONCE(!pfn_valid(pfn));
	zone = page_zone(pfn_to_page(pfn));

	do {
		unsigned j;
		base_pfn = pfn;
		for (j = pageblock_nr_pages; j; --j, pfn++) {
			WARN_ON_ONCE(!pfn_valid(pfn));
			if (page_zone(pfn_to_page(pfn)) != zone)
				return -EINVAL;
		}
		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
	} while (--i);

	mutex_init(&cma->lock);
	return 0;
}

static struct cma cma_areas[MAX_CMA_AREAS];
static unsigned cma_area_count;

static int __init cma_init_reserved_areas(void)
{
	int i;

	for (i = 0; i < cma_area_count; i++) {
		int ret = cma_activate_area(&cma_areas[i]);
		if (ret)
			return ret;
	}

	return 0;
}
core_initcall(cma_init_reserved_areas);

/**
 * dma_contiguous_reserve_area() - reserve custom contiguous area
 * @size: Size of the reserved area (in bytes),
 * @base: Base address of the reserved area optional, use 0 for any
 * @limit: End address of the reserved memory (optional, 0 for any).
 * @res_cma: Pointer to store the created cma region.
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the early allocator (memblock or bootmem)
 * has been activated and all other subsystems have already allocated/reserved
 * memory. This function allows to create custom reserved areas for specific
 * devices.
 */
int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
				       phys_addr_t limit, struct cma **res_cma)
{
	struct cma *cma = &cma_areas[cma_area_count];
	phys_addr_t alignment;
	int ret = 0;

	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
		 (unsigned long)size, (unsigned long)base,
		 (unsigned long)limit);

	/* Sanity checks */
	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
		pr_err("Not enough slots for CMA reserved regions!\n");
		return -ENOSPC;
	}

	if (!size)
		return -EINVAL;

	/* Sanitise input arguments */
	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
	base = ALIGN(base, alignment);
	size = ALIGN(size, alignment);
	limit &= ~(alignment - 1);

	/* Reserve memory */
	if (base) {
		if (memblock_is_region_reserved(base, size) ||
		    memblock_reserve(base, size) < 0) {
			ret = -EBUSY;
			goto err;
		}
	} else {
		/*
		 * Use __memblock_alloc_base() since
		 * memblock_alloc_base() panic()s.
		 */
		phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
		if (!addr) {
			ret = -ENOMEM;
			goto err;
		} else {
			base = addr;
		}
	}

	/*
	 * Each reserved area must be initialised later, when more kernel
	 * subsystems (like slab allocator) are available.
	 */
	cma->base_pfn = PFN_DOWN(base);
	cma->count = size >> PAGE_SHIFT;
	*res_cma = cma;
	cma_area_count++;

	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
		(unsigned long)base);

	/* Architecture specific contiguous memory fixup. */
	dma_contiguous_early_fixup(base, size);
	return 0;
err:
	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
	return ret;
}

static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
{
	mutex_lock(&cma->lock);
	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
	mutex_unlock(&cma->lock);
}

/**
 * dma_alloc_from_contiguous() - allocate pages from contiguous area
 * @dev:   Pointer to device for which the allocation is performed.
 * @count: Requested number of pages.
 * @align: Requested alignment of pages (in PAGE_SIZE order).
 *
 * This function allocates memory buffer for specified device. It uses
 * device specific contiguous memory area if available or the default
 * global one. Requires architecture specific dev_get_cma_area() helper
 * function.
 */
struct page *dma_alloc_from_contiguous(struct device *dev, int count,
				       unsigned int align)
{
	unsigned long mask, pfn, pageno, start = 0;
	struct cma *cma = dev_get_cma_area(dev);
	struct page *page = NULL;
	int ret;

	if (!cma || !cma->count)
		return NULL;

	if (align > CONFIG_CMA_ALIGNMENT)
		align = CONFIG_CMA_ALIGNMENT;

