> +#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.
