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swiotlb-xen: simplify the DMA sync method implementations 

Get rid of the grand multiplexer and implement the sync_single_for_cpu
and sync_single_for_device methods directly, and then loop over them
for the scatterlist based variants.

Note that this also loses a few comments related to highlevel DMA API
concepts, which have nothing to do with the swiotlb-xen implementation
details.

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Christoph Hellwig 2019-04-11 09:19:59 +02:00 committed by Konrad Rzeszutek Wilk
parent 8b35d9feed
commit 2e12dceef3
1 changed files with 28 additions and 56 deletions
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84
drivers/xen/swiotlb-xen.c
View File

@ -452,48 +452,28 @@ static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
}
/*
* Make physical memory consistent for a single streaming mode DMA translation
* after a transfer.
*
* If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
* using the cpu, yet do not wish to teardown the dma mapping, you must
* call this function before doing so. At the next point you give the dma
* address back to the card, you must first perform a
* xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
*/
static void
xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir,
enum dma_sync_target target)
xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction dir)
{
phys_addr_t paddr = xen_bus_to_phys(dev_addr);
phys_addr_t paddr = xen_bus_to_phys(dma_addr);
BUG_ON(dir == DMA_NONE);
xen_dma_sync_single_for_cpu(dev, dma_addr, size, dir);
if (target == SYNC_FOR_CPU)
xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir);
/* NOTE: We use dev_addr here, not paddr! */
if (is_xen_swiotlb_buffer(dev_addr))
swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
if (target == SYNC_FOR_DEVICE)
xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir);
if (is_xen_swiotlb_buffer(dma_addr))
swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_CPU);
}
void
xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir)
static void
xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
size_t size, enum dma_data_direction dir)
{
xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
}
phys_addr_t paddr = xen_bus_to_phys(dma_addr);
void
xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir)
{
xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
if (is_xen_swiotlb_buffer(dma_addr))
swiotlb_tbl_sync_single(dev, paddr, size, dir, SYNC_FOR_DEVICE);
xen_dma_sync_single_for_device(dev, dma_addr, size, dir);
}
/*
@ -538,38 +518,30 @@ out_unmap:
return 0;
}
/*
* Make physical memory consistent for a set of streaming mode DMA translations
* after a transfer.
*
* The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
* and usage.
*/
static void
xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
int nelems, enum dma_data_direction dir,
enum dma_sync_target target)
xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
int nelems, enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nelems, i)
xen_swiotlb_sync_single(hwdev, sg->dma_address,
sg_dma_len(sg), dir, target);
for_each_sg(sgl, sg, nelems, i) {
xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
sg->length, dir);
}
}
static void
xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir)
{
xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
}
static void
xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
int nelems, enum dma_data_direction dir)
{
xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nelems, i) {
xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
sg->length, dir);
}
}
/*