	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
		 count, align);

	if (!count)
		return NULL;

	mask = (1 << align) - 1;


	for (;;) {
		mutex_lock(&cma->lock);
		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
						    start, count, mask);
		if (pageno >= cma->count) {
			mutex_unlock(&cma->lock);
			break;
		}
		bitmap_set(cma->bitmap, pageno, count);
		/*
		 * It's safe to drop the lock here. We've marked this region for
		 * our exclusive use. If the migration fails we will take the
		 * lock again and unmark it.
		 */
		mutex_unlock(&cma->lock);

		pfn = cma->base_pfn + pageno;
		mutex_lock(&cma_mutex);
		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
		mutex_unlock(&cma_mutex);
		if (ret == 0) {
			page = pfn_to_page(pfn);
			break;
		} else if (ret != -EBUSY) {
			clear_cma_bitmap(cma, pfn, count);
			break;
		}
		clear_cma_bitmap(cma, pfn, count);
		pr_debug("%s(): memory range at %p is busy, retrying\n",
			 __func__, pfn_to_page(pfn));
		/* try again with a bit different memory target */
		start = pageno + mask + 1;
	}

	pr_debug("%s(): returned %p\n", __func__, page);
	return page;
}

/**
 * dma_release_from_contiguous() - release allocated pages
 * @dev:   Pointer to device for which the pages were allocated.
 * @pages: Allocated pages.
 * @count: Number of allocated pages.
 *
 * This function releases memory allocated by dma_alloc_from_contiguous().
 * It returns false when provided pages do not belong to contiguous area and
 * true otherwise.
 */
bool dma_release_from_contiguous(struct device *dev, struct page *pages,
				 int count)
{
	struct cma *cma = dev_get_cma_area(dev);
	unsigned long pfn;

	if (!cma || !pages)
		return false;

	pr_debug("%s(page %p)\n", __func__, (void *)pages);

	pfn = page_to_pfn(pages);

	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
		return false;

	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);

	free_contig_range(pfn, count);
	clear_cma_bitmap(cma, pfn, count);

