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Merge branch 'for-v3.16' of git://git.linaro.org/people/mszyprowski/l…
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…inux-dma-mapping into next

Pull CMA and DMA-mapping fixes from Marek Szyprowski:
 "A few fixes for dma-mapping and CMA subsystems"

* 'for-v3.16' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  CMA: correct unlock target
  drivers/base/dma-contiguous.c: erratum of dev_get_cma_area
  arm: dma-mapping: add checking cma area initialized
  arm: dma-iommu: Clean up redundant variable
  cma: Remove potential deadlock situation
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@torvalds
torvalds committed Jun 3, 2014
2 parents 312c76f + f70e3c4 commit ff806d0
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Showing 3 changed files with 35 additions and 17 deletions.
1 change: 0 additions & 1 deletion arch/arm/include/asm/dma-iommu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,6 @@ struct dma_iommu_mapping {
unsigned int extensions;
size_t bitmap_size; /* size of a single bitmap */
size_t bits; /* per bitmap */
unsigned int size; /* per bitmap */
dma_addr_t base;

spinlock_t lock;
Expand Down
17 changes: 9 additions & 8 deletions arch/arm/mm/dma-mapping.c
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Original file line number Diff line number Diff line change
Expand Up @@ -390,7 +390,7 @@ static int __init atomic_pool_init(void)
if (!pages)
goto no_pages;

if (IS_ENABLED(CONFIG_DMA_CMA))
if (dev_get_cma_area(NULL))
ptr = __alloc_from_contiguous(NULL, pool->size, prot, &page,
atomic_pool_init);
else
Expand Down Expand Up @@ -701,7 +701,7 @@ static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
addr = __alloc_simple_buffer(dev, size, gfp, &page);
else if (!(gfp & __GFP_WAIT))
addr = __alloc_from_pool(size, &page);
else if (!IS_ENABLED(CONFIG_DMA_CMA))
else if (!dev_get_cma_area(dev))
addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
else
addr = __alloc_from_contiguous(dev, size, prot, &page, caller);
Expand Down Expand Up @@ -790,7 +790,7 @@ static void __arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
__dma_free_buffer(page, size);
} else if (__free_from_pool(cpu_addr, size)) {
return;
} else if (!IS_ENABLED(CONFIG_DMA_CMA)) {
} else if (!dev_get_cma_area(dev)) {
__dma_free_remap(cpu_addr, size);
__dma_free_buffer(page, size);
} else {
Expand Down Expand Up @@ -1074,6 +1074,7 @@ static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
unsigned int order = get_order(size);
unsigned int align = 0;
unsigned int count, start;
size_t mapping_size = mapping->bits << PAGE_SHIFT;
unsigned long flags;
dma_addr_t iova;
int i;
Expand Down Expand Up @@ -1119,7 +1120,7 @@ static inline dma_addr_t __alloc_iova(struct dma_iommu_mapping *mapping,
}
spin_unlock_irqrestore(&mapping->lock, flags);

iova = mapping->base + (mapping->size * i);
iova = mapping->base + (mapping_size * i);
iova += start << PAGE_SHIFT;

return iova;
Expand All @@ -1129,21 +1130,22 @@ static inline void __free_iova(struct dma_iommu_mapping *mapping,
dma_addr_t addr, size_t size)
{
unsigned int start, count;
size_t mapping_size = mapping->bits << PAGE_SHIFT;
unsigned long flags;
dma_addr_t bitmap_base;
u32 bitmap_index;

if (!size)
return;

bitmap_index = (u32) (addr - mapping->base) / (u32) mapping->size;
bitmap_index = (u32) (addr - mapping->base) / (u32) mapping_size;
BUG_ON(addr < mapping->base || bitmap_index > mapping->extensions);

bitmap_base = mapping->base + mapping->size * bitmap_index;
bitmap_base = mapping->base + mapping_size * bitmap_index;

start = (addr - bitmap_base) >> PAGE_SHIFT;

if (addr + size > bitmap_base + mapping->size) {
if (addr + size > bitmap_base + mapping_size) {
/*
* The address range to be freed reaches into the iova
* range of the next bitmap. This should not happen as
Expand Down Expand Up @@ -1964,7 +1966,6 @@ arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size)
mapping->extensions = extensions;
mapping->base = base;
mapping->bits = BITS_PER_BYTE * bitmap_size;
mapping->size = mapping->bits << PAGE_SHIFT;

spin_lock_init(&mapping->lock);

Expand Down
34 changes: 26 additions & 8 deletions drivers/base/dma-contiguous.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@ struct cma {
unsigned long base_pfn;
unsigned long count;
unsigned long *bitmap;
struct mutex lock;
};

struct cma *dma_contiguous_default_area;
Expand Down Expand Up @@ -161,6 +162,7 @@ static int __init cma_activate_area(struct cma *cma)
init_cma_reserved_pageblock(pfn_to_page(base_pfn));
} while (--i);

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

Expand Down Expand Up @@ -261,6 +263,13 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
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.
Expand All @@ -269,7 +278,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
*
* 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 get_dev_cma_area() helper
* global one. Requires architecture specific dev_get_cma_area() helper
* function.
*/
struct page *dma_alloc_from_contiguous(struct device *dev, int count,
Expand All @@ -294,30 +303,41 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,

mask = (1 << align) - 1;

mutex_lock(&cma_mutex);

for (;;) {
mutex_lock(&cma->lock);
pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
start, count, mask);
if (pageno >= cma->count)
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) {
bitmap_set(cma->bitmap, pageno, count);
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;
}

mutex_unlock(&cma_mutex);
pr_debug("%s(): returned %p\n", __func__, page);
return page;
}
Expand Down Expand Up @@ -350,10 +370,8 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,

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

mutex_lock(&cma_mutex);
bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
free_contig_range(pfn, count);
mutex_unlock(&cma_mutex);
clear_cma_bitmap(cma, pfn, count);

return true;
}

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