Acked-by: Michal Nazarewicz <min...@mina86.com>
Acked-by: Zhang Yanfei <zhangyan...@cn.fujitsu.com>
Acked-by: Minchan Kim <minc...@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo....@lge.com>
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 4c88935..3116880 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -26,6 +26,7 @@
#include <linux/io.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
+#include <linux/cma.h>
#include <asm/memory.h>
#include <asm/highmem.h>
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 00e13ce..4eac559 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -283,16 +283,6 @@ config CMA_ALIGNMENT
If unsure, leave the default value "8".
-config CMA_AREAS
- int "Maximum count of the CMA device-private areas"
- default 7
- help
- CMA allows to create CMA areas for particular devices. This parameter
- sets the maximum number of such device private CMA areas in the
- system.
-
- If unsure, leave the default value "7".
-
endif
endmenu
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index c6eeb2c..0411c1c 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,25 +24,9 @@
#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>
-#include <linux/log2.h>
-
-struct cma {
- unsigned long base_pfn;
- unsigned long count;
- unsigned long *bitmap;
- unsigned int order_per_bit; /* Order of pages represented by one bit */
- struct mutex lock;
-};
-
-struct cma *dma_contiguous_default_area;
+#include <linux/cma.h>
#ifdef CONFIG_CMA_SIZE_MBYTES
#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
@@ -50,6 +34,8 @@ struct cma *dma_contiguous_default_area;
#define CMA_SIZE_MBYTES 0
#endif
+struct cma *dma_contiguous_default_area;
+
/*
* Default global CMA area size can be defined in kernel's .config.
* This is useful mainly for distro maintainers to create a kernel
@@ -156,169 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
}
}
-static DEFINE_MUTEX(cma_mutex);
-
-static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
-{
- return (1 << (align_order >> cma->order_per_bit)) - 1;
-}
-
-static unsigned long cma_bitmap_maxno(struct cma *cma)
-{
- return cma->count >> cma->order_per_bit;
-}
-
-static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
- unsigned long pages)
-{
- return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
-}
-
-static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
-{
- unsigned long bitmap_no, bitmap_count;
-
- bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
- bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
- mutex_lock(&cma->lock);
- bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
- mutex_unlock(&cma->lock);
-}
-
-static int __init cma_activate_area(struct cma *cma)
-{
- int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * 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));
- /*
- * alloc_contig_range requires the pfn range
- * specified to be in the same zone. Make this
- * simple by forcing the entire CMA resv range
- * to be in the same zone.
- */
- if (page_zone(pfn_to_page(pfn)) != zone)
- goto err;
- }
- init_cma_reserved_pageblock(pfn_to_page(base_pfn));
- } while (--i);
-
- mutex_init(&cma->lock);
- return 0;
-
-err:
- kfree(cma->bitmap);
- return -EINVAL;
-}
-
-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);
-
-static int __init __dma_contiguous_reserve_area(phys_addr_t size,
- phys_addr_t base, phys_addr_t limit,
- phys_addr_t alignment, unsigned int order_per_bit,
- struct cma **res_cma, bool fixed)
-{
- struct cma *cma = &cma_areas[cma_area_count];
- int ret = 0;
-
- pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
- __func__, (unsigned long)size, (unsigned long)base,
- (unsigned long)limit, (unsigned long)alignment);
-
- if (cma_area_count == ARRAY_SIZE(cma_areas)) {
- pr_err("Not enough slots for CMA reserved regions!\n");
- return -ENOSPC;
- }
-
- if (!size)
- return -EINVAL;
-
- if (alignment && !is_power_of_2(alignment))
- return -EINVAL;
-
- /*
- * Sanitise input arguments.
- * Pages both ends in CMA area could be merged into adjacent unmovable
- * migratetype page by page allocator's buddy algorithm. In the case,
- * you couldn't get a contiguous memory, which is not what we want.