	return true;
}
Commit	Line	Data
c64be2bb MS	1	/*
	2	* Contiguous Memory Allocator for DMA mapping framework
	3	* Copyright (c) 2010-2011 by Samsung Electronics.
	4	* Written by:
	5	* Marek Szyprowski <m.szyprowski@samsung.com>
	6	* Michal Nazarewicz <mina86@mina86.com>
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License as
	10	* published by the Free Software Foundation; either version 2 of the
	11	* License or (at your optional) any later version of the license.
	12	*/
	13
	14	#define pr_fmt(fmt) "cma: " fmt
	15
	16	#ifdef CONFIG_CMA_DEBUG
	17	#ifndef DEBUG
	18	# define DEBUG
	19	#endif
	20	#endif
	21
	22	#include <asm/page.h>
	23	#include <asm/dma-contiguous.h>
	24
	25	#include <linux/memblock.h>
	26	#include <linux/err.h>
	27	#include <linux/mm.h>
	28	#include <linux/mutex.h>
	29	#include <linux/page-isolation.h>
446c82fc	30	#include <linux/sizes.h>
c64be2bb MS	31	#include <linux/slab.h>
	32	#include <linux/swap.h>
	33	#include <linux/mm_types.h>
	34	#include <linux/dma-contiguous.h>
	35
c64be2bb MS	36	struct cma {
	37	unsigned long base_pfn;
	38	unsigned long count;
	39	unsigned long *bitmap;
7ee793a6	40	struct mutex lock;
c64be2bb MS	41	};
	42
	43	struct cma *dma_contiguous_default_area;
	44
	45	#ifdef CONFIG_CMA_SIZE_MBYTES
	46	#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
	47	#else
	48	#define CMA_SIZE_MBYTES 0
	49	#endif
	50
	51	/*
	52	* Default global CMA area size can be defined in kernel's .config.
73678804	53	* This is useful mainly for distro maintainers to create a kernel
c64be2bb MS	54	* that works correctly for most supported systems.
	55	* The size can be set in bytes or as a percentage of the total memory
	56	* in the system.
	57	*
	58	* Users, who want to set the size of global CMA area for their system
	59	* should use cma= kernel parameter.
	60	*/
4009793e VA	61	static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
4009793e VA	62	static phys_addr_t size_cmdline = -1;
c64be2bb MS	63
	64	static int __init early_cma(char *p)
	65	{
	66	pr_debug("%s(%s)\n", __func__, p);
	67	size_cmdline = memparse(p, &p);
	68	return 0;
	69	}
	70	early_param("cma", early_cma);
	71
	72	#ifdef CONFIG_CMA_SIZE_PERCENTAGE
	73
4009793e	74	static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
c64be2bb MS	75	{
	76	struct memblock_region *reg;
	77	unsigned long total_pages = 0;
	78
	79	/*
	80	* We cannot use memblock_phys_mem_size() here, because
	81	* memblock_analyze() has not been called yet.
	82	*/
	83	for_each_memblock(memory, reg)
	84	total_pages += memblock_region_memory_end_pfn(reg) -
	85	memblock_region_memory_base_pfn(reg);
	86
	87	return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
	88	}
	89
	90	#else
	91
4009793e	92	static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
c64be2bb MS	93	{
	94	return 0;
	95	}
	96
	97	#endif
	98
	99	/**
a2547380	100	* dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
c64be2bb MS	101	* @limit: End address of the reserved memory (optional, 0 for any).
	102	*
	103	* This function reserves memory from early allocator. It should be
	104	* called by arch specific code once the early allocator (memblock or bootmem)
	105	* has been activated and all other subsystems have already allocated/reserved
	106	* memory.
	107	*/
	108	void __init dma_contiguous_reserve(phys_addr_t limit)
	109	{
4009793e	110	phys_addr_t selected_size = 0;
c64be2bb MS	111
	112	pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
	113
	114	if (size_cmdline != -1) {
	115	selected_size = size_cmdline;
	116	} else {
	117	#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
	118	selected_size = size_bytes;
	119	#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
	120	selected_size = cma_early_percent_memory();
	121	#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
	122	selected_size = min(size_bytes, cma_early_percent_memory());
	123	#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
	124	selected_size = max(size_bytes, cma_early_percent_memory());
	125	#endif
	126	}
	127
a2547380	128	if (selected_size && !dma_contiguous_default_area) {
