Re: [PATCH v7 13/15] dma-direct: Allocate memory from restricted DMA pool if available

[Christoph Hellwig <hch@xxxxxx>]

> +#ifdef CONFIG_DMA_RESTRICTED_POOL
> +     if (swiotlb_free(dev, page, size))
> +             return;
> +#endif

Please avoid the ifdefs by either stubbing out the function to be a no-op
or by using IS_ENABLED.

> +#ifdef CONFIG_DMA_RESTRICTED_POOL
> +     page = swiotlb_alloc(dev, size);
> +     if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
> +             __dma_direct_free_pages(dev, page, size);
> +             page = NULL;
> +     }
> +#endif

Same here, for the stub it would just return NULL.