swiotlb_unmap_single 26 arch/x86/kernel/pci-swiotlb_64.c .unmap_single = swiotlb_unmap_single, swiotlb_unmap_single 12 include/asm-x86/swiotlb.h extern void swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr,