Re: [PATCH v9 09/14] swiotlb: Refactor swiotlb_tbl_unmap_single

[Christoph Hellwig]

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 
> ---
>  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(>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 

[PATCH v9 09/14] swiotlb: Refactor swiotlb_tbl_unmap_single

[Claire Chang]

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 
---
 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(>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);
+}
+
 void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir)
 {
-- 
2.32.0.272.g935e593368-goog