[v2 3/4] ARM: dma-mapping: Refactor out to introduce __alloc_fill_pages

Hiroshi Doyu
2012-08-23T06:11:20Z

__alloc_fill_pages() allocates power of 2 page number allocation at
most repeatedly.

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
---
arch/arm/mm/dma-mapping.c | 50 ++++++++++++++++++++++++++++++--------------
1 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index b64475a..7ab016b 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1022,20 +1022,11 @@ static inline void __free_iova(struct dma_iommu_mapping *mapping,
spin_unlock_irqrestore(&mapping->lock, flags);
}

-static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, gfp_t gfp)
+static int __alloc_fill_pages(struct page ***ppages, int count, gfp_t gfp)
{
- struct page **pages;
- int count = size >> PAGE_SHIFT;
- int array_size = count * sizeof(struct page *);
+ struct page **pages = *ppages;
int i = 0;

- if ((array_size <= PAGE_SIZE) || (gfp & GFP_ATOMIC))
- pages = kzalloc(array_size, gfp);
- else
- pages = vzalloc(array_size);
- if (!pages)
- return NULL;
-
while (count) {
int j, order = __fls(count);

@@ -1045,22 +1036,49 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size, gfp_t
if (!pages[i])
goto error;

- if (order)
+ if (order) {
split_page(pages[i], order);
- j = 1 << order;
- while (--j)
- pages[i + j] = pages[i] + j;
+ j = 1 << order;
+ while (--j)
+ pages[i + j] = pages[i] + j;
+ }

__dma_clear_buffer(pages[i], PAGE_SIZE << order);
i += 1 << order;
count -= 1 << order;
}

- return pages;
+ return 0;
+
error:
while (i--)
if (pages[i])
__free_pages(pages[i], 0);
+ return -ENOMEM;
+}
+
+static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
+ gfp_t gfp)
+{
+ struct page **pages;
+ int count = size >> PAGE_SHIFT;
+ int array_size = count * sizeof(struct page *);
+ int err;
+
+ if ((array_size <= PAGE_SIZE) || (gfp & GFP_ATOMIC))
+ pages = kzalloc(array_size, gfp);
+ else
+ pages = vzalloc(array_size);
+ if (!pages)
+ return NULL;
+
+ err = __alloc_fill_pages(&pages, count, gfp);
+ if (err)
+ goto error
+
+ return pages;
+
+error:
if ((array_size <= PAGE_SIZE) || (gfp & GFP_ATOMIC))
kfree(pages);
else
--
1.7.5.4