c64be2bb	129	pr_debug("%s: reserving %ld MiB for global area\n", __func__,
4009793e	130	(unsigned long)selected_size / SZ_1M);
c64be2bb	131
a2547380 MS	132	dma_contiguous_reserve_area(selected_size, 0, limit,
a2547380 MS	133	&dma_contiguous_default_area);
c64be2bb MS	134	}
	135	};
	136
	137	static DEFINE_MUTEX(cma_mutex);
	138
a2547380	139	static int __init cma_activate_area(struct cma *cma)
c64be2bb	140	{
a2547380 MS	141	int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
	142	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
	143	unsigned i = cma->count >> pageblock_order;
c64be2bb MS	144	struct zone *zone;
c64be2bb MS	145
a2547380 MS	146	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	147
	148	if (!cma->bitmap)
	149	return -ENOMEM;
	150
c64be2bb MS	151	WARN_ON_ONCE(!pfn_valid(pfn));
	152	zone = page_zone(pfn_to_page(pfn));
	153
	154	do {
	155	unsigned j;
	156	base_pfn = pfn;
	157	for (j = pageblock_nr_pages; j; --j, pfn++) {
	158	WARN_ON_ONCE(!pfn_valid(pfn));
	159	if (page_zone(pfn_to_page(pfn)) != zone)
	160	return -EINVAL;
	161	}
	162	init_cma_reserved_pageblock(pfn_to_page(base_pfn));
	163	} while (--i);
c64be2bb	164
7ee793a6	165	mutex_init(&cma->lock);
a2547380	166	return 0;
c64be2bb MS	167	}
c64be2bb MS	168
a2547380 MS	169	static struct cma cma_areas[MAX_CMA_AREAS];
a2547380 MS	170	static unsigned cma_area_count;
c64be2bb MS	171
	172	static int __init cma_init_reserved_areas(void)
	173	{
a2547380	174	int i;
c64be2bb	175
a2547380 MS	176	for (i = 0; i < cma_area_count; i++) {
	177	int ret = cma_activate_area(&cma_areas[i]);
	178	if (ret)
	179	return ret;
c64be2bb	180	}
a2547380	181
c64be2bb MS	182	return 0;
	183	}
	184	core_initcall(cma_init_reserved_areas);
	185
	186	/**
a2547380 MS	187	* dma_contiguous_reserve_area() - reserve custom contiguous area
	188	* @size: Size of the reserved area (in bytes),
	189	* @base: Base address of the reserved area optional, use 0 for any
c64be2bb	190	* @limit: End address of the reserved memory (optional, 0 for any).
a2547380	191	* @res_cma: Pointer to store the created cma region.
c64be2bb	192	*
a2547380 MS	193	* This function reserves memory from early allocator. It should be
	194	* called by arch specific code once the early allocator (memblock or bootmem)
	195	* has been activated and all other subsystems have already allocated/reserved
	196	* memory. This function allows to create custom reserved areas for specific
	197	* devices.
c64be2bb	198	*/
a2547380 MS	199	int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
a2547380 MS	200	phys_addr_t limit, struct cma **res_cma)
c64be2bb	201	{
a2547380	202	struct cma *cma = &cma_areas[cma_area_count];
4009793e	203	phys_addr_t alignment;
a2547380	204	int ret = 0;
c64be2bb MS	205
	206	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
	207	(unsigned long)size, (unsigned long)base,
	208	(unsigned long)limit);
	209
	210	/* Sanity checks */
a2547380	211	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
c64be2bb MS	212	pr_err("Not enough slots for CMA reserved regions!\n");
	213	return -ENOSPC;
	214	}
	215
	216	if (!size)
	217	return -EINVAL;
	218
	219	/* Sanitise input arguments */
7ce9bf1f	220	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
c64be2bb MS	221	base = ALIGN(base, alignment);
	222	size = ALIGN(size, alignment);
	223	limit &= ~(alignment - 1);
	224
	225	/* Reserve memory */
	226	if (base) {
	227	if (memblock_is_region_reserved(base, size) \|\|
	228	memblock_reserve(base, size) < 0) {
a2547380	229	ret = -EBUSY;
c64be2bb MS	230	goto err;
	231	}
	232	} else {
	233	/*
	234	* Use __memblock_alloc_base() since
	235	* memblock_alloc_base() panic()s.
	236	*/
	237	phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
	238	if (!addr) {
a2547380	239	ret = -ENOMEM;
c64be2bb	240	goto err;
c64be2bb MS	241	} else {
	242	base = addr;
	243	}
	244	}
	245
	246	/*
	247	* Each reserved area must be initialised later, when more kernel
	248	* subsystems (like slab allocator) are available.
	249	*/
a2547380 MS	250	cma->base_pfn = PFN_DOWN(base);
	251	cma->count = size >> PAGE_SHIFT;
	252	*res_cma = cma;
	253	cma_area_count++;