- */
- alignment = max(alignment,
- (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
- base = ALIGN(base, alignment);
- size = ALIGN(size, alignment);
- limit &= ~(alignment - 1);
-
- /* size should be aligned with order_per_bit */
- if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
- return -EINVAL;
-
- /* Reserve memory */
- if (base && fixed) {
- if (memblock_is_region_reserved(base, size) ||
- memblock_reserve(base, size) < 0) {
- ret = -EBUSY;
- goto err;
- }
- } else {
- phys_addr_t addr = memblock_alloc_range(size, alignment, base,
- 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;
- cma->order_per_bit = order_per_bit;
- *res_cma = cma;
- cma_area_count++;
-
- pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
- (unsigned long)base);
- return 0;
-
-err:
- pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
- return ret;
-}
-
/**
* dma_contiguous_reserve_area() - reserve custom contiguous area
* @size: Size of the reserved area (in bytes),
@@ -342,77 +165,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size,
phys_addr_t base,
{
int ret;
- ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
- res_cma, fixed);
+ ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
if (ret)
return ret;
/* Architecture specific contiguous memory fixup. */
- dma_contiguous_early_fixup(PFN_PHYS((*res_cma)->base_pfn),
- (*res_cma)->count << PAGE_SHIFT);
+ dma_contiguous_early_fixup(cma_get_base(*res_cma),
+ cma_get_size(*res_cma));
return 0;
}
-static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
- unsigned int align)
-{
- unsigned long mask, pfn, start = 0;
- unsigned long bitmap_maxno, bitmap_no, bitmap_count;
- struct page *page = NULL;
- int ret;
-
- if (!cma || !cma->count)
- return NULL;
-
- pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
- count, align);
-
- if (!count)
- return NULL;
-
- mask = cma_bitmap_aligned_mask(cma, align);
- bitmap_maxno = cma_bitmap_maxno(cma);
- bitmap_count = cma_bitmap_pages_to_bits(cma, count);
-
- for (;;) {
- mutex_lock(&cma->lock);
- bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
- bitmap_maxno, start, bitmap_count, mask);
- if (bitmap_no >= bitmap_maxno) {
- mutex_unlock(&cma->lock);
- break;
- }
- bitmap_set(cma->bitmap, bitmap_no, bitmap_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 + (bitmap_no << cma->order_per_bit);
- 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) {
- cma_clear_bitmap(cma, pfn, count);
- break;
- }
- cma_clear_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 = bitmap_no + mask + 1;
- }
-
- pr_debug("%s(): returned %p\n", __func__, page);
- return page;
-}
-
/**
* dma_alloc_from_contiguous() - allocate pages from contiguous area
* @dev: Pointer to device for which the allocation is performed.
@@ -427,35 +190,10 @@ static struct page *__dma_alloc_from_contiguous(struct
cma *cma, int count,
struct page *dma_alloc_from_contiguous(struct device *dev, int count,
unsigned int align)
{
- struct cma *cma = dev_get_cma_area(dev);
-
if (align > CONFIG_CMA_ALIGNMENT)
align = CONFIG_CMA_ALIGNMENT;
- return __dma_alloc_from_contiguous(cma, count, align);
-}
-
-static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
- int count)
-{
- 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);
- cma_clear_bitmap(cma, pfn, count);
-
- return true;
+ return cma_alloc(dev_get_cma_area(dev), count, align);
}
/**
@@ -471,7 +209,5 @@ static bool __dma_release_from_contiguous(struct cma *cma,
struct page *pages,
bool dma_release_from_contiguous(struct device *dev, struct page *pages,
int count)
{
- struct cma *cma = dev_get_cma_area(dev);
-
- return __dma_release_from_contiguous(cma, pages, count);
+ return cma_release(dev_get_cma_area(dev), pages, count);
}
diff --git a/include/linux/cma.h b/include/linux/cma.h
new file mode 100644
index 0000000..69d3726
--- /dev/null
+++ b/include/linux/cma.h
@@ -0,0 +1,21 @@
+#ifndef __CMA_H__
+#define __CMA_H__
+
+/*
+ * There is always at least global CMA area and a few optional
+ * areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS (1 + CONFIG_CMA_AREAS)
+
+struct cma;
+
+extern phys_addr_t cma_get_base(struct cma *cma);
+extern unsigned long cma_get_size(struct cma *cma);
+
+extern int __init cma_declare_contiguous(phys_addr_t size,
+ phys_addr_t base, phys_addr_t limit,
+ phys_addr_t alignment, unsigned int order_per_bit,
+ struct cma **res_cma, bool fixed);
+extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
+extern bool cma_release(struct cma *cma, struct page *pages, int count);
+#endif
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index 772eab5..569bbd0 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,18 +53,13 @@
#ifdef __KERNEL__
+#include <linux/device.h>
+
struct cma;
struct page;
-struct device;
#ifdef CONFIG_DMA_CMA
-/*
- * There is always at least global CMA area and a few optional device
- * private areas configured in kernel .config.
