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Commit c4dae366 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

swiotlb: refactor swiotlb_map_page 



Remove the somewhat useless map_single function, and replace it with a
swiotlb_bounce_page handler that handles everything related to actually
bouncing a page.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 4803b44e

kernel/dma/swiotlb.c

+30 −37
Original line number Diff line number Diff line
@@ -543,26 +543,6 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, 
	return tlb_addr;

}



/*

 * Allocates bounce buffer and returns its physical address.

 */

static phys_addr_t

map_single(struct device *hwdev, phys_addr_t phys, size_t size,

	   enum dma_data_direction dir, unsigned long attrs)

{

	dma_addr_t start_dma_addr;



	if (swiotlb_force == SWIOTLB_NO_FORCE) {

		dev_warn_ratelimited(hwdev, "Cannot do DMA to address %pa\n",

				     &phys);

		return SWIOTLB_MAP_ERROR;

	}



	start_dma_addr = __phys_to_dma(hwdev, io_tlb_start);

	return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size,

				      dir, attrs);

}



/*

 * tlb_addr is the physical address of the bounce buffer to unmap.

 */
@@ -714,6 +694,34 @@ static bool swiotlb_free_buffer(struct device *dev, size_t size, 
	return true;

}



static dma_addr_t swiotlb_bounce_page(struct device *dev, phys_addr_t *phys,

		size_t size, enum dma_data_direction dir, unsigned long attrs)

{

	dma_addr_t dma_addr;



	if (unlikely(swiotlb_force == SWIOTLB_NO_FORCE)) {

		dev_warn_ratelimited(dev,

			"Cannot do DMA to address %pa\n", phys);

		return DIRECT_MAPPING_ERROR;

	}



	/* Oh well, have to allocate and map a bounce buffer. */

	*phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),

			*phys, size, dir, attrs);

	if (*phys == SWIOTLB_MAP_ERROR)

		return DIRECT_MAPPING_ERROR;



	/* Ensure that the address returned is DMA'ble */

	dma_addr = __phys_to_dma(dev, *phys);

	if (unlikely(!dma_capable(dev, dma_addr, size))) {

		swiotlb_tbl_unmap_single(dev, *phys, size, dir,

			attrs | DMA_ATTR_SKIP_CPU_SYNC);

		return DIRECT_MAPPING_ERROR;

	}



	return dma_addr;

}



/*

 * Map a single buffer of the indicated size for DMA in streaming mode.  The

 * physical address to use is returned.
@@ -726,7 +734,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, 
			    enum dma_data_direction dir,

			    unsigned long attrs)

{

	phys_addr_t map, phys = page_to_phys(page) + offset;

	phys_addr_t phys = page_to_phys(page) + offset;

	dma_addr_t dev_addr = phys_to_dma(dev, phys);



	BUG_ON(dir == DMA_NONE);
@@ -739,22 +747,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, 
		return dev_addr;



	trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);



	/* Oh well, have to allocate and map a bounce buffer. */

	map = map_single(dev, phys, size, dir, attrs);

	if (map == SWIOTLB_MAP_ERROR)

		return DIRECT_MAPPING_ERROR;



	dev_addr = __phys_to_dma(dev, map);



	/* Ensure that the address returned is DMA'ble */

	if (dma_capable(dev, dev_addr, size))

		return dev_addr;



	attrs |= DMA_ATTR_SKIP_CPU_SYNC;

	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);



	return DIRECT_MAPPING_ERROR;

	return swiotlb_bounce_page(dev, &phys, size, dir, attrs);

}



/*