CMA: generalize CMA reserved area management functionality (a254129e) · Commits · 戴 / test

arch/arm/mm/dma-mapping.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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>

drivers/base/Kconfig

+0 −10

Original line number	Diff line number	Diff line
		@@ -289,16 +289,6 @@ 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

drivers/base/dma-contiguous.c

+8 −272

Original line number	Diff line number	Diff line
		@@ -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 (1UL << (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, 1UL << 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);
		}

include/linux/cma.h

0 → 100644

+27 −0

Original line number	Diff line number	Diff line
		#ifndef __CMA_H__
		#define __CMA_H__

		/*
		* There is always at least global CMA area and a few optional
		* areas configured in kernel .config.
		*/
		#ifdef CONFIG_CMA_AREAS
		#define MAX_CMA_AREAS (1 + CONFIG_CMA_AREAS)

		#else
		#define MAX_CMA_AREAS (0)

		#endif

		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

include/linux/dma-contiguous.h

+2 −9

Original line number	Diff line number	Diff line
		@@ -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;

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