Re: [RFC PATCH v3 3/6] swiotlb: Use restricted DMA pool if available

From: Christoph Hellwig
Date: Wed Jan 13 2021 - 07:45:23 EST


> +#ifdef CONFIG_SWIOTLB
> + if (unlikely(swiotlb_force == SWIOTLB_FORCE) || dev->dma_io_tlb_mem)
> return swiotlb_map(dev, phys, size, dir, attrs);
> +#endif

Please provide a wrapper for the dev->dma_io_tlb_mem check that
always returns false if the per-device swiotlb support is not enabled.

> index 7fb2ac087d23..1f05af09e61a 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -222,7 +222,6 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
> mem->orig_addr[i] = INVALID_PHYS_ADDR;
> }
> mem->index = 0;
> - no_iotlb_memory = false;

How does this fit in here?