Re: [PATCH v9 03/14] swiotlb: Set dev->dma_io_tlb_mem to the swiotlb pool used

[Claire Chang]

I'm not sure if this would break arch/x86/pci/sta2x11-fixup.c
swiotlb_late_init_with_default_size is called here
https://elixir.bootlin.com/linux/v5.13-rc5/source/arch/x86/pci/sta2x11-fixup.c#L60

On Fri, Jun 11, 2021 at 11:27 PM Claire Chang <tientzu@xxxxxxxxxxxx> wrote:
>
> Always have the pointer to the swiotlb pool used in struct device. This
> could help simplify the code for other pools.
>
> Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
> ---
>  drivers/of/device.c     | 3 +++
>  include/linux/device.h  | 4 ++++
>  include/linux/swiotlb.h | 8 ++++++++
>  kernel/dma/swiotlb.c    | 8 ++++----
>  4 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/of/device.c b/drivers/of/device.c
> index c5a9473a5fb1..1defdf15ba95 100644
> --- a/drivers/of/device.c
> +++ b/drivers/of/device.c
> @@ -165,6 +165,9 @@ int of_dma_configure_id(struct device *dev, struct device_node *np,
>
>         arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
>
> +       if (IS_ENABLED(CONFIG_SWIOTLB))
> +               swiotlb_set_io_tlb_default_mem(dev);
> +
>         return 0;
>  }
>  EXPORT_SYMBOL_GPL(of_dma_configure_id);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 4443e12238a0..2e9a378c9100 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -432,6 +432,7 @@ struct dev_links_info {
>   * @dma_pools: Dma pools (if dma'ble device).
>   * @dma_mem:   Internal for coherent mem override.
>   * @cma_area:  Contiguous memory area for dma allocations
> + * @dma_io_tlb_mem: Pointer to the swiotlb pool used.  Not for driver use.
>   * @archdata:  For arch-specific additions.
>   * @of_node:   Associated device tree node.
>   * @fwnode:    Associated device node supplied by platform firmware.
> @@ -540,6 +541,9 @@ struct device {
>  #ifdef CONFIG_DMA_CMA
>         struct cma *cma_area;           /* contiguous memory area for dma
>                                            allocations */
> +#endif
> +#ifdef CONFIG_SWIOTLB
> +       struct io_tlb_mem *dma_io_tlb_mem;
>  #endif
>         /* arch specific additions */
>         struct dev_archdata     archdata;
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index 216854a5e513..008125ccd509 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -108,6 +108,11 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr)
>         return mem && paddr >= mem->start && paddr < mem->end;
>  }
>
> +static inline void swiotlb_set_io_tlb_default_mem(struct device *dev)
> +{
> +       dev->dma_io_tlb_mem = io_tlb_default_mem;
> +}
> +
>  void __init swiotlb_exit(void);
>  unsigned int swiotlb_max_segment(void);
>  size_t swiotlb_max_mapping_size(struct device *dev);
> @@ -119,6 +124,9 @@ static inline bool is_swiotlb_buffer(phys_addr_t paddr)
>  {
>         return false;
>  }
> +static inline void swiotlb_set_io_tlb_default_mem(struct device *dev)
> +{
> +}
>  static inline void swiotlb_exit(void)
>  {
>  }
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 8a3e2b3b246d..29b950ab1351 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -344,7 +344,7 @@ void __init swiotlb_exit(void)
>  static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size,
>                            enum dma_data_direction dir)
>  {
> -       struct io_tlb_mem *mem = io_tlb_default_mem;
> +       struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
>         int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT;
>         phys_addr_t orig_addr = mem->slots[index].orig_addr;
>         size_t alloc_size = mem->slots[index].alloc_size;
> @@ -426,7 +426,7 @@ static unsigned int wrap_index(struct io_tlb_mem *mem, unsigned int index)
>  static int find_slots(struct device *dev, phys_addr_t orig_addr,
>                 size_t alloc_size)
>  {
> -       struct io_tlb_mem *mem = io_tlb_default_mem;
> +       struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
>         unsigned long boundary_mask = dma_get_seg_boundary(dev);
>         dma_addr_t tbl_dma_addr =
>                 phys_to_dma_unencrypted(dev, mem->start) & boundary_mask;
> @@ -503,7 +503,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
>                 size_t mapping_size, size_t alloc_size,
>                 enum dma_data_direction dir, unsigned long attrs)
>  {
> -       struct io_tlb_mem *mem = io_tlb_default_mem;
> +       struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
>         unsigned int offset = swiotlb_align_offset(dev, orig_addr);
>         unsigned int i;
>         int index;
> @@ -554,7 +554,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
>                               size_t mapping_size, enum dma_data_direction dir,
>                               unsigned long attrs)
>  {
> -       struct io_tlb_mem *mem = io_tlb_default_mem;
> +       struct io_tlb_mem *mem = hwdev->dma_io_tlb_mem;
>         unsigned long flags;
>         unsigned int offset = swiotlb_align_offset(hwdev, tlb_addr);
>         int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
> --
> 2.32.0.272.g935e593368-goog
>