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Subject[PATCH 15/26] iommu/dma: Refactor iommu_dma_alloc
Date
From: Robin Murphy <robin.murphy@arm.com>

Shuffle around the self-contained atomic and non-contiguous cases to
return early and get out of the way of the CMA case that we're about to
work on next.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[hch: slight changes to the code flow]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/iommu/dma-iommu.c | 60 +++++++++++++++++++--------------------
1 file changed, 30 insertions(+), 30 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 9658c4cc3cfe..504dd27312bb 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -956,14 +956,19 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
{
bool coherent = dev_is_dma_coherent(dev);
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
+ pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
size_t iosize = size;
+ struct page *page;
void *addr;

size = PAGE_ALIGN(size);
gfp |= __GFP_ZERO;

+ if (gfpflags_allow_blocking(gfp) &&
+ !(attrs & DMA_ATTR_FORCE_CONTIGUOUS))
+ return iommu_dma_alloc_remap(dev, iosize, handle, gfp, attrs);
+
if (!gfpflags_allow_blocking(gfp)) {
- struct page *page;
/*
* In atomic context we can't remap anything, so we'll only
* get the virtually contiguous buffer we need by way of a
@@ -985,39 +990,34 @@ static void *iommu_dma_alloc(struct device *dev, size_t size,
__free_pages(page, get_order(size));
else
dma_free_from_pool(addr, size);
- addr = NULL;
- }
- } else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
- pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
- struct page *page;
-
- page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
- get_order(size), gfp & __GFP_NOWARN);
- if (!page)
return NULL;
-
- *handle = __iommu_dma_map(dev, page_to_phys(page), iosize, ioprot);
- if (*handle == DMA_MAPPING_ERROR) {
- dma_release_from_contiguous(dev, page,
- size >> PAGE_SHIFT);
- return NULL;
- }
- addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
- prot,
- __builtin_return_address(0));
- if (addr) {
- if (!coherent)
- arch_dma_prep_coherent(page, iosize);
- memset(addr, 0, size);
- } else {
- __iommu_dma_unmap(dev, *handle, iosize);
- dma_release_from_contiguous(dev, page,
- size >> PAGE_SHIFT);
}
- } else {
- addr = iommu_dma_alloc_remap(dev, iosize, handle, gfp, attrs);
+ return addr;
}
+
+ page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
+ get_order(size), gfp & __GFP_NOWARN);
+ if (!page)
+ return NULL;
+
+ *handle = __iommu_dma_map(dev, page_to_phys(page), iosize, ioprot);
+ if (*handle == DMA_MAPPING_ERROR)
+ goto out_free_pages;
+
+ addr = dma_common_contiguous_remap(page, size, VM_USERMAP, prot,
+ __builtin_return_address(0));
+ if (!addr)
+ goto out_unmap;
+
+ if (!coherent)
+ arch_dma_prep_coherent(page, iosize);
+ memset(addr, 0, size);
return addr;
+out_unmap:
+ __iommu_dma_unmap(dev, *handle, iosize);
+out_free_pages:
+ dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+ return NULL;
}

static int __iommu_dma_mmap_pfn(struct vm_area_struct *vma,
--
2.20.1
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