> +#ifdef CONFIG_SWIOTLB
> + struct io_tlb_mem *dma_io_tlb_mem;
> #endif
Please add a new config option for this code instead of always building
it when swiotlb is enabled.
> +static int swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
> + size_t size)
Can you split the refactoring in swiotlb.c into one or more prep
patches?
> +static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
> + struct device *dev)
> +{
> + struct io_tlb_mem *mem = rmem->priv;
> + int ret;
> +
> + if (dev->dma_io_tlb_mem)
> + return -EBUSY;
> +
> + if (!mem) {
> + mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> + if (!mem)
> + return -ENOMEM;
What is the calling convention here that allows for a NULL and non-NULL
private data?
