xen_unmap_single calls xen_bus_to_phys, then passes dev_addr to is_xen_swiotlb_buffer that calls xen_bus_to_phys again. xen_bus_to_phys is potentially a slow operation that might involve walking a tree. We can avoid calling xen_bus_to_phys twice by removing the is_xen_swiotlb_buffer call and doing the check directly in xen_unmap_single using the physical address.
Signed-off-by: Stefano Stabellini <[email protected]> --- drivers/xen/swiotlb-xen.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 4d50058..6d9ca61 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -426,8 +426,8 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, xen_dma_unmap_page(hwdev, paddr, size, dir, attrs); - /* NOTE: We use dev_addr here, not paddr! */ - if (is_xen_swiotlb_buffer(dev_addr)) { + if (paddr >= virt_to_phys(xen_io_tlb_start) && + paddr < virt_to_phys(xen_io_tlb_end)) { swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); return; } -- 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
