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dma-iommu: refactor iommu_dma_alloc_remap

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Split out a new helper that only allocates a sg_table worth of
memory without mapping it into contiguous kernel address space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
This commit is contained in:
Christoph Hellwig 2021-01-28 14:44:15 +01:00
parent 7d5b5738d1
commit 8230ce9a4e
1 changed files with 36 additions and 33 deletions
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69
drivers/iommu/dma-iommu.c
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@ -650,23 +650,12 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
return pages;
}
/**
* iommu_dma_alloc_remap - Allocate and map a buffer contiguous in IOVA space
* @dev: Device to allocate memory for. Must be a real device
* attached to an iommu_dma_domain
* @size: Size of buffer in bytes
* @dma_handle: Out argument for allocated DMA handle
* @gfp: Allocation flags
* @prot: pgprot_t to use for the remapped mapping
* @attrs: DMA attributes for this allocation
*
* If @size is less than PAGE_SIZE, then a full CPU page will be allocated,
/*
* If size is less than PAGE_SIZE, then a full CPU page will be allocated,
* but an IOMMU which supports smaller pages might not map the whole thing.
*
* Return: Mapped virtual address, or NULL on failure.
*/
static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, pgprot_t prot,
static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
size_t size, struct sg_table *sgt, gfp_t gfp, pgprot_t prot,
unsigned long attrs)
{
struct iommu_domain *domain = iommu_get_dma_domain(dev);
@ -676,11 +665,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
struct page **pages;
struct sg_table sgt;
dma_addr_t iova;
void *vaddr;
*dma_handle = DMA_MAPPING_ERROR;
if (static_branch_unlikely(&iommu_deferred_attach_enabled) &&
iommu_deferred_attach(dev, domain))
@ -707,34 +692,26 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
if (!iova)
goto out_free_pages;
if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL))
if (sg_alloc_table_from_pages(sgt, pages, count, 0, size, GFP_KERNEL))
goto out_free_iova;
if (!(ioprot & IOMMU_CACHE)) {
struct scatterlist *sg;
int i;
for_each_sg(sgt.sgl, sg, sgt.orig_nents, i)
for_each_sg(sgt->sgl, sg, sgt->orig_nents, i)
arch_dma_prep_coherent(sg_page(sg), sg->length);
}
if (iommu_map_sg_atomic(domain, iova, sgt.sgl, sgt.orig_nents, ioprot)
if (iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot)
< size)
goto out_free_sg;
vaddr = dma_common_pages_remap(pages, size, prot,
__builtin_return_address(0));
if (!vaddr)
goto out_unmap;
sgt->sgl->dma_address = iova;
return pages;
*dma_handle = iova;
sg_free_table(&sgt);
return vaddr;
out_unmap:
__iommu_dma_unmap(dev, iova, size);
out_free_sg:
sg_free_table(&sgt);
sg_free_table(sgt);
out_free_iova:
iommu_dma_free_iova(cookie, iova, size, NULL);
out_free_pages:
@ -742,6 +719,32 @@ out_free_pages:
return NULL;
}
static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, pgprot_t prot,
unsigned long attrs)
{
struct page **pages;
struct sg_table sgt;
void *vaddr;
pages = __iommu_dma_alloc_noncontiguous(dev, size, &sgt, gfp, prot,
attrs);
if (!pages)
return NULL;
*dma_handle = sgt.sgl->dma_address;
sg_free_table(&sgt);
vaddr = dma_common_pages_remap(pages, size, prot,
__builtin_return_address(0));
if (!vaddr)
goto out_unmap;
return vaddr;
out_unmap:
__iommu_dma_unmap(dev, *dma_handle, size);
__iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
return NULL;
}
static void iommu_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{