	254
4009793e	255	pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
c64be2bb MS	256	(unsigned long)base);
	257
	258	/* Architecture specific contiguous memory fixup. */
	259	dma_contiguous_early_fixup(base, size);
	260	return 0;
	261	err:
4009793e	262	pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
a2547380	263	return ret;
c64be2bb MS	264	}
c64be2bb MS	265
7ee793a6 LA	266	static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
	267	{
	268	mutex_lock(&cma->lock);
	269	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
	270	mutex_unlock(&cma->lock);
	271	}
	272
c64be2bb MS	273	/**
	274	* dma_alloc_from_contiguous() - allocate pages from contiguous area
	275	* @dev: Pointer to device for which the allocation is performed.
	276	* @count: Requested number of pages.
	277	* @align: Requested alignment of pages (in PAGE_SIZE order).
	278	*
	279	* This function allocates memory buffer for specified device. It uses
	280	* device specific contiguous memory area if available or the default
bb56d0dc	281	* global one. Requires architecture specific dev_get_cma_area() helper
c64be2bb MS	282	* function.
	283	*/
	284	struct page dma_alloc_from_contiguous(struct device dev, int count,
	285	unsigned int align)
	286	{
	287	unsigned long mask, pfn, pageno, start = 0;
	288	struct cma *cma = dev_get_cma_area(dev);
bdd43cb3	289	struct page *page = NULL;
c64be2bb MS	290	int ret;
	291
	292	if (!cma \|\| !cma->count)
	293	return NULL;
	294
	295	if (align > CONFIG_CMA_ALIGNMENT)
	296	align = CONFIG_CMA_ALIGNMENT;
	297
	298	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
	299	count, align);
	300
	301	if (!count)
	302	return NULL;
	303
	304	mask = (1 << align) - 1;
	305
c64be2bb MS	306
c64be2bb MS	307	for (;;) {
7ee793a6	308	mutex_lock(&cma->lock);
c64be2bb MS	309	pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
c64be2bb MS	310	start, count, mask);
7ee793a6	311	if (pageno >= cma->count) {
f70e3c4f	312	mutex_unlock(&cma->lock);
bdd43cb3	313	break;
7ee793a6 LA	314	}
	315	bitmap_set(cma->bitmap, pageno, count);
	316	/*
	317	* It's safe to drop the lock here. We've marked this region for
	318	* our exclusive use. If the migration fails we will take the
	319	* lock again and unmark it.
	320	*/
	321	mutex_unlock(&cma->lock);
c64be2bb MS	322
c64be2bb MS	323	pfn = cma->base_pfn + pageno;
7ee793a6	324	mutex_lock(&cma_mutex);
c64be2bb	325	ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
7ee793a6	326	mutex_unlock(&cma_mutex);
c64be2bb	327	if (ret == 0) {
bdd43cb3	328	page = pfn_to_page(pfn);
c64be2bb MS	329	break;
c64be2bb MS	330	} else if (ret != -EBUSY) {
7ee793a6	331	clear_cma_bitmap(cma, pfn, count);
bdd43cb3	332	break;
c64be2bb	333	}
7ee793a6	334	clear_cma_bitmap(cma, pfn, count);
c64be2bb MS	335	pr_debug("%s(): memory range at %p is busy, retrying\n",
	336	__func__, pfn_to_page(pfn));
	337	/* try again with a bit different memory target */
	338	start = pageno + mask + 1;
	339	}
	340
bdd43cb3 MN	341	pr_debug("%s(): returned %p\n", __func__, page);
bdd43cb3 MN	342	return page;
c64be2bb MS	343	}
	344
	345	/**
	346	* dma_release_from_contiguous() - release allocated pages
	347	* @dev: Pointer to device for which the pages were allocated.
	348	* @pages: Allocated pages.
	349	* @count: Number of allocated pages.
	350	*
	351	* This function releases memory allocated by dma_alloc_from_contiguous().
	352	* It returns false when provided pages do not belong to contiguous area and
	353	* true otherwise.
	354	*/
	355	bool dma_release_from_contiguous(struct device dev, struct page pages,
	356	int count)
	357	{
	358	struct cma *cma = dev_get_cma_area(dev);
	359	unsigned long pfn;
	360
	361	if (!cma \|\| !pages)
	362	return false;
	363
	364	pr_debug("%s(page %p)\n", __func__, (void *)pages);
	365
	366	pfn = page_to_pfn(pages);
	367
	368	if (pfn < cma->base_pfn \|\| pfn >= cma->base_pfn + cma->count)
	369	return false;
	370
	371	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
	372
c64be2bb	373	free_contig_range(pfn, count);
7ee793a6	374	clear_cma_bitmap(cma, pfn, count);
c64be2bb MS	375
	376	return true;
	377	}