On Thu, 17 Jun 2021, Claire Chang wrote:
> Propagate the swiotlb_force into io_tlb_default_mem->force_bounce and
> use it to determine whether to bounce the data or not. This will be
> useful later to allow for different pools.
>
> Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Tested-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Tested-by: Will Deacon <will@xxxxxxxxxx>
Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> ---
> drivers/xen/swiotlb-xen.c | 2 +-
> include/linux/swiotlb.h | 11 +++++++++++
> kernel/dma/direct.c | 2 +-
> kernel/dma/direct.h | 2 +-
> kernel/dma/swiotlb.c | 4 ++++
> 5 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
> index 0c6ed09f8513..4730a146fa35 100644
> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -369,7 +369,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
> if (dma_capable(dev, dev_addr, size, true) &&
> !range_straddles_page_boundary(phys, size) &&
> !xen_arch_need_swiotlb(dev, phys, dev_addr) &&
> - swiotlb_force != SWIOTLB_FORCE)
> + !is_swiotlb_force_bounce(dev))
> goto done;
>
> /*
> diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
> index dd1c30a83058..8d8855c77d9a 100644
> --- a/include/linux/swiotlb.h
> +++ b/include/linux/swiotlb.h
> @@ -84,6 +84,7 @@ extern enum swiotlb_force swiotlb_force;
> * unmap calls.
> * @debugfs: The dentry to debugfs.
> * @late_alloc: %true if allocated using the page allocator
> + * @force_bounce: %true if swiotlb bouncing is forced
> */
> struct io_tlb_mem {
> phys_addr_t start;
> @@ -94,6 +95,7 @@ struct io_tlb_mem {
> spinlock_t lock;
> struct dentry *debugfs;
> bool late_alloc;
> + bool force_bounce;
> struct io_tlb_slot {
> phys_addr_t orig_addr;
> size_t alloc_size;
> @@ -109,6 +111,11 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
> return mem && paddr >= mem->start && paddr < mem->end;
> }
>
> +static inline bool is_swiotlb_force_bounce(struct device *dev)
> +{
> + return dev->dma_io_tlb_mem->force_bounce;
> +}
> +
> void __init swiotlb_exit(void);
> unsigned int swiotlb_max_segment(void);
> size_t swiotlb_max_mapping_size(struct device *dev);
> @@ -120,6 +127,10 @@ static inline bool is_swiotlb_buffer(struct device *dev, phys_addr_t paddr)
> {
> return false;
> }
> +static inline bool is_swiotlb_force_bounce(struct device *dev)
> +{
> + return false;
> +}
> static inline void swiotlb_exit(void)
> {
> }
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 7a88c34d0867..a92465b4eb12 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -496,7 +496,7 @@ size_t dma_direct_max_mapping_size(struct device *dev)
> {
> /* If SWIOTLB is active, use its maximum mapping size */
> if (is_swiotlb_active(dev) &&
> - (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE))
> + (dma_addressing_limited(dev) || is_swiotlb_force_bounce(dev)))
> return swiotlb_max_mapping_size(dev);
> return SIZE_MAX;
> }
> diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h
> index 13e9e7158d94..4632b0f4f72e 100644
> --- a/kernel/dma/direct.h
> +++ b/kernel/dma/direct.h
> @@ -87,7 +87,7 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev,
> phys_addr_t phys = page_to_phys(page) + offset;
> dma_addr_t dma_addr = phys_to_dma(dev, phys);
>
> - if (unlikely(swiotlb_force == SWIOTLB_FORCE))
> + if (is_swiotlb_force_bounce(dev))
> return swiotlb_map(dev, phys, size, dir, attrs);
>
> if (unlikely(!dma_capable(dev, dma_addr, size, true))) {
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 409694d7a8ad..13891d5de8c9 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -179,6 +179,10 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
> mem->end = mem->start + bytes;
> mem->index = 0;
> mem->late_alloc = late_alloc;
> +
> + if (swiotlb_force == SWIOTLB_FORCE)
> + mem->force_bounce = true;
> +
> spin_lock_init(&mem->lock);
> for (i = 0; i < mem->nslabs; i++) {
> mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);
> --
> 2.32.0.288.g62a8d224e6-goog
>