- */
-#define MAX_CMA_AREAS (1 + CONFIG_CMA_AREAS)
-
extern struct cma *dma_contiguous_default_area;
static inline struct cma *dev_get_cma_area(struct device *dev)
@@ -123,8 +118,6 @@ bool dma_release_from_contiguous(struct device *dev, struct
page *pages,
#else
-#define MAX_CMA_AREAS (0)
-
static inline struct cma *dev_get_cma_area(struct device *dev)
{
return NULL;
diff --git a/mm/Kconfig b/mm/Kconfig
index 3e9977a..f4899ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -508,6 +508,17 @@ config CMA_DEBUG
processing calls such as dma_alloc_from_contiguous().
This option does not affect warning and error messages.
+config CMA_AREAS
+ int "Maximum count of the CMA areas"
+ depends on CMA
+ default 7
+ help
+ CMA allows to create CMA areas for particular purpose, mainly,
+ used as device private area. This parameter sets the maximum
+ number of CMA area in the system.
+
+ If unsure, leave the default value "7".
+
config ZBUD
tristate
default n
diff --git a/mm/Makefile b/mm/Makefile
index 1eaa70b..bc0422b 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
obj-$(CONFIG_ZBUD) += zbud.o
obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
+obj-$(CONFIG_CMA) += cma.o
diff --git a/mm/cma.c b/mm/cma.c
new file mode 100644
index 0000000..0cf50da
--- /dev/null
+++ b/mm/cma.c
@@ -0,0 +1,333 @@
+/*
+ * Contiguous Memory Allocator
+ *
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Copyright IBM Corporation, 2013
+ * Copyright LG Electronics Inc., 2014
+ * Written by:
+ * Marek Szyprowski <m.szyprow...@samsung.com>
+ * Michal Nazarewicz <min...@mina86.com>
+ * Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
+ * Joonsoo Kim <iamjoonsoo....@lge.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 <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <linux/cma.h>
+
+struct cma {
+ unsigned long base_pfn;
+ unsigned long count;
+ unsigned long *bitmap;
+ unsigned int order_per_bit; /* Order of pages represented by one bit */
+ struct mutex lock;
+};
+
+static struct cma cma_areas[MAX_CMA_AREAS];
+static unsigned cma_area_count;
+static DEFINE_MUTEX(cma_mutex);
+
+phys_addr_t cma_get_base(struct cma *cma)
+{
+ return PFN_PHYS(cma->base_pfn);
+}
+
+unsigned long cma_get_size(struct cma *cma)
+{
+ return cma->count << PAGE_SHIFT;
+}
+
+static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
+{
+ return (1 << (align_order >> cma->order_per_bit)) - 1;
+}
+
+static unsigned long cma_bitmap_maxno(struct cma *cma)
+{
+ return cma->count >> cma->order_per_bit;
+}
+
+static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
+ unsigned long pages)
+{
+ return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
+}
+
+static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
+{
+ unsigned long bitmap_no, bitmap_count;
+
+ bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
+ bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+ mutex_lock(&cma->lock);
+ bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
+ mutex_unlock(&cma->lock);
+}
+
+static int __init cma_activate_area(struct cma *cma)
+{
+ int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * 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));
+ /*
+ * alloc_contig_range requires the pfn range
+ * specified to be in the same zone. Make this
+ * simple by forcing the entire CMA resv range
+ * to be in the same zone.
+ */
+ if (page_zone(pfn_to_page(pfn)) != zone)
+ goto err;
+ }
+ init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+ } while (--i);
+
+ mutex_init(&cma->lock);
+ return 0;
+
+err:
+ kfree(cma->bitmap);
+ return -EINVAL;
+}
+
+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);
+
+/**
+ * cma_declare_contiguous() - 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).
