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swiotlb: refactor coherent buffer freeing 

Factor out a new swiotlb_free_buffer helper that checks if an address
is allocated from the swiotlb bounce buffer, and if yes frees it.

This allows to simplify the swiotlb_free implemenation that uses
dma_direct_free to free the non-bounce buffer allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian König <christian.koenig@amd.com>
This commit is contained in:
Christoph Hellwig 2017-12-23 20:56:02 +01:00
parent aaf796dc6e
commit a25381aa3a
1 changed files with 21 additions and 14 deletions
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35
lib/swiotlb.c
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@ -780,22 +780,31 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
}
EXPORT_SYMBOL(swiotlb_alloc_coherent);
static bool swiotlb_free_buffer(struct device *dev, size_t size,
dma_addr_t dma_addr)
{
phys_addr_t phys_addr = dma_to_phys(dev, dma_addr);
WARN_ON_ONCE(irqs_disabled());
if (!is_swiotlb_buffer(phys_addr))
return false;
/*
* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single.
* DMA_ATTR_SKIP_CPU_SYNC is optional.
*/
swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE,
DMA_ATTR_SKIP_CPU_SYNC);
return true;
}
void
swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
dma_addr_t dev_addr)
{
phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
WARN_ON(irqs_disabled());
if (!is_swiotlb_buffer(paddr))
if (!swiotlb_free_buffer(hwdev, size, dev_addr))
free_pages((unsigned long)vaddr, get_order(size));
else
/*
* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single.
* DMA_ATTR_SKIP_CPU_SYNC is optional.
*/
swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE,
DMA_ATTR_SKIP_CPU_SYNC);
}
EXPORT_SYMBOL(swiotlb_free_coherent);
@ -1110,9 +1119,7 @@ void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
void swiotlb_free(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_addr, unsigned long attrs)
{
if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
swiotlb_free_coherent(dev, size, vaddr, dma_addr);
else
if (!swiotlb_free_buffer(dev, size, dma_addr))
dma_direct_free(dev, size, vaddr, dma_addr, attrs);
}