On Tue, Jun 15, 2021 at 09:27:09PM +0800, Claire Chang wrote:
> Add the functions, swiotlb_{alloc,free} to support the memory allocation
> from restricted DMA pool.
>
> The restricted DMA pool is preferred if available.
>
> Note that since coherent allocation needs remapping, one must set up
> another device coherent pool by shared-dma-pool and use
> dma_alloc_from_dev_coherent instead for atomic coherent allocation.
Note: when applied this should go before the next patch to make sure
bisection works fine.
> #ifdef CONFIG_DMA_RESTRICTED_POOL
> +struct page *swiotlb_alloc(struct device *dev, size_t size)
> +{
> + struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
> + phys_addr_t tlb_addr;
> + int index;
> +
> + /*
> + * Skip io_tlb_default_mem since swiotlb_alloc doesn't support atomic
> + * coherent allocation. Otherwise might break existing devices.
> + * One must set up another device coherent pool by shared-dma-pool and
> + * use dma_alloc_from_dev_coherent instead for atomic coherent
> + * allocation to avoid mempry remapping.
s/mempry/memory/g
Otherwise looks good:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
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