On Thu, 11 Apr 2019, Christoph Hellwig wrote:
> Refactor the code a bit to make further changes easier.
>
> Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
> ---
> drivers/xen/swiotlb-xen.c | 31 ++++++++++++++++---------------
> 1 file changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 9a951504dc12..5dcb06fe9667 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -391,13 +391,8 @@ static dma_addr_t xen_swiotlb_map_page(struct device
> *dev, struct page *page,
> if (dma_capable(dev, dev_addr, size) &&
> !range_straddles_page_boundary(phys, size) &&
> !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
> - (swiotlb_force != SWIOTLB_FORCE)) {
> - /* we are not interested in the dma_addr returned by
> - * xen_dma_map_page, only in the potential cache flushes
> executed
> - * by the function. */
> - xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
> - return dev_addr;
> - }
> + swiotlb_force != SWIOTLB_FORCE)
> + goto done;
>
> /*
> * Oh well, have to allocate and map a bounce buffer.
> @@ -410,19 +405,25 @@ static dma_addr_t xen_swiotlb_map_page(struct device
> *dev, struct page *page,
> return DMA_MAPPING_ERROR;
>
> dev_addr = xen_phys_to_bus(map);
> - xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
> - dev_addr, map & ~PAGE_MASK, size, dir,
> attrs);
>
> /*
> * 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);
> + if (unlikely(!dma_capable(dev, dev_addr, size))) {
> + swiotlb_tbl_unmap_single(dev, map, size, dir,
> + attrs | DMA_ATTR_SKIP_CPU_SYNC);
> + return DMA_MAPPING_ERROR;
> + }
>
> - return DMA_MAPPING_ERROR;
> + page = pfn_to_page(map >> PAGE_SHIFT);
> + offset = map & ~PAGE_MASK;
> +done:
> + /*
> + * we are not interested in the dma_addr returned by xen_dma_map_page,
> + * only in the potential cache flushes executed by the function.
> + */
> + xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
> + return dev_addr;
> }
>
> /*
> --
> 2.20.1
>
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
