Subject: Re: [PATCH v5 RFC 1/6] page_pool: frag API support for 32-bit arch with 64-bit DMA

From: Jakub Kicinski <[email-masked]>
Date: Fri, 7 Jul 2023 16:59:21 -0700

On Thu, 29 Jun 2023 20:02:21 +0800 Yunsheng Lin wrote:
> +		/* Return error here to avoid mlx5e_page_release_fragmented()
> +		 * calling page_pool_defrag_page() to write to pp_frag_count
> +		 * which is overlapped with dma_addr_upper in 'struct page' for
> +		 * arch with PAGE_POOL_DMA_USE_PP_FRAG_COUNT being true.
> +		 */
> +		if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT) {
> +			err = -EINVAL;
> +			goto err_free_by_rq_type;
> +		}

I told you not to do this in a comment on v4.
Keep the flag in page pool params and let the creation fail.