+ * @alignment: Alignment for the CMA area, should be power of 2 or zero
+ * @order_per_bit: Order of pages represented by one bit on bitmap.
+ * @res_cma: Pointer to store the created cma region.
+ * @fixed: hint about where to place the reserved area
+ *
+ * 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.
+ *
+ * If @fixed is true, reserve contiguous area at exactly @base. If false,
+ * reserve in range from @base to @limit.
+ */
+int __init cma_declare_contiguous(phys_addr_t size,
+ phys_addr_t base, phys_addr_t limit,
+ phys_addr_t alignment, unsigned int order_per_bit,
+ struct cma **res_cma, bool fixed)
+{
+ struct cma *cma = &cma_areas[cma_area_count];
+ int ret = 0;
+
+ pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+ __func__, (unsigned long)size, (unsigned long)base,
+ (unsigned long)limit, (unsigned long)alignment);
+
+ if (cma_area_count == ARRAY_SIZE(cma_areas)) {
+ pr_err("Not enough slots for CMA reserved regions!\n");
+ return -ENOSPC;
+ }
+
+ if (!size)
+ return -EINVAL;
+
+ if (alignment && !is_power_of_2(alignment))
+ return -EINVAL;
+
+ /*
+ * Sanitise input arguments.
+ * Pages both ends in CMA area could be merged into adjacent unmovable
+ * migratetype page by page allocator's buddy algorithm. In the case,
+ * you couldn't get a contiguous memory, which is not what we want.
+ */
+ alignment = max(alignment,
+ (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+ base = ALIGN(base, alignment);
+ size = ALIGN(size, alignment);
+ limit &= ~(alignment - 1);
+
+ /* size should be aligned with order_per_bit */
+ if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
+ return -EINVAL;
+
+ /* Reserve memory */
+ if (base && fixed) {
+ if (memblock_is_region_reserved(base, size) ||
+ memblock_reserve(base, size) < 0) {
+ ret = -EBUSY;
+ goto err;
+ }
+ } else {
+ phys_addr_t addr = memblock_alloc_range(size, alignment, base,
+ 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;
+ cma->order_per_bit = order_per_bit;
+ *res_cma = cma;
+ cma_area_count++;
+
+ pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
+ (unsigned long)base);
+ return 0;
+
+err:
+ pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
+ return ret;
+}
+
+/**
+ * cma_alloc() - allocate pages from contiguous area
+ * @cma: Contiguous memory region for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates part of contiguous memory on specific
+ * contiguous memory area.
+ */
+struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
+{
+ unsigned long mask, pfn, start = 0;
+ unsigned long bitmap_maxno, bitmap_no, bitmap_count;
+ struct page *page = NULL;
+ int ret;
+
+ if (!cma || !cma->count)
+ return NULL;
+
+ pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+ count, align);
+
+ if (!count)
+ return NULL;
+
+ mask = cma_bitmap_aligned_mask(cma, align);
+ bitmap_maxno = cma_bitmap_maxno(cma);
+ bitmap_count = cma_bitmap_pages_to_bits(cma, count);
+
+ for (;;) {
+ mutex_lock(&cma->lock);
+ bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
+ bitmap_maxno, start, bitmap_count, mask);
+ if (bitmap_no >= bitmap_maxno) {
+ mutex_unlock(&cma->lock);
+ break;
+ }
+ bitmap_set(cma->bitmap, bitmap_no, bitmap_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 + (bitmap_no << cma->order_per_bit);
+ 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) {
+ cma_clear_bitmap(cma, pfn, count);
+ break;
+ }
+ cma_clear_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 = bitmap_no + mask + 1;
+ }
+
+ pr_debug("%s(): returned %p\n", __func__, page);
+ return page;
+}
+
+/**
+ * cma_release() - release allocated pages
+ * @cma: Contiguous memory region for which the allocation is performed.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by alloc_cma().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool cma_release(struct cma *cma, struct page *pages, int count)
+{
+ 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);
+ cma_clear_bitmap(cma, pfn, count);
+
+ return true;
+}
