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Subject[RFC PATCH 2/3] DMA, CMA: use general CMA reserved area management framework
Date
Now, we have general CMA reserved area management framework,
so use it for future maintainabilty. There is no functional change.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index b3fe1cc..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 DMA_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 48cdac8..4bce4e1 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -24,23 +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>
-
-struct cma {
- unsigned long base_pfn;
- unsigned long count;
- unsigned long *bitmap;
- 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
@@ -48,6 +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
@@ -154,55 +142,6 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
}
}

-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_DMA_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),
@@ -224,176 +163,31 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
phys_addr_t limit, struct cma **res_cma,
bool fixed)
{
- 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 && 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;
- *res_cma = cma;
- cma_area_count++;
+ int ret;
+ struct cma *cma;

- pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
- (unsigned long)base);
+ ret = cma_declare_contiguous(size, base, limit, 0, 0, fixed, &cma);
+ if (ret)
+ return ret;

/* 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;
-}
+ *res_cma = cma;

-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);
+ return 0;
}

-/**
- * 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;
+ return cma_alloc(dev_get_cma_area(dev), count, align);
}

-/**
- * 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;
+ return cma_release(dev_get_cma_area(dev), pages, count);
}
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
index dfb1dc9..ecb85ac 100644
--- a/include/linux/dma-contiguous.h
+++ b/include/linux/dma-contiguous.h
@@ -53,9 +53,10 @@

#ifdef __KERNEL__

+#include <linux/device.h>
+
struct cma;
struct page;
-struct device;

#ifdef CONFIG_DMA_CMA

--
1.7.9.5


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