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x86: restore the old swiotlb alloc_coherent behavior

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This restores the old swiotlb alloc_coherent behavior (before the
alloc_coherent rewrite):

  http://lkml.org/lkml/2008/8/12/200

The old alloc_coherent avoids GFP_DMA allocation first and if the
allocated address is not fit for the device's coherent_dma_mask, then
dma_alloc_coherent does GFP_DMA allocation. If it fails,
alloc_coherent calls swiotlb_alloc_coherent (in short, we rarely used
swiotlb_alloc_coherent).

After the alloc_coherent rewrite, dma_alloc_coherent
(include/asm-x86/dma-mapping.h) directly calls swiotlb_alloc_coherent.
It means that we possibly can't handle a device having dma_masks >
24bit < 32bits since swiotlb_alloc_coherent doesn't have the above
GFP_DMA retry mechanism.

This patch fixes x86's swiotlb alloc_coherent to use the GFP_DMA retry
mechanism, which dma_generic_alloc_coherent() provides now
(pci-nommu.c and GART IOMMU driver also use
dma_generic_alloc_coherent).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
FUJITA Tomonori 2008-10-23 23:14:29 +09:00 committed by Ingo Molnar
parent 75bebb7f0c
commit 03967c5267
1 changed files with 13 additions and 1 deletions
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14
arch/x86/kernel/pci-swiotlb_64.c
View file

@ -18,9 +18,21 @@ swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
return swiotlb_map_single(hwdev, phys_to_virt(paddr), size, direction);
}
static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags)
{
void *vaddr;
vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
if (vaddr)
return vaddr;
return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
}
struct dma_mapping_ops swiotlb_dma_ops = {
.mapping_error = swiotlb_dma_mapping_error,
.alloc_coherent = swiotlb_alloc_coherent,
.alloc_coherent = x86_swiotlb_alloc_coherent,
.free_coherent = swiotlb_free_coherent,
.map_single = swiotlb_map_single_phys,
.unmap_single = swiotlb_unmap_single,