Hello,
On 2014-01-14 15:13, Akinobu Mita wrote:
This adds support for the DMA Contiguous Memory Allocator for intel-iommu.
This change enables dma_alloc_coherent() to allocate big contiguous
memory.
It is achieved in the same way as nommu_dma_ops currently does, i.e.
trying to allocate memory by dma_alloc_from_contiguous() and alloc_pages()
is used as a fallback.
Cc: Marek Szyprowski <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Don Dutile <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Akinobu Mita <[email protected]>
---
No change from the previous version
drivers/iommu/intel-iommu.c | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index fd426ca..172c2b0 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3004,7 +3004,7 @@ static void *intel_alloc_coherent(struct device *hwdev,
size_t size,
dma_addr_t *dma_handle, gfp_t flags,
struct dma_attrs *attrs)
{
- void *vaddr;
+ struct page *page = NULL;
int order;
size = PAGE_ALIGN(size);
@@ -3019,17 +3019,31 @@ static void *intel_alloc_coherent(struct device *hwdev,
size_t size,
flags |= GFP_DMA32;
}
- vaddr = (void *)__get_free_pages(flags, order);
- if (!vaddr)
+ if (!(flags & GFP_ATOMIC)) {
GFP_ATOMIC is not a flag, so please change the above check to:
if (flags & __GFP_WAIT)
I will also fix the similar issue in arch/x86/kernel/pci-dma.c
+ unsigned int count = size >> PAGE_SHIFT;
+
+ page = dma_alloc_from_contiguous(hwdev, count, order);
+ if (page && iommu_no_mapping(hwdev) &&
+ page_to_phys(page) + size > hwdev->coherent_dma_mask) {
+ dma_release_from_contiguous(hwdev, page, count);
+ page = NULL;
+ }
+ }
+
+ if (!page)
+ page = alloc_pages(flags, order);
+ if (!page)
return NULL;
- memset(vaddr, 0, size);
+ memset(page_address(page), 0, size);
- *dma_handle = __intel_map_single(hwdev, virt_to_bus(vaddr), size,
+ *dma_handle = __intel_map_single(hwdev, page_to_phys(page), size,
DMA_BIDIRECTIONAL,
hwdev->coherent_dma_mask);
if (*dma_handle)
- return vaddr;
- free_pages((unsigned long)vaddr, order);
+ return page_address(page);
+ if (!dma_release_from_contiguous(hwdev, page, size >> PAGE_SHIFT))
+ __free_pages(page, order);
+
return NULL;
}
@@ -3037,12 +3051,14 @@ static void intel_free_coherent(struct device *hwdev, size_t size, void *vaddr,
dma_addr_t dma_handle, struct dma_attrs *attrs)
{
int order;
+ struct page *page = virt_to_page(vaddr);
size = PAGE_ALIGN(size);
order = get_order(size);
intel_unmap_page(hwdev, dma_handle, size, DMA_BIDIRECTIONAL, NULL);
- free_pages((unsigned long)vaddr, order);
+ if (!dma_release_from_contiguous(hwdev, page, size >> PAGE_SHIFT))
+ __free_pages(page, order);
}
static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sglist,
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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