Re: [PATCH 3/8] xen-swiotlb: use io_tlb_end in xen_swiotlb_dma_supported

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Sun, Feb 07, 2021 at 05:09:29PM +0100, Christoph Hellwig wrote:
> Use the existing variable that holds the physical address for
> xen_io_tlb_end to simplify xen_swiotlb_dma_supported a bit, and remove
> the otherwise unused xen_io_tlb_end variable and the xen_virt_to_bus
> helper.
> 
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  drivers/xen/swiotlb-xen.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index a4026822a889f7..4298f74a083985 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -46,7 +46,7 @@
>   * API.
>   */
>  
> -static char *xen_io_tlb_start, *xen_io_tlb_end;
> +static char *xen_io_tlb_start;
>  static unsigned long xen_io_tlb_nslabs;
>  /*
>   * Quick lookup value of the bus address of the IOTLB.
> @@ -82,11 +82,6 @@ static inline phys_addr_t xen_dma_to_phys(struct device 
> *dev,
>       return xen_bus_to_phys(dev, dma_to_phys(dev, dma_addr));
>  }
>  
> -static inline dma_addr_t xen_virt_to_bus(struct device *dev, void *address)
> -{
> -     return xen_phys_to_dma(dev, virt_to_phys(address));
> -}
> -
>  static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
>  {
>       unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
> @@ -250,7 +245,6 @@ int __ref xen_swiotlb_init(int verbose, bool early)
>               rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, 
> xen_io_tlb_nslabs);
>  
>  end:
> -     xen_io_tlb_end = xen_io_tlb_start + bytes;
>       if (!rc)
>               swiotlb_set_max_segment(PAGE_SIZE);
>  
> @@ -558,7 +552,7 @@ xen_swiotlb_sync_sg_for_device(struct device *dev, struct 
> scatterlist *sgl,
>  static int
>  xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
>  {
> -     return xen_virt_to_bus(hwdev, xen_io_tlb_end - 1) <= mask;
> +     return xen_phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
>  }
>  
>  const struct dma_map_ops xen_swiotlb_dma_ops = {
> -- 
> 2.29.2
>