On Fri, Jun 11, 2021 at 11:26:54PM +0800, Claire Chang wrote:
> Add a new function, release_slots, to make the code reusable for supporting
> different bounce buffer pools, e.g. restricted DMA pool.
>
> Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
> ---
> kernel/dma/swiotlb.c | 35 ++++++++++++++++++++---------------
> 1 file changed, 20 insertions(+), 15 deletions(-)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 364c6c822063..a6562573f090 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -554,27 +554,15 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
> return tlb_addr;
> }
>
> -/*
> - * tlb_addr is the physical address of the bounce buffer to unmap.
> - */
> -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)
> +static void release_slots(struct device *dev, phys_addr_t tlb_addr)
> {
> - struct io_tlb_mem *mem = hwdev->dma_io_tlb_mem;
> + struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
> unsigned long flags;
> - unsigned int offset = swiotlb_align_offset(hwdev, tlb_addr);
> + unsigned int offset = swiotlb_align_offset(dev, tlb_addr);
> int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
> int nslots = nr_slots(mem->slots[index].alloc_size + offset);
> int count, i;
>
> - /*
> - * First, sync the memory before unmapping the entry
> - */
> - if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> - (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
> - swiotlb_bounce(hwdev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
> -
> /*
> * Return the buffer to the free list by setting the corresponding
> * entries to indicate the number of contiguous entries available.
> @@ -609,6 +597,23 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
> spin_unlock_irqrestore(&mem->lock, flags);
> }
>
> +/*
> + * tlb_addr is the physical address of the bounce buffer to unmap.
> + */
> +void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr,
> + size_t mapping_size, enum dma_data_direction dir,
> + unsigned long attrs)
> +{
> + /*
> + * First, sync the memory before unmapping the entry
> + */
> + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> + (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
> + swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_FROM_DEVICE);
> +
> + release_slots(dev, tlb_addr);
Can you give this a swiotlb_ prefix?
Otherwise looks good:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
