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Date:   Fri, 7 Jul 2023 16:59:21 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Yunsheng Lin <linyunsheng@huawei.com>
Cc:     <davem@davemloft.net>, <pabeni@redhat.com>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Alexander Duyck <alexander.duyck@gmail.com>,
        Liang Chen <liangchen.linux@gmail.com>,
        Alexander Lobakin <aleksander.lobakin@intel.com>,
        Saeed Mahameed <saeedm@nvidia.com>,
        Leon Romanovsky <leon@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH v5 RFC 1/6] page_pool: frag API support for 32-bit arch
 with 64-bit DMA
Message-ID: <20230707165921.565b1228@kernel.org>
In-Reply-To: <20230629120226.14854-2-linyunsheng@huawei.com>
References: <20230629120226.14854-1-linyunsheng@huawei.com>
        <20230629120226.14854-2-linyunsheng@huawei.com>
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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.