On Mon, Oct 24, 2016 at 08:04:37AM -0400, Alexander Duyck wrote:
> As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures
> beyond just ARM I need to make it so that the swiotlb will respect the
> flag. In order to do that I also need to update the swiotlb-xen since it
> heavily makes use of the functionality.
>
> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> Signed-off-by: Alexander Duyck <alexander.h.du...@intel.com>
> ---
> drivers/xen/swiotlb-xen.c | 40 ++++++++++++++++++++++----------------
> include/linux/swiotlb.h | 6 ++++--
> lib/swiotlb.c | 48
> +++++++++++++++++++++++++++------------------
> 3 files changed, 56 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 87e6035..cf047d8 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -405,7 +405,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev,
> struct page *page,
> */
> trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
>
> - map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
> + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
> + attrs);
> if (map == SWIOTLB_MAP_ERROR)
> return DMA_ERROR_CODE;
>
> @@ -416,11 +417,13 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev,
> struct page *page,
> /*
> * Ensure that the address returned is DMA'ble
> */
> - if (!dma_capable(dev, dev_addr, size)) {
> - swiotlb_tbl_unmap_single(dev, map, size, dir);
> - dev_addr = 0;
> - }
> - return dev_addr;
> + if (dma_capable(dev, dev_addr, size))
> + return dev_addr;
> +
> + swiotlb_tbl_unmap_single(dev, map, size, dir,
> + attrs | DMA_ATTR_SKIP_CPU_SYNC);
> +
> + return DMA_ERROR_CODE;
Why? This change (re-ordering the code - and returning DMA_ERROR_CODE instead
of 0) does not have anything to do with the title.
If you really feel strongly about it - then please send it as a seperate patch.
> }
> EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
>
> @@ -444,7 +447,7 @@ static void xen_unmap_single(struct device *hwdev,
> dma_addr_t dev_addr,
>
> /* NOTE: We use dev_addr here, not paddr! */
> if (is_xen_swiotlb_buffer(dev_addr)) {
> - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
> + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
> return;
> }
>
> @@ -557,16 +560,9 @@ void xen_swiotlb_unmap_page(struct device *hwdev,
> dma_addr_t dev_addr,
> start_dma_addr,
> sg_phys(sg),
> sg->length,
> - dir);
> - if (map == SWIOTLB_MAP_ERROR) {
> - dev_warn(hwdev, "swiotlb buffer is full\n");
> - /* Don't panic here, we expect map_sg users
> - to do proper error handling. */
> - xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
> - attrs);
> - sg_dma_len(sgl) = 0;
> - return 0;
> - }
> + dir, attrs);
> + if (map == SWIOTLB_MAP_ERROR)
> + goto map_error;
> xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
> dev_addr,
> map & ~PAGE_MASK,
> @@ -589,6 +585,16 @@ void xen_swiotlb_unmap_page(struct device *hwdev,
> dma_addr_t dev_addr,
> sg_dma_len(sg) = sg->length;
> }
> return nelems;
> +map_error:
> + dev_warn(hwdev, "swiotlb buffer is full\n");
> + /*
> + * Don't panic here, we expect map_sg users
> + * to do proper error handling.
> + */
> + xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
> + attrs | DMA_ATTR_SKIP_CPU_SYNC);
> + sg_dma_len(sgl) = 0;
> + return 0;
> }
This too. Why can't that be part of the existing code that was there?
